Datasheet
AD7801
–4–
REV. 0
PIN FUNCTION DESCRIPTIONS
Pin
No. Mnemonic Function
1–8 D7–D0 Parallel Data Inputs. 8-bit data is loaded to the input register of the AD7801 under the control of CS and WR.
9 CS Chip Select. Active low logic input.
10 WR Write Input. WR is an active low logic input used in conjunction with CS to write data to the input register.
11 DGND Digital Ground
12 PD Active low input used to put the part into low power mode reducing current consumption to less than 1 µA.
13 LDAC 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.
14 CLR 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.
15 V
DD
Power Supply Input. This part can be operated from +2.7 V to +5.5 V and should be decoupled to GND.
16 REFIN 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.
17 AGND Analog Ground reference point and return point for all analog current on the part.
18 NC No Connect Pin.
19 V
OUT
Analog Output Voltage from the DAC. The output amplifier can swing rail to rail on its output.
20 DGND Digital Ground reference point and return point for all digital current on the part.
PIN CONFIGURATION
14
13
12
11
17
16
15
20
19
18
10
9
8
1
2
3
4
7
6
5
TOP VIEW
(Not to Scale)
AD7801
NC = NO CONNECT
(MSB) DB7
AGND
NC
V
OUT
DGND
DB6
DB5
DB4
CLR
V
DD
REFINDB3
DB2
DB1
(LSB) DB0
CS
WR DGND
PD
LDAC