LTZ1000

LTZ1000/LTZ1000A - Ultra Precision Reference

Document overview

• Manufacturer or author: Linear Technology Corporation
• PDF pages: 8

Technical content

1000afeFor more information www.linear .com/L TZ1000 Typical applicaTion

FeaTures

applicaTions

DescripTion

The LT Z1000 and LT Z1000A are ultra-stable temperature controllable references. They are designed to provide 7V outputs with temperature drifts of 0.05ppm/°C, about 1.2µVP-P of noise and long-term stability of 2µV/√kHr. Included on the chip is a subsurface zener reference, a heater resistor for temperature stabilization, and a tem - perature sensing transistor. External circuitry is used to set operating currents and to temperature stabilize the reference. This allows maximum flexibility and best long- term stability and noise. The LT Z1000 and LT Z1000A references can provide su - perior performance to older devices such as the LM199, provided that the user implements the heater control and properly manages the thermal layout. To simplify thermal insulation, the LT Z1000A uses a proprietary die attach method to provide significantly higher thermal resistance than the LT Z1000. Low Noise Reference n 1.2µVP-P Noise n 2µV/√kHr Long-Term Stability n Very Low Hysteresis n 0.05ppm/°C Drift n Temperature Stabilized n 400°C/W Thermal Resistance for LT Z1000A Reduces Insulation Requirements n Specified for –55°C to 125°C Temperature Range n Offered in TO-99 package n Voltmeters n Calibrators n Standard Cells n Scales n Low Noise RF Oscillators Long-Term Stability L, LT, LT C, LT M, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. L TZ1000 OUTPUT 1N4148 LT®1006 VIN ≥ 10V 30k 3 7 0.02µF120/uni03A9

1000 TA01

(ppm) LONG-TERM STABILITY OF A TYPICAL DEVICE FROM TIME = 0 WITH NO PRECONDITIONING OR AGING

1000 TA01b

1000afe For more information www.linear .com/L TZ1000 absoluTe MaxiMuM raTings Co C Emi V 55°C ≤ TA ≤ 125°C 65°C ≤ TA ≤ 150°C (Note 1)

elecTrical characTerisTics

Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. PARAMETER CONDITIONS MIN TYP MAX UNITS Zener Voltage lZ = 5mA, (VZ + VBEQ1) IQ1 = 100µA lZ = 1mA, (VZ + VBEQ1) IQ1 = 100µA 7.0 6.9 7.2 7.15 7.5 7.45 V V Zener Change with Current 1mA ≤ I Z < 5mA 80 240 mV Zener Leakage Current VZ = 5V 20 200 µA Zener Noise lZ = 5mA, 0.1Hz < f < 10Hz 1Q1 = 100µA 1.2 2 µV P-P Heater Resistance IL ≤ 100µA 200 300 420 Ω Heater Breakdown Voltage 35 V T ransistor Q1 Breakdown IC = 10µA, LVCEO 15 20 V T ransistor Q2 Breakdown IC = 10µA, LVCEO 35 50 V Q1, Q2 Current Gain IC = 100µA 80 200 450 Thermal Resistance LT Z1000 Time = 5 Minutes LT Z1000A Time = 5 Minutes 400 °C/W °C/W Long-T erm Stability T = 65°C 2 µV√kHr (Note 2) Note 2: All testing is done at 25°C. Pulse testing is used for LT Z1000A to minimize temperature rise during testing. LT Z1000 and LT Z1000A devices are QA tested at –55°C and 125°C. pin conFiguraTion BOTTOM VIEW H8 PACKAGE TO-5 METAL CAN 6 2 TJMAX = 150°C, LT Z1000CH: θJA = 80°C/W LT Z1000ACH: θJA = 400°C/W orDer inForMaTion LEAD FREE FINISH PART MARKING PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LT Z1000ACH#PBF LT Z1000ACH 8-Lead TO-5 Metal Can (.200 Inch PCD) –55°C to 125°C LT Z1000CH#PBF LT Z1000CH 8-Lead TO-5 Metal Can (.200 Inch PCD) –55°C to 125°C LEAD BASED FINISH PART MARKING PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LT Z1000ACH LT Z1000ACH 8-Lead TO-5 Metal Can (.200 Inch PCD) –55°C to 125°C LT Z1000CH LT Z1000CH 8-Lead TO-5 Metal Can (.200 Inch PCD) –55°C to 125°C Consult LT C Marketing for parts specified with wider operating temperature ranges. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ This product is only offered in trays. For more information go to: http://www.linear.com/packaging/

1000afeFor more information www.linear .com/L TZ1000 Typical perForMance characTerisTics Zener Voltage vs Current Zener Voltage Noise Spectrum Zener Noise Die Temperature Rise vs Heater Power Die Temperature vs Time Die Temperature Rise vs Time pin FuncTions Pin 1: Heater Positive. Must have a higher positive value than Pin 2 and Pin 4. Pin 2: Heater Negative. Must have a higher positive value than Pin 4. Must have equal or lower potential than Pin 1. Pin 3: Zener Positive. Must have a higher positive value than Pin 4. Pin 4: Substrate and Zener Negative. Must have a higher positive value than Pin 7. If Q1 is zenered (about 7V) a permanent degradation in beta will result. Pin 5: Temperature Compensating T ransistor Collector. Pin 6: Temperature Sensing T ransistor Base. If the base emitter junction is zenered (about 7V) the transistor will suffer permanent beta degradation. Pin 7: Emitter of Sensing and Compensating T ransistors. Pin 8: Collector of Sensing T ransistor. ZENER CURRENT (mA) ZENER VOL TAGE CHANGE (mV) 100 4.0 ZENER ALONE ZENER WITH KELVIN SENSED Q1

1000 G01

FREQUENCY (Hz) 0.1 200ZENER VOL TAGE NOISE (nV/√Hz) 250 300 350 400 1 10 100 150 100 450 500 ZENER CURRENT = 0.5mA ZENER CURRENT = 4mA

1000 G02

TIME (SECONDS) ZENER VOL TAGE NOISE (2µV/D) 10 20 30 40 50 60 IZ = 4mA IZ = 0.5mA

1000 G03

DIE TEMPERATURE ABOVE AMBIENT (°C) HEATER POWER (W) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 10545 65 85 1259535 55 75 115 L TZ1000 L TZ1000A

1000 G04

TIME (SECONDS) DIE TEMPERATURE RISE (°C) 125 100 0.1 10 100 1000 HEATER POWER = 0.1W HEATER POWER = 0.2W HEATER POWER = 0.3W L TZ1000A

1000 G05

TIME (SECONDS) DIE TEMPERATURE RISE (°C) 125 100 0.1 10 100 1000 HEATER POWER = 0.3W HEATER POWER = 0.7W L TZ1000

1000 G06

HEATER POWER = 0.5W

1000afe For more information www.linear .com/L TZ1000 applicaTions inForMaTion LT Z1000 and LT Z1000A are capable of providing ultimate voltage reference performance. Temperature drifts of better than 0.03ppm/°C and long-term stability on the order of 1µV per month can be achieved. Noise of about 0.15ppm can also be obtained. This performance is at the expense of circuit complexity, since external influences can easily cause output voltage shifts of more than 1ppm. Thermocouple effects are one of the worst problems and can give apparent drifts of many ppm/°C as well as cause low frequency noise. The kovar input leads of the TO-5 package form thermocouples when connected to copper PC boards. These thermocouples generate outputs of 35µV/°C. It is mandatory to keep the zener and transistor leads at the same temperature, otherwise 1ppm to 5ppm shifts in the output voltage can easily be expected from these thermocouples. Air currents blowing across the leads can also cause small temperature variations, especially since the package is heated. This will look like 1ppm to 5ppm of low frequency noise occurring over a several minute period. For best results, the device should be located in an enclosed area and well shielded from air currents. Certainly, any temperature gradient externally generated, say from a power supply, should not appear across the critical circuitry. The leads to the transistor and zener should be connected to equal size PC traces to equalize the heat loss and maintain them at similar temperatures. The bottom portion of the PC board should be shielded against air currents as well. Resistors, as well as having resistance temperature coef- ficients, can generate thermocouple effects. Some types of resistors can generate hundreds of microvolts of thermo- couple voltage. These thermocouple effects in the resistor can also interfere with the output voltage. Wire wound resistors usually have the lowest thermocouple voltage, while tin oxide type resistors have very high thermocouple voltage. Film resistors, especially Vishay precision film resistors, can have low thermocouple voltage. Ordinary breadboarding techniques are not good enough to give stable output voltage with the LT Z1000 family devices. For breadboarding, it is suggested that a small printed circuit board be made up using the reference, the amplifier and wire wound resistors. Care must be taken to ensure that heater current does not flow through the same ground lead as the negative side of the reference (emitter of Q1). Current changes in the heater could add to, or subtract from, the reference voltage causing errors with temperature. Single point grounding using low resistance wiring is suggested. block DiagraM 1 8 Q2 Q1 3 5 62 4 7 *SUBSTRATE DEVICES–DO NOT FORWARD BIAS

1000 TA07

1000afeFor more information www.linear .com/L TZ1000 Typical applicaTions Negative Voltage Reference L T1013 1N4148 1N4148 ZENER – FORCE ZENER – SENSE ZENER + SENSE 0.022µF 0.1µF 0.1µF V– ≥ 10V 6 6 400k* R4/R5 RATIO 100ppm = ∆R(/uni03A9) 0.012/uni03A9 7/uni03A9 7/uni03A9 ∆R = 0.01% Z 1ppm 0.3ppm 0.2ppm 1ppm *PROVIDES TEMPERATURE COMPENSATION, DELETE FOR L TZ1000A BOTH A1 AND A2 CONTRIBUTE LESS THAN 2µV OF OUTPUT DRIFT OVER A 50°C RANGE APPROXIMATE CHANGE IN REFERENCE VOL TAGE FOR A 100ppm CHANGE IN RESISTOR VALUES: 2N3904 10k V+ 15V GND L T1013 8 5 70k 13k 70k 120

1000 TA02

Setting Control Temperature The emitter-base voltage of the control transistor sets the stabilization temperature for the LT Z1000. With the values given in the applications, temperature is normally 60°C. This provides 15°C of margin above a maximum ambient of 45°C, for example. Production variations in emitter-base voltage will typically cause about ±10°C variation. Since the emitter-base voltage changes about 2mV/°C and is very predictable, other temperatures are easily set. Because higher temperatures accelerate aging and decrease long-term stability, the lowest temperature consistent with the operating environment should be used. The LT Z1000A should be set about 10°C higher than the LT Z1000. This is because normal operating power dissipation in the LT Z1000A causes a temperature rise of about 10°C. Of course both types of devices should be insulated from ambient. Several minutes of warm-up is usual. For applications not requiring the extreme precision or the low noise of the LT Z1000, Linear Technology makes a broad line of voltage references. Devices like the LT1021 can provide drifts as low as 2ppm/°C and devices such as the LM399A can provide drifts of 1ppm/°C. Only applica- tions requiring the very low noise or low drift with time of the LT Z1000 should use this device. See Application Notes AN-82 and AN-86 for further information. Consult the Linear Technology Applications department for additional help. applicaTions inForMaTion

1000afe For more information www.linear .com/L TZ1000 Adjusting Temperature Coefficient in Unstabilized Applications Typical applicaTions 120/uni03A9 L T1006 70k 15V 1N4148 VOUT+ 0.022µF 200/uni03A9* HEATER 1N4148

1 MIN

• PULSE HEATER ON AND OFF TO HEAT AND COOL THE REFERENCE. ADJUST R1 FOR MINIMUM VOL TAGE CHANGE THROUGH A TEMPERATURE CYCLE. THE –2mV/°C TEMPCO OF THE V BE CANCELS THE +2mV/°C TEMPCO OF THE ZENER. 1000 TA05 Averaging Reference Voltage for Lower Noise and Better Stability Improving Supply Rejection 1.6k VIN 15V 0.01% OUTPUT 1.6k 30/uni03A9* 30/uni03A9* 150/uni03A9 150/uni03A9 *R = kT q IC

1000 TA03

1.5k 150/uni03A9 SUPPL Y REJECTION AT VOUT2 = 3mV/V SUPPL Y REJECTION AT V OUT1 = 20mV/V VOUT2 VOUT1 50/uni03A9

1000 TA04

7V Positive Reference Circuit 2N3904 1N4148 1N4148 L T1013 L T1013 0.1µF 0.002µF 0.1µF 400k* 10k 13k 120/uni03A9 70k 70k ZENER – SENSE ZENER + SENSE GROUND ZENER – FORCE HEATER RETURN (TIED TO GROUND) V+ 15V *PROVIDES TC COMPENSATION, DELETE FOR L TZ1000A APPROXIMATE CHANGE IN REFERENCE VOL TAGE FOR A 100ppm (0.01%) CHANGE IN RESISTOR VALUES: R4/R5 RATIO ∆R(/uni03A9) 0.012/uni03A9 7/uni03A9 7/uni03A9 ∆R = 0.01% Z 1ppm 0.3ppm 0.2ppm 1ppm BOTH A1 AND A2 CONTRIBUTE LESS THAN 2µV OF OUTPUT DRIFT OVER A 50°C RANGE 1000 TA06

1000afeFor more information www.linear .com/L TZ1000 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

revision hisTory

REV DATE DESCRIPTION PAGE NUMBER D 4/12 Corrected thermal information on H8 package drawing Corrected Order Information table Updated Block Diagram to show substrate diode Added 1N4148 label to diode in application circuit Added LTC6655 to Related Parts table E 11/15 Web links added Correction to Block Diagram, resistor added to substrate diode Pin numbers corrected on Negative Voltage Reference diagram all (Revision history begins at Rev D)

1000afe For more information www.linear .com/L TZ1000 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417  LINEAR TECHNOLOGY CORPORATION 1987 LT 1115 REV E • PRINTED IN USA (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear .com/L TZ1000 relaTeD parTs PART NUMBER DESCRIPTION COMMENTS LM399 7V Precision Shunt Reference 0.2% Accuracy, 0.5ppm/°C Drift, 20µVRMS Noise LT1021 5V, 7V and 10V Precision Reference Available in T0-5, –55°C to 125°C, Series or Shunt Operation LT1236 5V and 10V Low Drift Precision Reference 0.05% Accuracy, 5ppm/°C Drift, Series or Shunt Operation LT1389 1.25V, 2.5V, 4V and 5V Nanopower Shunt Reference 800nA, 0.05% Accuracy, 10ppm/°C Drift LT1634 1.25V and 2.5V Micropower Shunt Reference 0.05%, 10ppm/°C, 10µA Current LTC6655 Precision Low Noise Reference Family 2ppm/°C, Maximum Drift, 650nVP-P Noise (0.1Hz to 10Hz) .050 (1.270) MAX .016 – .021** (0.406 – 0.533) .010 – .045* (0.254 – 1.143) SEATING PLANE .040 (1.016) MAX .165 – .185 (4.191 – 4.699) GAUGE PLANE REFERENCE PLANE .500 – .750 (12.700 – 19.050) .305 – .335 (7.747 – 8.509) .335 – .370 (8.509 – 9.398) DIA .200 (5.080) TYP .027 – .045 (0.686 – 1.143) .028 – .034 (0.711 – 0.864) .110 – .160 (2.794 – 4.064) INSULATING STANDOFF 45° H8(TO-5) 0.200 PCD 0204 LEAD DIAMETER IS UNCONTROLLED BETWEEN THE REFERENCE PLANE AND THE SEATING PLANE FOR SOLDER DIP LEAD FINISH, LEAD DIAMETER IS .016 – .024 (0.406 – 0.610) PIN 1 H Package 8-Lead TO-5 Metal Can (.200 Inch PCD) (Reference LTC DWG # 05-08-1320) package DescripTion Please refer to http://www.linear.com/product/LT Z1000#packaging for the most recent package drawings.