VRE107 VRE107 P r o VRE107 duct Innovation From Precision Voltage Reference FEATURES ♦ Very High Accuracy: ±5 V, ±0.8 mV ♦ Extremely Low Drift: 0.74 ppm/°C (-55°C to +125°C) ♦ Excellent Stability: 6 ppm/1000 Hrs. Typical ♦ Excellent Line Regulation: 6 ppm/V Typical ♦ Wide Supply Range: ±13.5 V to ±22 V ♦ Hermetic 14-pin Ceramic DIP ♦ Military Processing Option APPLICATIONS ♦ Precision A/D and D/A Converters ♦ Transducer Excitation ♦ Accurate Comparator Threshold Reference ♦ High Resolution Servo Systems ♦ Digital Voltmeters ♦ High Precision Test and Measurement Instruments DESCRIPTION VRE107 Series Precision Voltage References provide ultrastable ±5 V outputs with ±0.8 mV initial accuracy and temperature coefficient as low as 0.74 ppm/°C over the full military temperature range. This impovement in accuracy is made possible by a unique, proprietary multipoint laser compensation technique. 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 VRE107 series the most accurate and stable 5 V references available. VRE107 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. Figure 1. BLOCK DIAGRAM VRE107DS www.cirrus.com Copyright © Cirrus Logic, Inc. 2009 (All Rights Reserved) NOV 20091 APEX − VRE107DSREVE VRE107 Product Innovation From SELECTION GUIDE Model Output (V) Temperature Operating Range Volt Deviation (MAX) ±5 ±5 -55°C to +125°C -55°C to +125°C ±0.7mV ±0.6mV VRE107M VRE107MA 1. CHARACTERISTICS AND SPECIFICATIONS Hermetic 14-pin Ceramic DIP Package Style HC ELECTRICAL SPECIFICATIONS VPS =±15V, T = +25°C, RL = 10K Ω UNLESS OTHERWISE NOTED. Model Parameter VRE107M Min Typ VRE107MA Max Min Typ Max Units ABSOLUTE MAXIMUM RATINGS Power Supply ±13.5 ±22 * * V Operating Temperature -55 +125 * * ºC Storage Temperature -65 +150 * * ºC Short Circuit Protection Continuous * ±5 * OUTPUT VOLTAGE VRE107 V OUTPUT VOLTAGE ERRORS Initial Error ±900 Warmup Drift TMIN - TMAX ±800 2 (Note1) 1 700 µV ppm 600 µV Long-Term Stability 6 * ppm/1000hrs. Noise (0.1 - 10Hz) 3 * µVpp OUTPUT CURRENT Range ±10 * mA REGULATION Line 6 10 * * ppm/V Load 3 * ppm/mA Range 10 * mV Temperature Coefficient 4 * µV/ºC/mV OUTPUT ADJUSTMENT POWER SUPPLY CURRENT (Note 2) VRE107 +PS 7 9 * * mA VRE107 -PS 4 6 * * mA NOTES: * Same as M 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. 2 VRE107DS VRE107 Product Innovation From TYPICAL PERFORMANCE GRAPHS VOUT vs. TEMPERATURE 0.7 VOUT vs. TEMPERATURE 0.6 -0.6 -0.7 Temperature oC VRE107M Temperature oC VRE107MA 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) 2. THEORY OF OPERATION The following discussion refers to the block diagram in Figure 1. A FET current source is used to bias a 6.3 V 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 V output. The gain is determined by the resistor networks R3 and R4: G=1 + R4/R3. The 6.3 V zener diode is used because it is the most stable diode over time and temperature. 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, a nonlinear compensation network of thermistors and resistors is used in the VRE107 VRE107DS 3 VRE107 Product Innovation From series references. This proprietary network eliminates most of the nonlinearity in the voltage vs. temperature function. By then adjusting the slope, The VRE107 series 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. 3. APPLICATION INFORMATION The proper connection of the VRE107 series voltage reference is shown below 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 VRE107 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 20 ppm. 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. EXTERNAL CONNECTIONS PIN CONFIGURATION TOP VIEW FINE +ADJ. FINE -ADJ. -5V +5V FINE +ADJ. FINE -ADJ. -PS NC VRE107 +PS NC REF. GND NC GND NC 3. Optional Fine Adjust for approximately ±10mV. CONTACTING CIRRUS LOGIC SUPPORT For all Apex Precision Power product questions and inquiries, call toll free 800-546-2739 in North America. For inquiries via email, please contact [email protected]. International customers can also request support by contacting their local Cirrus Logic Sales Representative. To find the one nearest to you, go to www.cirrus.com IMPORTANT NOTICE Cirrus Logic, Inc. and its subsidiaries ("Cirrus") believe that the information contained in this document is accurate and reliable. However, the information is subject to change without notice and is provided "AS IS" without warranty of any kind (express or implied). Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. 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