UA78L05CLPR datasheet(21/49 Pages) TI

21 / 49 page

8 Applications and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

8.1 Application Information

The UA78L series is designed for use as a linear regulator with only a few external components needed. The

UA78L can also be used to clean power-supply noise by attenuating ripple on the input signal.

8.2 Typical Application

The UA78L series is typically used as a fixed-output linear regulator, sourcing current up to 100 mA into a load.

UA78L00

INPUT

OUTPUT

COMMON

0.33 μF

0.1 μF

GND

Figure 8-1. Fixed-Output Regulator

8.2.1 Design Requirements

The COMMON pin must be tied to ground to set the OUTPUT pin to the desired fixed output voltage.

Although not required, a 0.33-µF bypass capacitor is recommended on the input, and a 0.1-µF bypass capacitor

is recommend on the output.

8.2.2 Detailed Design Procedure

8.2.2.1 Input and Output Capacitor Requirements

Although both input and output capacitor are not required for stability, good analog design practice is to

connect a capacitor from IN to COMMON and from OUT to COMMON. The input capacitor counteracts reactive

input sources and improves transient response, input ripple, and PSRR. Use an input capacitor if the source

impedance is more than 0.5 Ω. A higher value capacitor can be necessary if large, fast rise-time load or line

transients are anticipated or if the device is located several inches from the input power source.

Dynamic performance of the device is improved with the use of a large output capacitor. Use an output capacitor

within the range specified in the Recommended Operating Conditions table for stability.

8.2.2.2 Power Dissipation (PD)

Circuit reliability requires consideration of the device power dissipation, location of the circuit on the printed

circuit board (PCB), and correct sizing of the thermal plane. The PCB area around the regulator must have few

or no other heat-generating devices that cause added thermal stress.

To first-order approximation, power dissipation in the regulator depends on the input-to-output voltage difference

and load conditions. The following equation calculates power dissipation (PD).

PD = (VI – VO) × IO

(1)

www.ti.com

UA78L

SLVS010W – JANUARY 1976 – REVISED APRIL 2023

Submit Document Feedback

Product Folder Links: UA78L

UA78L05CLPR 数据表(PDF) 21 Page - Texas Instruments

UA78L05CLPR 数据表(HTML) 21 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

数据表下载