Datasheet

Table Of Contents

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Setup

Test Points

DLYAB Power Good Delay for Buck Controller A and B

GND (x4) Ground

PGA Power Good for Buck Controller A

PGB Power Good for Buck Controller B

PHA Buck Controller A phase pin

PHB Buck Controller B phase pin

SSA Soft Start for Buck Controller A

SSB Soft Start for Buck Controller B

VBAT Power Input

VIN Power Input after the reverse-polarity protection stage

VOUTA Buck Controller A output

VOUTB Buck Controller B output

2.2 Setup

The input voltage range for the device is from 4V-40V. At start-up, minimum input voltage is 6.5V. With the

settings of the EVM, for Buck B (set to 3.3V output) an input voltage of 4V is sufficient (after meeting the

start-up condition). Buck A, set to 5V output, naturally requires a higher supply voltage for proper

operation.

2.3 Operation

For proper operation of the TPS4335x, ENA, ENB, EXTSUP, RT and SYNC jumpers should be properly

configured. The recommended setting, using the switch and shorting blocks.

ENA enabled

ENB enabled

EXTSUP A

RT 400KHz

SYNC LPM

In this configuration, the regulators will turn on when power is applied. Delay sets the power-on reset

delay, slow, medium or fast. ENA and ENB turn the regulators on or off, disabled or enabled. EXTSUP

selects the power supply source for the gate drive. RT sets the switching frequency for the regulators to

approximately 240KHz, 400KHz or 600KHz. SYNC enabled LPM or forced continuous conduction mode

and is the external clock input for switching frequency synchronization of the buck converters. SYNC will

disable spread spectrum operation on the TPS43351-Q1 when set low or left open. The device can be

setup to run in low power mode, to reduce the quiescent operating current, by connecting the Sync test

point to ground. Low power mode will allow the device to switch into a PFM mode of operation if the load

current demand is low. It will automatically switch back to PWM mode as the load current increases.

Table 2. Regulator Configuration

OUTPUT MAXIMUM OUTPUT

REGULATOR

VOLTAGE CURRENT

Buck Controller A 5.0 V 2A

Buck Controller B 3.3 V 4A

SLVU484–June 2011 TPS4335xEVM Evaluation Module

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