Low-Cost, +5V, Serial-Input,

Voltage-Output, 16-Bit DAC

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CS

SCLK

DIN

D15

D14

D0

Figure 1. Timing Diagram

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CS

SCLK

DIN

MSB

LSB

D15

D8

D7 D6 D5 D4 D3 D2

D1 D0

DAC

UPDATED

D14 D13 D12 D11 D10 D9

Figure 2. 3-Wire Interface Timing Diagram

Detailed Description

The MAX5541 voltage-output, 16-bit digital-to-analog

converter (DAC) offers 16-bit monotonicity with less

than 1LSB differential linearity error. Serial-data transfer

minimizes the number of package pins required.

The MAX5541 is composed of two matched DAC sec-

tions, with a 12-bit inverted R-2R DAC forming the 12

LSBs and the 4 MSBs derived from 15 identically

matched resistors. This architecture allows the lowest

glitch energy to be transferred to the DAC output on

major-carry transitions. It also decreases the DAC out-

put impedance by a factor of eight compared to a stan-

dard R-2R ladder, allowing unbuffered operation in

medium-load applications. Figure 1 is the Timing

Diagram.

Digital Interface

The MAX5541 digital interface is a standard 3-wire con-

nection compatible with SPI/QSPI/MICROWIRE inter-

faces. The chip-select input (CS) frames the serial data

loading at the data input pin (DIN). Immediately follow-

ing CS’s high-to-low transition, the data is shifted

synchronously and latched into the input register on the

rising edge of the serial-clock input (SCLK). After 16

data bits have been loaded into the serial input regis-

ter, it transfers its contents to the DAC latch on CS’s

low-to-high transition (Figure 2). Note that if CS does

not remain low during the entire 16 SCLK cycles, data

will be corrupted. In this case, reload the DAC latch

with a new 16-bit word.

External Reference

The MAX5541 operates with external voltage refer-

ences from 2V to 3V. The reference voltage determines

the DAC’s full-scale output voltage.

Power-On Reset

The MAX5541 has a power-on reset circuit to set the

applied. This ensures that unwanted DAC output volt-

ages will not occur immediately following a system

power-up, such as after power loss. In bipolar mode,