Datasheet
AD8646/AD8647/AD8648
Rev. D | Page 5 of 20
V
SY
= 2.7 V, V
CM
= V
SY
/2, T
A
= +25
o
C, unless otherwise noted.
Table 2.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage V
OS
V
CM
= 0 V to 2.7 V 0.6 2.5 mV
−40°C < T
A
< +125°C 3.2 mV
Offset Voltage Drift ∆V
OS
/∆T −40°C < T
A
< +125°C 1.8 7.0 V/°C
Input Bias Current I
B
0.2 1 pA
−40°C < T
A
< +85°C 50 pA
−40°C < T
A
< +125°C 550 pA
Input Offset Current I
OS
0.1 0.5 pA
−40°C < T
A
< +85°C 50 pA
−40°C < T
A
< +125°C 250 pA
Input Voltage Range V
CM
0 2.7 V
Common-Mode Rejection Ratio CMRR V
CM
= 0 V to 2.7 V 62 79 dB
Large Signal Voltage Gain A
VO
R
L
= 2 kΩ, V
O
= 0.5 V to 2.2 V 95 102 dB
Input Capacitance
Differential C
DIFF
2.5 pF
Common Mode C
CM
7.8 pF
OUTPUT CHARACTERISTICS
Output Voltage High V
OH
I
OUT
= 1 mA 2.65 2.68 V
−40°C < T
A
< +125°C 2.60 V
Output Voltage Low V
OL
I
OUT
= 1 mA 11 25 mV
−40°C < T
A
< +125°C 30 mV
Output Current I
sc
Short circuit ±63 mA
Closed-Loop Output Impedance Z
OUT
At 1 MHz, A
V
= 1 5 Ω
POWER SUPPLY
Power Supply Rejection Ratio PSRR V
SY
= 2.7 V to 5.5 V 63 80 dB
Supply Current per Amplifier I
SY
1.6 2.0 mA
−40°C < T
A
< +125°C 2.5 mA
Supply Current Shutdown Mode
(AD8647 Only)
I
SD
Both amplifiers shut down,
V
IN_SDA
and V
IN_SDB
= 0 V
10 nA
−40°C < T
A
< +125°C 1 µA
SHUTDOWN INPUTS (AD8647)
Logic High Voltage (Enabled) V
INH
−40°C < T
A
< +125°C +2.0 V
Logic Low Voltage (Power-Down) V
INL
−40°C < T
A
< +125°C +0.8 V
Logic Input Current (Per Pin) I
IN
−40°C < T
A
< +125°C 1 µA
Output Pin Leakage Current
−40°C < T
A
< +125°C (shutdown active) 1 nA
DYNAMIC PERFORMANCE
Slew Rate SR R
L
= 2 kΩ 11 V/s
Gain Bandwidth Product GBP 24 MHz
Phase Margin Ø
m
53 Degrees
Settling Time t
s
To 0.1% 0.3 s
Amplifier Turn-On Time (AD8647) t
on
25°C, A
V
= 1, R
L
= 1 kΩ (see Figure 41) 1.2 s
Amplifier Turn-Off Time (AD8647) t
off
25°C, A
V
= 1, R
L
= 1 kΩ (see Figure 42) 1 s
NOISE PERFORMANCE
Peak-to-Peak Noise e
n
p-p 0.1 Hz to 10 Hz 2.3 V
Voltage Noise Density e
n
f = 1 kHz 8 nV/√Hz
f = 10 kHz 6 nV/√Hz
Channel Separation CS f = 10 kHz −115 dB
f = 100 kHz −110 dB