Datasheet

AD8305
Rev. B | Page 5 of 24
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
AD8305
12 VOUT
NOTES
1. CONNECT EPAD TO GROUND.
11 SCAL
10 BFIN
9 VLOG
VRDZ 1
VREF 2
IREF 3
VSUM 5
VNEG 6 VNEG 7
VPOS 8
INPT 4
16 COMM 15 COMM 14 COMM 13 COMM
PIN 1
INDICATOR
TOP VIEW
(Not to Scale)
03053-002
Figure 2. Pin Configuration
Table 3. Pin Function Descriptions
Pin No. Mnemonic Function
1 VRDZ
Top of a Resistive Divider Network that Offsets V
LOG
to Position the Intercept. Normally connected to VREF;
may also be connected to ground when bipolar outputs are to be provided.
2 VREF Reference Output Voltage of 2.5 V.
3 IREF Accepts (Sinks) Reference Current, I
REF
.
4 INPT
Accepts (Sinks) Photodiode Current, I
PD
. Usually connected to photodiode anode such that photo current
flows into INPT.
5 VSUM
Guard Pin. Used to shield the INPT current line and for optional adjustment of the INPT and I
REF
node
potential.
6, 7 VNEG Optional Negative Supply, V
N
(this pin is usually grounded; for details of usage, see the Applications section.
8 VPOS Positive Supply, (V
P
− V
N
) ≤ 12 V.
9 VLOG Output of the Logarithmic Front End.
10 BFIN Buffer Amplifier Noninverting Input.
11 SCAL Buffer Amplifier Inverting Input.
12 VOUT Buffer Output.
13 to 16 COMM Analog Ground.
EPAD The exposed pad must be soldered to ground.