OUT

NC

EN

IN

GND

BIAS

1

2

3

6

5

4

COUT

CIN

CBIAS

To Bias Supply

To Input Supply

To Load

To Enable

Signal

Ground Plane

Ground Plane

17

TPS720

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SBVS100E – JUNE 2008 – REVISED SEPTEMBER 2015

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9 Power Supply Recommendations

The input supply and bias supply for the LDO must be within its recommended operating conditions and provide

adequate headroom for the device to have a regulated output. The minimum capacitor requirements must be

met, and if the input supply is noisy, then additional input capacitors with low ESR can help improve transient

performance.

10 Layout

10.1 Layout Guidelines

To improve AC performance such as PSRR, output noise, and transient response, TI recommends designing the

board with separate ground planes for VIN and VOUT, with the ground plane connected only at the GND pin of the

device. In addition, the ground connection for the output capacitor should be connected directly to the GND pin of

the device. High equivalent series resistance (ESR) capacitors may degrade PSRR. The BIAS pin draws very

little current and can be routed as a signal (make sure to shield it from high-frequency coupling).

10.2 Layout Example

Figure 33. Recommended Layout

10.3 Thermal Considerations

Thermal protection disables the output when the junction temperature rises to approximately 160°C, allowing the

device to cool. When the junction temperature cools to approximately 140°C, the output circuitry is again

enabled. Depending on power dissipation, thermal resistance, and ambient temperature, the thermal protection

circuit may cycle on and off. This cycling limits the dissipation of the regulator, protecting it from damage as a

result of overheating.