MCP6285T-E/MS Microchip Technology, MCP6285T-E/MS Datasheet - Page 15

• Manufacturer Part Number: MCP6285T-E/MS
• Description: IC OPAMP 2.2V DUAL W/CS 8MSOP
• Manufacturer: Microchip Technology

Specifications of MCP6285T-E/MS

• Amplifier Type: General Purpose
• Number Of Circuits: 2
• Output Type: Rail-to-Rail
• Slew Rate: 2.5 V/µs
• Gain Bandwidth Product: 5MHz
• Current - Input Bias: 1pA
• Voltage - Input Offset: 3000µV
• Current - Supply: 450µA
• Current - Output / Channel: 25mA
• Voltage - Supply, Single/dual (±): 2.2 V ~ 6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• -3db Bandwidth: -

4.9
4.9.1
The MCP6281/1R/2/3/4/5 op amps can be used in
active-filter applications.
order Sallen-Key high-pass filter with a gain of 1. The
output bias voltage is set by the V
can be changed to any voltage within the output voltage
range.
FIGURE 4-8:
This filter, and others, can be designed using
Microchip’s Design Aids; see Section 5.2 “FilterLab®
Software”
Designer & Simulator”.
4.9.2
Analog integrators are used in filters, control loops and
measurement circuits.
common implementation, the inverting Miller integrator.
The non-inverting input is at V
properly biases up. The switch (SW) is used to zero the
output in some applications. Other applications use a
feedback loop to keep the output within its linear range
of operation.
FIGURE 4-9:
© 2008 Microchip Technology Inc.
V
IN
V
IN
Application Circuits
C
V
SALLEN-KEY HIGH-PASS FILTER
1
INVERTING MILLER INTEGRATOR
DD
and
R
/2
V
R
DD
C
R
1
2
/2
2
Section 5.3
MCP6281
+
–
Sallen-Key High-Pass Filter.
Miller Integrator.
Figure 4-9
Figure 4-8
SW
C
MCP6281
+
–
DD
DD
/2 so that the op amp
“Mindi™
/2 reference, which
shows a second-
shows the most
V
V
OUT
IN
V
OUT
=
sRC
V
Circuit
1
OUT
4.9.3
The MCP6285 provides the flexibility of Low-power
mode for dual op amps in an 8-pin package. The
MCP6285 eliminates the added cost and space in
battery-powered applications by using two single op
amps with Chip Select lines or a 10-pin device with one
Chip Select 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
Chip Select line becomes suitable. The circuits below
show possible applications for this device.
4.9.3.1
With the cascaded op amp configuration, op amp B can
be used to isolate the load from op amp A. In applica-
tions where op amp A is driving capacitive or low resis-
tance loads in the feedback loop (such as an integrator
circuit 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:
Buffer.
4.9.3.2
Figure 4-11
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 to set most of the gain
with op amp A and use op amp B with relatively small
gain (e.g., a unity-gain buffer).
Where:
MCP6281/1R/2/3/4/5
V
V
OSA
OSB
V
G
G
OUT
A
B
A
CASCADED OP AMP
APPLICATIONS
shows a cascaded gain circuit configura-
=
Load Isolation
Cascaded Gain
=
=
=
=
V
IN
G
MCP6285
op amp A gain
op amp B gain
op amp A input offset voltage
op amp B input offset voltage
A
G
Isolating the Load with a
CS
B
+
V
OSA
G
A
G
B
B
DS21811E-page 15
+
V
Load
OSB
V
G
OUTB
B