R5

60kW

REF50xx

TEMP

V

OUT

GND

TRIM/NR

V

IN

aT

aT

(10 A

m

at+25 C)

°

R2

R1

R3

R4

10kW

1kW

1.2V

DNC

TEMP

V

OUT

V

IN

GND

DNC

NC

TRIM/NR

REF50xx

+V

SUPPLY

10kW

1kW

470kW

DNC

TEMP

V

OUT

V

IN

GND

DNC

NC

TRIM/NR

REF50xx

C

BYPASS

1 Fto10 F

m

m

C

L

1 Fto50 F

m

m

+V

SUPPLY

V

OUT

DNC

TEMP

V

OUT

V

IN

GND

DNC

NC

TRIM/NR

REF50xx

1 F

m

+V

SUPPLY

REF5010, REF5020

REF5025, REF5030

REF5040, REF5045, REF5050

SBOS410E – JUNE 2007 – REVISED JUNE 2010

www.ti.com

APPLICATION INFORMATION

The REF50xx is family of low-noise, precision

requirement

of

2.7V,

these

references

can

be

bandgap voltage references that are specifically

operated with a supply of 200mV above the output

designed for excellent initial voltage accuracy and

voltage

in

an

unloaded

condition.

For

loaded

drift. Figure 28 shows a simplified block diagram of

conditions, a typical dropout voltage versus load plot

the REF50xx.

is shown in Figure 6 of the Typical Characteristics.

OUTPUT ADJUSTMENT USING THE TRIM/NR

PIN

The

REF50xx

provides

a

very

accurate,

be adjusted using the trim and noise reduction pin

(TRIM/NR, pin 5). Figure 30 shows a typical circuit

that allows an output adjustment of ±15mV

Figure 28. REF50xx Simplified Block Diagram

BASIC CONNECTIONS

Figure 29 shows the typical connections for the

Pin

REF50xx.

A

supply

bypass

capacitor

ranging

between 1mF to 10mF is recommended. A 1mF to

The REF50xx allows access to the bandgap through

the TRIM/NR pin. Placing a capacitor from the

TRIM/NR pin to GND (see Figure 31) in combination

or equal to 1.5

Ω to ensure output stability. To

low-pass filter. A capacitance of 1mF creates a

between 1

Ω and 1.5Ω.

low-pass filter with the corner frequency between

10Hz and 20Hz. Such a filter decreases the overall

capacitance results in a lower filter cutoff frequency,

further reducing output noise. Note that use of this

capacitor increases startup time.

Figure 29. Basic Connections

SUPPLY VOLTAGE

The REF50xx family of voltage references features

extremely low dropout voltage. With the exception of

Figure 31. Noise Reduction Using the TRIM/NR

the

REF5020,

which

has

a

minimum

supply

Pin

10

Submit Documentation Feedback

Copyright © 2007–2010, Texas Instruments Incorporated

Product Folder Link(s): REF5010 REF5020 REF5025 REF5030 REF5040 REF5045 REF5050