VRE105/107 Precision Reference Supplies THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 85745 • (520) 882-4000 FEATURES APPLICATIONS • VERY HIGH ACCURACY: 5.000 V ±0.4 mV • PRECISION A/D and D/A CONVERTERS • EXTREMELY LOW DRIFT: 0.6 ppm/°C -55°C to +125°C • TRANSDUCER EXCITATION • EXCELLENT STABILITY: 6 ppm/1000 Hrs. Typ. • ACCURATE COMPARATOR THRESHOLD REFERENCE • EXCELLENT LINE REGULATION: 6 ppm/V Typ. • WIDE SUPPLY RANGE: ±13.5 V to ±22.0 V • HERMETIC 14-PIN CERAMIC DIP • MILITARY PROCESSING OPTION • HIGH RESOLUTION SERVO SYSTEMS • DIGITAL VOLTMETERS • HIGH PRECISION TEST and MEASUREMENT INSTRUMENTS DESCRIPTION VRE105 Series Precision Voltage References provide ultrastable +5.000 V (VRE105) and ±5.000 V (VRE107) outputs with ±0.4 mV initial accuracy and temperature coefficient as low as 0.6 ppm/°C over the full military temperature range. This impovement in accuracy is made possible by a unique, proprietary multipoint laser compensation technique developed by Thaler Corporation. Significant improvements have been made in other performance parameters as well, including initial accuracy, warm-up drift, line regulation, and long-term stability, making the VRE105 series the most accurate and stable 5V references available. SELECTION GUIDE Type Output VRE105C VRE105CA VRE105M VRE105MA +5V +5V +5V +5V Temperature Max. Volt Operating Range Deviation -25°C to +85°C 0.4mV -25°C to +85°C 0.2mV -55°C to +125°C 0.6mV -55°C to +125°C 0.3mV VRE107C VRE107CA VRE107M VRE107MA ±5V ±5V ±5V ±5V -25°C to +85°C -25°C to +85°C -55°C to +125°C -55°C to +125°C 0.4mV 0.2mV 0.6mV 0.3mV VRE105 series devices are available in two operating temperature ranges, -25°C to +85°C and -55°C to +125°C, and two performance grades. All devices are packaged in 14-pin hermetic ceramic packages for maximum long-term stablity. "M" versions are screened for high reliability and quality. Superior stability, accuracy, and quality make these references ideal for precision applications such as A/D and D/A converters, high accuracy test and measurement instrumentation, and tranducer excitation. VRE105DS REV. C SEPT 1994 4-32 ELECTRICAL SPECIFICATIONS VRE105/107 Vps =±15V, T = 25°C, RL = 10KΩ unless otherwise noted. MODEL C PARAMETERS MIN CA TYP MAX MIN M TYP MAX MIN MA TYP MAX MIN TYP MAX UNITS ABSOLUTE MAXIMUM RATINGS Power Supply ±13.5 ±22 Operating Temperature -25 85 Storage Temperature -65 150 Short Circuit Protection Continuous * * * * * * * -55 * * 125 * * -55 * * 125 * * * * * * * * * * V °C °C OUTPUT VOLTAGE VRE105 VRE107 +5 ±5 V V OUTPUT VOLTAGE ERRORS Initial Error Warmup Drift Tmin - Tmax (1) Long-Term Stability Noise (.1-10Hz) 800 400 2 800 1 400 200 6 3 400 2 1 600 * * 300 * * * * µV ppm µV ppm/1000hr. µVpp OUTPUT CURRENT Range ±10 * * * mA REGULATION Line Load 6 3 10 * * * * * * * * * ppm/V ppm/mA OUTPUT ADJUSTMENT Range Temperature Coefficient POWER SUPPLY CURRENTS 10 4 * * * * mV µV/°C/mV (2) VRE105 +PS VRE107 +PS VRE107 -PS NOTES: * * 5 7 4 7 9 6 * * * * * * * * * * * * * * * * * * mA mA mA *Same as C Models. 1.Using the box method, the specified value is the maximum deviation from the output voltage at 25°C over the specified operating temperature range. 2.The specified values are unloaded. VRE105DS REV. C SEPT 1994 4-32 TYPICAL PERFORMANCE CURVES VOUT vs. TEMPERATURE VOUT vs. TEMPERATURE VOUT vs. TEMPERATURE VOUT vs. TEMPERATURE Temperature oC VRE105/107C Temperature oC VRE105/107CA Temperature oC VRE105/107M Temperature oC VRE105/107MA VRE105 QUIESCENT CURRENT VS. TEMP Temperature oC JUNCTION TEMP. RISE VS. OUTPUT CURRENT Output Current (mA) PSRR VS. FREQUENCY Frequency (Hz) VRE107 POSITIVE OUTPUT QUIESCENT CURRENT VS. TEMP Temperature oC JUNCTION TEMP. RISE VS. OUTPUT CURRENT Output Current (mA) PSRR VS. FREQUENCY Frequency (Hz) NEGATIVE OUTPUT QUIESCENT CURRENT VS. TEMP Temperature oC JUNCTION TEMP. RISE VS. OUTPUT CURRENT Output Current (mA) PSRR VS. FREQUENCY Frequency (Hz) VRE105DS REV. C SEPT.1994 4-34 DISCUSSION OF PERFORMANCE THEORY OF OPERATION APPLICATION INFORMATION The following discussion refers to the schematic below. A FET current source is used to bias a 6.3V zener diode. The zener voltage is divided by the resistor network R1 and R2. This voltage is then applied to the noninverting input of the operational amplifier which amplifies the voltage to produce a 5.000V output. The gain is determined by the resistor networks R3 and R4: G=1 + R4/R3. The 6.3V zener diode is used because it is the most stable diode over time and temperature. Figure 1 shows the proper connection of the VRE105 series voltage reference with the optional trim resistors. When trimming the VRE107, the positive voltage should be trimmed first since the negative voltage tracks the positive side. Pay careful attention to the circuit layout to avoid noise pickup and voltage drops in the lines. The current source provides a closely regulated zener current, which determines the slope of the reference's voltage vs. temperature function. By trimming the zener current, a lower drift over temperature can be achieved. But since the voltage vs. temperature function is nonlinear, this method leaves a residual error over wide temperature ranges. To remove this residual error, Thaler Corporation has developed a nonlinear compensation network of thermistors and resistors that is used in the VRE105 series references. This proprietary network eliminates most of the nonlinearity in the voltage vs. temperature function. By then adjusting the slope, Thaler Corporation produces a very stable voltage over wide temperature ranges. This network is less than 2% of the overall network resistance so it has a negligible effect on long term stability. The VRE105 series voltage references have the ground terminal brought out on two pins (pin 6 and pin 7) which are connected together internally. This allows the user to achieve greater accuracy when using a socket. Voltage references have a voltage drop across their power supply ground pin due to quiescent current flowing through the contact resistance. If the contact resistance was constant with time and temperature, this voltage drop could be trimmed out. When the reference is plugged into a socket, this source of error can be as high as 20ppm. By connecting pin 7 to the power supply ground and pin 6 to a high impedance ground point in the measurement circuit, the error due to the contact resistance can be eliminated. If the unit is soldered into place the contact resistance is sufficiently small that it doesn't effect performance. VRE105 VRE107 VRE105DS REV. C SEPT 1994 4-35 EXTERNAL CONNECTIONS FIGURE 1 3. Optional Fine Adjust for approximately ±10mV. PIN CONFIGURATION TOP VIEW TOP VIEW NC FINE ADJ. NC +5V NC -5V FINE ADJ. VRE105 FINE +ADJ. FINE -ADJ. +5V FINE +ADJ. FINE -ADJ. VRE107 +PS +PS -PS NC NC NC NC REF. GND NC REF. GND NC GND NC NC GND NC MECHANICAL 14-PIN HYBRID PACKAGE INCHES MILLIMETER INCHES MILLIMETER DIM MIN MAX MIN MAX DIM MIN MAX MIN MAX E .480 .500 12.1 12.7 A .120 .155 3.0 4.0 L .195 .215 4.9 5.4 Q .015 .035 0.4 0.9 D .775 .805 19.7 20.4 Q1 N/A .030 N/A 0.7 B .016 .020 0.4 0.5 C .009 .012 0.2 0.3 B1 .038 .042 0.9 1.0 G1 .290 .310 7.3 7.8 B2 .095 .105 2.4 2.6 S .085 .105 2.1 2.6 P .004 .006 0.10 0.15 VRE105DS REV. C SEPT 1994 4-36