Low-Power, 12-Bit Voltage-Output DACs

with Serial Interface

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13

The MAX5352’s total harmonic distortion plus noise

(THD+N) is typically less than -77dB (full-scale code),

and the MAX5353’s THD+N is typically less than

-72dB (full-scale code), given a 1Vp-p signal swing and

input frequencies up to 25kHz. The typical -3dB fre-

quency is 650kHz for both devices, as shown in the

Typical Operating Characteristics graphs.

Digitally Programmable Current Source

The circuit of Figure 12 places an NPN transistor

(2N3904 or similar) within the op-amp feedback loop to

implement a digitally programmable, unidirectional cur-

rent source. The output current is calculated with the

following equation:

where NB is the numeric value of the DAC’s binary

input code and R is the sense resistor shown in

Figure 12.

MAX5352

MAX5353

DAC

REF

OUT

FB

GND

+5V/+3.3V

Figure 8. Unipolar Output Circuit

Table 3. Bipolar Code Table

MAX5352

MAX5353

DAC

REF

OUT

10k

10k

GND

+5V/+3.3V

FB

Figure 9. Unipolar Rail-to-Rail Output Circuit

ANALOG OUTPUT

1111 1111 1111 (0)

1000 0000 0001 (0)

DAC CONTENTS

MSB

LSB

1000 0000 0000 (0)

0V

0111 1111 1111 (0)

0000 0000 0000 (0)

0000 0000 0001 (0)

+V

2047

2048

REF









+V

1

2048

REF









-V

1

2048

REF









-V

2047

2048

REF









-V

2048

2048

- V

REF

REF









=

NOTE: ( ) are for sub-bit.