TPS22981

SLVSBM6B – DECEMBER 2012 – REVISED NOVEMBER 2015

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Typical Application (continued)

8.2.1 Design Requirements

As the TPS22981 switches high-current levels, it is essential that all parallel output, power, and ground pins be

connected. For example, ground connections must be provided on all ground pins including pins 1, 2, 3, 13, 15,

and EP (the exposed package pad); both OUT pins (pins 12 and 14) must be connected; and so forth.

RSET_S0, RSET_S3, and RSET_V3P3 must be determined using Equation 1. Unused inputs may not be left

floating and should be connected to either ground or V3P3 depending on desired behavior.

8.2.2 Detailed Design Procedure

Design with TPS22981 is recommended as follows:

•

Determine suitable current limits for the low-voltage and high-voltage output levels (output provided on the

OUT pin). If S0 is being used, determine both high-voltage output levels and current-limiting values.

•

Determine values for the resistors to be applied to pins ISET_V3P3, ISET_S3, and ISET_S0 using Equation 1

and the desired current limits determined above.

•

If the FAULTZ output is being used, place a minimum 30-k

Ω resistor (100-kΩ recommended) between

FAULTZ and the V3P3.

9 Power Supply Recommendations

Power supply current capability should be suitable with respect to the maximum current limit levels selected (and

programmed with pins ISET_V3P3, ISET_S3, and ISET_S0).

VHV and V3P3 must be properly decoupled. A minimum 0.1-µF capacitor to ground is recommended as close to

the V3P3 pin as possible. VHV should be suitably decoupled based on the supply compliance and maximum

current levels anticipated. Inductance in the VHV line can result in overvoltage situations on the VHV pin when

loads are disconnected. Refer to the Input Inductive Bounce section and ensure that inductance levels,

capacitive decoupling, and current switching levels are designed to keep power supply voltage levels within

recommended operating conditions at all times.

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