Datasheet

MAX5500/MAX5501
16-BIT SERIAL WORD
A1 A0 C1 C0
D11................D0
MSB LSB
FUNCTION
0
0
1
1
0
1
0
1
0
0
0
0
1
1
1
1
12-bit DAC data
12-bit DAC data
12-bit DAC data
12-bit DAC data
Load input register A; DAC registers unchanged.
Load input register B; DAC registers unchanged.
Load input register C; DAC registers unchanged.
Load input register D; DAC registers unchanged.
0
0
1
1
0
1
0
1
1
1
1
1
1
1
1
1
12-bit DAC data
12-bit DAC data
12-bit DAC data
12-bit DAC data
Load input register A; all DAC registers updated.
Load input register B; all DAC registers updated.
Load input register C; all DAC registers updated.
Load input register D; all DAC registers updated.
0 1 0 0 XXXXXXXXXXXX Update all DAC registers from their respective input registers (startup).
1 0 0 0 12-bit DAC data Load all DAC registers from shift register (startup).
1 1 0 0 XXXXXXXXXXXX Shutdown (provided PDL = 1)
0 0 1 0 XXXXXXXXXXXX UPO goes low (default)
0 1 1 0 XXXXXXXXXXXX UPO goes high
0 0 0 0 XXXXXXXXXXXX No operation (NOP) to DAC registers
1 1 1 0 XXXXXXXXXXXX Mode 1, DOUT clocked out on SCLK’s rising edge. All DAC registers updated.
1 0 1 0 XXXXXXXXXXXX
Mode 0, DOUT clocked out on SCLK’s falling edge. All DAC registers updated
(default).
Table 1. Serial-Interface Programming Commands
Figure 5 shows the serial-interface timing requirements.
The CS input must be low to enable the DAC’s serial
interface. When CS is high, the interface control circuitry
is disabled. CS must go low for at least t
CSS
before the
rising serial clock (SCLK) edge to properly clock in the
first bit. When CS is low, data is clocked into the internal
shift register through the serial data input (DIN) on the
rising edge of SCLK. The maximum guaranteed clock
frequency is 10MHz. Data is latched into the appropriate
input/DAC registers on the rising edge of CS.
The programming command “load-all-dacs-from-shift-
register” allows all input and DAC registers to be simul-
taneously loaded with the same digital code from the
input shift register. The no operation (NOP) command
leaves the register contents unaffected. This feature is
used in a daisy-chain configuration (see the Daisy
Chaining Devices section).
The command to change the clock edge on which seri-
al data is shifted out of DOUT also loads data from all
input registers to their respective DAC registers.
Serial-Data Output (DOUT)
The serial-data output, DOUT, is the internal shift regis-
ter’s output. The MAX5500/MAX5501 can be pro-
grammed so that data is clocked out of DOUT on the
rising edge of SCLK (mode 1) or the falling edge (mode
0). In mode 0, output data at DOUT lags input data at
DIN by 16.5 clock cycles, maintaining compatibility with
MICROWIRE, SPI/QSPI, and other serial interfaces. In
mode 1, output data lags input data by 16 clock cycles.
On power-up, DOUT defaults to mode 0 timing.
User-Programmable Logic Output (UPO)
The user-programmable logic output, UPO, allows an
external device to be controlled through the
MAX5500/MAX5501 serial interface (Table 1).
Low-Power, Quad, 12-Bit
Voltage-Output DACs with Serial Interface
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