AD8625 Analog Devices, AD8625 Datasheet - Page 14

• Manufacturer Part Number: AD8625
• Description: Precision, Low Power, Single-Supply, JFET Amplifier
• Manufacturer: Analog Devices

Specifications of AD8625

• -3db Bandwidth: 5MHz
• Slew Rate: 5V/µs
• Vos: 50µV
• Ib: 0.25pA
• # Opamps Per Pkg: 4
• Input Noise (nv/rthz): 16nV/rtHz
• Vcc-vee: 5V to 26V
• Isy Per Amplifier: 850µA
• Packages: SOIC,SOP

AD8625/AD8626/AD8627
The AD862x can safely withstand input voltages 15 V below
V
terminal is less than 26 V. Figure 41 through Figure 43 show the
AD862x in different configurations accommodating signals
close to the negative rail. The amplifier input stage typically
maintains picoamp-level input currents across that input
voltage range.
SY
if the total voltage between the positive supply and the input
0V
5V
0V
Figure 42. Unity Gain Follower Response to 40 mV Step,
Figure 41. Gain-of-Two Inverter Response to 2.5 V Step,
V
SY
V
R
SY
L
= 5V, 0V
= 600
= 5V
Centered 40 mV above Ground
Centered 1.25 V below Ground
Ω
60mV
20mV
0V
0V
–2.5V
10k
TIME (2
TIME (2
Ω
μ
μ
s/DIV)
s/DIV)
5V
20k
+5V
Ω
600
Ω
Rev. E | Page 14 of 20
The AD862x is designed for 16 nV/√Hz wideband input voltage
noise and maintains low noise performance to low frequencies,
as shown in Figure 35. This noise performance, along with the
AD862x’s low input current and current noise, means that the
AD862x contributes negligible noise for applications with large
source resistances.
The AD862x has a unique bipolar rail-to-rail output stage that
swings within 5 mV of the rail when up to 2 mA of current is
drawn. At larger loads, the drop-out voltage increases, as shown
in Figure 17 and Figure 18. The AD862x’s wide bandwidth and
fast slew rate allows it to be used with faster signals than older
single-supply JFETs. Figure 44 shows the response of the
AD862x, configured in unity gain, to a V
50 kHz. The full-power bandwidth (FPBW) of the part is close
to 100 kHz.
Figure 44. Unity Gain Follower Response to 20 V, 50 kHz Input Signal
0V
0V
Figure 43. Gain-of-Two Inverter Response to 20 mV Step,
V
R
SY
L
= 600
=
±
13V
Ω
Centered 20 mV below Ground
0V
–10mV
–30mV
10k
TIME (2
TIME (5
Ω
μ
μ
s/DIV)
s/DIV)
20k
+5V
Ω
IN
of 20 V p-p at
V
SY
= 5V