Analog Devices EVAL-AD8460SDZ User Manual page 17

AD8460
Evaluation Board User Guide
Evaluation Board Hardware Features
A. SPI Connectors
In addition to the FMC and SDP connectors, the EVAL-AD8460SDZ evaluation board includes a SPI breakout jumper for
custom controller board operation.
B. Full-Scale Adjustment Through REF_IO Jumper
The EVAL-AD8460SDZ evaluation board includes a REF_IO jumper to reduce the output voltage span by applying an
external voltage reference to jumper pin 2, which is connected to REFIO. It can be driven with a voltage in the range of
1.2 V maximum to as low as 0.12 V, reducing the full-scale output span from +/−40 V to as low as +/−4 V. This is the
recommended option for applications requiring dynamically adjustable span.
C. Full-Scale Adjustment Through R
SET
The EVAL-AD8460SDZ evaluation board has a 2 kΩ 0.01% resistor, R6, that sets the reference current, I . The range
REF
of this R resistor is 2 kΩ to 20 kΩ, corresponding to 600 µA to 60 µA, respectively when REFIO is 1.2 V.
SET
I = 1.2 V/2 kΩ = 600 µA
REF
D. Compensation (COMP_H AND COMP_L)
The EVAL-AD8460SDZ evaluation board includes provisions with 0603 footprints for compensation capacitors, COMP_H
and COMP_L. These capacitors must be high voltage types to withstand the full-scale range of the output signal; minimum
100 V capacitors are recommended when running on the +/−50 V supplies.
E. Thermal Monitor (TMP) and Thermal Management
The TMP pin can be used to monitor relative changes in die temperature. The typical TMP pin voltage at room temperature
is 1.75 V and changes at approximately 6 mV/°C. More precise temperature readings can be achieved through a one-
time room temperature calibration.
The TMP pin can be connected to the SDN_IO pin for optional thermal shutdown by installing a 0 Ω resistor at R11. The
AD8460's thermal monitoring capability is independent of any overtemperature shutdown threshold and may be used
whether TMP is strapped to SDN_IO.
F. Shutdown Feature (SDN_SHUTDOWN, SDN_RESET, and S4 Switch Buttons)
The EVAL-AD8460SDZ evaluation board includes switch buttons SDN_SHUTDOWN and SDN_RESET to pull the
SDN_IO pin on the AD8460 to logic high or logic low, respectively. When SDN_IO is pulled high, the AD8460's supply
current is reduced to ~100 µA and the internal high voltage driver is disabled.
The S4 switch button toggles the SDN_RESET pin on the AD8460 high. This is an alternative way of exiting a state of
shutdown.
G. RESET Feature (S3 Switch Button)
The EVAL-AD8460SDZ evaluation board includes the switch button S3 to manually toggle the RESETB pin to GND to
reset all the hardware features to default.
analog.com Rev.0 17 of 31