ad5501 Analog Devices, Inc., ad5501 Datasheet - Page 12

• Manufacturer Part Number: ad5501
• Description: High Voltage, 12-bit Voltage Output Dac
• Manufacturer: Analog Devices, Inc.

AD5501
=1) the output voltage is 15 V (assuming LDAC is low or has
been pulsed low). When the user switches to 60 V mode
( R_SEL =0) the output stays at 15 V until the user writes a new
value to the DAC register. LDAC must be low or be pulsed low
for the output to change.
CLR FUNCTION
The AD5501 has a hardware CLR pin that is an asynchronous
clear input. The CLR input is falling edge sensitive. Bringing the
CLR line low clears the contents of the Input register and the
DAC registers to 0x000. The CLR pulse activation time, i.e. the
falling edge of CLR to when the output starts to change, is typically
TBD ns.
LDAC FUNCTION
The DAC output can be updated using the hardware LDAC pin.
LDAC is normally high. On the falling edge of LDAC data is
copied from the Input register to the DAC register and the DAC
output is updated (Asynchronous update mode, see Figure 3). If
the LDAC is kept low or is low on the falling edge of the 16
SCLK the DAC register and DAC output are updated
automatically when new data is received in the Input register
(Synchronous update mode, see Figure 3).
TEMPERATURE SENSOR
The AD5501 can be programmed to enter thermal shutdown
mode if the temperature on the die exceeds 130°C. Setting Bit 1
of the Control register (see Table 9) to 0 enables this function
(enabled by default on power-up). In thermal shutdown mode
the analog section of the device is powered down, the DAC
th
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outputs are disconnected but the digital section remains
operational, which is equivalent to setting the power-down bit
in the Control register. To indicate that the AD5501 has entered
temperature shutdown mode, bit 0 of the Control register is set
to 1 and the ALARM pin goes low. The AD5501 remains in
temperature shutdown mode with bit 0 set to 1 and the ALARM
pin low, even if the die temperature falls, until bit 0 in the
Control register is cleared to 0.
POWER DISSIPATION
Drawing current from the V
the die and package of the AD5501. The die temperature (T
should not exceed 130°C for normal operation. If bit 1 of the
Control register is set and the die temperature exceeds 130°C
the AD5501 enters thermal shutdown mode as described in the
previous section. The amount of heat generated can be
calculated using the formula
T
Where:
T
T
P
θ
Absolute Maximum Ratings for this value).
JA
TOTAL
J
J
A
= T
is the package junction temperature
is the ambient temperature
is the thermal impedance of the AD5501 package (see the
A
is the total power being consumed by the AD5501
+ (P
TOTAL
× θ
Preliminary Technical Data
JA
)
OUT
pin causes a temperature rise in
J
)