VRE405 VRE405 (R) P r o VRE405 dd uu cc tt IInnnnoovvaatti ioonn FFr roomm Precision Dual Voltage Reference FEATURES DESCRIPTION The VRE405 is a low cost, high precision, 5 V reference. Available in 14-pin DIP or SMT packages, the device is ideal for new designs that need a high performance reference. 5 V Output, 0.8 mV Temperature Drift: 1.0 ppm/C Low Noise: 3 VP-P (0.1-10hz) Tracking Error: 0.3 mV Excellent Line Regulation: 6 ppm/V Typical Surface Mount and DIP Package Options APPLICATIONS The VRE405 is recommended for use as a reference for high precision D/A and A/D converters which require an external precision reference. The device is ideal for calibrating scale factor on high resolution A/D converters. The VRE405 offers superior performance over monolithic references. The device provides ultrastable 5 V output with 0.8 mV initial accuracy and a temperature coefficient of 1.0 ppm/C. This improvement in accuracy is made possible by a unique, patented multipoint laser compensation technique. Another key feature of this reference is the 0.3 mV tracking error between the positive and negative output voltages over the operating temperature range. This is extremely important in high performance systems for reducing overall system errors. For designs which use the DIP package in a socket, there is a reference ground pin to eliminate the reference ground errors. Figure 1. BLOCK DIAGRAM SELECTION GUIDE Model Initial Error (mV) Temp. Coeff. (ppm/C) Temp. Range (C) Package Options VRE405AS VRE405AD VRE405BS VRE405BD VRE405CS VRE405CD 0.8 0.8 1.0 1.0 1.1 1.1 1.0 1.0 2.0 2.0 2.2 2.2 0C to +70C 0C to +70C 0C to +70C 0C to +70C 0C to +70C 0C to +70C SMT14 (GE) DIP14 (KE) SMT14 (GE) DIP14 (KE) SMT14 (GE) DIP14 (KE) VRE405DS www.cirrus.com 14-pin Surface Mount Package Style GE Copyright (c) Cirrus Logic, Inc. 20109 (All Rights Reserved) 14-pin DIP Package Style KE MAY 20101 APEX - VRE405DSREVC VRE405 Product Innovation From 1. CHARACTERISTICS AND SPECIFICATIONS ELECTRICAL SPECIFICATIONS VPS =15V, T = +25C, RL = 10K Unless Otherwise Noted. Model VRE405A Parameter VRE405B VRE405C Min Typ Max Min Typ Max Min Typ Max Units 13.5 15 22 * * * * * * V +70 * * * * C +150 * * * * C ABSOLUTE RATINGS Power Supply Operating Temperature Storage Temperature 0 -65 Short Circuit Protection Continuous * * 5.0 * * OUTPUT VOLTAGE VRE405 V OUTPUT VOLTAGE ERRORS Initial Error (Note 1) 0.80 Warmup Drift 1.00 1 TMIN - TMAX (Note2) 1.0 Tracking Error Long-Term Stability Noise (0.1 - 10Hz) 2 (Note 3) 1.10 3 2.0 mV ppm 2.2 ppm/C 0.3 0.4 0.5 mV 6 * * ppm/1000hrs. 3 * * Vpp OUTPUT CURRENT Range 10 * mA REGULATION Line 3 * * ppm/V Load 3 * * ppm/mA 20 * * mV +PS 7 * * mA -PS 4 * * mA OUTPUT ADJUSTMENT Range POWER SUPPLY CURRENT (Note 4) NOTES: * Same as A Models. 1. The specified values are without external trim. 2. The temperature coefficient (TC) is determined by the box method using the following formula: VMAX - VMIN T.C. = x 106 VNOMINAL x (TMAX - TMIN) 4. The tracking error is the deviation between the positive and negative output over the operating temp. range. 5. The specified values are unloaded. 2 VRE405DS VRE405 Product Innovation From 2. TYPICAL PERFORMANCE CURVES VOUT vs. TEMPERATURE 1 Upper Limit 0 Lower Limit 0 0.25 0 -0.25 -0.5 -0.5 -0.75 -0.75 -0.75 -1 -1 -0.5 0 10 20 30 40 50 60 70 Temperature, C VRE405A Upper Limit 0.5 0.25 -0.25 -0.25 VOUT vs. TEMPERATURE 0.75 0.5 VOUT (mV) 0.5 0.25 1 Upper Limit 0.75 0.75 VOUT (mV) VOUT vs. TEMPERATURE VOUT (mV) 1 Lower Limit 0 10 20 30 40 50 60 70 Temperature, C VRE405B -1 0 Lower Limit 10 20 30 40 50 60 70 Temperature, C VRE405C POSITIVE OUTPUT (TYP) QUIESCENT CURRENT VS. TEMP Temperature oC JUNCTION TEMP. RISE VS. OUTPUT CURRENT Output Current (mA) PSRR VS. FREQUENCY Frequency (Hz) NEGATIVE OUTPUT (TYP) QUIESCENT CURRENT VS. TEMP Temperature oC VRE405DS JUNCTION TEMP. RISE VS. OUTPUT CURRENT Output Current (mA) PSRR VS. FREQUENCY Frequency (Hz) 3 VRE405 Product Innovation From 3. 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 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 that 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 VRE405 reference has it's ground terminal brought out on two pins (pin 6 and 7) which are connected 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 does not effect performance. PIN CONFIGURATION N/C 1 14 N/C VOUT 2 13 +VOUT N/C 3 VRE405 12 N/C - VIN 4 11 +VIN N/C 5 TOP VIEW 10 N/C REF. GND 6 9 N/C GND 7 8 N/C - 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 apex.support@cirrus.com. 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. 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