Datasheet
DAC081S101
SCLK 5
DOUT 4
SYNC 6
2
3
LM6211
10 PF
0.1 PF
V
S
-
+
1
V
S
+IN
-IN
C2
B1
0.1 PF
1 PF
+5V
4
5
6
1,2 7,8
7 SCLK
6 DOUT
5 CS
C1
6 SYNC
5 SCLK
4 DOUT
2
3
4.096V
1
V
OUT
120 pF
+
-
A2
-
+
A1
3
4
2
1
5
+5V
100 k: 0.2 PF
180:
100 k:
0.2 PF
470 pF
470 pF
1
8
4
2.048V
V
REF
+5V
2
3
+5V
5
1
2
4
3
A
V
= 100
180:
2.02 k:
PRESSURE SENSOR
0.2 mV/Volt/PSI
A1, A2 = LM6211
B1 = LM4140ACM-2.0
C1 = DAC081S101
C2 = ADC121S625
LM6211
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SNOSAH2C –FEBRUARY 2006–REVISED MARCH 2013
Figure 42. Hydraulic Pressure Monitoring System
DAC OUTPUT AMPLIFIER
Op amps are often used to improve a DAC's output driving capability. High performance op amps are required as
I-V converters at the outputs of high resolution current output DACs. Since most DACs operate with a single
supply of 5V, a rail-to-rail output swing is essential for this application. A low offset voltage is also necessary to
prevent offset errors in the waveform generated. Also, the output impedance of DACs is quite high, more than a
few kΩ in some cases, so it is also advisable for the op amp to have a low input bias current. An op amp with a
high input impedance also prevents the loading of the DAC, and hence, avoids gain errors. The op amp should
also have a slew rate which is fast enough to not affect the settling time of the DAC output.
The LM6211, with a CMOS input stage, ultra low input bias current, a wide bandwidth (20 MHz) and a rail-to-rail
output swing for a supply voltage of 24V is an ideal op amp for such an application. Figure 43 shows a typical
circuit for this application. The op amp is usually expected to add another time constant to the system, which
worsens the settling time, but the wide bandwidth of the LM6211 (20 MHz) allows the system performance to
improve without any significant degradation of the settling time.
Figure 43. DAC Driver Circuit
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