Datasheet VRE304-6JD, VRE304-6CS, VRE304-6CD, VRE304-6BD, VRE304-6BS Datasheet (THALER)

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VRE304-6 Low Cost Precision Reference

DESCRIPTION

FEATURES

The VRE304-6 is a low cost, high precision

4.096V reference. Packaged in the industry standard 8 pin DIP, the device is ideal for upgrading systems that use lower performance references.

The device provides ultrastable +4.096V output with ±0.409 mV (.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 developed by Thaler Corporation. 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 VRE304-6 series the most accurate reference available in the standard 8 pin DIP package.

For enhanced performance, the VRE304-6 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.

VRE304-6

TOP

VIEW

1 2 3

N/C +V

TEMP

GND

NOISE REDUCTION

REF. GND

OUT

TRIM

PIN CONFIGURATION

The VRE304-6 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 VRE3046 offers superior performance over monolithic references.

• 4.096 V OUTPUT ± 0.409 mV (.01%)

• TEMPERATURE DRIFT: 0.6 ppm/°C

• LOW NOISE: 3µV

p-p

(0.1-10Hz)

• INDUSTRY STD PINOUT- 8 PIN DIP OR

SURFACE MOUNT PACKAGE

•EXCELLENT LINE REGULATION: 6ppm/V Typ.

• OPERATES ON +15V SUPPLY

FIGURE 1

VRE304-6DS REV. D JUN 1999

SELECTION GUIDE

Model

Temp. Range

°C

Temp.

Coeff.

ppm/°C

VRE304-6A 0.41 0.6 0°C to +70°C VRE304-6B 0.64 1.0 0°C to +70°C VRE304-6C 0.82 2.0 0°C to +70°C VRE304-6J 0.41 0.6 -40°C to +85°C VRE304-6K 0.64 1.0 -40°C to +85°C VRE304-6L 0.82 2.0 -40°C to +85°C

For package option add D for DIP or S for Surface Mount to end of model number.

Initial

Error

THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 85745 • (520) 882-4000

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MODEL A/J B/K C/L

PARAMETER MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS

ABSOLUTE RATINGS

Power Supply +13 +15 +22 * * * * * * V Operating Temp. (A,B,C) 0 +70 * * * * °C Operating Temp. (J,K,L) -40 +85 * * * * °C Storage Temperature -65 +150 * * * * °C Short Circuit Protection Continuous * *

OUTPUT VOLTAGE

VRE304-6 4.096 * * V Temp. Sensor Voltage 630 * * mV

OUTPUT VOLTAGE ERRORS

Initial Error 0.41 0.64 0.82 mV Warmup Drift 1 2 3 ppm T

min

- T

max

0.6 1.0 2.0 ppm/ °C Long-Term Stability 6 * * ppm/1000hrs Noise (.1-10Hz) 3 * * µVpp

OUTPUT CURRENT

Range ±10 * * mA

REGULATION

Line 6 10 * * * * ppm/V Load 3 * * ppm/mA

OUTPUT ADJUSTMENT

Range 10 * * mV

POWER SUPPLY CURRENTS

VRE304-6 +PS 5 7 * * * * mA

VRE304-6

NOTES: *Same as A/J Models.

1. The temp. reference TC is 2.1mV/ °C

2. The specified values are without external trim.

3. The temperature coefficient is determined by the box method using the following formula:

max

- V

min

T.C. = x 10

nominal

x (T

max-Tmin

)

(1)

(5)

(2)

(3)

VRE304-6DS REV. D JUN 1999

Vps =+15V, T = 25°C, RL = 10KΩ unless otherwise noted.

ELECTRICAL SPECIFICATIONS

4. The specified values are without the external noise reduction capacitor.

5. The specified values are unloaded.

(4)

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TYPICAL PERFORMANCE CURVES

TemperatureoC

VRE304-6A

OUT

vs. TEMPERATURE

TemperatureoC

VRE304-6B

OUT

vs. TEMPERATURE

VRE304-6DS REV. D JUN 1999

OUT

vs. TEMPERATURE

TemperatureoC

VRE304-6C

TemperatureoC

VRE304-6J

OUT

vs. TEMPERATURE

TemperatureoC

VRE304-6K

OUT

vs. TEMPERATURE

TemperatureoC

VRE304-6L

OUT

vs. TEMPERATURE

QUIESCENT CURRENT VS. TEMP

TemperatureoC

JUNCTION TEMP. RISE VS. OUTPUT CURRENT

Output Current (mA)

PSRR VS. FREQUENCY

Frequency (Hz)

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DISCUSSION OF PERFORMANCE

VRE304-6DS REV. D JUN 1999

THEORY OF OPERATION

The following discussion refers to the schematic in

figure 2 below. 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 4.096V 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.

Thaler Corporation has developed 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, Thaler Corporation produces a very stable voltage over wide temperature ranges.

VRE304-6

FIGURE 2

This network is less than 2% of the overall network resistance so it has a negligible effect on long term stability.

Figure 3 shows the proper connection of the VRE304-6 series voltage references with the optional trim resistor for initial error and the optional capacitor for noise reduction. The VRE304-6 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 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.

EXTERNAL CONNECTIONS

FIGURE 3

+ V

OUT

+ V

VRE304-6

10k?

1µF

OPTIONAL NOISE REDUCTION CAPACITOR

OPTIONAL FINE TRIM ADJUSTMENT

V TEMP OUT

REF. GND

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VRE304-6DS REV. D JUN 1999

FIGURE 3

MECHANICAL SPECIFICATIONS

INCHES MILLIMETER DIM MIN MAX MIN MAX DIM MIN MAX MIN MAX A .110 .120 2.794 3.048 D1 .372 .380 9.45 9.65 B .095 .105 2.413 2.667 E .425 .435 10.80 11.05 B1 .021 .027 0.533 0.686 E1 .397 .403 10.08 10.24 C .055 .065 1.397 1.651 E2 .264 .270 6.71 6.86 C1 .012 .020 0.305 0.508 P .085 .095 2.16 2.41 C2 .020 .040 0.508 1.016 S .045 .055 1.14 1.40 D .395 .405 10.03 10.29

INCHES MILLIMETER

E2 E1 E

C C2

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VRE304-4DS REV. D JUN 1999

MECHANICAL SPECIFICATIONS

E2 E1 E

INCHES MILLIMETER DIM MIN MAX MIN MAX DIM MIN MAX MIN MAX A .170 .180 4.318 4.572 E .425 .435 10.80 11.05 B .095 .105 2.413 2.667 E1 .397 .403 10.08 10.24 B1 .016 .020 0.406 0.508 E2 .264 .270 6.71 6.86 C .008 .011 0.203 0.279 G .290 .310 7.36 7.87 C1 .055 .065 1.397 1.651 L .175 .225 4.46 5.72 D .395 .405 10.03 10.29 P .085 .095 2.16 2.41 D1 .372 .380 9.45 9.65 S .045 .055 1.14 1.40

INCHES MILLIMETER