MCP6272 Microchip Technology Inc., MCP6272 Datasheet - Page 12

• Manufacturer Part Number: MCP6272
• Description: 170 ?a, 2 Mhz Rail-to-rail Op Am
• Manufacturer: Microchip Technology Inc.

MCP6271/1R/2/3/4/5
4.0
The MCP6271/1R/2/3/4/5 family of op amps is
manufactured using Microchip’s state of the art CMOS
process, specifically designed for low cost, low power
and general purpose applications. The low supply
voltage, low quiescent current and wide bandwidth
make the MCP6271/1R/2/3/4/5 ideal for battery
powered applications.
4.1
The input stage of the MCP6271/1R/2/3/4/5 op amps
uses two differential CMOS input stages in parallel.
One operates at low common mode input voltage (V
which is aproximately equal to V
operation) and the other at high V
ogy, the input operates with V
supply rail (see
offset voltage (V
and V
The transition between the two input stage occurs
when V
6). For the best distortion and gain linearity, with non-
inverting gains, avoid this region of operation.
4.1.1
The input devices are designed to not exhibit phase
inversion when the input pins exceed the supply
voltages.
exceeding both supplies with no phase inversion.
4.1.2
The ESD protection on the inputs can be depicted as
shown in
protect the input transistors, and to minimize input bias
current (I
when they try to go more than one diode drop below
V
above V
allow normal operation, and low enough to bypass
quick ESD events within the specified limits.
FIGURE 4-1:
Structures.
DS21810E-page 12
SS
. They also clamp any voltages that go too far
V
V
V
DD
IN
DD
SS
CM
DD
+
APPLICATION INFORMATION
Rail-to-Rail Inputs
+ 0.3V to ensure proper operation.
B
). The input ESD diodes clamp the inputs
Figure
≈ V
; their breakdown voltage is high enough to
Bond
Bond
Bond
Figure 2-34
PHASE REVERSAL
INPUT VOLTAGE AND CURRENT
LIMITS
Pad
Pad
Pad
DD
Figure 2-7
OS
– 1.1V (see
4-1. This structure was chosen to
) is measured at V
Simplified Analog Input ESD
Stage
Input
shows
and
CM
Figure 2-3
Figure
IN
up to 0.3V past either
+ and V
an
CM
. With this topol-
Bond
CM
Pad
2-10). The input
input
and
= V
IN
– in normal
SS
V
Figure 2-
IN
voltage
– 0.3V
–
CM
,
In order to prevent damage and/or improper operation
of these amplifiers, the circuit must limit the currents
(and voltages) at the input pins (see Absolute Maxi-
mum Ratings † at the beginning of Section 1.0 “Elec-
trical
recommended approach to protecting these inputs.
The internal ESD diodes prevent the input pins (V
and V
resistors R
of the input pins. Diodes D
pins (V
dump any currents onto V
shown, resistors R
through D
FIGURE 4-2:
Inputs.
It is also possible to connect the diodes to the left of the
resistor R
the diodes D
mechanism. The resistors then serve as in-rush current
limiters; the DC current into the input pins (V
V
A significant amount of current can flow out of the
inputs (through the ESD diodes) when the common
mode voltage (V
Figure
need to limit the useable voltage range.
4.2
The output voltage range of the MCP6271/1R/2/3/4/5
op amps is V
(max.) when R
V
IN
DD
–) should be very small.
V
V
= 5.5V. Refer to
1
2
IN
IN
2-32. Applications that are high impedance may
Characteristics”).
–) from going too far below ground, and the
+ and V
Rail-to-Rail Output
R
R
1
1
1
1
2
and D
and R
and R
1
R
R
>
>
and D
1
2
D
V
V
L
DD
1
SS
SS
IN
= 10 kΩ is connected to V
2
2
2
–) from going too far above V
D
CM
.
– 15 mV (min.) and V
. In this case, the currents through
– (minimum expected V
– (minimum expected V
limit the possible current drawn out
2
1
2
Figure 2-17
) is below ground (V
need to be limited by some other
and R
Protecting the Analog
© 2006 Microchip Technology Inc.
MCP627X
DD
2 mA
2 mA
1
and D
Figure 4-2
2
. When implemented as
V
also limit the current
DD
for more information.
2
prevent the input
shows
SS
1
2
)
)
V
DD
SS
OUT
+ 15 mV
IN
DD
); see
/2 and
+ and
, and
the
IN
+