AD7801
PIN CONFIGURATION
(MSB) DB7 1
DB6 2
DB5 3
DB4 4
DB3 5
20 DGND
19 V
OUT
18 NC
17 AGND
AD7801
16 REFIN
TOP VIEW 15 V
DB2 6
DD
(Not to Scale)
14
CLR
DB1 7
(LSB) DB0 8
CS
9
WR
10
13
LDAC
12
PD
11 DGND
NC = NO CONNECT
PIN FUNCTION DESCRIPTIONS
Pin
No.
1–8
9
10
11
12
13
14
15
16
17
18
19
20
Mnemonic
D7–D0
CS
WR
DGND
PD
LDAC
CLR
V
DD
REFIN
AGND
NC
V
OUT
DGND
Function
Parallel Data Inputs. 8-bit data is loaded to the input register of the AD7801 under the control of
CS
and
WR.
Chip Select. Active low logic input.
Write Input.
WR
is an active low logic input used in conjunction with
CS
to write data to the input register.
Digital Ground
Active low input used to put the part into low power mode reducing current consumption to less than 1
µA.
Load DAC Logic Input. When this logic input is taken low the DAC output is updated with the contents of
its DAC register. If
LDAC
is permanently tied low the DAC is updated on the rising edge of
WR.
Asynchronous Clear Input (Active Low). When this input is taken low the DAC register is loaded with all
zeroes and the DAC output is cleared to zero volts.
Power Supply Input. This part can be operated from +2.7 V to +5.5 V and should be decoupled to GND.
External Reference Input. This can be used as the reference for the DAC. The range on this reference input is
1 V to V
DD
/2. If REFIN is tied directly to V
DD
the internal V
DD
/2 reference is selected.
Analog Ground reference point and return point for all analog current on the part.
No Connect Pin.
Analog Output Voltage from the DAC. The output amplifier can swing rail to rail on its output.
Digital Ground reference point and return point for all digital current on the part.
–4–
REV. 0
AD [ ANALOG DEVICES ]
