
ADN2850
Data Sheet
Rev. E | Page 8 of 28
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
SDI
SDO
GND
V1
VSS
W1
CLK
B1
CS
PR
WP
VDD
V2
W2
B2
RDY
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
ADN2850
TOP VIEW
(Not to Scale)
0
2
6
0
-0
0
5
Figure 4. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
Mnemonic
Description
1
CLK
Serial Input Register Clock. Shifts in one bit at a time on positive clock edges.
2
SDI
Serial Data Input. Shifts in one bit at a time on positive clock CLK edges. MSB loads first.
3
SDO
Serial Data Output. Serves readback and daisy-chain functions. Command 9 and Command 10 activate the SDO
output for the readback function, delayed by 24 or 25 clock pulses, depending on the clock polarity before and
previously shifted out SDI can be used for daisy-chaining multiple devices. Whenever SDO is used, a pull-up
resistor in the range of 1 k to 10 k is needed.
4
GND
Ground Pin, Logic Ground Reference.
5
VSS
Negative Supply. Connect to 0 V for single-supply applications. If VSS is used in dual supply, it must be able to sink
2 mA for 15 ms when storing data to EEMEM.
6
V1
Log Output Voltage 1. Generates voltage from an internal diode configured transistor.
7
W1
Wiper Terminal of RDAC1. ADDR (RDAC1) = 0x0.
8
B1
Terminal B of RDAC1.
9
B2
Terminal B of RDAC2.
10
W2
Wiper terminal of RDAC2. ADDR (RDAC2) = 0x1.
11
V2
Log Output Voltage 2. Generates voltage from an internal diode configured transistor.
12
VDD
Positive Power Supply.
13
AA
WPEE
Optional Write Protect. When active low,
AA
WPEE
AA
prevents any changes to the present contents, except
AA
PREE
AA
strobe.
CMD_1 and COMD_8 refresh the RDAC register from EEMEM. Tie
AA
WPEE
AA
to VDD, if not used.
14
AA
PREE
Optional Hardware Override Preset. Refreshes the scratchpad register with current contents of the EEMEM
register. Factory default loads midscale 51210 until EEMEM is loaded with a new value by the user.
AA
PREE
AA
is activated
at the logic high transition. Tie
AA
PREE
AA
to VDD, if not used.
15
AA
CSEE
Serial Register Chip Select Active Low. Serial register operation takes place when
AA
CSEE
AA
returns to logic high.
16
RDY
Ready. Active high open-drain output. Identifies completion of Instruction 2, Instruction 3, Instruction 8,
Instruction 9, Instruction 10, and
AA
PREE
AA
.