AD5522JSVD AD [Analog Devices], AD5522JSVD Datasheet - Page 27

• Manufacturer Part Number: AD5522JSVD
• Description: Quad Parametric Measurement Unit With Integrated 16-Bit Level Setting DACs
• Manufacturer: AD [Analog Devices]

Preliminary Technical Data
FORCE CURRENT, FI
In the force current mode, the voltage at FIN is now converted
to a current and applied to the DUT. The feedback path is now
the current measure amplifier, feeding back the voltage
measured across the sense resistor and MEASOUT reflects the
voltage measured across the DUT. See Figure 25.
For the suggested current ranges, the maximum voltage drop
across the sense resistors is ±1V, however, to allow for
correction of errors, there is some over range available in the
current ranges. The maximum full-scale voltage range that can
be loaded to the FIN DAC is ±11.5V; the forced current may be
calculated as follows:
Where:
FI = Forced Current
VFIN = Voltage of the FIN DAC, See V
RSENSE = Selected Sense Resistor
Gain of Current Measure Instrumentation amplifier, it may be
set (via the serial interface) to 5 or 10.
The ISENSE amplifier is biased by the Offset DAC output
voltage, in such as way as to center the Measure current output
irrespective of the voltage span used.
Using the 5kΩ sense resistor and ISENSE gain of 10, the
maximum current range possible is ±225μA. Similarly for the
other current ranges, there is an over range of 12.5% to allow for
correction.
MEASOUT
FI
x1/x0.2
=
RSENSE
VFIN
×
Gain
OUT
OFFSET DAC
BIAS TO
CENTER
IRANGE
for DAC levels.
DAC
AGND
FIN
x5 or x10
Figure 25. .Forcing current, measuring voltage
x1
+
-
+
-
+
-
Rev. PrM | Page 27 of 48
+
+
-
-
+
-
+
-
INTERNAL RANGE SELECT
(5uA, 20uA, 200uA, 2mA)
Rsense
10kΩ
EXTMEASIH
DUTGND
EXTFOH
FOH
MEASVH
C FF
EXTMEASIL
DUT
Rsense
up to
(64mA)
AD5522