Precision Voltage Reference FEATURES ♦ Very High Accuracy: +4.5 V Output, ±0.8 mV ♦ Extremely Low Drift: 1.48 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 to +22.0 V ♦ Hermetic 14-pin Ceramic DIP ♦ Military Processing Options ♦ 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 VRE104 Series Precision Voltage References provide ultrastable +4.5 V outputs with up to ±0.8 mV initial accuracy and temperature coefficient as low as 1.48 ppm/°C over the full military temperature range. These references are specifically designed to be used with the Crystal Semiconductor line of successive-approximation type Analog to Digital Converters (ADCs). This line of ADCs sets new standards for temperature drift, which can only be as good as the external reference used. The VRE104 combined with an ADC will provide the lowest drift data conversion obtainable. VRE104 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 stability. “M” versions are screened for high reliability and quality. Superior stability, accuracy, and quality make the VRE104 ideal for all precision applications which may require a 4.5 V reference. High-accuracy test and measurement instrumentation, and transducer excitation are some other applications which can benefit from the high accuracy of the VRE104. Figure 1. BLOCK DIAGRAM Copyright © Apex Microtechnology, Inc. 2012 (All Righ

VRE104 SELECTION GUIDE Output (V) Temperature Operating Range Hermetic 14-pin Ceramic DIP Package Style HC 1. CHARACTERISTICS AND SPECIFICATIONS ELECTRICAL SPECIFICATIONS VPS =+15V, T = 25°C, RL = 10K Ω UNLESS OTHERWISE NOTED. Grade ABSOLUTE MAXIMUM RATINGS Power Supply Operating Temperature Storage Temperature Short Circuit Protection OUTPUT VOLTAGE ERRORS Initial Error Warmup Drift TMIN - TMAX Long-Term Stability OUTPUT CURRENT Range REGULATION Line Temperature Coefficient OUTPUT ADJUSTMENT POWER SUPPLY CURRENT (Note 2) VRE104 +PS NOTES: * Same as C Models. 1. Using the box method, the specified...

2. TYPICAL PERFORMANCE GRAPHS QUIESCENT CURRENT VS. TEMP JUNCTION TEMP. RISE VS. OUTPUT CURRENT PSRRVS. FREQUENCY 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 noninvert- ing input of the operational amplifier which amplifies the voltage to produce a 4.5 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 overtime and temperature....

The proper connection of the VRE104 series voltage references is shown below with the optional trim resistors. Pay careful attention to the circuit layout to avoid noise pickup and voltage drops in the lines. The VRE104 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...

NEED TECHNICAL HELP? CONTACT APEX SUPPORT! For all Apex Microtechnology 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 Apex Microtechnology Sales Representative. To find the one nearest to you, go to www.apexanalog.com IMPORTANT NOTICE Apex Microtechnology, Inc. has made every effort to insure the accuracy of the content contained in this document. However, the information is subject to change without notice and is provided...