AD8250-EVALZ Analog Devices Inc, AD8250-EVALZ Datasheet - Page 20

• Manufacturer Part Number: AD8250-EVALZ
• Description: BOARD EVALUATION AD8250
• Manufacturer: Analog Devices Inc
• Series: iCMOS®r

Specifications of AD8250-EVALZ

• Channels Per Ic: 1 - Single
• Amplifier Type: Instrumentation
• Output Type: Single-Ended
• Slew Rate: 25 V/µs
• -3db Bandwidth: 10MHz
• Current - Output / Channel: 37mA
• Operating Temperature: -40°C ~ 85°C
• Current - Supply (main Ic): 4.1mA
• Voltage - Supply, Single/dual (±): 10 V ~ 30 V, ±5 V ~ 15 V
• Board Type: Fully Populated
• Utilized Ic / Part: AD8250
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD8250
APPLICATIONS
DIFFERENTIAL OUTPUT
In certain applications, it is necessary to create a differential
signal. High resolution ADCs often require a differential input.
In other cases, transmission over a long distance can require
differential signals for better immunity to interference.
Figure 57 shows how to configure the AD8250 to output a
differential signal. An op amp, the AD817, is used in an inverting
topology to create a differential voltage. V
midpoint according to the equation shown in the figure. Errors
from the op amp are common to both outputs and are thus
common mode. Likewise, errors from using mismatched resistors
cause a common-mode dc offset error. Such errors are rejected
in differential signal processing by differential input ADCs or
instrumentation amplifiers.
When using this circuit to drive a differential ADC, V
set using a resistor divider from the ADC reference to make the
output ratiometric with the ADC.
+5V
–5V
AMPLITUDE
V
IN
+12V
+IN
10μF
–12V
REF
0.1μF
0.1μF
sets the output
10μF
+
–
DGND
AD8250
+12V
–12V
Figure 57. Differential Output with Level Shift
G = 1
DGND
WR
REF
A1
can be
A0
REF
4.99kΩ
4.99kΩ
Rev. B | Page 20 of 24
–12V
10pF
0.1µF
SETTING GAINS WITH A MICROCONTROLLER
–
V
V
OUT
AD817
OUT
B = –V
A = V
0.1µF
+
2
2
IN
IN
+12V
Figure 56. Programming Gain Using a Microcontroller
–IN
+IN
10μF
10μF
+ V
+ V
REF
REF
V
0V
AMPLITUDE
AMPLITUDE
REF
0.1µF
0.1µF
+2.5V
–2.5V
+2.5V
–2.5V
0V
0V
0V
+15V
–15V
+
–
AD8250
DGND
WR
A1
A0
REF
CONTROLLER
DGND
TIME
TIME
MICRO-