REF53

GND

REF_S

IN

EN

CREF

VIN

IL * RL + VREF

CIN

REF_F

GND

R

I

Q

I = V

REF / R

LOAD

I

L = I + IQ

Figure 9-4. REF53-Q1 Configuration as Constant Current Source

Table 9-2 shows the measured results as per the design shown in Figure 9-4.

Table 9-2. Constant Current Source Results

VREF

R

CALCULATED CURRENT

MEASURED CURRENT

1.25V

1.4kΩ

0.978mA

0.998mA

1.25V

127Ω

9.93mA

9.98mA

1.25V

62Ω

20.24mA

20.33mA

9.3 Power Supply Recommendation

The REF53-Q1 family of references features a low-dropout voltage. These references can operate with a supply

of only 250mV above the output voltage for 5mA output current conditions at room temperature. TI recommends

a supply bypass capacitor ranging from 0.1µF to 10µF. REF53-Q1 family have excellent PSRR which relaxes the

requirement of clean power supply for the designer.

During start-up the REF53-Q1 can experience moments of high input current due to the output capacitors. The

input current can momentarily rise to short-circuit current ISC.

9.4 Layout

9.4.1 Layout Guidelines

• Place the power-supply bypass capacitor as close as possible to the supply and ground pins. The

recommended value of this bypass capacitor is from 0.1μF to 10μF. If necessary, add additional decoupling

capacitance to compensate for noisy or high-impedance power supplies. Place the smallest capacitor closest

to the device.

• The output must be decoupled with a from 1μF to 100μF low ESR capacitor.

• Connect the REF_S (sense) to the REF_F (force) pin externally through a trace. Short these traces close

to the point of load. Make sure the sense signal path is low resistance and is not exposed to high noise

generating devices on the board.

www.ti.com

REF53-Q1

SNVSCU8 – AUGUST 2026

Copyright © 2026 Texas Instruments Incorporated

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Product Folder Links: REF53-Q1