Datasheet

AD8305
Rev. B | Page 3 of 24
SPECIFICATIONS
V
P
= 5 V, V
N
= 0 V, T
A
= 25°C, R
REF
= 200 kΩ, and VRDZ connected to VREF, unless otherwise noted.
Table 1.
Parameter Conditions Min Typ Max Unit
INPUT INTERFACE Pin 4, INPT, Pin 3, IREF
Specified Current Range, I
PD
Flows toward INPT pin 10 nA
1 mA
Input Current Min/Max Limits Flows toward INPT pin 10 mA
Reference Current, I
REF
, Range Flows toward IREF pin 10 nA
1 mA
Summing Node Voltage Internally preset; may be altered by the user 0.46 0.5 0.54 V
Temperature Drift −40°C < T
A
< +85°C 0.015 mV/°C
Input Offset Voltage V
INPT
− V
SUM
, V
IREF
− V
SUM
−20 +20 mV
LOGARITHMIC OUTPUT Pin 9, VLOG
Logarithmic Slope 190 200 210 mV/dec
−40°C < T
A
< +85°C 185 215 mV/dec
Logarithmic Intercept
1
0.3 1 1.7 nA
−40°C < T
A
< +85°C 0.1 2.5 nA
Law Conformance Error 10 nA < I
PD
< 1 mA 0.1 0.4 dB
Wideband Noise
2
I
PD
> 1 μA 0.7 mV√Hz
Small Signal Bandwidth
2
I
PD
> 1 μA 0.7 MHz
Maximum Output Voltage 1.7 V
Minimum Output Voltage Limited by V
N
= 0 V 0.01 V
Output Resistance 4.375 5 5.625 kΩ
REFERENCE OUTPUT Pin 2, VREF
Voltage With Reference to Ground 2.435 2.5 2.565 V
−40°C < T
A
< +85°C 2.4 2.6 V
Maximum Output Current Sourcing (grounded load) 20 mA
Incremental Output Resistance Load current < 10 mA 2 Ω
OUTPUT BUFFER Pin 10, BFIN; Pin 11, SCAL; Pin 12, VOUT
Input Offset Voltage −20 +20 mV
Input Bias Current Flowing out of Pin 10 or Pin 11 0.4 mA
Incremental Input Resistance 35 MΩ
Output Range R
L
= 1 kΩ to ground V
P
− 0.1 V
Incremental Output Resistance Load current < 10 mA 0.5 Ω
Peak Source/Sink Current 25 mA
Small Signal Bandwidth GAIN = 1 15 MHz
Slew Rate 0.2 V to 4.8 V output swing 15 V/μs
POWER SUPPLY Pin 8, VPOS; Pin 6 and Pin 7, VNEG
Positive Supply Voltage (V
P
− V
N
) ≤ 12 V 3 5 12 V
Quiescent Current 5.4 6.5 mA
Negative Supply Voltage (Optional) (V
P
− V
N
) ≤ 12 V −5.5 0 V
1
Other values of logarithmic intercept can be achieved by adjusting R
REF
.
2
Output noise and incremental bandwidth are functions of input current, measured using output buffer connected for GAIN = 1.