TPS70445, TPS70448, TPS70451, TPS70458, TPS70402

DUAL-OUTPUT LOW-DROPOUT VOLTAGE REGULATORS

WITH INTEGRATED SVS FOR SPLIT VOLTAGE SYSTEMS

SLVS307B – SEPTEMBER 2000 – REVISED APRIL 2003

28

POST OFFICE BOX 655303

APPLICATION INFORMATION

input capacitor

For a typical application, a ceramic input bypass capacitor (0.22

µF – 1 µF) is recommended to ensure device

stability. This capacitor should be as close to the input pins as possible. Due to the impedance of the input supply,

large transient currents cause the input voltage to droop. If this droop causes the input voltage to drop below

the UVLO threshold, the device turns off. Therefore, it is recommended to place a larger capacitor in parallel

with the ceramic bypass capacitor at the regulator’s input. The size of this capacitor is dependent upon the

output current, response time of the main power supply, and the main power supply’s distance to the regulator.

At a minimum, the capacitor should be sized to ensure that the input voltage does not drop below the minimum

UVLO threshold voltage during normal operating conditions.

output capacitor

As with most LDO regulators, the TPS704xx requires an output capacitor connected between each OUT and

and the ESR (equivalent series resistance) must be between 50 m

Ω and 800 mΩ. The minimum recommended

aluminum electrolytic, and multilayer ceramic capacitors are all suitable, provided they meet the requirements

described above. Larger capacitors provide a wider range of stability and better load transient response. Below

is a partial listing of surface-mount capacitors usable with the TPS704xx for fast transient response application.

This information, along with the ESR graphs, is included to assist in selection of suitable capacitance for the

user’s application. When necessary to achieve low height requirements along with high output current and/or

high load capacitance, several higher ESR capacitors can be used in parallel to meet the guidelines above.

VALUE

MFR.

PART NO.

680

µF

Kemet

T510X6871004AS

470

µF

Sanyo

4TPB470M

150

µF

Sanyo

4TPC150M

220

µF

Sanyo

2R5TPC220M

100

µF

Sanyo

6TPC100M

68

µF

Sanyo

10TPC68M

68

µF

Kemet

T495D6861006AS

47

µF

Kemet

T495D4761010AS

33

µF

Kemet

T495C3361016AS

22

µF

Kemet

T495C2261010AS