LP2980

1 PF

Input

Voltage

ON /OFF

DAC124S085

DIN

SCLK

SYNC

0.1 PF

1 PF

0.1 PF

Input

Voltage

0.01 PF

DAC124S085

DIN

SCLK

SYNC

0.1 PF

LP3985

22

DAC124S085

SNAS348G – MAY 2006 – REVISED APRIL 2016

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Copyright © 2006–2016, Texas Instruments Incorporated

Using References as Power Supplies (continued)

(4)

and

where

•

temperature

•

•

•

(5)

10.1.3 LP3985

The LP3985 is a low-noise, ultra-low dropout voltage regulator with a 3% accuracy over temperature. It is a good

choice for applications that do not require a precision reference for the DAC124S085. It comes in 3.0-V, 3.3-V,

and 5-V versions, among others, and sports a low 30-µV noise specification at low frequencies. Because low

frequency noise is relatively difficult to filter, this specification could be important for some applications. The

LP3985 comes in a space-saving 5-pin SOT-23 and 5-bump DSBGA packages.

Figure 39. LP3985 Regulator

An input capacitance of 1 µF without any ESR requirement is required at the LP3985 input, while a 1-µF ceramic

capacitor with an ESR requirement of 5 m

Ω to 500 mΩ is required at the output. Careful interpretation and

understanding of the capacitor specification is required to ensure correct device operation.

10.1.4 LP2980

The LP2980 is an ultra-low dropout regulator with a 0.5% or 1.0% accuracy over temperature, depending upon

grade. It is available in 3.0-V, 3.3-V, and 5-V versions, among others.

Figure 40. LP2980 Regulator