ADR1000

ADR1000 (Rev.C)

Document overview

• Manufacturer or author: Analog Devices, Inc.
• PDF pages: 10

Technical content

Oven-Compensated, Buried Zener, 6.62 V Voltage Reference Rev. C DOCUMENT FEEDBACK TECHNICAL SUPPORT

FEATURES

►High long-term stability ►0.5 ppm/year long-term drift, typical (after first 3000 hours) ►Low Zener reference noise: 0.14 ppm p-p (0.9 µV p-p) ►Low temperature coefficient: <0.2 ppm/°C ►On-chip heater and temperature sensor ►Specified for −40°C to +125°C operation ►Pin‐ compatible upgrade to LTZ1000

APPLICATIONS

►High accuracy instrumentation ►Multimeters ►Weigh scales ►Electric balance ►Automatic test equipment ►Metrology equipment ►Standard cells ►Calibrators FUNCTIONAL BLOCK DIAGRAM Figure 1. GENERAL DESCRIPTION The ADR1000 is a 6.62 V, output highly stable, oven-controlled, buried Zener reference component built on an Analog Devices, Inc., proprietary bipolar process and is a pin-compatible replacement for the LTZ1000. Included on the chip is a buried Zener reference, a heater resistor for temperature stabilization, and a temperature sensing transistor. External circuitry is used to set the operating cur- rents and the temperature of the reference, allowing the maximum flexibility to achieve maximum long-term stability and minimum noise. The ADR1000 application circuit can achieve a temperature coeffi- cient of <0.2 ppm/°C and a long-term drift of 0.5 ppm per year (typical) after the first 3000 hours when properly implemented with the recommended external circuitry shown in Figure 9 and with the recommended layout. The low long-term drift of the ADR1000 is well suited for any appli- cation that must maintain accuracy over long calibration intervals or product lifetime. The low thermal drift ensures the output is constant with temperature variation because the on‑ chip heater of the ADR1000 maintains a constant temperature higher than the expected ambient range. The ADR1000 is specified for operation over the extended industrial temperature range of −40°C to +125°C. To obtain the optimal thermal drift performance, the temperature set point of the heater needs to be 10°C higher than the maximum ambient temperature to provide optimum stability of the buried Zener reference. The ADR1000 comes packaged in an industry-standard, 8-pin TO-99 metal can package that is hermetically sealed to resist the effects of humidity. Table 1. Related Products

analog.com Rev. C | 2 of 10

REVISION HISTORY

7/2026—Rev. B to Rev. C

analog.com Rev. C | 3 of 10

ELECTRICAL CHARACTERISTICS

TA = 25°C, unless otherwise noted. Table 2. Parameter Symbol Test Conditions/Comments Min Typ Max Unit ZENER REFERENCE VOLTAGE (VBZ1 + VBEQ1)1 VREF Zener current (IBZ1) = 5 mA, CQ1 current (ICQ1) = 100 µA 6.57 6.62 6.67 V IBZ1 = 1 mA, ICQ1 = 100 µA 6.54 6.59 6.64 V ZENER LEAKAGE CURRENT IZ Zener voltage (VZ) = 5 V 1 1.5 µA ZENER REFERENCE NOISE (VZ + VBEQ1) eN p-p IBZ1 = 5 mA, ICQ1 = 100 µA, 0.1 Hz < f < 10 Hz 0.14 ppm p-p 0.9 µV p-p eN IBZ1 = 5 mA, ICQ1 = 100 µA f = 0.1 Hz 300 nV/√Hz f = 10 Hz 30 nV/√Hz f = 1 kHz 24 nV/√Hz HEATER RESISTANCE RHTR Heater current (IHEATER) = 1 mA 230 242 255 Ω BREAKDOWN VOLTAGE Heater BVHTR IHEATER < 10 µA to Pin 4 (IZSET) 70 80 V Transistor Q1 BVCEO ICQ1 < 10 µA 15 18 V Transistor Q2 BVCEO CQ2 current (ICQ2) < 10 µA 28 39 V CURRENT GAIN Q1 hFE_Q1 ICQ1 = 100 µA, VCE = 600 mV 280 400 620 A/A Q2 hFE_Q2 ICQ1 = 100 µA, VCE = 600 mV 190 300 410 A/A TEMPERATURE COEFFICIENT TCVREF Using the circuit shown in Figure 9 with the <0.2 ppm/°C recommended layout THERMAL HYSTERESIS ΔVREF_TH IBZ1 = 5 mA, ICQ1 = 100 µA, ΔTA = 100°C 1 ppm 6.62 µV THERMAL RESISTANCE θJA Time = 5 minutes 216 °C/W LONG-TERM DRIFT ΔVREF_LTD IBZ1 = 5 mA, ICQ1 = 100 µA, TA = 25°C, chip set temperature (TSET) = 75°C 200 hours (early life drift) 8.9 ppm 1000 hours 7.7 ppm 2000 hours 6.6 ppm 3000 hours 6.2 ppm 1 year (after first 3000 hours) 0.5 ppm 1 VBZ1 is the buried Zener diode voltage, and VBEQ1 is the base emitter voltage of the temperature compensating transistor.

ing conditions for extended periods may affect product reliability. environment. Close attention to PCB thermal design is required. Table 4. Thermal Resistance1 devices and circuit boards can discharge without detection. taken to avoid performance degradation or loss of functionality.

Figure 2. Pin Configuration Table 5. Pin Function Descriptions 1 HTR+ Heater Positive. HTR+ must have a higher positive value than HTR− (Pin 2) and IZSET (Pin 4). 2 HTR− Heater Negative. HTR− must have a higher positive value than IZSET (Pin 4) and must have equal or lower potential than HTR+ (Pin 1). 3 VREF Zener Positive. VREF must have a higher positive value than IZSET (Pin 4). 4 IZSET Substrate and Zener Negative. IZSET must have a higher positive value than GND (Pin 7). 5 CQ1 Temperature Compensating Transistor Collector (Q1). 6 BQ2 Temperature Sensing Transistor Base (Q2). 7 GND Emitter of Sensing and Compensating Transistors. 8 CQ2 Collector of Sensing Transistor (Q2).

TSET is the heated chip temperature. IZ is the desired Zener current. 7 Ω is the bulk resistance to the Zener anode. current of ICQ1 = 100 µA, and results are shown in Figure 5. a few millidegrees over a 100°C ambient temperature change. satisfied is the chip set temperature (TSET). Table 6. Recommended Values for Varying the Set Temperature in 5° Increments

Legal Terms and Conditions Information furnished by Analog Devices is believed to be accurate and reliable "as is". However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. All Analog Devices products contained herein are subject to release and availability. analog.com Rev. C | 10 of 10 Package Drawing Option Package Type Package Description H-08 TO-99 8-Pin Metal Header For the latest package outline information and land patterns (footprints), go to Package Index. Updated: June 07, 2026 ORDERING GUIDE Model1 Temperature Range Package Description Packing Quantity Package Option ADR1000AHZ -40°C to +125°C 8-Pin TO-99 BOX, 100 H-08-1 1 Z = RoHS Compliant Part.