Low Power, 8.5 mW, 2.3 V to 5.5 V,

Programmable Waveform Generator

AD9837

Rev. 0

Informatio

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served.

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FEATURES

Digitally programmable frequency and phase

8.5 mW power consumption at 2.3 V

MCLK speed: 16 MHz (B grade), 5 MHz (A grade)

28-bit resolution: 0.06 Hz at 16 MHz reference clock

Sinusoidal, triangular, and square wave outputs

2.3 V to 5.5 V power supply

3-wire SPI interface

Extended temperature range: −40°C to +125°C

Power-down option

10-lead LFCSP

APPLICATIONS

Frequency stimulus/waveform generation

Liquid and gas flow measurement

Sensory applications: proximity, motion,

and defect detection

Line loss/attenuation

Test and medical equipment

Sweep/clock generators

Time domain reflectometry (TDR) applications

GENERAL DESCRIPTION

The AD9837 is a low power, programmable waveform generator

capable of producing sine, triangular, and square wave outputs.

Waveform generation is required in various types of sensing,

actuation, and time domain reflectometry (TDR) applications.

The output frequency and phase are software programmable,

allowing easy tuning. The frequency registers are 28 bits wide:

with a 16 MHz clock rate, resolution of 0.06 Hz can be achieved;

with a 5 MHz clock rate, the AD9837 can be tuned to 0.02 Hz

resolution.

The AD9837 is written to via a 3-wire serial interface. This serial

interface operates at clock rates up to 40 MHz and is compatible

with DSP and microcontroller standards. The device operates

with a power supply from 2.3 V to 5.5 V.

The AD9837 has a power-down (sleep) function. Sections of the

device that are not being used can be powered down to minimize

the current consumption of the part. For example, the DAC can

be powered down when a clock output is being generated.

The AD9837 is available in a 10-lead LFCSP_WD package.

FUNCTIONAL BLOCK DIAGRAM

SERIAL INTERFACE

AND

CONTROL LOGIC

SCLK

SDATA

FSYNC

16-BIT CONTROL REGISTER

12-BIT PHASE1 REG

12-BIT PHASE0 REG

MUX

SIN

ROM

10-BIT DAC

MUX

12

ON-BOARD

REFERENCE

AGND

DGND

VDD

PHASE

ACCUMULATOR

(28-BIT)

REGULATOR

CAP/2.5V

2.5V

AVDD/

DVDD

MUX

DIVIDE

BY 2

MSB

MUX

FULL-SCALE

CONTROL

AD9837

COMP

VOUT

R

200Ω

MCLK

28-BIT FREQ1 REG

28-BIT FREQ0 REG

Figure 1.