AD5754 Analog Devices, AD5754 Datasheet - Page 27

• Manufacturer Part Number: AD5754
• Description: Complete, Quad, 16-Bit, Serial Input, Unipolar/Bipolar Voltage Output DAC
• Manufacturer: Analog Devices

Specifications of AD5754

• Resolution (bits): 16bit
• Dac Update Rate: 100kSPS
• Dac Settling Time: 8µs
• Max Pos Supply (v): +16.5V
• Single-supply: Yes
• Dac Type: Voltage Out
• Dac Input Format: Ser,SPI

FEATURES
ANALOG OUTPUT CONTROL
In many industrial process control applications, it is vital that the
output voltage be controlled during power-up. When the supply
voltages change during power-up, the V
via a low impedance path (approximately 4 kΩ). To prevent the
output amplifiers from being shorted to 0 V during this time,
Transmission Gate G1 is also opened (see Figure 42). These
conditions are maintained until the power supplies have
stabilized and a valid word is written to a DAC register. At this
time, G2 opens and G1 closes.
POWER-DOWN MODE
Each DAC channel of the AD5724/AD5734/AD5754 can be
individually powered down. By default, all channels are in
power-down mode. The power status is controlled by the power
control register (see Table 26 and Table 27 for details). When a
channel is in power-down mode, its output pin is clamped to
ground through a resistance of approximately 4 kΩ and the
output of the amplifier is disconnected from the output pin.
CONTROL
VOLTAGE
MONITOR
Figure 42. Analog Output Control Circuitry
AND
G1
G2
OUT
pins are clamped to 0 V
V
OUT
A
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OVERCURRENT PROTECTION
Each DAC channel of the AD5724/AD5734/AD5754 incorporates
individual overcurrent protection. The user has two options for
the configuration of the overcurrent protection: constant current
clamp or automatic channel power-down. The configuration of
the overcurrent protection is selected via the clamp enable bit in
the control register.
Constant Current Clamp (Clamp Enable = 1)
If a short circuit occurs in this configuration, the current is
clamped at 20 mA. This event is signaled to the user by the
setting of the appropriate overcurrent (OC
control register. Upon removal of the short-circuit fault, the
OC
Automatic Channel Power-Down (Clamp Enable = 0)
If a short circuit occurs in this configuration, the shorted
channel powers down and its output is clamped to ground via a
resistance of approximately 4 kΩ. At this time, the output of the
amplifier is disconnected from the output pin. The short-circuit
event is signaled to the user via the overcurrent (OC
the power-up (PU
down. After the fault is rectified, the channels can be powered
up again by setting the PU
THERMAL SHUTDOWN
The AD5724/AD5734/AD5754 incorporate a thermal shutdown
feature that automatically shuts down the device if the core
temperature exceeds approximately 150°C. The thermal shutdown
feature is disabled by default and can be enabled via the TSD
enable bit of the control register. In the event of a thermal
shutdown, the TSD bit of the power control register is set.
X
bit is cleared.
X
) bits indicate which DACs have powered
AD5724/AD5734/AD5754
X
bits.
X
) bit in the power
X
) bits, and