ad5932 Analog Devices, Inc., ad5932 Datasheet - Page 9

• Manufacturer Part Number: ad5932
• Description: Programmable Frequency Scan Waveform Generator
• Manufacturer: Analog Devices, Inc.

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Table 4. Pin Function Descriptions
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Mnemonic
COMP
AVDD
DVDD
CAP/2.5V
DGND
MCLK
SYNCOUT
MSBOUT
INTERRUPT
CTRL
SDATA
SCLK
FSYNC
STANDBY
AGND
VOUT
Description
DAC Bias Pin. This pin is used for decoupling the DAC bias voltage to AVDD.
Positive Power Supply for the Analog Section. AVDD can have a value from 2.3 V to 5.5 V. A 0.1 μF decoupling
capacitor should be connected between AVDD and AGND.
Positive Power Supply for the Digital Section. DVDD can have a value from 2.3 V to 5.5 V. A 0.1 μF decoupling
capacitor should be connected between DVDD and DGND.
Digital Circuitry. Operates from a 2.5 V power supply. This 2.5 V is generated from DVDD using an on-board
regulator. The regulator requires a decoupling capacitor of typically 100 nF, which is connected from CAP/2.5V
to DGND. If DVDD is equal to or less than 2.7 V, CAP/2.5V can be shorted to DVDD.
Ground for All Digital Circuitry.
Digital Clock Input. DDS output frequencies are expressed as a binary fraction of the frequency of MCLK.
The output frequency accuracy and phase noise are determined by this clock.
Digital Output for Scan Status Information. User-selectable for end of scan (EOS) or frequency increments through
the control register (SYNCOP bit). This pin must be enabled by setting the SYNCOUTEN bit in the control register to 1.
Digital Output. The inverted MSB of the DAC data is available at this pin. This output pin must be enabled by
setting the MSBOUTEN bit in the control register to 1.
Digital Input. This pin acts as an interrupt during a frequency scan. A low-to-high transition is sampled by the
internal MCLK, which resets internal state machines. This results in the DAC output going to midscale.
Digital Input. Triple function pin for initialization, start, and external frequency increments. A low-to-high transition,
sampled by the internal MCLK, is used to initialize and start internal state machines, which then execute the pre-
programmed frequency scan sequence. When in auto-increment mode, a single pulse executes the entire scan
sequence. When in external increment mode, each frequency increment is triggered by low-to-high transitions.
Serial Data Input. The 16-bit serial data-word is applied to this input with the register address first, followed by
the MSB to LSBs of the data.
Serial Clock Input. Data is clocked into the AD5932 on each falling SCLK edge.
Active Low Control Input. This is the frame synchronization signal for the serial data. When FSYNC is taken low,
the internal logic is informed that a new word is being loaded into the device.
Active High Digital Input. When this pin is high, the internal MCLK is disabled, and the reference DAC and regulator
are powered down. For optimum power saving, it is recommended that the AD5932 be reset before it is put into
standby, as this results in a shutdown current of typically 20 μA.
Ground for All Analog Circuitry.
Voltage Output. The analog outputs from the AD5932 are available here. An external resistive load is not required,
because the device has a 200 Ω resistor on board. A 20 pF capacitor to AGND is recommended to act as a low-pass
filter and to reduce clock feedthrough.
SYNCOUT
CAP/2.5V
MSBOUT
COMP
DGND
DVDD
MCLK
AVDD
Figure 7. Pin Configuration
1
2
3
4
5
6
7
8
Rev. 0 | Page 9 of 28
(Not to Scale)
AD5932
TOP VIEW
15
14
13
12
11
10
16
9
VOUT
AGND
STANDBY
FSYNC
SCLK
SDATA
CTRL
INTERRUPT
AD5932