R5

60kW

REF5025

TEMP

V

OUT

GND

TRIM/NR

V

IN

aT

aT

(10mA

at +25°C)

R2

R1

R3

R4

10kW

1kW

1.2V

DNC

TEMP

V

OUT

V

IN

GND

DNC

NC

TRIM/NR

REF5025

+V

SUPPLY

10kW

1kW

470W

DNC

TEMP

V

OUT

V

IN

GND

DNC

NC

TRIM/NR

REF5025

C

BYPASS

1 F to 10 F

m

m

C

L

1 F to 50 F

m

m

+V

SUPPLY

V

OUT

DNC

TEMP

V

OUT

V

IN

GND

DNC

NC

TRIM/NR

REF5025

C1

1 F

m

+V

SUPPLY

REF5025-HT

www.ti.com

SBOS502D – SEPTEMBER 2009 – REVISED APRIL 2012

APPLICATION INFORMATION

The REF5025 is a low-noise, precision bandgap

voltage reference that is specifically designed for

USING THE TRIM/NR PIN

excellent initial voltage accuracy and drift. Figure 24

The REF5025 provides a very accurate voltage

shows a simplified block diagram of the REF5025.

noise and shift the output voltage from the nominal

value by configuring the trim and noise reduction pin

(TRIM/NR, pin 5). The TRIM/NR pin provides a ±15-

mV

adjustment

of

the

device

bandgap,

which

Figure 26 shows a typical circuit using the TRIM/NR

temperature coefficients of the resistors can degrade

the temperature drift at the output.

Figure 24. REF5025 Simplified Block Diagram

BASIC CONNECTIONS

Figure 25 shows the typical connections for the

REF5025.

A

supply

bypass

capacitor

ranging

between 1

μF to 10 μF is recommended. A 1-μF to

The REF5025 allows access to the bandgap through

50-

the TRIM/NR pin. Placing a capacitor from the

TRIM/NR pin to GND (as Figure 27 illustrates) in

be less than or equal to 1.5

Ω. The ESR minimizes

combination with the internal 1-k

Ω resistor creates a

gain peaking of the internal 1.2-V reference and thus

low-pass filter that lowers the overall noise measured

for a low-pass filter with a corner frequency of

14.5 Hz. Higher capacitance results in a lower cutoff

frequency.

Figure 25. Basic Connections

SUPPLY VOLTAGE

Figure 27. Noise Reduction Using TRIM/NR Pin

The

REF5025

features

extremely

low

dropout

voltage. For loaded conditions, a typical dropout

voltage versus load plot is shown in Figure 8 of

Typical Characteristics.

Copyright © 2009–2012, Texas Instruments Incorporated

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