
REV. A
AD8305
–3–
ABSOLUTE MAXIMUM RATINGS
1
Supply Voltage V
P
– V
N
. . . . . . . . . . . . . . . . . . . . . . . . . . .12 V
Input Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 mA
Internal Power Dissipation . . . . . . . . . . . . . . . . . . . . .500 mW
JA2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
∞
C/W
Maximum Junction Temperature . . . . . . . . . . . . . . . . . 125
∞
C
Operating Temperature Range . . . . . . . . . . . .–40
∞
C to +85
∞
C
Storage Temperature Range . . . . . . . . . . . . .–65
∞
C to +150
∞
C
Lead Temperature Range (Soldering 60 sec) . . . . . . . . . 300
∞
C
NOTES
1
Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
2
With package die paddle soldered to thermal pad containing nine vias connected
to inner and bottom layers.
PIN CONFIGURATION
AD8305
TOP VIEW
12 VOUT
11 SCAL
10 BFIN
9 VLOG
VRDZ 1
VREF 2
IREF 3
INPT 4
V
V
V
V
1
1
1
1
PIN 1
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.
Reference Output Voltage of 2.5 V.
Accepts (Sinks) Reference Current, I
REF.
Accepts (Sinks) Photodiode Current, I
PD
. Usually connected to photodiode anode such that photo
current flows into INPT.
Guard Pin. Used to shield the INPT current line and for optional adjustment of the INPT and I
REF
node potential.
Optional Negative Supply, V
N
. (This pin is usually grounded; for details of usage, see the Applications section).
Positive Supply, (V
P
– V
N
)
£
12 V.
Output of the Logarithmic Front End.
Buffer Amplifier Noninverting Input.
Buffer Amplifier Inverting Input.
Buffer Output.
Analog Ground.
2
3
4
VREF
IREF
INPT
5
VSUM
6, 7
8
9
10
11
12
13–16
VNEG
VPOS
VLOG
BFIN
SCAL
VOUT
COMM
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although the
AD8305 features proprietary ESD protection circuitry, permanent damage may occur on devices
subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended
to avoid performance degradation or loss of functionality.
ORDERING GUIDE
Temperature
Range
Package
Description
Package
Option
Model
AD8305ACP
AD8305ACP-REEL7 7" Tape and Reel
AD8305-EVAL
–40
∞
C to +85
∞
C
16-Lead LFCSP CP-16
Evaluation Board