AD780BRZ Analog Devices Inc, AD780BRZ Datasheet - Page 6

• Manufacturer Part Number: AD780BRZ
• Description: IC PREC V-REF 2.5V/3.0V 8-SOIC
• Manufacturer: Analog Devices Inc
• Type: Voltage Referencer

Specifications of AD780BRZ

• Temperature Coefficient: 3ppm/°C
• Design Resources: Using AD8599 as an Ultralow Distortion Driver for the AD7991 (CN0043) Using AD8599 as an Ultralow Distortion Driver for the AD7995 (CN0044) Using AD8599 as an Ultralow Distortion Driver for the AD7999 (CN0045) Using AD7328 in Appls with Single-Ended Industrial-Level Signals (CN0047) AD5382 Channel Monitor Function (CN0012) AD5383 Channel Monitor Function (CN0015) AD5390/91/92 Channel Monitor Function (CN0030) Measuring -48 V High-Side Current Using AD629, AD8603, AD780, and AD7453 (CN0100) High Voltage, High Precision Current Sensing with Output Level Shifting Using AD8210 and AD8274 (CN0116)
• Reference Type: Series and Shunt, Programmable
• Voltage - Output: 2.5V, 3V
• Tolerance: ±1mV
• Voltage - Input: 4 ~ 36 V
• Number Of Channels: 1
• Current - Quiescent: 1mA
• Current - Output: 10mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Topology: Series
• Input Voltage: 4V To 36V
• Reference Voltage: 2.5V
• Reference Voltage Tolerance: 1mV
• Voltage Reference Case Style: SOIC
• No. Of Pins: 8
• Fixed / Adjust / Prog: Programmable
• Output Voltage (max): 2.5/3V
• Reference Voltage Accuracy (max): 1
• Line Regulation: 10uV/V
• Load Regulation: 75uV/mA
• Input Voltage (max): 36V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: SOIC N
• Current, Output: 0 to 10 mA
• Current, Supply: 0.75 mA
• Power Dissipation: 500 mW
• Regulation, Line: 10 μV/V
• Regulation, Load: 75 μV/mA
• Regulator Type: Negative Voltage Out, Series/Shunt
• Temperature, Operating, Range: -40 to +85 °C
• Voltage, Input: 5 V
• Voltage, Noise: 4 μVp-p
• Voltage, Output: 2.501 or 3.001 V
• Voltage, Supply: 4.5 to 5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Cathode: -
• Lead Free Status / Rohs Status: Compliant

AD780
APPLYING THE AD780
The AD780 can be used without any external components to
achieve specified performance. If power is supplied to Pin 2 and
Pin 4 is grounded, Pin 6 provides a 2.5 V or 3.0 V output
depending on whether Pin 8 is left unconnected or grounded.
A bypass capacitor of 1 µF (+V
load capacitance in the application is expected to be greater
than 1 nF. The AD780 in 2.5 V mode typically draws 700 µA of
I
Initial error can be nulled using a single 25 kΩ potentiometer
connected between V
with an adjustment range of 4%, and is only included here for
compatibility purposes with other references. A fine trim can be
implemented by inserting a large value resistor (e.g., 1 MΩ to
5 MΩ) in series with the wiper of the potentiometer (see
Figure 5). The trim range, expressed as a fraction of the output,
is simply greater than or equal to 2.1 kΩ/R
2.5 V or 3.0 V mode.
The external null resistor affects the overall temperature
coefficient by a factor equal to the percentage of V
For example, a 1 mV (0.03%) shift in the output caused by the
trim circuit, with a 100 ppm/°C null resistor, adds less than
0.06 ppm/°C to the output drift (0.03% × 200 ppm/°C, since the
resistors internal to the AD780 also have temperature
coefficients of less than 100 ppm/°C).
NOISE PERFORMANCE
The impressive noise performance of the AD780 can be further
improved, if desired, by adding two capacitors: a load capacitor
(C1) between the output and ground, and a compensation
capacitor (C2) between the TEMP pin and ground. Suitable
values are shown in Figure 6.
q
at 5 V. This increases by ~2 µA/V up to 36 V.
1µF
NC = NO CONNECT
1
3
Figure 5. Optional Fine-Trim Circuit
NC
TEMP
+V
GND
2
IN
OUT
4
AD780
, TRIM, and GND. This is a coarse trim
O/P SELECT
2.5V – NC
3.0V – GND
IN
8
V
TRIM
NC
OUT
7
to GND) should be used if the
6
5
R
NULL
NULL
for either the
OUT
R POT
nulled.
Rev. E | Page 6 of 12
C1 and C2 also improve the settling performance of the AD780
when subjected to load transients. The improvement in noise
performance is shown in Figure 7, Figure 8, Figure 9, and
Figure 10.
100
AMPLIFIER GAIN = 100
NO AMPLIFIER
0.1
100
100
10
Figure 6. Compensation and Load Capacitor Combinations
0%
0%
90
10
90
10
1
0.1
Figure 7. Standalone Noise Performance
Figure 8. Standalone Noise Performance
100µV
20µV
LOAD CAPACITOR, C1 (µF)
10Hz TO 10kHz
1
0.1 TO 10Hz
10
10ms
1s
100