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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT
CMOS VOLTAGE REGULATOR
S-1155 Series
www.datasheet4u.com
The S-1155 Series, developed based on CMOS technology, is a positive
voltage regulator with a super low dropout voltage, high output voltage
accuracy, and low current consumption.
The S-1155 Series provides the very small dropout voltage and the large
output current due to the built-in transistor with low on-resistance. The
overcurrent protector prevents the load current from exceeding the
capacitance of output transistor. The thermal shutdown circuit prevents
damage caused by heat, the rush current control circuit limits the
excessive rush current during start-up.
The ON/OFF circuit ensures longer battery life. Various capacitors, also
small ceramic capacitors, can be used for this IC more than for the
conventional regulator ICs which have CMOS technology.
The small package SOT-89-5 enables high-density mounting.
„ Features
Output voltage :
Low equivalent series resistance capacitor :
Input voltage :
High-accuracy output voltage :
Low dropout voltage :
Low current consumption :
Output current :
High ripple rejection :
Built-in overcurrent protection circuit :
Built-in thermal shutdown circuit :
Built-in rush current control circuit :
Built-in power on/off circuit :
Small package :
Lead-free product
1.0 to 5.0 V, selectable in 0.05 V step.
Ceramic capacitor of 4.7 µF or more can be used as the
I/O capacitor.
1.5 to 5.5 V
±1.0% (1.0 to 1.45 V output product : ±15 mV)
70 mV typ. (3.0 V output product, at IOUT = 200 mA)
During operation : 70 µA typ., 90 µA max. (3.0 V output
product)
During shutdown : 0.1 µA typ., 1.0 µA max.
500 mA (3.0 V output product, at VIN VOUT(S) + 1.0 V)*1
70 dB typ. (at 1.0 kHz, VOUT = 1.0 V)
limits overcurrent of output transistor
prevents damage caused by heat
limits excessive rush current during start-up
Longer battery life
SOT-89-5
*1. Attention should be paid to the power dissipation of the package when the output current is large.
„ Applications
Power supply for battery-powered devices
Power supply for TV, notebook PCs and home electric appliances
Constant-voltage power supply for portable equipment
„ Packages
Package Name
SOT-89-5
Package
UP005-A
Drawing Code
Tape
UP005-A
Reel
UP005-A
Seiko Instruments Inc.
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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
Block Diagram
www.datasheet4u.com
VIN
*1
Overcurrent
protection circuit
Thermal shutdown circuit
ON/OFF
ON/OFF circuit
+
Reference
voltage circuit
VSS
*1. Parasitic diode
Figure 1
Rev.1.1_00
VOUT
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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
„ Product Name Structure
www.dataUshseeerts4uc.aconmselect the product type, output voltage, and package type for the S-1155 Series. Refer to “1. Product
Name” regarding the contents of product name, “2. Product Name List” regarding details of product name.
1. Product Name
S-1155 x xx - U5T1 G
Package name (abbreviation) and packing specifications*1
U5T1 : SOT-89-5, Tape
Value of output voltage*2
10 to 50
(e.g., when the output voltage is 1.0 V, it is expressed as 10.)
Product type*3
A : ON/OFF pin negative logic
B : ON/OFF pin positive logic
*1. Refer to the taping specifications.
*2. If you request the product which has 0.05 step, contact our sales office.
*3. Refer to “3. Shutdown pin (ON/OFF pin)” in “„ Operation”.
Seiko Instruments Inc.
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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
2. Product Name List
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Table 1
Output Voltage
SOT-89-5
1.0 V ±15 mV
S-1155B10-U5T1G
1.1 V ±15 mV
S-1155B11-U5T1G
1.2 V ±15 mV
S-1155B12-U5T1G
1.3 V ±15 mV
S-1155B13-U5T1G
1.4 V ±15 mV
S-1155B14-U5T1G
1.5 V ±1.0%
S-1155B15-U5T1G
1.6 V ±1.0%
S-1155B16-U5T1G
1.7 V ±1.0%
S-1155B17-U5T1G
1.8 V ±1.0%
S-1155B18-U5T1G
1.85 V ±1.0%
S-1155B1J-U5T1G
1.9 V ±1.0%
S-1155B19-U5T1G
2.0 V ±1.0%
S-1155B20-U5T1G
2.1 V ±1.0%
S-1155B21-U5T1G
2.2 V ±1.0%
S-1155B22-U5T1G
2.3 V ±1.0%
S-1155B23-U5T1G
2.4 V ±1.0%
S-1155B24-U5T1G
2.5 V ±1.0%
S-1155B25-U5T1G
2.6 V ±1.0%
S-1155B26-U5T1G
2.7 V ±1.0%
S-1155B27-U5T1G
2.8 V ±1.0%
S-1155B28-U5T1G
2.85 V ±1.0%
S-1155B2J-U5T1G
2.9 V ±1.0%
S-1155B29-U5T1G
3.0 V ±1.0%
S-1155B30-U5T1G
3.1 V ±1.0%
S-1155B31-U5T1G
3.2 V ±1.0%
S-1155B32-U5T1G
3.3 V ±1.0%
S-1155B33-U5T1G
3.4 V ±1.0%
S-1155B34-U5T1G
3.5 V ±1.0%
S-1155B35-U5T1G
3.6 V ±1.0%
S-1155B36-U5T1G
3.7 V ±1.0%
S-1155B37-U5T1G
3.8 V ±1.0%
S-1155B38-U5T1G
3.9 V ±1.0%
S-1155B39-U5T1G
4.0 V ±1.0%
S-1155B40-U5T1G
4.1 V ±1.0%
S-1155B41-U5T1G
4.2 V ±1.0%
S-1155B42-U5T1G
4.3 V ±1.0%
S-1155B43-U5T1G
4.4 V ±1.0%
S-1155B44-U5T1G
4.5 V ±1.0%
S-1155B45-U5T1G
4.6 V ±1.0%
S-1155B46-U5T1G
4.7 V ±1.0%
S-1155B47-U5T1G
4.8 V ±1.0%
S-1155B48-U5T1G
4.9 V ±1.0%
S-1155B49-U5T1G
5.0 V ±1.0%
S-1155B50-U5T1G
Remark Please contact our sales office for products with an
output voltage other than those specified above or type
A products.
Rev.1.1_00
4 Seiko Instruments Inc.


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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
„ Pin Configuration
SOT-89-5
www.datasheet4u.comTop view
54
12 3
Figure 2
Table 2
Pin No.
Symbol
Description
1 ON/OFF Shutdown pin
2
VSS
GND pin
3
NC*1
No connection
4 VIN Input voltage pin
5
VOUT
Output voltage pin
*1. The NC pin is electrically open.
The NC pin can be connected to VIN or VSS.
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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
Rev.1.1_00
„ Absolute Maximum Ratings
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Parameter
Input voltage
Output voltage
Power dissipation
Operating ambient temperature
Storage temperature
*1. When mounted on board
[Mounted board]
(1) Board size :
(2) Name :
Symbol
VIN
VON/OFF
VOUT
PD
Topr
Tstg
Table 3
(Ta = 25°C unless otherwise specified)
Absolute Maximum Rating
Unit
VSS 0.3 to VSS + 6
VSS 0.3 to VIN + 0.3
VSS 0.3 to VIN + 0.3
1000*1
V
V
V
mW
40 to +85
°C
40 to +125
°C
114.3 mm × 76.2 mm × t1.6 mm
JEDEC STANDARD51-7
Caution The absolute maximum ratings are rated values exceeding which the product could suffer physical
damage. These values must therefore not be exceeded under any conditions.
1200
1000
800
600
400
200
0
0 50 100 150
Ambient temperature (Ta) [°C]
Figure 3 Power Dissipation of Package (When Mounted on Board)
Condition
SOT-89-5 (When mounted on board)
Table 4
Power Dissipation
1000 mW
Thermal Resistance Value (θja)
100°C/W
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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
„ Electrical Characteristics
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Parameter
Output voltage*1
Output current*2
Dropout voltage*3
Line regulation
Load regulation
Output voltage
temperature
coefficient*4
Current consumption
during operation
Current consumption
during shutdown
Input voltage
Symbol
VOUT(E)
IOUT
Vdrop
VOUT1
VIN VOUT
VOUT2
VOUT
Ta VOUT
ISS1
ISS2
VIN
Table 5 (1 / 2)
Conditions
VIN = VOUT(S) + 1.0 V,
IOUT = 100 mA
1.0 V VOUT(S) < 1.5 V
1.5 V VOUT(S) 4.5 V
VIN = 5.5 V,
IOUT = 100 mA
VIN VOUT(S) + 1.0 V
4.5 V < VOUT(S) 5.0 V
1.0 V VOUT(S) 4.5 V
VIN = 5.5 V
IOUT = 200 mA
4.5 V < VOUT(S) 5.0 V
1.0 V VOUT(S) < 1.1 V
1.1 V VOUT(S) < 1.2 V
1.2 V VOUT(S) < 1.3 V
1.3 V VOUT(S) < 1.4 V
1.4 V VOUT(S) < 1.5 V
1.5 V VOUT(S) < 2.6 V
2.6 V VOUT(S) 5.0 V
VOUT(S) + 0.5 V VIN
5.5 V,
IOUT = 100 mA
1.0 V VOUT(S) < 3.6 V
3.6 V VOUT(S) 4.8 V
5.3 V VIN 5.5 V,
IOUT = 100 mA
4.8 V < VOUT(S) 5.0 V
VIN = VOUT(S) + 1.0 V,
1 mA IOUT 200 mA
1.0 V VOUT(S) 4.5 V
VIN = 5.5 V,
1 mA IOUT 200 mA
4.5 V < VOUT(S) 5.0 V
VIN = VOUT(S) + 1.0 V,
IOUT = 100 mA,
40 Ta 85°C
1.0 V VOUT(S) 4.5 V
VIN = 5.5 V,
IOUT = 100 mA,
40 Ta 85°C
4.5 V < VOUT(S) 5.0 V
VIN = VOUT(S) + 1.0 V, ON/OFF pin = ON,
no load, 1.0 V VOUT(S) < 1.8 V
VIN = VOUT(S) + 1.0 V, ON/OFF pin = ON,
no load, 1.8 V VOUT(S) 4.5 V
VIN = 5.5 V, ON/OFF pin = ON,
no load, 4.5 V < VOUT(S) 5.0 V
VIN = VOUT(S) + 1.0 V,
ON/OFF pin = OFF,
no load
1.0 V VOUT(S) 4.5 V
VIN = 5.5 V,
ON/OFF pin = OFF,
no load
4.5 V < VOUT(S) 5.0 V
(Ta = 25°C unless otherwise specified)
Min.
Typ. Max.
Unit
Test
Circuit
VOUT(S) VOUT(S) VOUT(S)
0.015
+ 0.015
V
1
VOUT(S)
× 0.99
VOUT(S) VOUT(S)
× 1.01
V
1
VOUT(S)
× 0.99
500*5
VOUT(S)
VOUT(S)
× 1.01
V
mA
1
3
500*5
mA 3
0.5 0.54 0.58 V
1
0.44 0.48
V
1
0.34 0.38
V
1
0.24 0.28
V
1
0.14 0.18
V
1
0.10 0.15
V
1
0.07 0.10
V
1
0.05 0.2 %/V
1
2.5 10 mV 1
2.5 10 mV 1
15 30 mV 1
15 30 mV 1
− ±130 ppm/°C 1
− ±130 ppm/°C 1
90 110 µA
2
70 90 µA 2
70 90 µA 2
0.1 1.0 µA 2
0.1 1.0 µA 2
1.5 5.5 V
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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
Rev.1.1_00
www.datashePeta4rua.mcoemter
Symbol
Shutdown pin input
voltage “H”
VSH
Shutdown pin input
voltage “L”
VSL
Shutdown pin input
current “H”
Shutdown pin input
current “L”
ISH
ISL
Ripple rejection
RR
Short-circuit current
ISHORT
Thermal shutdown
detection temperature
TSD
Table 5 (2 / 2)
Conditions
VIN = VOUT(S) + 1.0 V,
RL = 1.0 k,
determined by VOUT
output level
VIN = 5.5 V,
RL = 1.0 k,
determined by VOUT
output level
VIN = VOUT(S) + 1.0 V,
RL = 1.0 k,
determined by VOUT
output level
VIN = 5.5 V,
RL = 1.0 k,
determined by VOUT
output level
1.0 V VOUT(S) 4.5 V
4.5 V < VOUT(S) 5.0 V
1.0 V VOUT(S) 4.5 V
4.5 V < VOUT(S) 5.0 V
VIN = 5.5 V, VON/OFF = 5.5 V
VIN = 5.5 V, VON/OFF = 0 V
VIN = VOUT(S) + 1.0 V,
f = 1 kHz,
Vrip = 0.5 Vrms,
IOUT = 100 mA
VIN = 5.5 V,
f = 1 kHz,
Vrip = 0.5 Vrms,
IOUT = 100 mA
VIN = VOUT(S) + 1.0 V,
ON/OFF pin = ON,
VOUT = 0 V
VIN = 5.5 V,
ON/OFF pin = ON,
VOUT = 0 V
1.0 V VOUT(S) < 1.2 V
1.2 V VOUT(S) 3.0 V
3.0 V < VOUT(S) 4.5 V
4.5 V < VOUT(S) 5.0 V
1.0 V VOUT(S) 4.5 V
4.5 V < VOUT(S) 5.0 V
Junction temperature
(Ta = 25°C unless otherwise specified)
Min.
Typ. Max.
Unit
Test
Circuit
1.0 − − V 4
1.0 − − V 4
− − 0.3 V 4
− − 0.3 V 4
0.1 0.1 µA 4
0.1 0.1 µA 4
70 dB 5
65 dB 5
60 dB 5
60 dB 5
200 mA 3
200 mA 3
150 − °C
Thermal shutdown
release temperature
TSR
Junction temperature
120 − °C
*1. VOUT(S) : Specified output voltage
VOUT(E) : Actual output voltage
The output voltage when fixing IOUT (= 100 mA) and inputting VOUT(S) + 1.0 V or 5.5 V
*2. The output current at which the output voltage becomes 95% of VOUT(E) after gradually increasing the output current.
*3. Vdrop = VIN1 (VOUT3 × 0.98)
VOUT3 is the output voltage when VIN = VOUT(S) + 1.0 V or 5.5 V, and IOUT = 200 mA.
VIN1 is the input voltage at which the output voltage becomes 98% of VOUT3 after gradually decreasing the input voltage.
*4. The change in temperature [mV/°C] is calculated using the following equation.
VOUT
[ ] [ ] [ ]Ta
mV/ °C
**11
=
VOUT(S)
V
**22 ×
VOUT
Ta VOUT
ppm/°C **33 ÷ 1000
*1. Change in temperature of the output voltage
*2. Specified output voltage
*3. Output voltage temperature coefficient
*5. The output current can be at least this value.
Due to limitation of the package power dissipation, this value may not be satisfied. Attention should be paid to the
power dissipation of the package when the output current is large.
This specification is guaranteed by design.
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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
„ Test Circuits
1.
www.datasheet4u.com
VIN VOUT
ON/OFF
VSS
Set to power
ON
Figure 4
+
A
+
V
2. +
A VIN
VOUT
ON/OFF
VSS
Set to VIN or GND
Figure 5
3. +
VIN VOUT
A
ON/OFF
VSS
+
V
Set to power
ON
Figure 6
4.
VIN VOUT
+
A ON/OFF
VSS
+
V RL
Figure 7
5.
VIN VOUT
ON/OFF
VSS
+
V RL
Set to power
ON
Figure 8
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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
„ Standard Circuit
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Input
CIN*1
VIN VOUT
ON/OFF
VSS
Output
CL*2
Rev.1.1_00
Single GND
GND
*1. CIN is a capacitor for stabilizing the input.
*2. Ceramic capacitor of 4.7 µF or more can be used as CL.
Figure 9
Caution The above connection diagram and constant will not guarantee successful operation. Perform
thorough evaluation using the actual application to set the constant.
„ Application Conditions
Input capacitor (CIN) : 4.7 µF or more
Output capacitor (CL) : 4.7 µF or more (ceramic capacitor)
Caution
1. Set input capacitor (CIN) and output capacitor (CL) as CIN = CL.
2. Generally, series regulator may oscillate depending on the external components. Confirm that
no oscillation occurs in the application for which the above capacitors are used.
„ Selection of Input and Output Capacitors (CIN, CL)
The S-1155 Series requires an output capacitor between the VOUT and VSS pin for phase compensation. Operation
is stabilized by a ceramic capacitor with an output capacitance of 4.7 µF or more over the entire temperature range.
When using an OS capacitor, a tantalum capacitor, or an aluminum electrolytic capacitor, the capacitance must be 4.7
µF or more.
The values of output overshoot and undershoot, which are transient response characteristics, vary depending on the
value of output capacitor.
The required value of capacitance for the input capacitor differs depending on the application.
Set the value for input capacitor (CIN) and output capacitor (CL) as follows.
CIN 4.7 µF
CL 4.7 µF
CIN = CL
Caution
The S-1155 Series may oscillate if setting the value as CIN 4.7 µF, CL 4.7 µF, CIN < CL.
Define the values by sufficient evaluation including the temperature characteristics under the usage
condition.
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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
„ Explanation of Terms
1. Low dropout voltage regulator
www.datasheeTth4uis.cIoCm’s voltage regulator has the low dropout voltage due to its built-in transistor with low on-resistance.
2. Output voltage (VOUT)
The accuracy of the output voltage is ensured at ±1.0% or ±15 mV*2 under the specified conditions of fixed input
voltage*1, fixed output current, and fixed temperature.
*1. Differs depending on the product.
*2. When VOUT < 1.5 V : ±15 mV, When 1.5 V VOUT : ±1.0%
Caution
If the above conditions change, the output voltage value may vary and exceed the accuracy
range of the output voltage. See “„ Electrical Characteristics” and “„ Characteristics (Typical
Data)” for details.
3. Line regulation  VOUT1 
 VIN VOUT
Indicates the dependency of the output voltage against the input voltage. That is, the value shows how much the
output voltage changes due to a change in the input voltage after fixing output current constant.
4. Load regulation (VOUT2)
Indicates the dependency of the output voltage against the output current. That is, the value shows how much the
output voltage changes due to a change in the output current after fixing output current constant.
5. Dropout voltage (Vdrop)
Indicates the difference between the output voltage and the input voltage VIN1, which is the input voltage (VIN) when;
decreasing input voltage VIN gradually until the output voltage has dropped to the value of 98% of output voltage
VOUT3, which is at VIN = VOUT(S) + 1.0 V or 5.5 V.
Vdrop = VIN1 (VOUT3 × 0.98)
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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
Rev.1.1_00
6. Temperature coefficient of output voltage  VOUT 
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Ta VOUT
The shadowed area in Figure 10 is the range where VOUT varies in the operating temperature range when the
temperature coefficient of the output voltage is ±130 ppm/°C.
VOUT [V]
Ex. S-1155B30 Typ.
+0.39 mV / °C
VOUT(E)*1
0.39 mV / °C
40 25
85 Ta [°C]
*1. VOUT(E) is the value of the output voltage measured at 25°C.
Figure 10
A change in the temperature of the output voltage [mV/°C] is calculated using the following equation.
VOUT
Ta
[mV
/
°C]*1
=
[VOUT(S) V
]*2
×
VOUT
Ta VOUT
[ppm
/
°C]*3
÷ 1000
*1. Change in temperature of output voltage
*2. Specified output voltage
*3. Output voltage temperature coefficient
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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
„ Operation
1. Basic operation
www.datasheeFti4guu.croem11 shows the block diagram of the S-1155 Series.
The error amplifier compares the reference voltage (Vref) with Vfb, which is the output voltage resistance-divided by
feedback resistors Rs and Rf. It supplies the gate voltage necessary to maintain the constant output voltage which
is not influenced by the input voltage and temperature change, to the output transistor.
VIN
Current
supply
Vref
Error amplifier
+
Reference voltage
circuit
*1
Rf
Vfb
Rs
VOUT
VSS
*1. Parasitic diode
Figure 11
2. Output transistor
In the S-1155 Series, a low on-resistance P-channel MOS FET is used as the output transistor.
Be sure that VOUT does not exceed VIN + 0.3 V to prevent the voltage regulator from being damaged due to inverse
current which flows, because of a parasitic diode between the VIN and VOUT pin, when the potential of VOUT
became higher than VIN.
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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
Rev.1.1_00
3. Shutdown pin (ON/OFF pin)
This pin starts and stops the regulator.
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When the ON/OFF pin is set to the shutdown level, the entire internal circuit stops operating, and the built-in
P-channel MOS FET output transistor between the VIN and VOUT pin is turned off, in order to reduce the current
consumption significantly. The VOUT pin is set to the VSS level by the internal dividing resistor of several hundred
kbetween the VOUT and VSS pin.
Note that the current consumption increases when a voltage of 0.3 V to 1.0 V is applied to the ON/OFF pin.
The ON/OFF pin is configured as shown in Figure 12. Since the ON/OFF pin is neither pulled down nor pulled up
internally, do not use it in the floating state.
When not using the ON/OFF pin, connect it to the VSS pin in the product A type, and connect it to the VIN pin in B
type.
Table 6
Logic Type
A
A
B
B
ON/OFF Pin
“L”: Power on
“H”: Power off
“L”: Power off
“H”: Power on
Internal Circuits
Operate
Stop
Stop
Operate
VOUT Pin Voltage
Set value
VSS level
VSS level
Set value
Current Consumption
ISS1
ISS2
ISS2
ISS1
VIN
ON/OFF
VSS
Figure 12
4. Overcurrent protection circuit
The S-1155 Series has an overcurrent protection circuit having the characteristics shown in (1) Output Voltage vs.
Output Current (When load current is increased) (Ta = 25°C) in “„ Characteristics (Typical Data)”, in order to
protect the output transistor against an excessive output current and short circuiting between the VOUT and VSS
pin. The current (ISHORT) when the output pin is short-circuited is internally set at approx. 200 mA (Typ.), and the
initial value is restored for the output voltage, if releasing a short circuit once.
Caution
This overcurrent protection circuit does not work as for thermal protection. If this IC long keeps
short circuiting inside, pay attention to the conditions of input voltage and the load current so
that, under the usage conditions including short circuit, the loss of the IC will not exceed power
dissipation of the package.
14 Seiko Instruments Inc.


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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
5. Thermal shutdown circuit
The S-1155 Series has a thermal shutdown circuit to protect the device from damage due to overheat. When the
www.datasheejut4nuc.tcioomn temperature rises to 150°C (Typ.), the thermal shutdown circuit operates to stop regulating. When the
junction temperature drops to 120°C (Typ.), the thermal shutdown circuit is released to restart regulating.
Due to self-heating of the S-1155 Series, if the thermal shutdown circuit starts operating, it stops regulating so that
the output voltage drops. When regulation stops, the S-1155 does not itself generate heat so that the IC’s
temperature drops. When the temperature drops, the thermal shutdown circuit is released to restart regulating, thus
this IC generates heat again. Repeating this procedure makes waveform of the output voltage pulse-like form.
Stop/Restart of regulation continues unless decreasing either/both of the input voltage and the output voltage in
order to reduce the internal current consumption, or decreasing the ambient temperature.
Table 7
Thermal Shutdown Circuit
Operation : 150°C (Typ.)*1
Release : 120°C (Typ.)*1
*1. Junction temperature
VOUT Pin Voltage
VSS level
Set value
6. Rush current control circuit
The S-1155 Series has a rush current control circuit to control the rush current generated during power-on or when
the ON/OFF pin is ON. This circuit limits the rush current (400 mA, Typ.) immediately after power-on or from the
ON/OFF pin is ON until the specified time (100 µs min.) which is set internally.
Caution
The junction temperature drops to 120°C (Typ.) by the operation of thermal shutdown circuit,
after stopping regulation, the circuit is released to restart regulation; in this case, note that the
period to limit rush current may become shorter (10 µs min.).
Seiko Instruments Inc.
15


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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
Rev.1.1_00
„ Precautions
Wiring patterns for the VIN, VOUT and GND pins should be designed so that the impedance is low. When mounting
www.datashaenet4ouu.tcpoumt capacitor between the VOUT and VSS pin (CL) and a capacitor for stabilizing the input between the VIN
and VSS pin (CIN), the distance from the capacitors to these pins should be as short as possible.
Note that the output voltage may increase when a series regulator is used at low load current (1.0 mA or less).
Note that the output voltage may generally increase due to the leakage current from a driver when a series regulator
is used at high temperature.
Generally series regulator may oscillate, depending on the selection of external parts. The following conditions are
recommended for this IC. However, be sure to perform sufficient evaluation under the actual usage conditions for
selection, including the temperature characteristics. Regarding the equivalent series resistance (RESR) for the output
capacitor, refer to (5) Example of Equivalent Series Resistance vs. Output Current Characteristics (Ta = 25°C)
in “„ Reference Data”.
Input capacitor (CIN) : 4.7 µF or more
Output capacitor (CL) : 4.7 µF or more
The voltage regulator may oscillate when the impedance of the power supply is high and the input capacitance is
small, or an input capacitor is not connected. Note that the voltage regulator may oscillate when the value of the
input capacitor is greater than that of the output capacitor.
Ringing may occur when these three conditions below are satisfied. Before selecting an input capacitor, be sure to
evaluate sufficiently under the actual usage conditions, including the temperature characteristics.
The power supply inductance is high.
The load current is 100 mA or more.
The difference between the input voltage and the output voltage is close to the value of dropout voltage.
If the output capacitance is small, power supply’s fluctuation and the characteristics of load fluctuation become worse.
Sufficiently evaluate the output voltage’s fluctuation with the actual device.
A momentary overshoot may be output when the power supply suddenly increases, and the output capacitance is
small. It is therefore important to sufficiently evaluate the output voltage at power application in actual device.
The application conditions for the input voltage, output voltage, and load current should not exceed power dissipation
of the package.
Do not apply an electrostatic discharge to this IC that exceeds the performance ratings of the built-in electrostatic
protection circuit.
In determining the output current, attention should be paid to the output current value specified in Table 5 in “„
Electrical Characteristics” and footnote *5 of the table.
SII claims no responsibility for any disputes arising out of or in connection with any infringement by products including
this IC of patents owned by a third party.
16 Seiko Instruments Inc.


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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
„ Characteristics (Typical Data)
(1) Output Voltage vs. Output Current (when load current is increased) (Ta = 25°C)
www.daSta-s1h1e5e5t4Bu1.c0om
1.2
1.0
0.8
0.6
0.4
0.2
0
0
VIN = 1.5 V
5.5 V
3.0 V
2.0 V
200 400 600 800 1000
IOUT [mA]
S-1155B30
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
VIN = 3.5 V
4.0 V
200 400 600
IOUT [mA]
5.0 V
5.5 V
800 1000
S-1155B50
6
5
4
3
2
1
0
0
VIN = 5.3 V
5.5 V
200 400 600 800 1000
IOUT [mA]
Remark In determining the output current, attention
should be paid to the following.
1. The minimum value of output current
in Table 5 and footnote *5 in “„ Electrical
Characteristics
2. Power dissipation of the package
(2) Output Voltage vs. Input Voltage (Ta = 25°C)
S-1155B10
1.1
1.0
0.9 IOUT = 1 mA
0.8 50 mA
0.7 100 mA
0.6
0.5
0.5 1.0 1.5 2.0 2.5 3.0
VIN [V]
S-1155B50
5.1
5.0
4.9
IOUT = 1 mA
4.8
4.7
4.6
4.5
4.5
4.7
50 mA
100 mA
4.9 5.1
VIN [V]
5.3
5.5
S-1155B30
3.1
3.0
2.9
2.8
IOUT = 1 mA
50 mA
100 mA
2.7
2.6
2.5
2.5 3.0 3.5 4.0 4.5 5.0
VIN [V]
Seiko Instruments Inc.
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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
Rev.1.1_00
(3) Dropout Voltage vs. Output Current
S-1155B10
www.datasheet40u..4co0m
0.35
0.30
0.25 Ta = 85°C
-40°C
0.20
0.15
0.10 25°C
0.05
0
0 100 200 300 400 500 600
IOUT [mA]
S-1155B50
0.20
0.15
0.10
Ta = 85°C
25°C
-40°C
0.05
0
0 100 200 300 400 500 600
IOUT [mA]
(4) Dropout Voltage vs. Set Output Voltage
0.40
0.35
0.30
0.25
0.20
0.15
IOUT = 500 mA
300 mA
10 mA
0.10
0.05
0
01234 5
VOTA [V]
6
S-1155B30
0.20
0.15
0.10
0.05
0
0
Ta = 85°C
25°C
-40°C
100 200 300 400 500 600
IOUT [mA]
18 Seiko Instruments Inc.


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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
(5) Output Voltage vs. Ambient Temperature
S-1155B10
www.datasheet41u.1.c0o0m
1.075
1.050
1.025
1.000
0.975
0.950
0.925
0.900
40 25
0 25 50
Ta [°C]
S-1155B50
5.30
5.20
5.10
5.00
4.90
4.80
4.70
40 25
0 25
Ta [°C]
50
75 85
75 85
(6) Current Consumption vs. Input Voltage
S-1155B10
120
100
Ta = 85 °C
80
60 25 °C
40 40 °C
20
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VIN [V]
S-1155B50
80
70 Ta = 85°C
60
50 25°C
40
30
-40°C
20
10
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VIN [V]
S-1155B30
3.20
3.15
3.10
3.05
3.00
2.95
2.90
2.85
2.80
40 25
0 25
Ta [°C]
50
75 85
S-1155B30
80
70 Ta = 85°C
60
50
25°C
40
30
-40°C
20
10
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VIN [V]
Seiko Instruments Inc.
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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
Rev.1.1_00
(7) Ripple Rejection (Ta = 25°C)
S-1155B10
www.datasheet4u.com
100
80
60
VIN = 2.0 V, COUT = 4.7 µF
IOUT = 1 mA
30 mA
100 mA
40
20
0
10
S-1155B50
100
80
60
40
20
100 1K 10K 100K 1M
Frequency [Hz]
VIN = 5.5 V, COUT = 4.7 µF
IOUT = 1 mA
30 mA
100 mA
0
10 100 1K 10K 100K 1M
Frequency [Hz]
S-1155B30
100
80
60
40
20
0
10
VIN = 4.0 V, COUT = 4.7 µF
IOUT = 1 mA
30 mA
100 mA
100 1K 10K 100K 1M
Frequency [Hz]
20 Seiko Instruments Inc.


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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
„ Reference Data
(1) Characteristics of Input Transient Response (Ta = 25°C)
w S-w1155B1w0 . d a t a s S-1h155B30e e t 4 u . c
IOUT = 100 mA, tr = tf = 5.0 µs, COUT = 4.7 µF, CIN = 4.7 µF IOUT = 100 mA, tr = tf = 5.0 µs, COUT = 4.7 µF, CIN = 4.7 µF
1.15
4 3.20
6
1.10 VIN
1.05
1.00
VOUT
3 3.15 VIN
3.10
2 3.05 VOUT
1 3.00
2.95
5
4
3
2
1
0.95 0
200 0 200 400 600 800 1000 1200
2.90 0
200 0 200 400 600 800 1000 1200
t [µs]
t [µs]
S-1155B50
IOUT = 100 mA, tr = tf = 5.0 µs, COUT = 4.7 µF, CIN = 4.7 µF
5.25 7
5.20 VIN
6
5.15 5
5.10 4
5.05 VOUT
5.00
3
2
4.95 1
4.90 0
200 0 200 400 600 800 1000 1200
t [µs]
(2) Characteristics of Load Transient Response (Ta = 25°C)
S-1155B10
VIN = 2.0 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 50 100 mA
1.20 150
1.15 IOUT
1.10
100
50
1.05
1.00 VOUT
0
50
0.95 100
0.90 150
200 0 200 400 600 800 1000 1200
t [µs]
S-1155B30
VIN = 4.0 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 50 100 mA
3.20 150
3.15 IOUT
3.10
100
50
3.05
3.00
VOUT
0
50
2.95 100
2.90 150
200 0 200 400 600 800 1000 1200
t [µs]
S-1155B50
VIN = 5.5 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 50 100 mA
5.20 150
5.15 IOUT
5.10
100
50
5.05
5.00 VOUT
0
50
4.95 100
4.90 150
200 0 200 400 600 800 1000 1200
t [µs]
o
Seiko Instruments Inc.
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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
Rev.1.1_00
(3) Transient Response Characteristics of ON/OFF Pin (Ta = 25°C)
S-1155B10
VIN = 2.0 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 100 mA
www.datasheet54u.com
3
42
3 VON/OFF
1
20
1
0 VOUT
1
2
1
500
3
0 500 1000 1500 2000
t [µs]
S-1155B30
VIN = 4.0 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 100 mA
10 6
84
6 VON/OFF
2
40
2
0 VOUT
2
4
2
500
6
0 500 1000 1500 2000
t [µs]
S-1155B50
VIN = 5.5 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 100 mA
20 9
16 6
12 VON/OFF
3
80
4
0 VOUT
3
6
4
500
9
0 500 1000 1500 2000
t [µs]
(4) Characteristics of Rush Current (Ta = 25°C)
S-1155B10
VIN = 2.0 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 100 mA
6 1.2
4
VON/OFF
2
1.0
0.8
0 VOUT
2 IOUT
4
0.6
0.4
0.2
6
50
0
0
50 100 150 200
t [µs]
S-1155B30
VIN = 4.0 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 100 mA
6
4 VON/OFF
1.2
1.0
2 0.8
0 VOUT
0.6
2
4 IOUT
0.4
0.2
6 0
50 0 50 100 150 200
t [µs]
VIN = 2.0 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 500 mA
6 1.2
4
VON/OFF
2
1.0
0.8
0
2
4 IOUT
VOUT
0.6
0.4
0.2
6 0
100 0 100 200 300 400 500
t [µs]
VIN = 4.0 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 500 mA
6
4 VON/OFF
1.2
1.0
2 0.8
0 VOUT
2
4 IOUT
0.6
0.4
0.2
6 0
100 0 100 200 300 400 500
t [µs]
22 Seiko Instruments Inc.


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Rev.1.1_00
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
S-1155B50
VIN = 5.5 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 100 mA
6 1.2
www.datashee4t4u.com
1.0
2 VON/OFF
0 VOUT
0.8
0.6
2
4 IOUT
0.4
0.2
6 0
100 0 100 200 300 400 500
t [µs]
VIN = 5.5 V, COUT = 4.7 µF, CIN = 4.7 µF, IOUT = 500 mA
6 1.2
4 VON/OFF
1.0
2 0.8
0 VOUT
0.6
2
4
IOUT
0.4
0.2
6 0
100 0 100 200 300 400 500
t [µs]
(5) Example of Equivalent Series Resistance vs. Output Current Characteristics (Ta = 25°C)
100
0.1
0 0.1
CIN = CL = 4.7 µF
Stable
IOUT [mA]
500
VIN
CIN S-1155 Series
ON/OFF
VSS
VOUT
CL
RESR
Seiko Instruments Inc.
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HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series
Rev.1.1_00
„ Marking Specifications
SOT-89-5
www.datasheet4u.com
SOT-89-5
Top view
54
(1) to (3) : Product abbreviation (refer to Product Name vs. Product Code)
(4) to (6) : Lot number
12 3
Product Name vs. Product Code
Product Name
Product Code
(1) (2) (3)
Product Name
Product Code
(1) (2) (3)
S-1155B10-U5T1G
S-1155B11-U5T1G
S-1155B12-U5T1G
S-1155B13-U5T1G
S-1155B14-U5T1G
S-1155B15-U5T1G
S-1155B16-U5T1G
S-1155B17-U5T1G
S-1155B18-U5T1G
S-1155B1J-U5T1G
S-1155B19-U5T1G
S-1155B20-U5T1G
S-1155B21-U5T1G
S-1155B22-U5T1G
S-1155B23-U5T1G
S-1155B24-U5T1G
S-1155B25-U5T1G
S-1155B26-U5T1G
S-1155B27-U5T1G
S-1155B28-U5T1G
S-1155B2J-U5T1G
SKA
SKB
SKC
SKD
SKE
SKF
SKG
SKH
SK
I
SK J
SKK
SKL
S KM
SKN
SKO
SKP
SKQ
SKR
SKS
SKT
SKU
S-1155B30-U5T1G
S-1155B31-U5T1G
S-1155B32-U5T1G
S-1155B33-U5T1G
S-1155B34-U5T1G
S-1155B35-U5T1G
S-1155B36-U5T1G
S-1155B37-U5T1G
S-1155B38-U5T1G
S-1155B39-U5T1G
S-1155B40-U5T1G
S-1155B41-U5T1G
S-1155B42-U5T1G
S-1155B43-U5T1G
S-1155B44-U5T1G
S-1155B45-U5T1G
S-1155B46-U5T1G
S-1155B47-U5T1G
S-1155B48-U5T1G
S-1155B49-U5T1G
S-1155B50-U5T1G
S KW
SKX
SKY
SKZ
SLA
SLB
SLC
SLD
SLE
SLF
SLG
SLH
SL
I
SL J
SLK
SLL
S LM
SLN
SLO
SLP
SLQ
S-1155B29-U5T1G
SKV
Remark Please contact our sales office for products with an output voltage other than those specified above or
type A products.
24 Seiko Instruments Inc.


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5
4.5±0.1
1.6±0.2
4
12
3
1.5±0.1 1.5±0.1
1.5±0.1
0.4±0.05
0.4±0.1
0.45±0.1
0.4±0.1
0.3
45°
No. UP005-A-P-SD-1.1
TITLE SOT895-A-PKG Dimensions
No.
SCALE
UNIT
UP005-A-P-SD-1.1
mm
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ø1.5
+0.1
-0
2.0±0.05
4.0±0.1(10 pitches : 40.0±0.2)
5° max.
ø1.5
+0.1
-0
4.75±0.1
8.0±0.1
0.3±0.05
2.0±0.1
321
45
Feed direction
No. UP005-A-C-SD-1.1
TITLE
No.
SCALE
UNIT
SOT895-A-Carrier Tape
UP005-A-C-SD-1.1
mm
Seiko Instruments Inc.


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16.5max.
Enlarged drawing in the central part
13.0±0.3
(60°) (60°)
No. UP005-A-R-SD-1.1
TITLE
No.
SCALE
UNIT
SOT895-A-Reel
UP005-A-R-SD-1.1
QTY.
1,000
mm
Seiko Instruments Inc.


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The information described herein is subject to change without notice.
Seiko Instruments Inc. is not responsible for any problems caused by circuits or diagrams described herein
whose related industrial properties, patents, or other rights belong to third parties. The application circuit
examples explain typical applications of the products, and do not guarantee the success of any specific
mass-production design.
When the products described herein are regulated products subject to the Wassenaar Arrangement or other
agreements, they may not be exported without authorization from the appropriate governmental authority.
Use of the information described herein for other purposes and/or reproduction or copying without the
express permission of Seiko Instruments Inc. is strictly prohibited.
The products described herein cannot be used as part of any device or equipment affecting the human
body, such as exercise equipment, medical equipment, security systems, gas equipment, or any apparatus
installed in airplanes and other vehicles, without prior written permission of Seiko Instruments Inc.
Although Seiko Instruments Inc. exerts the greatest possible effort to ensure high quality and reliability, the
failure or malfunction of semiconductor products may occur. The user of these products should therefore
give thorough consideration to safety design, including redundancy, fire-prevention measures, and
malfunction prevention, to prevent any accidents, fires, or community damage that may ensue.



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