Precision Amplifiers (V
OS
<
1 mV, Bandwidth
<
50 MHz)
Zero Input Crossover Distortion (ZCO) Amplifiers
10
µA,
Rail-to-Rail I/O, Zero Input Crossover Distortion Amplifier
The
family solves the crossover distortion problem by using an on-chip charge pump to power the input differential pair. The charge pump
creates a supply voltage higher than the voltage of the battery, allowing the input stage to handle a wide range of input signal voltages without using a
second differential pair. With this solution, the input voltage can vary from one supply extreme to the other with no distortion, thereby restoring the full
common-mode dynamic range of the op amp.
Features
• PSRR:
100 dB minimum
• CMRR:
105 dB typical
• Very
low supply current: 10
mA
per amplifier maximum
• 1.8
V to 5.5 V single-supply or
60.9
V to
62.5
V
dual-supply operation
• 3
mV offset voltage maximum
• Very
low input bias current: 0.5 pA typical
Applications
• Pressure
and position sensors
• Remote
security
• Medical
monitors
• Battery-powered
consumer equipment
• Hazard
detectors
V
OS
( V)
140
120
100
80
60
40
20
0
ZCO
AMPLIFIER
TYPICAL
AMPLIFIER
• Rail-to-rail
input/output
0
0.5
1.0
1.5
2.0
2.5
V
CM
(V)
3.0
3.5
4.0
4.5
5.0
Input offset voltage vs. common mode voltage.
+5V
VDD
S1A
+5V
10k
RED
TIMING
S1B
IN1
D1
+5V
0.1 F
CONNECT TO
RED LED CIRCUIT
10.3mA
22
IRLMS2002
22pF
1/2
ADA4505-2
1k
+5V
53.6k
+1.25V
S2A
121
0.1%
ADG1636
CONNECT TO
INFRARED LED CIRCUIT
D2
15.2mA
22
IRLMS2002
22pF
EN
VSS GND
1k
82.5
0.1%
ADR1581
+5V
0.1 F
10k
IR
TIMING
+5V
10k
ENABLE
S2B
IN2
1/2
ADA4505-2
Circuit Note CN-0125, Precision Pulse Oximeter LED Current Sink Reference Circuit,
www.analog.com/CN0125.
Zero Input Crossover Distortion (ZCO) Amplifiers
Process
Part
Number
No. of
Amps
1
2
4
1
2
4
Supply
BW @ Slew
Voltage Rail-to-Rail
1
A
CL
Min Rate
(Min/Max)
(MHz) (V/ms)
1.8/5.5
RRIO
0.050
0.006
V
OS
Max
(mV)
TcV
OS
(mv/°C Typ)
CMRR PSRR A
VO
Noise
I /Amp I
B
Max
Min Min Min (nV/
√
Hz)
S
(mA Max) (pA)
(dB) (dB) (dB) @ 1 kHz
90
100
105
65
0.010
2
Packaging
WLCSP/SOT-23
WLCSP/MSOP
WLCSP/TSSOP
WLCSP/SOT-23
Price
@ 1k
(OEM $US)
0.55
0.67
1.15
0.59
0.71
1.20
CMOS
3
2
CMOS
1
2
1.8/5.5
RRIO
0.095
0.013
2.5
2
90
100
105
45
0.020
10
RRIO: rail-to-rail input/output, RRO: rail-to-rail output, SS: single supply (IVR includes –V
SY
).
Check data sheet for test conditions and actual product specification—may be different for single/dual/quad amplifiers for part numbers with
2
mark.
16
|
Operational Amplifier Selection Guide
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