LM338 datasheet(7/12 Pages) LINER

7 / 12 page

LT138A/LT338A

LM138/LM338

APPLICATIONS INFORMATION

negative side of the load. Although it may not be immedi-

ately obvious, best load regulation is obtained when the

top of the resistor divider, R1, is connected

directly to the

case

not to the load. This is illustrated in Figure 3. If R1

were connected to the load, the effective resistance be-

tween the regulator and the load would be:

Parasitic Line

sis









tan

Connected as shown, RP is not multiplied by the divider

ratio. RP is about 0.004Ω per foot using 16 gauge wire.

This translates to 4mV/ft at 1A load current, so it is

important to keep the positive lead between regulator and

load as short as possible, and use large wire or PC board

traces.

LT338A

PARASITIC

LINE RESISTANCE

VIN

CONNECT

R1 TO CASE

CONNECT

R2 TO LOAD

138A/338A F03

VOUT

ADJ

VIN

Figure 3. Connections for Best Load Regulation

TYPICAL APPLICATIONS

Improving Ripple Rejection

LT338A

VIN

121

Ω

365

Ω

µF

*C1 IMPROVES RIPPLE REJECTION, XC

SHOULD BE SMALL COMPARED TO R2

CL*

µF

138A/338A TA03

VOUT

ADJ

VIN

1.2V to 25V Adjustable Regulator

LT338A

VIN

240

Ω

C1*

µF

NEEDED IF DEVICE IS FAR FROM FILTER CAPACITORS

OPTIONAL, IMPROVES TRANSIENT RESPONSE

138A/338A TA04

VOUT

ADJ

VOUT

†

VIN

C2**

µF

†VOUT = 1.25V

1 +

()

LM338 Arkusz danych(PDF) 7 Page - Linear Technology

LM338 Arkusz danych(HTML) 7 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12

Arkusz danych Pobierz

Link URL