Datasheet

Table Of Contents

Background and EVM Limitations

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1 Background and EVM Limitations

The TPS65258 PMIC is designed to provide 3A , 2A and 2A continuous outputs with an operational range

of 4.5 to 16V and a externally set switching frequency ranging from 300kHz to 2.2MHz, with automatic

PFM/PWM operation . When the PMIC is not fully loaded, buck1 can be loaded to 3.5A and buck 2 and 3

to 2.5A. The device also features two USB distribution switches.

As there are many possible options to set the converters, table 1 presents the performance specification

summary for the EVM.

Table 1. Input Voltage and Output Current Summary

Evaluation Module Test Conditions Output Current Range

Buck1, 1.2 V, 3A

Vin = 4.5 V to 15 V Buck2, 1.8 V, 3A

TPS65258EVM

Fsw = 500 KHz Buck3, 3.3 V, 3A

(25°C ambient)

This evaluation module is designed to provide access to the features of the TPS65258. Some

modifications can be made to this module to test performance at different input and output voltages,

current and frequency operation. Please contact TI Field Applications Group for advice on these matters.

2 Power-up Procedure

1. Define which converters are to be enabled or disabled by connecting jumpers to JP3, JP11 and JP20

accordingly, or to wiring external drive signals to the ENx headers.

2. If PGOOD signal is required connect JP27 or wire the PGOOD pin to a pull-up supply

3. Define the strategy to enable the USB switches, either with jumpers or external drive signals to the

USBENx pins

4. If USBx_nFAULT signals are required connect JP26 and J35 jumpers or wire the alarms pin to a

pull-up supply

5. Connect loads to the output connectors.

6. Apply a DC voltage to header J3. Polarity is marked on the silk-screen.

7. Converters will start according to the setting on JP3, JP11 and JP20. Check the outputs 8. To power

the USB switches apply a DC voltage to JP4 and JP5. Enable the switches with JP5 and JP34. Check

the outputs

3 TPS65258EVM Schematic

The resistor and capacitor values have been chosen according to the guidelines presented on the

TPS65258 spec that will be available at

http://focus.ti.com/docs/prod/folders/print/TPS65258.html

Note that for the purpose of gains-phase measurements R14, R17 and R37 (zero ohm on the EVM) need

to be replaced by suitable low value resistors as per the network analyzer setup required. Test points

connections are provided on either end of the resistors to allow for easy measurement.

TPS65258 High Current, Synchronous Step Down Three Buck Switcher SLVU569–September 2011

Evaluation Module with Two USB Switches

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