AD7943/AD7945/AD7948
AD7943 PIN FUNCTION DESCRIPTIONS
Pin Mnemonic
I
OUT1
I
OUT2
AGND
Description
DAC current output terminal 1.
DAC current output terminal 2. This should be connected to the AGND pin.
This pin connects to the back gates of the current steering switches. In normal operation, it should be connected
to the signal ground of the system. In biased single-supply operation it may be biased to some voltage between
0 V and the 1.23 V. See Figure 11 for more details.
This is the Strobe 1 input. Data is clocked into the input shift register on the rising edge of this signal.
STB3
must be high. STB2, STB4 must be low.
Active low inputs. When both of these are low, the DAC register is updated and the output will change to
reflect this.
Serial Data Input. Data on this line will be clocked into the input shift register on one of the Strobe inputs,
when they are enabled.
This is the Strobe 2 input. Data is clocked into the input shift register on the rising edge of this signal.
STB3
must be high. STB1, STB4 must be low.
This is the Strobe 3 input. Data is clocked into the input shift register on the falling edge of this signal. STB1,
STB2, STB4, must be low.
This is the Strobe 4 input. Data is clocked into the input shift register on the rising edge of this signal.
STB3
must be high. STB1, STB2 must be low.
Digital Ground.
Asynchronous CLR input. When this input is taken low, all 0s are loaded to the DAC latch.
Power supply input. This is nominally +5 V for Normal Mode Operation and +3.3 V to +5 V for Biased
Mode Operation.
DAC reference input.
DAC feedback resistor pin.
AD7945 PIN FUNCTION DESCRIPTIONS
STB1
LD1, LD2
SRI
STB2
STB3
STB4
DGND
CLR
V
DD
V
REF
R
FB
Pin Mnemonic
I
OUT1
AGND
DGND
DB11–DB0
CS
WR
V
DD
V
REF
R
FB
Description
DAC current output terminal 1.
This pin connects to the back gates of the current steering switches. The DAC I
OUT2
terminal is also connected
internally to this point.
Digital Ground.
Digital Data Inputs.
Active Low, Chip Select Input.
Active Low, Write Input.
Power supply input. This is nominally +5 V for Normal Mode Operation and +3.3 V to +5 V for Biased Mode
Operation.
DAC reference input.
DAC feedback resistor pin.
REV. B
–9–
AD [ ANALOG DEVICES ]
