ADR512ARTZ-REEL7 Analog Devices Inc, ADR512ARTZ-REEL7 Datasheet - Page 5

• Manufacturer Part Number: ADR512ARTZ-REEL7
• Description: IC VREF SHUNT 1.2V LN SOT23-3
• Manufacturer: Analog Devices Inc

Specifications of ADR512ARTZ-REEL7

• Temperature Coefficient: 60ppm/°C
• Design Resources: 30 V Low Cost DAC Using AD5292 Digital Potentiometer (CN0111) Programmable Bidirectional Current Source Using AD5292 and ADA4091-4 (CN0117) Versatile High Precision Programmable Current Sources Using DACs, Op Amps, and MOSFET Transistors (CN0151)
• Reference Type: Shunt
• Voltage - Output: 1.2V
• Tolerance: ±0.3%
• Number Of Channels: 1
• Current - Cathode: 100µA
• Current - Output: 10mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-3, TO-236-3, Micro3™, SSD3, SST3
• Topology: Shunt
• Reference Voltage: 1.2V
• Reference Voltage Tolerance: 3.5mV
• Voltage Reference Case Style: SOT-23
• No. Of Pins: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Input: -
• Current - Quiescent: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: ADR512ARTZ-REEL7; ADR512ARTZ-REEL7TR

Adjustable Precision Voltage Source
The ADR512, combined with a precision low input bias op amp
such as the AD8610, can be used to output a precise adjustable
voltage. Figure 2 illustrates the implementation of this application
using the ADR512.
The output of the op amp, V
circuit, which is completely dependent on resistors R2 and R1.
An additional capacitor in parallel with R2 can be added to filter
out high frequency noise. The value of C2 is dependent on the
value of R2.
Output Voltage Trim
Using a mechanical or digital potentiometer, the output voltage
of the ADR512 can be trimmed ± 0.5%. The circuit in Figure 3
illustrates how the output voltage can be trimmed, using a 10 kΩ
potentiometer.
Using the ADR512 with Precision Data Converters
The compact ADR512 package and the device’s low minimum
operating current requirement make it ideal for use in battery-
powered portable instruments, such as the AD7533 CMOS
multiplying DAC, that use precision data converters.
REV. 0
V
Figure 2. Adjustable Precision Voltage Source
OUT
ADR512
= +
R
BIAS
ADR512
1
V
Figure 3. Output Voltage Trim
CC
R
R
R
1.2V
2
1
BIAS
R1
V
CC
AD8610
C2 (OPTIONAL)
OUT
R2
100k
, is determined by the gain of the
R1
V
OUT
POT
50k
= 1.2(1 + R2/R1)
V
OUT
(4)
–5–
Figure 4 shows the ADR512 serving as an external reference to
the AD7533, a CMOS multiplying DAC. Such a DAC requires
a negative voltage input in order to provide a positive output
range. In this application, the ADR512 is supplying a –1.2 V
reference to the REF input of the AD7533.
Precise Negative Voltage Reference
The ADR512 is suitable for use in applications where a precise
negative voltage reference is desired, including the application
detailed in Figure 4.
Figure 5 shows the ADR512 configured to provide a –1.2 V output.
Since the ADR512 characteristics resemble those of a Zener diode,
the cathode shown in Figure 5 will be 1.2 V higher with respect
to the anode (V+ with respect to V– on the ADR512 package).
Since the cathode of the ADR512 is tied to ground, the anode
must be –1.2 V.
R1 in Figure 5 should be chosen so that 100 µA to 10 mA is
provided to properly bias the ADR512.
The resistor R1 should be chosen so that power dissipation is at
a minimum. An ideal resistor value can be determined through
manipulation of Equation 5.
R
Figure 5. Precise –1.2 V Reference Configuration
ADR512
Figure 4. ADR512 as a Reference for a 10-Bit
CMOS DAC (AD7533)
1 =
V
DD
I
R2
–V
DD
V
DD
ADR512
MSB
G
N
0
1
1
3
2
R1
–V
1
DD
–
AD7533
–1.2V
15
9
LSB
V
OUT
ADR512
= 0V TO 1.2V
(5)