DIA7965

Version 1.0, Dec 2023

www.dioo.com

© 2023 DIOO MICROCIRCUITS CO., LTD.

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9. Function Description

The DIA7965 series of LDO linear regulators are ultra-high PSRR and low noise devices with excellent line and

load transient performance. These LDOs are designed for power-sensitive applications. A precision bandgap

and error amplifier provide overall ±2% accuracy. Low output noise, very high PSRR, and low dropout voltage

make this device ideal for most battery-operated handheld equipment. The DIA7965 is fully protected in case of

current overload, output short circuit, and overheating.

9.1. Input capacitor selection (CIN)

The DIA7965 is specifically designed to work with a standard ceramic input capacitor. An Input capacitor

connected as close as possible is necessary to ensure device stability. The X7R or X5R capacitor should be

used because of its minimal variation in values and equivalent series resistance (ESR) over temperature. The

value of the input capacitor should be 1 µF or larger to ensure the optimum dynamic performance. This capacitor

will provide a low impedance path for unwanted AC signals or noise modulated onto constant input voltage.

There is no requirement for the ESR of the input capacitor but it is recommended to use ceramic capacitors for

their low ESR and ESL. A good input capacitor will limit the influence of input trace inductance and source

resistance during sudden load current changes.

9.2. Output capacitor selection (COUT)

The DIA7965 requires an output capacitance, and the value of the input capacitor should be 1 µF or larger for

stability. Use X5R and X7R ceramic capacitors because of its minimal variation in value and equivalent series

resistance (ESR) over temperature. Select a minimum effective capacitance of 0.7 μF for COUT, considering

capacitance changes with temperature, DC bias and package size. A capacitance of 0.7 μF or higher can satisfy

the requirement of all levels of VIN, VOUT, and load.

Larger output capacitors and lower ESR could improve the load transient response or high frequency PSRR. It is

not recommended to use tantalum capacitors on the output due to their large ESR. The equivalent series

resistance of tantalum capacitors is also strongly dependent on the temperature, increasing at low temperatures.

9.3. Enable operation

The DIA7965 uses the EN pin to enable or disable its device and discharge function (just for DIA7965A). If the

EN pin voltage is pulled below 0.4 V, the device is guaranteed to be disabled. The active discharge transistor in

the devices with the active discharge feature is activated and the output voltage VOUT is pulled to GND through

an internal circuitry with an effective resistance of about 100 Ω.

If the EN pin voltage is higher than 1.0 V the device is guaranteed to be enabled. The internal active discharge

circuitry is switched off and the desired output voltage is available at the output pin. In case of the enable

function is not required, the EN pin should be connected directly to the input pin.