1 LTZ1000/LTZ1000A . Ultra Precision Reference Features Description n VP-P Noise The LTZ1000 and LTZ1000A are Ultra -stable temperature n 2 V/ kHr Long-Term Stability controllable references. They are designed to provide 7V. n Very Low Hysteresis outputs with temperature drifts of C, about n C Drift VP-P of noise and long-term stability of 2 V/ kHr. n Temperature Stabilized n 400 C/W Thermal Resistance for LTZ1000A Reduces Included on the chip is a subsurface zener Reference , a heater resistor for temperature stabilization, and a tem- Insulation Requirements n Specified for 55 C to 125 C Temperature Range perature sensing transistor. External circuitry is used to n Offered in TO-99 package set operating currents and to temperature stabilize the Reference .
2 This allows maximum flexibility and best long- term stability and noise. Applications The LTZ1000 and LTZ1000A references can provide su- n Voltmeters perior performance to older devices such as the LM199, n Calibrators provided that the user implements the heater control and n Standard Cells properly manages the thermal layout. To simplify thermal n Scales insulation, the LTZ1000A uses a proprietary die attach n Low Noise RF Oscillators method to provide significantly higher thermal resistance than the LTZ1000. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical Application Low Noise Reference Long-Term Stability 2.
3 LTZ1000 VIN 10V. OUTPUT. 30k 7 1N4148. 3. +. 6. (ppm). LT 1006 0. 2.. 4. 120 F. 2. 1000 TA01 0 10 20 30. DAYS. LONG-TERM STABILITY OF A TYPICAL DEVICE FROM TIME = 0. WITH NO PRECONDITIONING OR AGING. 1000 TA01b 1000afe For more information 1. LTZ1000/LTZ1000A . Absolute Maximum Ratings Pin Configuration (Note 1). Heater to BOTTOM VIEW. Collector Emitter Breakdown 8. Collector Emitter Breakdown 7. Q2. 1. Emitter Base Reverse Operating Temperature 55 C TA 125 C 6 2. Storage Temperature 65 C TA 150 C Q1. 7V. Substrate Forward 5 3. 4. H8 PACKAGE. TO-5 METAL CAN. TJMAX = 150 C, LTZ1000CH: JA = 80 C/W. LTZ1000 ACH: JA = 400 C/W. Order Information LEAD FREE FINISH PART MARKING PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE. LTZ1000 ACH#PBF LTZ1000 ACH 8-Lead TO-5 Metal Can (.)
4 200 Inch PCD) 55 C to 125 C. LTZ1000CH#PBF LTZ1000CH 8-Lead TO-5 Metal Can (.200 Inch PCD) 55 C to 125 C. LEAD BASED FINISH PART MARKING PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE. LTZ1000 ACH LTZ1000 ACH 8-Lead TO-5 Metal Can (.200 Inch PCD) 55 C to 125 C. LTZ1000CH LTZ1000CH 8-Lead TO-5 Metal Can (.200 Inch PCD) 55 C to 125 C. Consult LTC Marketing for parts specified with wider operating temperature ranges. For more information on lead free part marking, go to: This product is only offered in trays. For more information go to: Electrical (Note Characteristics 2). PARAMETER CONDITIONS MIN TYP MAX UNITS. Zener Voltage lZ = 5mA, (VZ + VBEQ1) IQ1 = 100 A V. lZ = 1mA, (VZ + VBEQ1) IQ1 = 100 A V. Zener Change with Current 1mA IZ < 5mA 80 240 mV.
5 Zener Leakage Current VZ = 5V 20 200 A. Zener Noise lZ = 5mA, < f < 10Hz 2 VP-P. 1Q1 = 100 A. Heater Resistance IL 100 A 200 300 420 . Heater Breakdown Voltage 35 V. Transistor Q1 Breakdown IC = 10 A, LVCEO 15 20 V. Transistor Q2 Breakdown IC = 10 A, LVCEO 35 50 V. Q1, Q2 Current Gain IC = 100 A 80 200 450. Thermal Resistance LTZ1000 Time = 5 Minutes 80 C/W. LTZ1000A Time = 5 Minutes 400 C/W. Long-Term Stability T = 65 C 2 V kHr Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 2: All testing is done at 25 C. Pulse testing is used for LTZ1000A to may cause permanent damage to the device. Exposure to any Absolute minimize temperature rise during testing. LTZ1000 and LTZ1000A devices Maximum Rating condition for extended periods may affect device are QA tested at 55 C and 125 C.
6 Reliability and lifetime. 1000afe 2 For more information LTZ1000/LTZ1000A . Typical Performance Characteristics Zener Voltage vs Current Zener Voltage Noise Spectrum Zener Noise 100 500. IZ = 4mA. 90 450. ZENER VOLTAGE NOISE (nV/ Hz). ZENER VOLTAGE NOISE (2 V/D). ZENER VOLTAGE CHANGE (mV). 80 400. ZENER ALONE. 70 350. 60 300. 50 250 IZ = ZENER CURRENT = 40 200. 30 150. 20 100. ZENER WITH KELVIN. ZENER CURRENT = 4mA. 10 SENSED Q1 50. 0 0. 0 1 10 100 0 10 20 30 40 50 60. ZENER CURRENT (mA) FREQUENCY (Hz) TIME (SECONDS). 1000 G01. 1000 G02 1000 G03. Die Temperature Rise vs Heater Power Die Temperature vs Time Die Temperature Rise vs Time 125 125. LTZ1000A LTZ1000. 100 HEATER POWER = 100. DIE TEMPERATURE RISE ( C). DIE TEMPERATURE RISE ( C).
7 HEATER POWER (W). LTZ1000. 75 75 HEATER POWER = HEATER POWER = 50 HEATER POWER = 50. LTZ1000A. 25 25. HEATER POWER = HEATER POWER = 0 0 0. 25 35 45 55 65 75 85 95 105 115 125 1 10 100 1000 1 10 100 1000. DIE TEMPERATURE ABOVE AMBIENT ( C) TIME (SECONDS) TIME (SECONDS). 1000 G06. 1000 G05. 1000 G04. Pin Functions Pin 1: Heater Positive. Must have a higher positive value Pin 5: Temperature Compensating Transistor Collector. than Pin 2 and Pin 4. Pin 6: Temperature Sensing Transistor Base. If the base Pin 2: Heater Negative. Must have a higher positive value emitter junction is zenered (about 7V) the transistor will than Pin 4. Must have equal or lower potential than Pin 1. suffer permanent beta degradation. Pin 3: Zener Positive. Must have a higher positive value Pin 7: Emitter of Sensing and Compensating Transistors.
8 Than Pin 4. Pin 8: Collector of Sensing Transistor. 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. 1000afe For more information 3. LTZ1000/LTZ1000A . Block Diagram 1 8 3 5. *. Q2 Q1. *. *. 2 6 4 7. *SUBSTRATE DEVICES DO NOT FORWARD BIAS. 1000 TA07. Applications Information LTZ1000 and LTZ1000A are capable of providing ultimate should be connected to equal size PC traces to equalize voltage Reference performance. Temperature drifts of better the heat loss and maintain them at similar temperatures. than C and long-term stability on the order of The bottom portion of the PC board should be shielded 1 V per month can be achieved.
9 Noise of about against air currents as well. can also be obtained. This performance is at the expense Resistors, as well as having resistance temperature coef- of circuit complexity, since external influences can easily ficients, can generate thermocouple effects. Some types of cause output voltage shifts of more than 1ppm. resistors can generate hundreds of microvolts of thermo- Thermocouple effects are one of the worst problems and couple voltage. These thermocouple effects in the resistor can give apparent drifts of many ppm/ C as well as cause can also interfere with the output voltage. Wire wound low frequency noise. The kovar input leads of the TO-5 resistors usually have the lowest thermocouple voltage, package form thermocouples when connected to copper while tin oxide type resistors have very high thermocouple PC boards.
10 These thermocouples generate outputs of voltage. Film resistors, especially Vishay Precision film 35 V/ C. It is mandatory to keep the zener and transistor resistors, can have low thermocouple voltage. leads at the same temperature, otherwise 1ppm to 5ppm Ordinary breadboarding techniques are not good enough shifts in the output voltage can easily be expected from to give stable output voltage with the LTZ1000 family these thermocouples. devices. For breadboarding, it is suggested that a small Air currents blowing across the leads can also cause small printed circuit board be made up using the Reference , the temperature variations, especially since the package is amplifier and wire wound resistors. Care must be taken to heated. This will look like 1ppm to 5ppm of low frequency ensure that heater current does not flow through the same noise occurring over a several minute period.