MCP6S92-E/SN Microchip Technology, MCP6S92-E/SN Datasheet - Page 27

• Manufacturer Part Number: MCP6S92-E/SN
• Description: IC PGA 2CH R-R I/O SPI 8SOIC
• Manufacturer: Microchip Technology

Specifications of MCP6S92-E/SN

• Package / Case: 8-SOIC (3.9mm Width)
• Amplifier Type: Programmable Gain
• Number Of Circuits: 2
• Output Type: Rail-to-Rail
• Slew Rate: 22 V/µs
• -3db Bandwidth: 18MHz
• Current - Input Bias: 1pA
• Voltage - Input Offset: 400µV
• Current - Supply: 1mA
• Current - Output / Channel: 25mA
• Voltage - Supply, Single/dual (±): 2.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Number Of Channels: 1
• Available Set Gain: 30.1 dB (Typ)
• Input Offset Voltage: 4 mV @ 5.5 V
• Input Bias Current (max): 0.000001 uA (Typ) @ 5.5 V
• Operating Supply Voltage: 3 V or 5 V
• Supply Current: 1.6 mA @ 5.5V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: MCP6SX2DM-PCTLPD - BOARD DAUGHTER PICTAIL MCP6SX2
• Gain Bandwidth Product: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

6.0
6.1
Figure 6-1 shows a MCP6S91 with the V
2.5V and V
signals centered on 2.5V, instead of ground-referenced
signals. The voltage reference MCP1525 is buffered by
a MCP6021, which gives a low output impedance
reference voltage from DC to high frequencies. The
source driving the V
impedance less than 0.1 to maintain reasonable gain
accuracy.
FIGURE 6-1:
Reference Voltage.
6.2
Large capacitive loads can cause stability problems
and reduced bandwidth for the MCP6S91/2/3 family of
PGAs (Figure 2-26 and Figure 2-28). As the load
capacitance increases, there is a corresponding
increase in frequency response peaking and step
response overshoot and ringing. This happens
because a large load capacitance decreases the
internal amplifier’s phase margin and bandwidth.
When driving large capacitive loads with these PGAs
(i.e., > 60 pF), a small series resistor at the output
(R
stability by making the load resistive at higher
frequencies. The bandwidth will be generally lower
than the bandwidth with no capacitive load.
 2004 Microchip Technology Inc.
ISO
in Figure 6-2) improves the internal amplifier’s
APPLICATIONS INFORMATION
Changing External Reference
Voltage
Capacitive Load and Stability
2.5V
REF
V
DD
V
DD
IN
MCP1525
= 5.0V. This allows the PGA to amplify
1µF
REF
V
MCP6S91
PGA with Different External
REF
pin should have an output
MCP6021
V
DD
V
DD
V
OUT
REF
pin at
FIGURE 6-2:
Capacitive Loads.
Figure 6-3 gives recommended R
different capacitive loads. After selecting R
circuit, double-check the resulting frequency response
peaking and step response overshoot on the bench.
Modify R
all gains.
FIGURE 6-3:
6.3
Good PC board layout techniques will help achieve the
performance shown in the Electrical Characteristics
and Typical Performance Curves. It will also help
minimize Electromagnetic Compatibility (EMC) issues.
6.3.1
Separate different circuit functions: digital from analog,
low-speed from high-speed, and low-power from high-
power. This will reduce crosstalk.
Keep sensitive traces short and straight. Separate
them from interfering components and traces. This is
especially important for high-frequency (low rise time)
signals.
V
IN
1,000
100
10
ISO
Layout Considerations
10 p
10
COMPONENT PLACEMENT
’s value until the response is reasonable at
MCP6S9X
MCP6S91/2/3
L oad C apacitance (F)
100 p
PGA Circuit for Large
Recommended R
100
R
ISO
1 n
DS21908A-page 27
1,000
ISO
C
ISO
ISO
values for
L
V
OUT
.
for your
10 n
10,000