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POWER MANAGEMENT

5

SC191

Pin Descriptions

Pin#

Pin Name Pin Function

1BP

Regulated output, with respect to VIN, of the front-end LDO. A 4.7μF decoupling capacitor

should be connected to this pin. This output is connected directly to the internal switching

MOSFETs.

2

PVIN

Input power supply for the power devices.

3

VIN

Input power supply for the analog functions.

4EN

Enable (digital input): high input enables the SC191, a low disables and reduces the quiescent

current to < 1μA. In shutdown LX becomes high impedance.

5

VOUT

Regulated output voltage and feedback for the SC191.

6

GND

Ground: this pin should be connected directly to PGND on the user’s PCB.

7

PGND

Power Ground: this pin should be connected directly to GND on the user’s PCB and should

be the reference point for the input, output and BP capacitor GND connections. These ground

paths should be separate and as short as possible to minimize circuit noise.

8

LX

Inductor connection to the switching MOSFETs.

Control

Logic

500mV

OSC and Slope

Generator

VOUT

EN

VIN

PVIN

BP

LX

PGND

GND

LDO

Error Amp

Front-End

LDO

Current

Amp

PWM

Comp

Error

Amp

Nlimit

Comp

Plimit

Amp

4

6

5

1

2

3

7

8

Voltage

References

VREF1

VREF1

500mV

Block Diagram