REF10 ® Precision VOLTAGE REFERENCE FEATURES DESCRIPTION ● +10.00V OUTPUT ● HIGH ACCURACY: ±0.005V Untrimmed The REF10 is a precision voltage reference which provides a +10.00V output. The drift is laser-trimmed to 1ppm/°C max (KM grade) over the full specification range. This is in contrast to some references which guarantee drift over a limited portion of their specification temperature range. The REF10 achieves its precision without a heater. This results in low quiescent current, fast warm-up, excellent stability, and low noise. ● VERY-LOW DRIFT: 1ppm/°C max ● EXCELLENT STABILITY: 10ppm/1000hrs typ ● LOW NOISE: 6µVp-p typ, 0.1Hz to 10Hz ● WIDE SUPPLY RANGE: Up to 35V APPLICATIONS ● PRECISION CALIBRATED VOLTAGE STANDARD ● TRANSDUCER EXCITATION ● D/A AND A/D CONVERTER REFERENCE ● PRECISION CURRENT REFERENCE The output can be adjusted with minimal effect on drift or stability. Single supply operation over 13.5V to 35V supply range and excellent overall specifications make the REF10 an ideal choice for the most demanding applications such as precision system standard, D/A and A/D references, transducer excitation, etc. ● ACCURATE COMPARATOR THRESHOLD REFERENCE ● DIGITAL VOLTMETERS ● TEST EQUIPMENT TIME STABILITY 5 R2 7kΩ 2 6 R1 12kΩ VZ +VCC VOUT R3 2kΩ 3 Voltage Change (ppm) VTRIM R4 156kΩ D21 70 60 50 40 30 20 10 0 –10 –20 –30 –40 –50 –60 –70 0 International Airport Industrial Park • Mailing Address: PO Box 11400 Tel: (520) 746-1111 • Twx: 910-952-1111 • Cable: BBRCORP • © 1984 Burr-Brown Corporation 1k 2k 3k Time (Hours) 4 Common • Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd. • Tucson, AZ 85706 Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 PDS-528B Printed in U.S.A October, 1993 SPECIFICATIONS ELECTRICAL TA = +25°C, and ±15VDC power supply, unless otherwise noted. REF10JM, KM, RM, SM PARAMETER OUTPUT VOLTAGE Initial Trim Range(1) vs Temperature(2): KM JM SM RM vs Supply (line regulation) vs Output Current (load regulation) vs Time(3) CONDITIONS MIN TYP MAX UNITS TA = +25°C 9.995 –0.100 10.000 0.001 0.001 10 10.005 +0.250 1 3 3 6 0.002 0.002 ±50 V V ppm/°C ppm/°C ppm/°C ppm/°C %/V %/mA ppm/1000hr 6 25 µVp-p 0°C to +70°C 0°C to +70°C –55°C to +125°C –55°C to +125°C VCC = 13.5 to 35V IL = 0 to ±10mA TA = +25°C NOISE 0.1Hz to 10Hz OUTPUT CURRENT Source or Sink ±10 INPUT VOLTAGE RANGE mA 13.5 QUIESCENT CURRENT IOUT = 0 4.5 WARM-UP TIME To 0.1% 10 TEMPERATURE RANGE Specification: JM, KM RM, SM Operating: JM, KM RM, SM Storage 35 V 6 mA µs 0 –55 –25 –55 –65 °C °C °C °C °C +70 +125 +85 +125 +125 NOTES: (1) Trimming the offset voltage will affect the drift slightly. See Installation and Operating Instructions for details. (2) The “box method” is used to specify output voltage drift vs temperature. See the Discussion of Performance section. (3) Sample tested with power applied continuously. ORDERING INFORMATION ABSOLUTE MAXIMUM RATINGS MODEL PACKAGE TEMPERATURE RANGE MAX DRIFT (ppm/°C) REF10JM REF10KM REF10RM REF10SM Metal TO-99 Metal TO-99 Metal TO-99 Metal TO-99 0°C to +70°C 0°C to +70°C –55°C to +125°C –55°C to +125°C 3 1 6 3 Input Voltage ........................................................................................ 40V Power Dissipation at +25°C ............................................................ 200mV Operating Temperature J, K .................................................................................. –25°C to +85°C R, S ............................................................................... –55°C to +125°C Storage Temperature Range .......................................... –65°C to +125°C Lead Temperature (soldering, 10s) ................................................ +300°C Short-Circuit Protection at +25°C to Common or +15VDC ........................................................ Continuous PACKAGE INFORMATION MODEL REF10JM REF10KM REF10RM REF10SM PACKAGE PACKAGE DRAWING NUMBER(1) 8-Pin Metal TO-99 8-Pin Metal TO-99 8-Pin Metal TO-99 8-Pin Metal TO-99 001 001 001 001 PIN CONFIGURATION TAB Top View NC 8 NC 1 NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix D of Burr-Brown IC Data Book. 7 NC +VCC 2 6 VOUT 5 Trim VZ(1) 3 4 Common NC = No Internal Connection. NOTE: (1) Pin 3 is an unbuffered 6.3V output. Any load will affect the output voltage and drift. A load of 1µA on pin 3 will typically change the output voltage by 50µV and the drift by 0.1ppm/°C. The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems. ® REF10 2 TYPICAL PERFORMANCE CURVES TA = +25°C, and ±15VDC power supply, unless otherwise noted. POWER TURN-ON RESPONSE RESPONSE TO THERMAL SHOCK 400 15 10 200 Output Voltage Cahnge (µV) Error From Final Value (mV) 20 5 0 –5 0 –200 –10 Device Immersed in +70°C Fluorinert Bath TA = +70°C TA = +25°C –400 –15 –20 0 Power Turn-On 5 10 15 20 Time (µs) JUNCTION TEMPERATURE RISE vs OUTPUT CURRENT POWER SUPPLY REJECTION vs FREQUENCY 100 Max temp rise for +85°C ambient 90 Junction Temperature Rise Above Ambient (°C) Power Supply Rejection (dB) 100 80 70 60 50 80 VCC = 35V Max temp rise for +125°C ambient 60 VCC = 25V 40 VCC = 20V VCC = 15V 20 40 0 30 0 100 1k 10k 100k 0 2 Frequency (Hz) 4 6 8 10 Output Current (mA) QUIESCENT CURRENT vs TEMPERATURE OUTPUT VOLTAGE ADJUSTMENT vs RS 5 10k Output Voltage Adjustment (mV) Quiescent Current (mA) VCC = 30V 4 3 2 1 See Optional Output Voltage Fine Adjust, Figure 4. 1k Voltage Increase 100 Voltage Decrease 10 1 –75 –50 –25 0 25 50 75 100 125 10k Temperature (°C) 100k 1M 10M 100M RS (Ω) ® 3 REF10 TYPICAL PERFORMANCE CURVES (CONT) TA = +25°C, and ±15VDC power supply, unless otherwise noted. TYPICAL HEATED ZENER NOISE Noise Voltage (µV) (Referred to Input) Noise Voltage (µV) (Referred to Input) TYPICAL REF10 NOISE 6 4 2 0 –2 –4 –6 6 4 2 0 –2 –4 –6 Low Frequency Noise (see Noise Test Circuit) Low Frequency Noise (see Noise Test Circuit) Noise Voltage (µV) (Referred to Input) TYPICAL BANDGAP REFERENCE NOISE 20Ω 6 2kΩ Oscilloscope 4 – 2 100µF 0 DUT 8KΩ OPA27 + 2µF –2 15.8kΩ –4 Gain = 100V/V f 3dB = 0.1Hz and 10Hz –6 NOISE TEST CIRCUIT Low Frequency Noise (see Noise Test Circuit) ® REF10 4 THEORY OF OPERATION VUPPER BOUND The following discussion refers to the diagram on the first page. Output Voltage (V) +10.0007 In operation, approximately 6.3V is applied to the noninverting input of op amp A1 by zener diode DZ1. This voltage is amplified by A1 to produce the 10.00V output. The gain is determined by R1 and R2: G = (R1 + R2)/R1. R1 and R2 are actively laser-trimmed to produce an exact 10.00V output. The zener operating current is derived from the regulated output voltage through R3. This feedback arrangement provides closely regulated zener current. R3 is actively laser-trimmed to set the zener current to a level which results in low drift at the output of A1. R4 allows usertrimming of the output voltage by providing for a small external adjustment of amplifier gain. Since the TCR of R4 closely matches the TCR of the gain setting resistors, the voltage trim has minimal effect on the drift of the reference. Typical Drift 700µV Worst-case ∆VOUT for REF10KM VNOMINAL +10.0000 Diagonal 1ppm/°C for REF10KM V2 VUPPER BOUND +9.9993 0 (TLOW) 25 Temperature (°C) 70 (THIGH) FIGURE 1. REF10KM Output Voltage Drift. INSTALLATION AND OPERATING INSTRUCTIONS DISCUSSION OF PERFORMANCE BASIC CIRCUIT CONNECTION Figure 2 shows the proper connection of the REF10. To achieve the specified performance, pay careful attention to layout. A low resistance star configuration will reduce voltage errors, noise pickup, and noise coupled from the power supply. Commons should be connected as indicated being sure to minimize interconnection resistances. The REF10 is designed for applications requiring a precision voltage reference where both the initial value at room temperature and the drift over temperature are of importance to the user. Two basic methods of specifying voltage reference drift versus temperature are in common usage in the industry—the “butterfly method” and the “box method.” The REF10 is specified with the more commonly used box method. The “box” is formed by the high and low specification temperatures and a diagonal, the slope of which is equal to the maximum specified drift. (1) 2 For the REF10, each J and K unit is tested at temperatures of 0°C, +25°C, +50°C, and +70°C. Each R and S unit is tested at –55°C, –25°C, 0°C, +25°C, +50°C, +75°C, +100°C and +125°C. The minimum and maximum test voltages must meet this condition: ( V1 (2) VCC + 1µF Tantalum 6 REF10 ) RL1 V OUT MAX – V OUT MIN / 10V 6 Drift X 10 ≤ Specification T – T HIGH LOW RL2 RL3 4 (2) (1) This assures the user that the variations of output voltage that occur as the temperature changes within the specification range, TLOW to THIGH, will be contained within a box whose diagonal has a slope equal to the maximum specified drift. Since the shape of the actual drift curve is not known, the vertical position of the box is not exactly known either. It is, however, bounded by VUPPER BOUND and VLOWER BOUND (see Figure 1). NOTES: (1) Lead resistances here of up to a few Ω have negligible effect on performance. (2) A resistance of 0.1Ω in series with these leads will cause a 1mV error when the load current is at its maximum of 10mA. This results in a 0.01% error of 10V. FIGURE 2. REF10 Installation. Figure 1 uses the REF10KM as an example. It has a drift specification of 1ppm/°C maximum and a specification temperature range of 0°C to +70°C. The “box” height (V1 to V2) is 700µV, and upper bound and lower bound voltages are a maximum of 700µV away from the voltage at +25°C. OPTIONAL OUTPUT VOLTAGE ADJUSTMENT Optional output voltage adjustment circuits are shown in Figures 3 and 4. Trimming the output voltage will change the voltage drift by approximately 0.01ppm/°C per mV of trimmed voltage. In the circuit in Figure 3, any mismatch in TCR between the two sections of the potentiometer will also ® 5 REF10 affect drift, but the effect of the ∆TCR is reduced by a factor of 40 by the internal resistor divider. A high quality potentiometer with good mechanical stability, such as a cermet, should be used. The circuit in Figure 3 has a range of approximately +250mV to –100mV. The circuit in Figure 4 has less range but provides higher resolution. The mismatch in TCR between RS and the internal resistors can introduce some slight drift. This effect is minimized if RS is kept significantly larger than the 156kΩ internal resistor. A TCR of 100ppm/°C is normally sufficient. A variety of application circuits are shown in Figures 5 through 11. +VCC 2 REF10 R 1kΩ 6 OPA27 VOUT = +10V C 100µF +VCC 4 + 1µF Tantalum 2 fCO = VOUT 1 2π RC = 1.6Hz FIGURE 5. Precision Reference with Filtering. 6 +10V REF10 +15V 20kΩ Output Voltage Adjust VTRIM 5 2 4 6 +10V Out REF10 Minimum range (+2.5%, –1.0%) and minimal degradation of drift. 2 5 FIGURE 3. REF10 Optional Output Voltage Adjust. 6 4 See Information in Typical Performance Curves +VCC + 1µF Tantalum 2 VOUT 6 1 3 The TCR of RS can affect VOUT drift if RS is made small. INA105 FIGURE 6. ±10V Reference. +10V REF10 VTRIM RS(1) 5 +VCC 20kΩ Output Voltage Adjust 2 4 NOTE: (1) RS typically 4MΩ. Higher resolution, reduced range. REF10 R 6 FIGURE 4. REF10 Optional Output Voltage Fine Adjust. APPLICATION INFORMATION 4 High accuracy, extremely-low drift, and small size make the REF10 ideal for demanding instrumentation and system voltage reference applications. Since no heater is required, low power supply current designs are readily achievable. Also the REF10 has lower output noise and much faster warm-up times than heated references, permitting high precision without extra power or additional supplies. It should be considered that operating any integrated circuit at an elevated temperature will reduce its MTTF. OPA111 IOUT = 10V R IOUT , R ≥ 1kΩ FIGURE 7. Positive Precision Current Source. ® REF10 6 –10V Out 35V to 55V +VCC 2 2 6 REF10 6 +30V +10V INA105 REF10 2 5 4 4 2 6 3 REF10 +5 +20V 6 EO = E1/2, ±0.01% 1 4 2 REF10 FIGURE 10. +5V and +10V Reference. +10V 6 +VCC = 24V 2 820Ω 4 REF10 NOTES: (1) REF10s can be stacked to obtain voltages in multiples of 10V. (2) The supply voltage should be between 10n +5 and 10n +25 where n is the number of REF10s. (3) Output current of each REF10 must not exceed its rated output current of ±10mA. This includes the current delivered to the lower REF10. 6 +10V 600Ω 4 600Ω ∆V 600Ω 600Ω FIGURE 8. Stacked References. 2 6 At 10V, the 600Ω bridge requires 16.7mA. An 820Ω resistor connected directly from the bridge to the positive supply provides the bulk of the bridge current. The REF10 need only supply an error current to keep the bridge at 10V. Since the REF10 can sink or source up to 10mA, the circuit shown can tolerate supply variations of up to 24V, ±8V, or bridge resistance drift from 400Ω to 1400Ω. +5V Out REF10 2 FIGURE 11. +10V Reference with Output Current Boost Using a Resistor to Drive a 600Ω Bridge. INA105 5 4 –5V Out 6 1 3 FIGURE 9. ±5V Reference. ® 7 REF10