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FB

PGND

SW

VIN

EN

Undervoltage

Lockout

Bias supply

Control Logic

+

−

LoadComparator

1.25 MHz

Oscillator

Vref = 0.5 V

Driver

Shoot−thru

Logic

Soft

Start

+

−

+

−

Current limit Comparator

SkipComparator

Gm

Saw Tooth

Generator

V

I

+

−

Vcomp

S

R

+

−

Comp High

Comp Low

Comp Low 2

Comp High

Comp Low

Comp Low 2

−

+

Comparator

Compensation

Ref

Ref

PGND

VIN

GND

MODE

MODE

SW

(See Note A)

TPS62020, TPS62021

SLVS076B – JUNE 2003 – REVISED APRIL 2004

PIN ASSIGNMENTS (continued)

Terminal Functions

TERMINAL

I/O

DESCRIPTION

NAME

NO.

EN

1

I

should not be left floating and must be terminated.

VIN

2, 3

I

Supply voltage input

GND

4

Analog ground

FB

5

I

Feedback. Connect an external resistor divider to this pin.

MODE

6

I

The difference between TPS62020 and TPS62021 is the logic level of the MODE pin. The TPS62021 has an

MODE

active-low MODE pin. The TPS62020 is forced into fixed-frequency PWM mode by pulling the MODE pin high.

Pulling the MODE pin low enables the Power Save Mode, operating in PFM mode (Pulse frequency modulation)

at light load current, and in fixed frequency PWM at medimum to heavy load currents. In contrast, the TPS62021

is forced into PWM mode by pulling the MODE pin low.

SW

7, 8

I/O

This is the switch pin of the converter and connected to the drain of the internal power MOSFETs

PGND

9, 10

Power ground

FUNCTIONAL BLOCK DIAGRAM

NOTE A: The TPS62020 has an active-high MODE pin. The TPS62020 has an active-low MODE pin.

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