In shutdown mode, the MAX5253 output amplifiers and

the reference inputs enter a high-impedance state. The

serial interface remains active. Data in the input regis-

ters is retained in shutdown, allowing the MAX5253 to

recall the output states prior to entering shutdown. Exit

shutdown mode by either recalling the previous config-

uration or by updating the DACs with new data. When

powering up the device or bringing it out of shutdown,

allow 20µs for the outputs to stabilize.

Serial-Interface Configurations

The MAX5253’s 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 MAX5253’s response out-

lined in Table 1. The connection between DOUT and

the serial-interface port is not necessary, but may be

used for data echo. Data held in the MAX5253’s shift

register can be shifted out of DOUT and returned to the

microprocessor (µP) for data verification.

The MAX5253’s digital inputs 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).

Serial-Interface Description

The MAX5253 requires 16 bits of serial data. Table 1

lists the serial-interface programming commands. For

certain commands, the 12 data bits are “don’t cares.”

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 composed of

two DAC address bits (A1, A0) and two control bits

(C1,C0), followed by the 12 data bits D11…D0 (Figure

4).The 4-bit address/control code determines:

• The register(s) to be updated

• The clock edge on which data is to be clocked out

via the serial-data output (DOUT)

• The state of the user-programmable logic output

(UPO)

• If the part is to go into shutdown mode (assuming

PDL is high)

• How the part is configured when exiting shutdown

mode.

+3V, Quad, 12-Bit Voltage-Output DAC

with Serial Interface

_______________________________________________________________________________________

9

SCLK

DIN

DOUT*

CS

SK

SO

SI*

I/O

MAX5253

MICROWIRE

PORT

*THE DOUT-SI CONNECTION IS NOT REQUIRED FOR WRITING TO THE MAX5253,

BUT MAY BE USED FOR READBACK PURPOSES.

Figure 2. Connections for Microwire

DOUT*

DIN

SCLK

CS

MISO*

MOSI

SCK

I/O

SPI/QSPI

PORT

SS

+3.3V

CPOL = 0,CPHA = 0

*THE DOUT-MISO CONNECTION IS NOT REQUIRED FOR WRITING TO THE MAX5253,

BUT MAY BE USED FOR READBACK PURPOSES.

MAX5253

Figure 3. Connections for SPI/QSPI

Figure 4. Serial-Data Format

MSB ..................................................................................LSB

16 Bits of Serial Data

Address

Bits

Control

Bits

Data Bits

MSB.............................................LSB

A1

A0

C1

C0

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

12 Data Bits

4 Address/

Control Bits