Datasheet
Table Of Contents
- 1.0 Electrical Characteristics
- 2.0 Typical Performance Curves
- FIGURE 2-1: Input Offset Voltage.
- FIGURE 2-2: Input Bias Current at TA = +85˚C.
- FIGURE 2-3: Input Offset Voltage vs. Common Mode Input Voltage, with VDD = 2.0V.
- FIGURE 2-4: Input Offset Voltage Drift.
- FIGURE 2-5: Input Bias Current at TA = +125˚C.
- FIGURE 2-6: Input Offset Voltage vs. Common Mode Input Voltage, with VDD = 5.5V.
- FIGURE 2-7: Common Mode Input Voltage Range Lower Limit vs. Temperature.
- FIGURE 2-8: Input Offset Voltage vs. Output Voltage.
- FIGURE 2-9: CMRR, PSRR vs. Frequency.
- FIGURE 2-10: Common Mode Input Voltage Range Upper Limit vs. Temperature.
- FIGURE 2-11: Input Bias, Input Offset Currents vs. Temperature.
- FIGURE 2-12: CMRR, PSRR vs. Temperature.
- FIGURE 2-13: Input Bias, Offset Currents vs. Common Mode Input Voltage, with TA = +85˚C.
- FIGURE 2-14: Quiescent Current vs. Supply Voltage.
- FIGURE 2-15: Open-Loop Gain, Phase vs. Frequency.
- FIGURE 2-16: Input Bias, Offset Currents vs. Common Mode Input Voltage, with TA = +125˚C.
- FIGURE 2-17: Output Voltage Headroom vs. Output Current Magnitude.
- FIGURE 2-18: Gain Bandwidth Product, Phase Margin vs. Temperature.
- FIGURE 2-19: Maximum Output Voltage Swing vs. Frequency.
- FIGURE 2-20: Input Noise Voltage Density vs. Frequency.
- FIGURE 2-21: Output Short Circuit Current vs. Supply Voltage.
- FIGURE 2-22: Slew Rate vs. Temperature.
- FIGURE 2-23: Input Noise Voltage Density vs. Common Mode Input Voltage, with f = 1 kHz.
- FIGURE 2-24: Channel-to-Channel Separation vs. Frequency (MCP6272 and MCP6274).
- FIGURE 2-25: Quiescent Current vs. Chip Select (CS) Voltage, with VDD = 2.0V (MCP6273 and MCP6275 only).
- FIGURE 2-26: Large Signal Non-inverting Pulse Response.
- FIGURE 2-27: Small Signal Non-inverting Pulse Response.
- FIGURE 2-28: Quiescent Current vs. Chip Select (CS) Voltage, with VDD = 5.5V (MCP6273 and MCP6275 only).
- FIGURE 2-29: Large Signal Inverting Pulse Response.
- FIGURE 2-30: Small Signal Inverting Pulse Response.
- FIGURE 2-31: Chip Select (CS) to Amplifier Output Response Time, with VDD = 2.0V (MCP6273 and MCP6275 only).
- FIGURE 2-32: Input Current vs. Input Voltage.
- FIGURE 2-33: Chip Select (CS) to Amplifier Output Response Time, with VDD = 5,5V (MCP6273 and MCP6275 only).
- FIGURE 2-34: The MCP6271/1R/2/3/4/5 Show no Phase Reversal.
- 3.0 Pin Descriptions
- 4.0 Application Information
- 4.1 Rail-to-Rail Inputs
- 4.2 Rail-to-Rail Output
- 4.3 Capacitive Loads
- 4.4 MCP6273/5 Chip Select
- 4.5 Cascaded Dual Op Amps (MCP6275)
- 4.6 Unused Amplifiers
- 4.7 Supply Bypass
- 4.8 PCB Surface Leakage
- 4.9 Application Circuits
- FIGURE 4-8: Active Full-wave Rectifier.
- FIGURE 4-9: Non-Inverting Integrator.
- FIGURE 4-10: Isolating the Load with a Buffer.
- FIGURE 4-11: Cascaded Gain Circuit Configuration.
- FIGURE 4-12: Difference Amplifier Circuit.
- FIGURE 4-13: Integrator Circuit with Active Compensation.
- FIGURE 4-14: Second Order Multiple Feedback Low-Pass Filter with an Extra Pole- Zero Pair.
- FIGURE 4-15: Second Order Sallen-Key Low-Pass Filter with an Extra Pole-Zero Pair and Chip Select.
- FIGURE 4-16: Capacitorless Second Order Low-Pass Filter with Chip Select.
- 5.0 Design Tools
- 6.0 Packaging Information
© 2008 Microchip Technology Inc. DS21810F-page 17
MCP6271/1R/2/3/4/5
4.9.3 CASCADED OP AMP
APPLICATIONS
The MCP6275 provides the flexibility of Low power
mode for dual op amps in an 8-pin package. The
MCP6275 eliminates the added cost and space in a
battery powered application by using two single op
amps with Chip Select (CS
) lines or a 10-pin device
with one CS
line for both op amps. Since the two op
amps are internally cascaded, this device cannot be
used in circuits that require active or passive elements
between the two op amps. However, there are several
applications where this op amp configuration with a CS
line becomes suitable. The circuits below show
possible applications for this device.
4.9.3.1 Load Isolation
With the cascaded op amp configuration, op amp B can
be used to isolate the load from op amp A. In
applications where op amp A is driving capacitive or
low resistive loads in the feedback loop (such as an
integrator or filter circuit) the op amp may not have
sufficient source current to drive the load. In this case,
op amp B can be used as a buffer.
FIGURE 4-10: Isolating the Load with a
Buffer.
4.9.3.2 Cascaded Gain
Figure 4-11 shows a cascaded gain circuit configura-
tion with Chip Select. Op amps A and B are configured
in a non-inverting amplifier configuration. In this
configuration, it is important to note that the input offset
voltage of op amp A is amplified by the gain of op amp
A and B, as shown below:
Therefore, it is recommended that you set most of the
gain with op amp A and use op amp B with relatively
small gain (e.g., a unity gain buffer).
FIGURE 4-11: Cascaded Gain Circuit
Configuration.
4.9.3.3 Difference Amplifier
Figure 4-12 shows op amp A configured as a difference
amplifier with Chip Select. In this configuration, it is
recommended that well matched resistors (e.g., 0.1%)
be used to increase the Common Mode Rejection Ratio
(CMRR). Op amp B can be used to provide additional
gain and isolate the load from the difference amplifier.
FIGURE 4-12: Difference Amplifier Circuit.
4.9.3.4 Inverting Integrator with Active
Compensation and Chip Select
Figure 4-13 uses an active compensator (op amp B) to
compensate for the non-ideal op amp characteristics
introduced at higher frequencies. This circuit uses
op amp B as a unity gain buffer to isolate the
integration capacitor C
1
from op amp A and drives the
capacitor with a low impedance source. Since both op
amps are matched very well, they provide a high quality
integrator.
FIGURE 4-13: Integrator Circuit with Active
Compensation.
A
CS
V
OUTB
MCP6275
B
Load
V
OUT
V
IN
G
A
G
B
V
OSA
G
A
G
B
V
OSB
G
B
++=
Where:
G
A
= op amp A gain
G
B
= op amp B gain
V
OSA
= op amp A input offset voltage
V
OSB
= op amp B input offset voltage
A
CS
R
4
R
3
R
2
R
1
V
IN
V
OUT
MCP6275
B
A
CS
R
2
R
1
R
4
R
3
V
OUT
MCP6275
V
IN2
B
R
2
R
1
V
IN1
A
CS
R
1
C
1
V
OUT
MCP6275
V
IN
B