MCP601-I/SL Microchip Technology, MCP601-I/SL Datasheet - Page 11

• Manufacturer Part Number: MCP601-I/SL
• Description: 2.7V to 5.5V Single Supply CMOS Op Amps
• Manufacturer: Microchip Technology

3.0
The MCP601/2/3/4 family of op amps are fabricated on
Microchip’s state-of-the-art CMOS process. They are
unity-gain stable and suitable for a wide range of
general purpose applications.
3.1
The MCP601/2/3/4 amplifier family is designed to not
exhibit phase reversal when the input pins exceed the
supply rails. Figure 2-33 shows an input voltage that
exceeds both supplies with no resulting phase
inversion.
The Common Mode Input Voltage Range (V
includes ground in single-supply systems (V
does not include V
input behaves linearly as long as the Common Mode
Input Voltage (V
limits (V
Input voltages that exceed the input voltage range
(V
sive current to flow into or out of the input pins. Current
beyond ±2 mA may cause reliability problems.
Applications that exceed this rating must externally
limit the input current with a resistor (R
Figure 3-1.
FIGURE 3-1:
into an input pin.
3.2
There are two specifications that describe the output
swing capability of the MCP601/2/3/4 family of op amps.
The first specification (Maximum Output Voltage Swing)
defines the absolute maximum swing that can be
achieved under the specified load conditions. For
instance, the output voltage swings to within 15 mV of
the negative rail with a 25 k load to V
shows how the output voltage is limited when the input
goes beyond the linear region of operation.
2004 Microchip Technology Inc.
SS
– 0.3V to V
V
SS
APPLICATIONS INFORMATION
IN
Input
Rail-to-Rail Output
R
R
IN
– 0.3V to V
IN
----------------------------------------------------------------------------- -
V
-------------------------------------------------------------------------- -
maximum expected V
DD
CM
SS
R
) is kept within the specified V
– 1.2V at +25°C) can cause exces-
DD
IN
–
. This means that the amplifier
DD
minimum expected V
R
IN
– 1.2V at +25°C).
+
–
MCP60X
limits the current flow
2 mA
2 mA
IN
DD
IN
–
/2. Figure 2-33
), as shown in
V
IN
DD
SS
), but
CMR
CMR
)
The second specification that describes the output
swing capability of these amplifiers is the Linear Output
Voltage Swing. This specification defines the maximum
output swing that can be achieved while the amplifier is
still operating in its linear region. To verify linear
operation in this range, the large signal (DC Open-Loop
Gain (A
supply rails. The measurement must exceed the
specified gains in the specification table.
3.3
The MCP603 is a single amplifier with Chip Select
(CS). When CS is pulled high, the supply current drops
to -0.7 µA (typ.), which is pulled through the CS pin to
V
a high-impedance state. Pulling CS low enables the
amplifier and, if the CS pin is left floating, the amplifier
may not operate properly. Figure 1-1 is the Chip Select
timing diagram and shows the output voltage, supply
currents and CS current in response to a CS pulse.
Figure 2-27 shows the measured output voltage
response to a CS pulse.
3.4
Driving large capacitive loads can cause stability
problems for voltage feedback op amps. As the load
capacitance increases, the feedback loop’s phase
margin decreases and the closed-loop bandwidth is
reduced. This produces gain peaking in the frequency
response with overshoot and ringing in the step
response.
When driving large capacitive loads with these op
amps (e.g., > 40 pF when G = +1), a small series
resistor at the output (R
feedback loop’s phase margin (stability) by making the
output load resistive at higher frequencies. The
bandwidth will be generally lower than the bandwidth
with no capacitive load.
FIGURE 3-2:
stabilizes large capacitive loads.
Figure 3-3 gives recommended R
different capacitive loads and gains. The x-axis is the
normalized load capacitance (C
it easier to interpret the plot for arbitrary gains. G
circuit’s noise gain. For non-inverting gains, G
gain are equal. For inverting gains, G
(e.g., -1 V/V gives G
SS
. When this happens, the amplifier output is put into
R
OL
MCP603 Chip Select (CS)
Capacitive Loads
G
)) is measured at points 100 mV inside the
+
–
MCP60X
MCP601/2/3/4
N
R
= +2 V/V).
Output resistor R
ISO
F
in Figure 3-2) improves the
L
/G
R
N
ISO
) in order to make
DS21314F-page 11
C
ISO
N
L
= 1 + |Gain|
ISO
values for
N
and the
V
N
OUT
is the