Precision Amplifiers (VOS < 1 mV, Bandwidth < 50 MHz)
Zero Input Crossover Distortion (ZCO) Amplifiers
ADA4505-2: 10 µA, Rail-to-Rail I/O, Zero Input Crossover Distortion Amplifier
The ADA4505-x 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
140
120
100
80
•ꢀCMRR: 105 dB typical
•ꢀVery low supply current: 10 mA per amplifier maximum
TYPICAL
AMPLIFIER
•ꢀ1.8 V to 5.5 V single-supply or 60.9 V to 62.5 V
dual-supply operation
•ꢀRail-to-rail input/output
•ꢀ3 mV offset voltage maximum
•ꢀVery low input bias current: 0.5 pA typical
60
ZCO
AMPLIFIER
40
Applications
•ꢀPressure and position sensors
•ꢀRemote security
20
•ꢀMedical monitors
0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
•ꢀBattery-powered consumer equipment
•ꢀHazard detectors
VCM (V)
Input offset voltage vs. common mode voltage.
+5V
0.1ꢀF
+5V
VDD
CONNECT TO
RED LED CIRCUIT
S1A
10.3mA
D1
22ꢁ
+5V
1/2
ADA4505-2
IRLMS2002
S1B
IN1
10kꢁ
RED
TIMING
22pF
1kꢁ
121ꢁ ꢂ0.1%
ADG1636
+5V
53.6kꢁ
CONNECT TO
INFRARED LED CIRCUIT
+1.25V
S2A
15.2mA
D2
22ꢁ
ADR1581 +5V
0.1ꢀF
1/2
ADA4505-2
IRLMS2002
S2B
IN2
10kꢁ
IR
TIMING
22pF
+5V
EN
VSS GND
1kꢁ
10kꢁ
82.5ꢁ ꢂ0.1%
ENABLE
Circuit Note CN-0125, Precision Pulse Oximeter LED Current Sink Reference Circuit, www.analog.com/CN0125.
Zero Input Crossover Distortion (ZCO) Amplifiers
Supply
BW @ Slew
CMRR PSRR AVO
Min Min Min (nV/
(dB) (dB) (dB) @ 1 kHz
Noise
Price
@ 1k
(OEM $US)
Part
Number
No. of
Amps
V
OS Max
(mV)
TcVOS
(mv/°C Typ)
IS/Amp IB Max
(mA Max) (pA)
Process
Voltage Rail-to-Rail1 ACL Min Rate
√
H
z)
Packaging
(Min/Max)
(MHz) (V/ms)
ADA4505-12
ADA4505-2
ADA4505-4
1
2
4
WLCSP/SOT-23
WLCSP/MSOP
WLCSP/TSSOP
0.55
0.67
1.15
CMOS
CMOS
1.8/5.5
RRIO
RRIO
0.050 0.006
3
2
2
90
90
100 105
100 105
65
45
0.010
0.020
2
AD85052
AD8506
AD8508
1
2
4
0.59
0.71
1.20
1.8/5.5
0.095 0.013
2.5
10
WLCSP/SOT-23
1 RRIO: rail-to-rail input/output, RRO: rail-to-rail output, SS: single supply (IVR includes –VSY).
2
Check data sheet for test conditions and actual product specification—may be different for single/dual/quad amplifiers for part numbers with 2 mark.
Operational Amplifier Selection Guide
16
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