Document
Fo r tune
Semiconductor Corporation
FS8861 1.0A Adjustable and Fixed Voltage LDO Linear Regulator
General Description
The FS8861 is a low-dropout linear regulator that operates the input voltage from +2.5V to +7.0V and delivers 1.0A load current.
The FS8861 is available in two types, either fixed or adjustable output voltage. The output voltage of the fixed types is preset at an internally trimmed voltage 1.8V, 2.5V, or 3.3V. The output range of the adjustable types is from 1.25V to 5V.
The FS8861 consists of a 1.25V reference, an error amplifier, and a P-channel pass transistor allows the low 65µA (Typ.) ground pin current. Other features include short-circuit protection and thermal shutdown protection.
Features
Low dropout voltage 700mV at 1.0A typ. Adjustable output voltage (FS8861-CJ) or fixed output voltage (FS8861-xxCJ) at 1.8V, 2.5V, or 3.3V High output voltage accuracy
Fixed output voltage : 35mV
Adjustable output voltage : 50mV
Small output capacitor Output current limit
Thermal overload shutdown protection
SOT-223 Package
Applications
Active SCSI Terminators High Efficiency Linear Regulators Monitor Microprocessor Low Voltage Micro-Controllers Post Regulator for Switching Power
Ordering Information
FS8861-xx x x
Package
Pin Out
J SOT-223 1.GND 2.OUT 3.IN
Note : For the adjustable voltage types, the GND pin is replaced with the ADJ pin
Temperature Range C Commercial Standard
Output Voltage (Fixed voltage types only)
18 : 1.8V
25 : 2.5V 33 : 3.3V
SOT-223
GND
FS8861 xxCJxxxx
1
GND/ ADJ
2 OUT
3 IN
Package Marking Information EX FS8861-33CJ
FS8861 33CJxxxx
xxxx Date Code
EX FS8861-CJ ADJ
FS8861 CJxxxx
xxxx Date Code
FORTUNE SEMICONDUCTOR CO. TEL : +886-2-2809-4742
HTTP://WWW.FSC.COM.TW FAX: +886-2-2809-4874
1/10
TD0309-2401 VER. 1.0
Fo r tune
Semiconductor Corporation
FS8861 1.0A Adjustable and Fixed Voltage LDO Linear Regulator
Pin Description
Part NO.
Symbol
Description
Pin 1 GND/ADJ Ground output or Adjustable output.
FS8861-xxCJ
Pin 2
OUT
Regulator input.
Pin 3
IN
Regulator output.
IN is the regulator input. Supply voltage can range from 2.5V to 7.0V. Bypass with a 10µF capacitor to GND.
OUT is the output voltage. Sources up to 1.0A. Bypass with a 10µF capacitor to GND.
GND provides the reference for all voltages. This pin also functions as a heat sink. It is recommended that solder it to a large pad or the circuit-board ground plane for better power dissipation.
ADJ provides VREF=1.25V Typ. for adjustable VOUT.
Typical Application Schematic
VIN
10uF
VIN
10uF
FS8861-CJ
VREF IADJ
FS8861-xxCJ
VOUT
10uF
VOUT
= VREF
× (1 +
R2 R1
)
+
I
ADJ
× R2
10uF
VOUT
FORTUNE SEMICONDUCTOR CO. TEL : +886-2-2809-4742
HTTP://WWW.FSC.COM.TW FAX: +886-2-2809-4874
2/10
TD0309-2401 VER. 1.0
Fo r tune
Semiconductor Corporation
FS8861 1.0A Adjustable and Fixed Voltage LDO Linear Regulator
Function Block Diagram
IN
Shutdown Logic
1.25V Bandgap Reference
Current Limit
Thermal Protection
Fixed Voltage Type
I.