max5383eztt Maxim Integrated Products, Inc., max5383eztt Datasheet - Page 9

• Manufacturer Part Number: max5383eztt
• Description: Low-cost, Low-power, 8-bit Dacs With 3-wire Serial Interface In Sot23
• Manufacturer: Maxim Integrated Products, Inc.

input register, it transfers its contents to the DAC latch
on CS’s low-to-high transition (Figure 3). Note that if CS
is not kept low during the entire 16 SCLK cycles, data
will be corrupted. In this case, reload the DAC latch
with a new 16-bit word. The serial clock (SCLK) can
idle either high or low between transitions. Figure 4
shows the complete 3-wire serial interface transmis-
sion. Table 3 lists serial interface mapping.
Since the MAX5385 generates an output voltage pro-
portional to V
accuracy of the on-board reference, thereby affecting
the overall accuracy of the DAC. The circuit in Figure 5
rejects this power-supply noise by powering the device
directly with a precision voltage reference, improving
overall system accuracy. The MAX6103 (+3V, 75ppm)
or the MAX6105 (+5V, 75ppm) precision voltage refer-
ences are ideal choices due to the low power require-
ments of the MAX5385. This solution is also useful
when the required full-scale output voltage is different
from the available supply voltages.
Table 2. Shutdown Modes
Table 3. Serial Interface Mapping
X = Don’t care
Device Powered by an External Reference
Low-Cost, Low-Power, 8-Bit DACs with 3-Wire
XX00
XX00
XX00
XX00
XX01
XX10
XX11
MSB
[D13 AND D12]
DAC CODE
01
10
11
DD
Applications Information
, a noisy power supply will affect the
_______________________________________________________________________________________
XXXX
XXXX
XXXX
0000
1111
0000
1000
16-BIT SERIAL WORD
Shutdown
Shutdown
Shutdown
MODE
XXXX
XXXX
XXXX
0000
1111
0001
0000
Serial Interface in SOT23
OUTPUT RESISTANCE TO
The digital interface for the 8-bit DAC is based on a
3-wire standard that is compatible with SPI, QSPI, and
MICROWIRE interfaces. The three digital inputs (CS, DIN,
and SCLK) load the digital input serially into the DAC.
All the digital inputs include Schmitt-trigger buffers to
accept slow-transition interfaces. This means that opto-
couplers can interface directly to the MAX5383/
MAX5384/MAX5385 without additional external logic.
The digital inputs are compatible with CMOS logic levels
and can be driven with voltages up to +5.5V regardless
of the supply voltage.
Careful PC board layout is important for best system
performance. To reduce crosstalk and noise injection,
keep analog and digital signals separate. To ensure
that the ground return from GND to the supply ground
is short and low impedance, a ground plane is recom-
mended. Bypass V
as close as possible to the device. If the supply is
excessively noisy, connect a 10Ω resistor in series with
the supply and V
XXXX
XXXX
XXXX
XXXX
XXXX
XXXX
XXXX
LSB
GROUND (Ω)
Power-Supply Bypassing and Layout
100k
1M
1k
Digital Inputs and Interface Logic
V
V
DD
V
REF
REF
REF
DD
ANALOG
OUTPUT
and add additional capacitance.
× (255/256)
× (128/256)
× (1/256)
0V
0V
0V
0V
with a 0.1µF capacitor to ground
MAXIMUM SUPPLY
CURRENT ( µA)
Normal operation
Normal operation
Normal operation
Normal operation
100kΩ to GND
1MΩ to GND
1kΩ to GND
FUNCTION
Shutdown,
Shutdown,
Shutdown,
1
1
1
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