AD5522JSVUZ Analog Devices Inc, AD5522JSVUZ Datasheet - Page 32

• Manufacturer Part Number: AD5522JSVUZ
• Description: Quad PPMU With DACs And LVDS/SPI
• Manufacturer: Analog Devices Inc

Specifications of AD5522JSVUZ

• Design Resources: Parametric Measurement Unit and Supporting Components for PAD Appls Using AD5522 and AD7685 (CN0104)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD5522
MEASURE CURRENT GAINS
The measure current amplifier has two gain settings, 5 and 10.
The two gain settings allow users to achieve the quoted/specified
current ranges with large or small voltage swing. Use the 10 gain
setting with a 5 V reference, and use the 5 gain setting with a
2.5 V reference. Both combinations ensure the specified current
ranges. Using other VREF/gain setting combinations should
achieve smaller current ranges only. Achieving greater current
ranges than the specified ranges is outside the intended opera-
tion of the AD5522. The maximum guaranteed voltage across
R
Following are examples of VREF/gain setting combinations. In
these examples, the offset DAC is at its default value of 0xA492.
•
•
SENSE
VREF = 5 V results in a ±11.25 V range. Using a gain setting
of 10, there is ±1.125 V maximum across R
current ranges of ±5.625 μA, ±22.5 μA, and so on (inclu-
ding overrange of ±12.5% to allow for error correction).
VREF = 2.5 V results in a ±5.625 V range. Using a gain setting
of 5 results in current ranges of ±5.625 μA, ±22.5 μA, and
so on (including overrange of ±12.5% to allow for error
correction).
= ±1.125 V.
MEASOUTx
REFGND
VREF
50Ω
ADDRESS
DATA
ATTB
AGND
ATT
R
VOFFSET
MV
MI
DAC
ATT
SENSE
, resulting in
Figure 48. Measure Block and VMID Influence
ATTB
ATTB
ATT = ATTENUATION FOR MEASOUTx ×0.2
MI = MEASURE CURRENT
MV = MEASURE VOLTAGE
SEL×5 = MI GAIN = 5
SEL×10 = MI GAIN = 10
2R
5R
5R
5R
VDAC_MIN
VOFFSET
VTOP
VDAC_MID
7R
Rev. D | Page 32 of 64
DAC HV AMP
2R
VMIN
AGND
7R
VREF = 3.5 V results in a ±7.87 V range. Using a gain setting of
10, there is ±0.785 V maximum across R
current ranges of ±3.92 μA, ±15.74 μA, and so on (including
overrange of ±12.5% to allow for error correction).
VMID VOLTAGE
The midcode voltage (VMID) is used in the measure current
amplifier block to center the current ranges about 0 A. This
is required to ensure that the quoted current ranges can be
achieved when using offset DAC settings other than the default.
VMID corresponds to 0x8000 or the DAC midcode value, that
is, the middle of the voltage range set by the offset DAC setting
(see Table 13). See the block diagram in Figure 48.
or
DAC HV AMP
VMID = 4.5 × VREF × (32,768/2
(OFFSET_DAC_CODE/2
VMID = 3.5 × VREF × ((42,130 − OFFSET_DAC_CODE)/2
VMIN = −3.5 × VREF × (OFFSET_DAC_CODE/2
10R
1R
1R
VMID
INAMP10
INAMP1
10R
MEASURE
VOLTAGE
1R
1R
IN-AMP
1R
1R
MEASURE
CURRENT
1R
1R
IN-AMP
SEL×10
SEL×10
16
))
SEL×5
SEL×5
16
) − (3.5 × VREF ×
INT/EXTMEASIHx
INT/EXTMEASILx
MEASVHx
DUTGND
SENSE
, resulting in
16
)
16
)