Document
KA3525A
SMPS Controller
www.fairchildsemi.com
Features
• 5V ±1% Reference • Oscillator Sync Terminal • Internal Soft Start • Deadtime Control • Under Voltage Lockout
Description
The KA3525A is a monolithic integrated circuit that includes all of the control circuits necessary for a pulse width modulating regulator. There are a voltage reference, an error amplifier, a pulse width modulator, an oscillator, an under voltage lockout, a soft start circuit, and the output driver in the chip.
16-DIP
Internal Block Diagram
1
VREF 16 VCC 15 GND 12
BAND GAP REF 5V
U.V.L.O.
EA(-) 1 EA(+) 2 EAOUT 9
_
ERR AMP +
C8
(SOFT START)
5K 10
SHUT DOWN
CT 5
7
5K DISCHARGE
_
PWM COMP +
LATCH SR
OSCILLATOR
F/F
Q Q
36
SYNC RT
4
OSC OUTPUT
VC 13
11
OUTPUT A
14
OUTPUT B
©2002 Fairchild Semiconductor Corporation
Rev. 1.0.1
KA3525A
Absolute Maximum Ratings
Parameter Supply Voltage Collector Supply Voltage Output Current, Sink or Source Reference Output Current Oscillator Charging Current Power Dissipation (TA = 25°C) Operating Temperature Storage Temperature Lead Temperature (Soldering, 10sec)
Symbol VCC VC IO IREF
ICHG(OSC) PD
TOPR TSTG TLEAD
Value 40 40 500 50 5
1000 0 ~ +70 -65 ~ +150
+300
Unit V V mA mA mA
m/W °C °C °C
Electrical Characteristics
(VCC = 20V, TA = 0 to +70°C, unless otherwise specified)
Parameter REFERENCE SECTION Reference Output Voltage Line Regulation Load Regulation Short Circuit Output Current Total Output Variation (Note1) Temperature Stability (Note1) Long Term Stability (Note1) OSCILLATOR SECTION Initial Accuracy (Note1, 2) Frequency Change With Voltage Maximum Frequency Minimum Frequency Clock Amplitude (Note1, 2) Clock Width (Note1, 2) Sync Threshold Sync Input Current
Symbol
Conditions
VREF ∆VREF ∆VREF
ISC ∆VREF
STT ST
TJ = 25°C VCC = 8 to 35V IREF = 0 to 20mA VREF = 0, TJ = 25°C Line, Load and Temperature
TJ = 125°C ,1KHRS
ACCUR ∆f/∆VCC f(MAX)
f(MIN) V(CLK) tW(CLK) VTH(SYNC) II(SYNC)
TJ = 25°C VCC = 8 to 35V (Note1, 2) RT = 2kΩ, CT = 470pF RT = 200kΩ, CT = 0.1uF
TJ = 25°C
Sync = 3.5V
Min. Typ. Max. Unit
5.0 5.1 5.2 V - 9 20 mV - 20 50 mV - 80 100 mA
4.95 - 5.25 V - 20 50 mV - 20 50 mV
- ±3 ±6 - ±0.8 ±2 400 430 - 60 120 34 0.3 0.6 1 1.2 2 2.8 - 1.3 2.5
% % kHz Hz V µs V mA
2
KA3525A
Electrical Characteristics (Continued)
(VCC = 20V, TA = 0 to +70°C, unless otherwise specified)
Parameter
Symbol
ERROR AMPLIFIER SECTION (VCM = 5.1V)
Input Offset Voltage
VIO
Input Bias Current
IBIAS
Input Offset Current
IIO
Open Loop Voltage Gain
GVO
Common Mode Rejection Ratio
CMRR
Power Supply Rejection Ratio
PSRR
PWM COMPARATOR SECTION
Minimum Duty Cycle
D(MIN)
Maximum Duty Cycle
D(MAX)
Input Threshold Voltage (Note2)
VTH1
Input Threshold Voltage (Note2)
VTH2
SOFT-START SECTION
Soft Start Current
ISOFT
Soft Start Low Level Voltage
VSL
Shutdown Threshold Voltage
VTH(SD)
Shutdown Input Current
IN(SD)
OUTPUT SECTION
Low Output Voltage I
VOL I
Low Output Voltage II
VOL II
High Output Voltage I
VCH I
High Output Voltage II
VCH II
Under Voltage Lockout
VUV
Collector Leakage Current
ILKG
Rise Time (Note1)
tR
Fall Time (Note1)
tF
STANDBY CURRENT
Supply Current
ICC
Conditions
RL ≥ 10MΩ VCM = 1.5 to 5.2V VCC = 8 to 3.5V
Zero Duty Cycle Max Duty Cycle
VSD = 0V, VSS = 0V VSD = 25V
VSD = 2.5V
ISINK = 20mA ISINK = 100mA ISOURCE = 20mA ISOURCE = 100mA V8 and V9 = High VCC = 35V CL = 1uF, TJ = 25°C CL = 1uF, TJ = 25°C
VCC = 35V
Min. Typ. Max. Unit
- 1.5 10 mV - 1 10 µA - 0.1 1 µA 60 80 - dB 60 90 - dB 50 60 - dB
- -0 45 49 0.7 0.9 - 3.2 3.6
% % V V
25 51 80 µA - 0.3 0.7 V 0.9 1.3 1.7 V - 0.3 1 mA
- 0.1 0.4 V - 0.05 2 V 18 19 - V 17 18 - V 678V - 80 200 µA - 80 600 ns - 70 300 ns
- 12 20 mA
Note : 1. These parameters. although guaranteed over the recommended operating conditions, are not 100% tested in production 2. Tested at fOSC=40kHz (RT =3.6K, CT =0.01uF, RI = 0Ω)
3
KA3525A
Test Circuit
16
3k
RWM ADJ
10k
Vcc 0.1
15 12
BAND GAP REF 5V
U.V.L.O.
1.5K
_
1 ERR
AMP
2+
10K 0.01
SOFT START + 8
5.0uF
10
9
5.0k
_
ERR AMP
+
LATCH S
SR
OSCILLATOR
36
CLOCK
F/F
VREF
5.0k
SHUTDOWN
5.0k
5
CT
RAMP
7
100 DEAD TIME RT
0.009
0.001 +
0.1
3.6k
A B
13 VC 0.1
OUT A
11
10k
10k
14
OUT B
4
Mechanical Dimensions
Package
6.40 ±0.20 0.252 ±0.008
#1 #16
16-DIP
( 0.81 ) 0.032
KA3525A
0.46 ±0.10 0.018 ±0.004 1.50 ±0.10 0.059 ±0.004
19.40 ±0.20 0.764 ±0.008
MAX
19.80 0.780
2.54 0.100
#8
7.62 0.300
#9
3.25 ±0.20 0.128 ±0.008
5.08 0.200
MAX
0~15°
0.25
+0.10 –0.05
0.010
+0.004 –0.002
0.38 0.014
MIN
3.30 ±0.30 0.130 ±0.012
5
KA3525A
Ordering Information
Product Number KA3525A
Package 16-DIP
Operating Temperature 0 ~ +70°C
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATI.