MCP609-I/ST Microchip Technology, MCP609-I/ST Datasheet - Page 17

• Manufacturer Part Number: MCP609-I/ST
• Description: IC OPAMP 2.5V QUAD R-R 14TSSOP
• Manufacturer: Microchip Technology

Specifications of MCP609-I/ST

• Slew Rate: 0.08 V/µs
• Amplifier Type: General Purpose
• Number Of Circuits: 4
• Output Type: Rail-to-Rail
• Gain Bandwidth Product: 155kHz
• Current - Input Bias: 1pA
• Voltage - Input Offset: 250µV
• Current - Supply: 18.7µA
• Current - Output / Channel: 17mA
• Voltage - Supply, Single/dual (±): 2.5 V ~ 6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 14-TSSOP
• Op Amp Type: Low Power
• No. Of Amplifiers: 4
• Bandwidth: 155kHz
• Supply Voltage Range: 2.5V To 5.5V
• Amplifier Case Style: TSSOP
• No. Of Pins: 14
• Number Of Channels: 4
• Voltage Gain Db: 121 dB
• Common Mode Rejection Ratio (min): 75 dB
• Input Offset Voltage: 0.25 mV
• Operating Supply Voltage: 3 V, 5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• -3db Bandwidth: -
• Lead Free Status / Rohs Status: Details

4.6
An unused op amp in a quad package (MCP609)
should be configured as shown in
circuits prevent the output from toggling and causing
crosstalk. Circuits A sets the op amp at its minimum
noise gain. The resistor divider produces any desired
reference voltage within the output voltage range of the
op amp; the op amp buffers that reference voltage.
Circuit B uses the minimum number of components
and operates as a comparator, but it may draw more
current.
FIGURE 4-6:
4.7
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
cause 5 pA of current to flow, which is greater than the
MCP606/7/8/9 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 shown in
FIGURE 4-7:
for Inverting Gain.
© 2009 Microchip Technology Inc.
V
DD
¼ MCP609 (A)
V
R
R
REF
1
2
Unused Op Amps
PCB Surface Leakage
=
V
V
DD
DD
⋅
V
------------------ -
R
IN
Guard Ring
1
Unused Op Amps.
Example Guard Ring Layout
-
R
+
2
V
R
REF
2
12
Ω. A 5V difference would
V
IN
+
¼ MCP609 (B)
Figure
V
V
4-6. These
Figure
SS
DD
4-7.
1.
2.
4.8
4.8.1
The MCP606/7/8/9 op amps can be used to sense the
load current on the low-side of a battery using the
circuit in
power supply (minus the current required to power the
MCP606) flows through a sense resistor (R
converts it to voltage. This is gained by the the amplifier
and resistors, R
of the amplifier is at the load’s negative supply (V
the gain from R
FIGURE 4-8:
Sensor.
Since the input bias current and input offset voltage of
the MCP606 are low, and the input is capable of
swinging below ground, there is very little error
generated by the amplifier. The quiescent current is
very low, which helps conserve battery power. The
rail-to-rail output makes it possible to read very low
currents.
Non-inverting Gain and Unity-gain Buffer:
a)
b)
Inverting Gain and Transimpedance Gain
(convert current to voltage, such as photo
detectors) amplifiers:
a)
b)
2.5V
6.0V
to
Figure
Connect the non-inverting pin (V
input with a wire that does not touch the
PCB surface.
Connect the guard ring to the inverting input
pin (V
common mode input voltage.
Connect the guard ring to the non-inverting
input pin (V
to the same reference voltage as the op
amp (e.g., V
Connect the inverting pin (V
with a wire that does not touch the PCB
surface.
Application Circuits
V
LOW-SIDE BATTERY CURRENT
SENSOR
OUT
IN
SEN
G
R
4-8. In this circuit, the current from the
5 kΩ
10Ω
–). This biases the guard ring to the
R
=
SEN
and R
G
MCP606/7/8/9
to V
V
IN
DD
LM
+). This biases the guard ring
Low Side Battery Current
F
OUT
/2 or ground).
50 kΩ
. Since the non-inverting input
+
R
I
MCP606
L
F
is R
R
SEN
F
/R
(
R F
G
IN
DS11177F-page 17
.
⁄
–) to the input
R
G
IN
)
SEN
+) to the
To Load
To Load
(V
(V
I
), which
V
L
LM
LP
OUT
)
)
LM
),