SC1531 PDF Datasheet – Power Management, Smart LDO

Part Number: SC1531

Function: 200mA & 250mA Smart LDO ( Power Management )

Package: SO-8 Type

Manufacturer: Semtech Corporation

Images:SC1531 pdf pinout


The SC1531 is designed to maintain a glitch-free 3.3V output when at least one of two inputs, 5V (VIN) and 3.3V (VAUX), is present. SC1531(A).  Whenever VIN exceeds a predetermined threshold value, u the internal 3.3V linear regulator is enabled, and DR is u pulled high. u When VIN falls below a lower threshold value, DR is pulled u low and the internal linear regulator is turned off. DR has been designed to drive the gate of an external low threshold P-channel MOSFET, which can be used to connect the 3.3V supply directly to the regulator output.

This ensures an uninterrupted 3.3V output even if VIN falls out of specification. A typical RDS(ON) of 400mW is recommended (320mW for SC1531A). When both supplies are simultaneously available, the drive pin (DR) will be pulled High, turning off the external PMOS switch. The internal 5V detector has its upper threshold (for VIN rising) set to 4.18V (typical) while the lower threshold (for VIN falling) is at 4.05V (typical) giving a hysteresis of approximately 130mV. The SENSE pin, which is connected to the load, connects internally to the inverting input of the LDO error amplifier. It enables tight regulation of the load voltage (while the 5V supply is present) despite variations in load current. […]


1. Glitch-free transition between input sources

2. Internal logic selects input source

3. Gate drive for external PMOS bypass switch

4. 5V detection with hysteresis

5. 1% regulated output voltage accuracy

6. 200mA load current capability (250mA for SC1531A)

7. Remote sense

SC1531 datasheet


1. Desktop Computer

2. Network Interface Cards (NICs)

3. Power supplies with multiple input sources

SC1531 PDF Datasheet