Datasheet

LP2980
1 PF
Input
Voltage
ON /
OFF
V
IN
V
OUT
V
OUT
= 0V to 5V
DAC101C081/5
0.1 PF
SDA
SCL
V
REF
V
A
1 PF
0.1 PF
Input
Voltage
0.01 PF
V
OUT
= 0V to 5V
DAC101C081/5
0.1 PF
LP3985
SDA
SCL
V
REF
V
A
DAC101C081, DAC101C081Q, DAC101C085
SNVS801A –APRIL 2012–REVISED MARCH 2013 www.ti.com
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 DAC101C081. It comes in 3.0V, 3.3V and
5V versions, among others, and sports a low 30 µV noise specification at low frequencies. Since 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 32. Using the LP3985 Regulator
An input capacitance of 1.0µF without any ESR requirement is required at the LP3985 input, while a 1.0µF
ceramic capacitor with an ESR requirement of 5mΩ to 500mΩ is required at the output. Careful interpretation
and understanding of the capacitor specification is required to ensure correct device operation.
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 3.0V, 3.3V and 5V versions, among others.
Figure 33. Using the LP2980 Regulator
Like any low dropout regulator, the LP2980 requires an output capacitor for loop stability. This output capacitor
must be at least 1.0µF over temperature, but values of 2.2µF or more will provide even better performance. The
ESR of this capacitor should be within the range specified in the LP2980 data sheet. Surface-mount solid
tantalum capacitors offer a good combination of small size and ESR. Ceramic capacitors are attractive due to
their small size but generally have ESR values that are too low for use with the LP2980. Aluminum electrolytic
capacitors are typically not a good choice due to their large size and have ESR values that may be too high at
low temperatures.
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