max5523euat Maxim Integrated Products, Inc., max5523euat Datasheet - Page 16

• Manufacturer Part Number: max5523euat
• Description: Dual, Ultra-low-power, 10-bit, Voltage-output Dacs
• Manufacturer: Maxim Integrated Products, Inc.

The MAX5522–MAX5525 feature two power modes to
conserve power during idle periods. In normal opera-
tion, the device is fully operational. In shutdown mode,
the device is completely powered down, including the
internal voltage reference in the MAX5523/MAX5525.
The MAX5523/MAX5525 also offer a standby mode in
which all circuitry is powered down except the internal
voltage reference. Standby mode keeps the reference
powered up while the remaining circuitry is shut down,
allowing it to be used as a system reference. It also
helps reduce the wake-up delay by not requiring the ref-
erence to power up when returning to normal operation.
The MAX5522–MAX5525 feature a software-program-
mable shutdown mode that reduces the supply current
and the interface input-current to 0.18µA (max). Writing
an input control word with control bits C[3:0] = 1110
(Table 2) places the device in shutdown mode. In shut-
down, the MAX5522/MAX5524 reference input and DAC
output buffers go high impedance. Placing the MAX5523/
MAX5525 into shutdown turns off the internal reference
and the DAC output buffers go high impedance. The seri-
al interface still remains active for all devices.
Table 2 shows several commands that bring the
MAX5522–MAX5525 back to normal operation. The
power-up time from shutdown is required before the
DAC outputs are valid.
Note: For the MAX5523/MAX5525, standby mode can-
not be entered directly from shutdown mode. The
device must be brought into normal operation first
before entering standby mode.
The MAX5523/MAX5525 feature a software-program-
mable standby mode that reduces the typical supply
current to 3µA (max). Standby mode powers down all
circuitry except the internal voltage reference. Place
the device in standby mode by writing an input control
word with control bits C[3:0] = 1100 (Table 2). The
internal reference and serial interface remain active
while the DAC output buffers go high impedance.
Dual, Ultra-Low-Power,
10-Bit, Voltage-Output DACs
16
______________________________________________________________________________________
Standby Mode (MAX5523/MAX5525 Only)
Power Modes
Shutdown Mode
For the MAX5523/MAX5525, standby mode cannot be
entered directly from shutdown mode. The device must
be brought into normal operation first before entering
standby mode. To enter standby from shutdown, issue
the command to return to normal operation followed
immediately by the command to go into standby.
Table 2 shows several commands that bring the
MAX5523/MAX5525 back to normal operation. When
transitioning from standby mode to normal operation,
only the DAC power-up time is required before the DAC
outputs are valid.
The MAX5522/MAX5524 accept a reference with a volt-
age range extending from 0 to V
(V
age source as:
where N is the numeric value of the DAC’s binary input
code (0 to 1023), V
the externally set voltage gain for the MAX5524, and
gain is one for the MAX5522.
In shutdown mode, the reference input enters a high-
impedance state with an input impedance of 2.5G (typ).
The MAX5523/MAX5525 internal voltage reference is
software configurable to one of four voltages. Upon
power-up, the default reference voltage is 1.214V.
Configure the reference voltage using D8 and D9 data
bits (Table 3) when the control bits are as follows C[3:0]
= 1100, 1101, or 1110 (Table 2). V
minimum of 200mV above V
Table 3. Reference Output Voltage
Programming
OUT
D9
0
0
1
1
) is represented by a digitally programmable volt-
V
OUT
D8
0
1
0
1
= (V
REF
REF
is the reference voltage, gain is
x N / 256) x gain
REFERENCE VOLTAGE (V)
REF
for proper operation.
DD
Reference Output
DD
Reference Input
. The output voltage
1.214
1.940
2.425
3.885
must be kept at a