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 15
MCP6271/1R/2/3/4/5
4.6 Unused Amplifiers
An unused op amp in a quad package (MCP6274)
should be configured as shown in Figure 4-6. These
circuits prevent the output from toggling and causing
crosstalk. In Circuit A, R
1
and R
2
produce a voltage
within its output voltage range (V
OH
, V
OL
). The op amp
buffers this voltage, which can be used elsewhere in
the circuit. Circuit B uses the minimum number of
components and operates as a comparator.
FIGURE 4-6: Unused Op Amps.
4.7 Supply Bypass
With this family of operational amplifiers, the power
supply pin (V
DD
for single supply) should have a local
bypass capacitor (i.e., 0.01 µF to 0.1 µF) within 2 mm
for good, high frequency performance. It also needs a
bulk capacitor (i.e., 1 µF or larger) within 100 mm to
provide large, slow currents. This bulk capacitor can be
shared with nearby analog parts.
4.8 PCB Surface Leakage
In applications where low input bias current is critical,
Printed Circuit Board (PCB) surface leakage effects
need to be considered. Surface leakage is caused by
humidity, dust or other contamination on the board.
Under low humidity conditions, a typical resistance
between nearby traces is 10
12
Ω. A 5V difference would
cause 5 pA of current to flow. This is greater than the
MCP6271/1R/2/3/4/5 family’s bias current at 25°C
(1 pA, typical).
The easiest way to reduce surface leakage is to use a
guard ring around sensitive pins (or traces). The guard
ring is biased at the same voltage as the sensitive pin.
An example of this type of layout is illustrated in
Figure 4-7.
FIGURE 4-7: Example Guard Ring Layout
for Inverting Gain.
1. For Inverting Gain and Transimpedance
Amplifiers (convert current to voltage, such as
photo detectors):
a) Connect the guard ring to the non-inverting
input pin (V
IN
+). This biases the guard ring
to the same reference voltage as the op
amp (e.g., V
DD
/2 or ground).
b) Connect the inverting pin (V
IN
–) to the input
with a wire that does not touch the PCB
surface.
2. Non-inverting Gain and Unity Gain Buffer:
a) Connect the non-inverting pin (V
IN
+) to the
input with a wire that does not touch the
PCB surface.
b) Connect the guard ring to the inverting input
pin (V
IN
–). This biases the guard ring to the
common mode input voltage.
¼ MCP6274 (A)
V
DD
¼ MCP6274 (B)
R
1
R
2
V
DD
V
DD
V
REF
V
REF
V
DD
R
2
R
1
R
2
+
------------------
⋅=
Guard Ring
V
SS
V
IN
–V
IN
+