Datasheet

TPS7A3401

SBVS163 –JUNE 2011

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APPLICATION INFORMATION

POWER FOR PRECISION ANALOG

DC/DC converters are generally the preferred

One of the primary TPS7A3401 applications is to solution to step up or down a voltage rail when

provide low-noise voltage rails to analog circuitry in current consumption is not negligible. They offer high

order to improve system accuracy and precision. efficiency with minimum heat generation, but they

have one primary disadvantage: they introduce a

The TPS7A3401 negative high-voltage linear

high-frequency component, and the associated

regulator provides a low-noise voltage rail to analog

harmonics, on top of the dc output signal.

circuitry, such as operational amplifiers, ADCs, and

DACs. This high-frequency component, if not filtered

properly, degrades analog circuitry performance,

Because of the low noise levels at high voltages,

reducing overall system accuracy and precision.

analog circuitry with high-voltage input supplies can

be used. This characteristic allows for analog The TPS7A3401 offers a wide-bandwidth, high

solutions to optimize the voltage range, thereby power-supply rejection ratio (PSRR). It is highly

maximizing system accuracy. recommended to use the maximum performance

schematic shown in Figure 18. Also, verify that the

fundamental frequency (and its first harmonic, if

POST DC/DC CONVERTER FILTERING

possible) is within the bandwidth of the regulator

Most of the time, the voltage rails available in a

PSRR, shown in Figure 15.

system do not match the voltage specifications

demanded by one or more of its circuits; these rails

must be stepped up or down, depending on specific

voltage requirements.