max5500 Maxim Integrated Products, Inc., max5500 Datasheet - Page 8

• Manufacturer Part Number: max5500
• Description: Low-power, Quad, 12-bit Voltage-output Dacs With Serial Interface
• Manufacturer: Maxim Integrated Products, Inc.

Low-Power, Quad, 12-Bit
Voltage-Output DACs with Serial Interface
The MAX5500/MAX5501s’ 3-wire serial interface is
compatible with both MICROWIRE (Figure 2) and
SPI/QSPI (Figure 3). The serial input word consists of
two address bits and two control bits followed by 12
data bits (MSB first), as shown in Figure 4. The 4-bit
address/control code determines the MAX5500/
MAX5501s’ response outlined in Table 1. The connec-
tion between DOUT and the serial-interface port is not
necessary, but may be used for data echo. Data held in
the shift register can be shifted out of DOUT and
returned to the µP for data verification.
The digital inputs of the MAX5500/MAX5501 are double
buffered. Depending on the command issued through the
serial interface, the input register(s) can be loaded without
affecting the DAC register(s), the DAC register(s) can be
loaded directly, or all four DAC registers can be updated
simultaneously from the input registers (Table 1).
The MAX5500/MAX5501 require 16 bits of serial data.
Table 1 lists the serial-interface programming com-
mands. For certain commands, the 12 data bits are
don’t-care bits. Data is sent MSB first and can be sent
in two 8-bit packets or one 16-bit word (CS must remain
low until 16 bits are transferred). The serial data is com-
posed of two DAC address bits (A1, A0) and two control
Figure 2. Connections for MICROWIRE
8
*THE DOUT-SI CONNECTION IS NOT REQUIRED FOR WRITING TO THE
MAX5500/MAX5501, BUT CAN BE USED FOR READBACK PURPOSES.
_______________________________________________________________________________________
MAX5500
MAX5501
Serial-Interface Configurations
DOUT*
SCLK
DIN
CS
Serial-Interface Description
SK
SO
SI*
I/O
MICROWIRE
PORT
bits (C1, C0), followed by the 12 data bits D11–D0
(Figure 4). The 4-bit address/control code determines:
Figure 3. Connections for SPI/QSPI
Figure 4. Serial-Data Format
ADDRESS
MSB.................................................................................................................................LSB
A1
• The register(s) to be updated
• The clock edge on which data is to be clocked out
• The state of the user-programmable logic output
• If the device is to enter shutdown mode (assuming
• How the device is configured when exiting out of
*THE DOUT-MISO CONNECTION IS NOT REQUIRED FOR WRITING TO THE
BITS
CONTROL BITS
MAX5500/MAX5501, BUT CAN BE USED FOR READBACK PURPOSES.
through the serial-data output (DOUT)
(UPO)
PDL is high)
shutdown mode
4 ADDRESS/
A0 C1
MAX5500
MAX5501
CONTROL
BITS
C0
MSB...........................................................................................LSB
D11..............................................................................................D0
DOUT*
SCLK
DIN
CS
16 BITS OF SERIAL DATA
12 DATA BITS
DATA BITS
CPOL = 0, CPHA = 0
MISO*
MOSI
SCK
I/O
SPI/QSPI
PORT
+5V
SS