AD8626 Analog Devices, AD8626 Datasheet - Page 13

• Manufacturer Part Number: AD8626
• Description: Precision, Low Power, Single-Supply, JFET Amplifier in MSOP
• Manufacturer: Analog Devices

Specifications of AD8626

• -3db Bandwidth: 5MHz
• Slew Rate: 5V/µs
• Vos: 50µV
• Ib: 0.25pA
• # Opamps Per Pkg: 2
• Input Noise (nv/rthz): 16nV/rtHz
• Vcc-vee: 5V to 26V
• Isy Per Amplifier: 850µA
• Packages: SOIC,SOP

APPLICATIONS INFORMATION
The AD862x is one of the smallest and most economical
JFETs offered. It has true single-supply capability and has
an input voltage range that extends below the negative rail,
allowing the part to accommodate input signals below ground.
The rail-to-rail output of the AD862x provides the maximum
dynamic range in many applications. To provide a low offset,
low noise, high impedance input stage, the AD862x uses
n-channel JFETs. The input common-mode voltage extends
from 0.2 V below –V
the amplifier, configured in the unity gain buffer, closer than
2 V to the positive rail causes an increase in common-mode
voltage error, as illustrated in Figure 15, and a loss of amplifier
bandwidth. This loss of bandwidth causes the rounding of the
output waveforms shown in Figure 39 and Figure 40, which
have inputs that are 1 V and 0 V from +V
The AD862x does not experience phase reversal with input
signals close to the positive rail, as shown in Figure 29. For
input voltages greater than +V
AD862x’s noninverting input prevents phase reversal at the
expense of greater input voltage noise. This current-limiting
resistor should also be used if there is a possibility of the input
voltage exceeding the positive supply by more than 300 mV, or
if an input voltage is applied to the AD862x when ±V
Either of these conditions damages the amplifier if the
condition exists for more than 10 seconds. A 100 kΩ resistor
allows the amplifier to withstand up to 10 V of continuous
overvoltage, while increasing the input voltage noise by a
negligible amount.
S
to 2 V below +V
SY
, a resistor in series with the
S
. Driving the input of
S
, respectively.
SY
= 0.
Rev. E | Page 13 of 20
5V
0V
4V
0V
4V
0V
0V
4V
Figure 39. Unity Gain Follower Response to 0 V to 4 V Step
Figure 40. Unity Gain Follower Response to 0 V to 5 V Step
V
V
SY
SY
= 5V
= 5V
OUTPUT
OUTPUT
INPUT
INPUT
AD8625/AD8626/AD8627
TIME (2
TIME (2
μ
μ
s/DIV)
s/DIV)