VRE306
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VRE306 Precision Voltage Reference FEATURES • • • • • • +6 V Output, ± 0.6 mV (0.01%) Temperature Drift: 0.6 ppm/°C Low Noise: 4 μVP-P (0.1-10 Hz) Industry Standard Pinout: 8-pin Surface Mount Package Excellent Line Regulation: 6 ppm/V Typical Output Trim Capability APPLICATIONS The VRE306 is recommended for use as a reference for 14, 16, or 18 bit D/A converters which require an external precision reference. The device is also ideal for calibrating scale factor on high resolution A/D converters. The VRE306 offers superior performance over monolithic references. DESCRIPTION The VRE306 is a low cost, high precision +6 V reference. Available in an industry standard 8-pin surface mount package, the device is ideal for upgrading systems that use lower performance references. The device provides ultrastable +6 V output with ±0.6 mV (0.01%) initial accuracy and a temperature coefficient of 0.6 ppm/°C. This improvement in accuracy is made possible by a unique, patented 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 VRE306 series the most accurate reference available in a standard 8-pin SMT package. For enhanced performance, the VRE306 has an external trim option for users who want less than 0.01% initial error. For ultra low noise applications, an external capacitor can be attached between the noise reduction pin and the ground pin. A reference ground pin is provided to eliminate socket contact resistance errors. SELECTION GUIDE Model VRE306AS Temp. Coeff. (ppm/°C) © Apex Microtechnology Inc. All rights reserved

TYPICAL CONNECTION Figure 1: Typical Connection Noise Reduction Fine Trim

VRE306 SPECIFICATIONS VIN = +15 V, T = +25°C, RL = 10 kΩ unless otherwise noted. ABSOLUTE MAXIMUM RATINGS Parameter Power Supply Operating Temperature Storage Temperature Short Circuit Protection ELECTRICAL SPECIFICATIONS Parameter Output Voltage Temp. Sensor Voltage 1 Initial Error Warmup Drift TMIN - TMAX Long-Term Stability Noise (0.1 - 10Hz) Output Current Line Regulation Load Regulation Output Adjustment Power Supply Current, +PS 1. The temp. reference TC is 2.1 mV/ °C 2. The specified values are without external trim. 3. The temperature coefficient (TC) is determined by the box method...

TYPICAL PERFORMANCE GRAPHS Figure 2: VOUT vs. Temperature Figure 3: Power Supply Current vs. Figure 4: Junction Temp. Rise vs Output Current Figure 5: PSSRRvs. Frequency

VRE306 BLOCK DIAGRAM Figure 6: Block Diagram VIN THEORY OF OPERATION The following discussion refers to the block diagram in Figure 6. 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 6.0V 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...

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 4 to the power supply ground and pin 7 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 does not effect performance. Pay careful attention to the circuit layout to avoid noise pickup and voltage drops in the lines.

PACKAGE OPTIONS 1. Dimensions ore inches & [millimeters], 2. Bracketed alternate units are for reference only. 3. Pins: Phosphor bronze, Sn/Ag 96/4 solder dipped. 4. Material: Alumina Ceramic substrate and cover. 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 apex.support@apexanalog.com. International customers can also request support by contacting their local Apex Microtechnology Sales Representative. To find the one nearest to you, IMPORTANT...