AD780ARZ Analog Devices Inc, AD780ARZ Datasheet - Page 7

• Manufacturer Part Number: AD780ARZ
• Description: IC REFERENCE PREC 2.5/3.0V 8SOIC
• Manufacturer: Analog Devices Inc

Specifications of AD780ARZ

• Temperature Coefficient: 7ppm/°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: ±5mV
• 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: 5mV
• Voltage Reference Case Style: SOIC
• No. Of Pins: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Cathode: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

NOISE COMPARISON
The wideband noise performance of the AD780 can also be
expressed in ppm. The typical performance with C1 and C2 is
0.6 ppm; without external capacitors, typical performance is
1.2 ppm.
This performance is, respectively, 7× and 3× lower than the
specified performance of the LT1019.
TEMPERATURE PERFORMANCE
The AD780 provides superior performance over temperature by
means of a combination of patented circuit design techniques,
precision thin-film resistors, and drift trimming. Temperature
performance is specified in terms of ppm/°C; because of
nonlinearity in the temperature characteristic, the box test
method is used to test and specify the part. The nonlinearity
takes the form of the characteristic S-shaped curve shown in
Figure 11. The box test method forms a rectangular box around
this curve, enclosing the maximum and minimum output
voltages over the specified temperature range. The specified
drift is equal to the slope of the diagonal of this box.
Figure 10. Reduced Noise Performance with C1 = 100 µF, C2 = 100 nF
NO AMPLIFIER
100
0%
90
10
1µF
NC = NO CONNECT
C2
20µV
Figure 9. Noise Reduction Circuit
1
3
NC
TEMP
+V
GND
2
10Hz TO 10kHz
IN
4
AD780
O/P SELECT
2.5V – NC
3.0V – GND
8
TRIM
V
NC
OUT
7
6
5
10ms
C1
Rev. E | Page 7 of 12
TEMPERATURE OUTPUT PIN
The AD780 provides a TEMP output (Pin 3) that varies linearly
with temperature. This output can be used to monitor changes
in system ambient temperature, and to initiate calibration of the
system, if desired. The voltage V
temperature coefficient is approximately 2 mV/°C.
Figure 12 shows the typical V
temperature taken at the output of the op amp with a
noninverting gain of 5.
Since the TEMP voltage is acquired from the band gap core
circuit, current pulled from this pin has a significant effect on
V
suitable op amp, e.g., an OP07, AD820, or AD711 (all of which
would result in less than a 100 µV change in VOUT). The
relationship between I
∆V
or
∆V
OUT
OUT
OUT
. Care must be taken to buffer the TEMP output with a
–0.4
–0.8
4.25
4.00
3.75
3.50
3.25
3.00
2.75
2.50
2.25
2.00
= 5.8 mV/µA I
= 6.9 mV/µA I
2.0
1.6
1.2
0.8
0.4
0
–60
–75
CIRCUIT CALIBRATED AT 25°C
REFER TO FIGURE 13
Figure 12. Temperature Pin Transfer Characteristic
Figure 11. Typical AD780BN Temperature Drift
–40
–50
–20
–25
TEMP
TEMP
TEMP
0
0
(2.5 V Range)
(3.0 V Range)
TEMPERATURE (°C)
TEMPERATURE (°C)
and V
20
TEMP
25
TEMP
OUT
40
characteristic curve over
50
is
is 560 mV at 25°C, and the
60
10mV PER °C
75
80
100
100
125
120
AD780
140
150