CS3001-ISZ Cirrus Logic Inc, CS3001-ISZ Datasheet - Page 12

• Manufacturer Part Number: CS3001-ISZ
• Description: IC OPAMP SGL PREC LV 8-SOIC
• Manufacturer: Cirrus Logic Inc

Specifications of CS3001-ISZ

• Amplifier Type: Instrumentation
• Number Of Circuits: 1
• Output Type: Rail-to-Rail
• Slew Rate: 5 V/µs
• Current - Input Bias: 100pA
• Voltage - Input Offset: 10µV
• Current - Supply: 2.1mA
• Voltage - Supply, Single/dual (±): 2.7 V ~ 6.7 V, ±1.35 V ~ 3.35 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC
• For Use With: 598-1495 - BOARD EVAL OPAMP FOR CS30XX
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output / Channel: -
• -3db Bandwidth: -
• Gain Bandwidth Product: -
• Other names: 598-1140-5

3.2.2
Condition #1: |Av| ≤ 50 and R1 ≤ 100 Ω
The Opamp is inherently stable for |Av| ≤ 50 and
R1 ≤ 100 Ω . No C2 compensation capacitor across
R2 is required.
•
•
Condition #2: |Av| ≤ 50 and R1 > 100 Ω
Compensation capacitor C2 across R2 is required.
Calculate C2 using the following formula:
•
Condition #3: |Av| > 50
Compensation capacitor C2 across R2 is required.
Calculate and verify a value for C2 using the fol-
lowing steps.
Calculate the Compensation Capacitor Value:
1) Calculate a value for C2 using the following
To simplify the calculation, set the pole of the filter
to P1 = 1 MHz. P1 must be set higher than the
opamp’s internal 50 kHz crossover frequency.
2) Calculate a second value for C2 using the fol-
3) Use the larger of the two values calculated in
12
|Av| = 1 configuration has 70° phase margin
and 20 dB gain margin.
|Av| = 50 configuration has phase margin be-
tween 40° for C
C
C2 ≥ (R1 • C
formula:
C2 = 1 / [2π (R1| |R2) • P1], where P1 = 1 MHz
lowing formula:
C2 ≥ (R1 • C
steps 1 & 2.
LOAD
Gain Calculations Summary and
Recommendations
= 0 pF.
in
in
) / R2, where Cin = 50 pF
) / R2, where Cin = 50 pF
LOAD
≤ 100 pF and 60° for
Verify the Opamp Compensation:
Verify the opamp compensation using the open-
loop gain and phase response Bode plot in
Figure 15.
transfer function and verify the following design
criteria are met:
•
•
•
3.3
The CS3001 single amplifier provides a power-
down function on pin 1. If this pin is left open the
amplifier will operate normally. If the powerdown
is asserted low, the amplifier will go into a low
power state. There is a pull-up resistor (approxi-
mately 800 kΩ) inside the amplifier from pin 1 to
the V+ supply. The current through this pull-up re-
sistor is the main source of current drain in the
powerdown state.
-
-
-
Pole P1 > opamp internal 50 kHz crossover fre-
quency
Z1 < opamp internal 50 kHz crossover frequency
Gain margin above the open-loop gain transfer
function is required. A gain margin of +20 dB
above the open loop gain transfer function is
optimal.
P1 = 1 / [2π (R1| |R2) • C2], where P1 = 1 MHz
To simplify the calculation, set the pole to
P1 = 1 MHz.
Z1 = 1 / (2π R2 • C2)
Powerdown (PDWN)
Plot the calculated closed loop gain
CS3001
CS3002
DS490F9