LM78L datasheet(21/42 Pages) TI2

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*Solid tantalum

VO = VG + 5V, R1 = (–VIN / IQ(LM78L05))

VO = 5V (R2 / R4) for (R2 + R3) = (R4 + R5)

A 0.5V output corresponds to (R2 / R4) = 0.1, (R3 / R4) = 0.9

Figure 7-9. Variable Output Regulator Circuit (0.5V to 18V)

7.3 Power Supply Recommendations

The linear regulator input supply must not exceed the maximum input voltage allowed by the device. The

minimum input voltage required to maintain line regulation (VIN(MIN)) must be met with extra headroom when

possible to keep the output well regulated.

While not required, TI recommends a 0.33µF or higher capacitor be placed at the input to counteract the effect of

source resistance and inductance, which can in some cases cause symptoms of system level instability such as

ringing or oscillation, especially in the presence of load transients.

7.4 Layout

7.4.1 Layout Guidelines

Place bypass capacitors as close to the LM78Lxx as possible.

Keep traces short and wide to reduce the amount of parasitic elements in the system, especially at the input

and output pins. The actual length and thickness of traces depends on the current carrying capability and heat

dissipation required by the end system.

Additional copper and vias connected to ground facilitate additional thermal dissipation, improving the effective

thermal resistance of the device and preventing the device from reaching thermal overload. With PCB board

layout optimization, RθJA can be improved by 35% to 55% compared to the values found in the Thermal

Information table. See the An empirical analysis of the impact of board layout on LDO thermal performance

application note for more details.

www.ti.com

LM78L

SNVS754M – JANUARY 2000 – REVISED FEBRUARY 2026

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LM78L Datasheet(PDF) 21 Page - Texas Instruments