saved, allowing the MAX5154/MAX5155 to recall the

output state prior to entering shutdown when returning

to normal mode. Exit shutdown by recalling the previ-

ous condition or by updating the DAC with new infor-

mation. When returning to normal operation (exiting

shutdown), wait 20µs for output stabilization.

Serial Interface

The MAX5154/MAX5155 3-wire serial interface is com-

patible with both Microwire (Figure 2) and SPI/QSPI

(Figure 3) serial-interface standards. The 16-bit serial

input word consists of an address bit, two control bits,

12 bits of data (MSB to LSB), and one sub bit as shown

in Figure 4. The address and control bits determine the

MAX5154/ MAX5155’s response, as outlined in Table 1.

Low-Power, Dual, 12-Bit Voltage-Output DACs

with Serial Interface

10

______________________________________________________________________________________

FUNCTION

A0

C1

C0

D11.......................D0

(MSB)

(LSB)

0

0

1

12-bit DAC data

Load input register A; DAC registers are unchanged.

0

1

1

12-bit DAC data

Load all DAC registers from the shift register

(start up both DACs with new data.).

1

1

0

12-bit DAC data

Load input register B; all DAC registers are updated.

0

1

0

12-bit DAC data

Load input register A; all DAC registers are updated.

1

0

1

12-bit DAC data

Load input register B; DAC registers are unchanged.

0

0

0

1 1 0 x xxxxxxxx

Shut down DAC A (provided PDL = 1).

0

0

0

1 0 1 x xxxxxxxx

Update DAC register B from input register B

(start up DAC B with data previously stored in input register B).

0

0

0

0 0 1 x xxxxxxxx

Update DAC register A from input register A

(start up DAC A with data previously stored in input register A).

1

1

1

xxxxxxxxxxxx

Shut down both DACs (provided PDL = 1).

1

0

0

xxxxxxxxxxxx

Update both DAC registers from their respective input registers

(start up both DACs with data previously stored in the input registers).

0

0

0

1 1 1 x xxxxxxxx

Shut down DAC B (provided PDL = 1).

0

0

0

0 1 0 x xxxxxxxx

UPO goes low (default).

0

0

0

0 1 1 x xxxxxxxx

UPO goes high.

0

0

0

1 0 0 1 xxxxxxxx

Mode 1, DOUT clocked out on SCLK’s rising edge.

0

0

0

1 0 0 0 xxxxxxxx

Mode 0, DOUT clocked out on SCLK’s falling edge (default).

0

0

0

0 0 0 x xxxxxxxx

No operation (NOP).

Table 1. Serial-Interface Programming Commands

x = Don’t care

Note: D11, D10, D9, and D8 become control bits when A0, C1, and C0 = 0. S0 is a sub bit, always zero.

SCLK

DIN

CS

SK

SO

I/O

MICROWIRE

PORT

MAX5154

MAX5155

Figure 2. Connections for Microwire

16-BIT SERIAL WORD

S0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0