REF81 Temperature Controlled Precision Voltage Reference with 0.05ppm/°C

Temperature Drift and < 1ppm Stability

1 Features

• Buried zener core 7.6V output

• Industry standard fixed output voltage

– 1X gain: 2.5V, 4.096V, 5V

– 2X gain: 5V, 8.192V, 10V

• No external buffer for 1X and 2X gain output

• Industry standard fixed output initial accuracy

– 1X gain: ±0.05%

– 2X gain: ±0.1%

• Ultra-low temperature drift: 0.05ppm/°C

• Operating temperature range: 0°C to 70°C

• Excellent long term stability: 0.3ppm (1khr to 5khr)

• 1/f noise (0.1Hz to 10Hz) : 0.12ppmpk-pk

• Integrated heater with temperature stable indicator

• Input Voltage range: 10V to 16.5V

• Heater supply range: 10V to 42V

• Hermetically sealed ceramic package (20-pin

LCCC)

2 Applications

• Parametric measurement unit

• Lab and field instrumentation

• Precision weight scales

• Battery test equipment

• Digital multimeter

• Source measurement unit

• Data acquisition

3 Description

The REF81 device utilizes precision buried zener

core with integrated heater to generate stable

7.6V.

The

device

further

integrates

precision

resistor dividers and a buffer to offer industry

standard voltage references to drive precision data

converters. Integrated temperature control with an

internal heater enables the reference voltage to

stay constant irrespective of ambient temperature

variations and achieve extremely low temperature

drift of 0.05ppm/°C. The integration of control loop,

precision resistances, and buffer enables ease of

design and eliminates need of external precision

components.

The REF81 family is available in a 20-pin LCCC

package. The LCCC package is a hermetically sealed

ceramic package that enables ultra low long-term

stability specification of 1ppm, which is critical for

applications that demand a longer operational window

without calibration. The package also offers excellent

immunity against humidity variation.

Package Information

PART NAME

PACKAGE (1)

PACKAGE SIZE (2)

REF81

NAJ (LCCC, 20)

8.89mm × 8.89mm

(1)

For all available packages, see Mechanical, Packaging, and

Orderable Information.

(2)

The package size (length × width) is a nominal value and

includes pins, where applicable.

OP-STBL

T-SET

REF_GND

HEATM

Heater

Regulator

Buried Zener

Reference

RTOP

RBOT

+

–

VDD

BUFF_GND

R

GAIN_RFB

GAIN_RI

R

BUFF_OUT

+15V

10V

-15V

Stable Temp

Indicator

1X Gain

3.3V

0.5X Gain

REF81 Block Diagram (With Typical External Connections)

REF81

SLVSJJ3A – JULY 2025 – REVISED JULY 2026

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.