TPS2838, TPS2839

TPS2848, TPS2849

SLVS367A – MARCH 2001 – REVISED JUNE 2001

4

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Terminal Functions

TERMINAL

NAME

NO.

DESCRIPTION

NAME

TPS283x

TPS284x

DESCRIPTION

ADJ

6

—

Adjust. The adjust pin is the feedback pin for the drive regulator (TPS283X only)

AGND

8

7

Analog ground

BOOT

16

14

Bootstrap. A capacitor is connected between the BOOT and BOOTLO pins to develop the floating

bootstrap voltage for the high-side MOSFET. The capacitor value is typically between 0.1

µF and 1 µF.

BOOTLO

14

12

Boot low. This pin connects to the junction of the high-side and low-side MOSFETs.

DELAY

4

4

Delay. Connecting a capacitor between this pin and ground adjusts the deadtime for high-side driver

DT

7

6

Deadtime control. Connect DT to the junction of the high-side and low-side MOSFETs

ENABLE

1

1

Enable. If ENABLE is low, both drivers are off.

HIGHDR

15

13

High drive. This pin is the output drive for the high-side power MOSFET.

IN

2

2

Input. This pin is the input signal to the MOSFET drivers.

LOWDR

11

9

Low drive. This pin is the output drive for the low-side power MOSFET.

NC

10

5

No internal connection

PGND

9

8

Power ground. This pin is connected to the FET power ground.

PWRRDY

3

3

Power ready. This open-drain pin indicates a power good for VDRV and VCC.

SYNC

5

—

Synchronous rectifier enable. If SYNC is low, the low-side driver is always off; if SYNC is high, the

low-side driver provides gate drive to the low-side MOSFET.

VCC

13

11

Input power supply. It is recommended that a capacitor (minimum 1

µF) be connected from VCC to

PGND. Note that VCC must be 2 V higher than VDRV.

VDRV

12

10

Drive regulator output voltage. It is recommended that a capacitor (minimum 1

µF) be connected from

VDRV to PGND. Note that VCC must be 2 V higher than VDRV.

detailed description

low-side driver

source and sink.

high-side driver

minimum, source and sink. The high-side driver can be configured as a GND-reference driver or as a

floating-bootstrap driver. The internal bootstrap diode is a Schottky, for improved drive efficiency. The maximum

voltage that can be applied from BOOT to ground is 30 V.

dead-time (DT) control

Dead-time control prevents shoot-through current from flowing through the main power FETs during switching

transitions by controlling the turnon times of the MOSFET drivers. The high-side driver is not allowed to turn

on until the gate drive voltage to the low-side FET is low, and the low-side driver is not allowed to turn on until

the voltage at the junction of the power FETs (BOOTLO) is low. The TTL-compatible DT terminal connects to

the junction of the power FETs.

ENABLE

The ENABLE terminal enables the drivers. When enable is low, the output drivers are low. ENABLE is a

TTL-compatible digital terminal.