SR = 54V/s
VS = ؎13V
RL = 2k⍀
G = –1
AD8610/AD8620
VS = ؎13V
RL = 2k⍀
G = –1
SR = 56V/s
TIME – 400ns/DIV
Figure 9. (+SR) of AD8610/AD8620 in Unity Gain of –1
VS = ؎13V
RL = 2k⍀
G = –1
SR = 42.1V/s
TIME – 400ns/DIV
Figure 10. (+SR) of OPA627 in Unity Gain of –1
VS = ؎13V
RL = 2k⍀
G = –1
SR = 54V/s
TIME – 400ns/DIV
Figure 12. (–SR) of OPA627 in Unity Gain of –1
The AD8610 has a very fast slew rate of 60 V/µs even when config-
ured in a noninverting gain of +1. This is the toughest condition to
impose on any amplifier since the input common-mode capacitance
of the amplifier generally makes its SR appear worse. The slew
rate of an amplifier varies according to the voltage difference
between its two inputs. To observe the maximum SR as specified
in the AD8610 data sheet, a difference voltage of about 2 V between
the inputs must be ensured. This will be required for virtually any
JFET op amp so that one side of the op amp input circuit is com-
pletely off, maximizing the current available to charge and discharge
the internal compensation capacitance. Lower differential
drive voltages will produce lower slew rate readings. A JFET-
input op amp with a slew rate of 60 V/µs at unity gain with
VIN = 10 V might slew at 20 V/µs if it is operated at a gain of
+100 with VIN = 100 mV.
The slew rate of the AD8610/AD8620 is double that of the OPA627
when configured in a unity gain of +1 (see Figures 13 and 14).
VS = ؎13V
RL = 2k⍀
G = +1
SR = 85V/s
TIME – 400ns/DIV
Figure 11. (–SR) of AD8610/AD8620 in Unity Gain of –1
TIME – 400ns/DIV
Figure 13. (+SR) of AD8610/AD8620 in Unity Gain of +1
REV. D
–11–