VRE305AD

VRE305 Precision Voltage Reference RoHS COMPLIANT FEATURES • • • • • • +5V Output, ± 0.5mV (0.01%) Temperature Drift: 0.6ppm/°C Low Noise: 3μVP-P (0.1-10 Hz) Industry Standard Pinout: 8-pin DIP or Surface Mount Package Excellent Line Regulation: 6ppm/V Typical Output Trim Capability APPLICATIONS The VRE305 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 VRE305 offers superior performance over monolithic references. DESCRIPTION The VRE305 is a low cost, high precision +5V reference. Packaged in an industry standard 8-pin DIP or SMT, the device is ideal for upgrading systems that use lower performance references. The device provides ultrastable +5V output with ±0.5mV (0.01%) initial accuracy and a temperature coefficient of 0.6ppm/°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 VRE305 series the most accurate reference available in a standard 8-pin DIP or SMT. For enhanced performance, the VRE305 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 VRE305AD VRE305AS VRE305CD VRE305CS www.apexanalog.com Initial Error (mV) Temp. Coeff. (ppm/°C) Temp Range (°C) Package Options 0.5 0.5 1.0 1.0 0.6 0.6 2.0 2.0 0°C to +70°C 0°C to +70°C 0°Cto +70°C 0°C to +70°C DIP8 (KD) SIP8 (GD) DIP8 (KD) SIP8 (GD) © Apex Microtechnology Inc. All rights reserved Nov 2020 VRE305DS Rev L VRE305 TYPICAL CONNECTION Figure 1: Typical Connection PIN DESCRIPTIONS 2 Pin Number Name Description 1 No connection. 2 NC VIN The supply voltage connection. 3 4 5 6 7 8 TEMP GND TRIM OUT REF_GND NOISE Provides voltage proportional to package temperature for monitoring purposes. Ground. Optional fine adjustment. Connect to a voltage divider between OUT and GND. 5V output. Provided for accurate ground sensing. Internally connected to GND. Optional noise reduction. Connect a 1µF capacitor between this pin and GND. VRE305DS Rev L VRE305 SPECIFICATIONS VIN= +15V, T = +25°C, RL = 10 kΩ unless otherwise noted. ABSOLUTE MAXIMUM RATINGS Parameter Power Supply Operating Temperature Storage Temperature Short Circuit Protection Soldering Temperature (10 sec max) AS/AD CS/CD Units Min Typ Max Min Typ Max +13.5 0 -65 +15 +22 +70 +150 * * * * * * * V °C °C * °C Continuous * +260 ELECTRICAL SPECIFICATIONS Parameter AS/AD Min Typ CS/CD Max Min Typ Max Units Output Voltage +5.0 * V Temp. Sensor Voltage 1 630 * mV Initial Error 2 Warmup Drift TMIN - TMAX 0.5 1.00 1 3 3 0.6 mV ppm 2.0 ppm/°C Long-Term Stability 6 * ppm/1000hrs. Noise (0.1 - 10 Hz) 4 Output Current Line Regulation Load Regulation Output Adjustment 3 * µVpp Power Supply Current, +PS 5 ±10 * 6 3 10 10 * * * * 5 7 * * mA ppm/V ppm/mA mV mA 1. The temp. coefficient is -2.1mV/ °C. 2. The specified values are without external trim 3. The temperature coefficient (TC) is determined by the box method using the following formula: V MAX – V MIN 6 TC = ----------------------------------------------------------------------  10 V NOMINAL   T MAX – T MIN  4. The specified values are without the external noise reduction capacitor. 5. The specified values are unloaded. Note: * Same as AS/AD models. VRE305DS Rev L 3 VRE305 TYPICAL PERFORMANCE GRAPHS Figure 3: VOUT vs. Temperature (VRE305C) 1.00 1.00 0.75 0.75 0.50 0.50 Upper Limit 0.25 ѐVOUT (mV) ѐVOUT (mV) Figure 2: VOUT vs. Temperature (VRE305A) 0 Upper Limit 0.25 0 -0.25 -0.25 Lower Limit -0.50 -0.50 -0.75 -0.75 -1.00 -1.00 0 20 30 40 50 60 70 Lower Limit 0 20 30 Figure 4: Power Supply Current vs. Temp. 70 40 :ƵŶĐƟŽŶdĞŵƉĞƌĂƚƵƌĞ ZŝƐĞďŽǀĞŵďŝĞŶƚ;ΣͿ Quiescent Current (mA) 60 Figure 5: Junction Temp. Rise vs. Output Current 7.0 6.0 5.0 4.0 -50 0 50 Temperature (°C) 4 50 Temperature (°C) Temperature (°C) 3.0 40 100 30 5V =1 C VC 20 10 0 0 2 4 6 8 10 Output Current (mA) VRE305DS Rev L VRE305 Figure 6: PSRR vs. Frequency 120 100 PSRR (dB) 80 60 40 20 0 10 100 1k 10k 100k 1M 10M Frequency (Hz) VRE305DS Rev L 5 VRE305 BLOCK DIAGRAM Figure 7: Block Diagram VIN VOUT THEORY OF OPERATION The following discussion refers to the block diagram in Figure 8. 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 5V 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. The current source provides a closely regulated Zener current, which determines the slope of the references’ 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 compensation technique is not well suited for wide temperature ranges. A nonlinear compensation network of thermistors and resistors is used in the VRE series voltage references. This proprietary network eliminates most of the nonlinearity in the voltage vs. temperature function. By adjusting the slope, a very stable voltage is produced 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 proper connection of the VRE305 series voltage references with the optional trim resistor for initial error and the optional capacitor for noise reduction is shown in Figure 1. The VRE305 reference has the ground terminal brought out on two pins (pin 4 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 6 VRE305DS Rev L VRE305 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 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. PIN CONFIGURATION Figure 8: Pin Configuration VRE305DS Rev L 7 VRE305 PACKAGE OPTIONS Part Number Apex Package Style Description VRE305AD VRE305AS VRE305CD VR305CS KD GD KD GD 8-pin DIP 8-pin Surface mount DIP 8-pin DIP 8-pin Surface mount DIP PACKAGE STYLE KD ϲ͘ƉŽdžLJƐĞĂůĞĚ͕ŶŽŶͲŚĞƌŵĞƟĐƉĂĐŬĂŐĞ 8 VRE305DS Rev L VRE305 PACKAGE STYLE GD ϲ͘ƉŽdžLJƐĞĂůĞĚ͕ŶŽŶͲŚĞƌŵĞƟĐƉĂĐŬĂŐĞ 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, 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 "AS IS" without warranty of any kind (expressed or implied). Apex Microtechnology reserves the right to make changes without further notice to any specifications or products mentioned herein to improve reliability. This document is the property of Apex Microtechnology and by furnishing this information, Apex Microtechnology grants no license, expressed or implied under any patents, mask work rights, copyrights, trademarks, trade secrets or other intellectual property rights. Apex Microtechnology owns the copyrights associated with the information contained herein and gives consent for copies to be made of the information only for use within your organization with respect to Apex Microtechnology integrated circuits or other products of Apex Microtechnology. This consent does not extend to other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale. APEX MICROTECHNOLOGY PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED TO BE SUITABLE FOR USE IN PRODUCTS USED FOR LIFE SUPPORT, AUTOMOTIVE SAFETY, SECURITY DEVICES, OR OTHER CRITICAL APPLICATIONS. PRODUCTS IN SUCH APPLICATIONS ARE UNDERSTOOD TO BE FULLY AT THE CUSTOMER OR THE CUSTOMER’S RISK. Apex Microtechnology, Apex and Apex Precision Power are trademarks of Apex Microtechnology, Inc. All other corporate names noted herein may be trademarks of their respective holders. VRE305DS Rev L 9