ANALOG DEVICES AD8502, AD8504 Service Manual
1 μA Micropower CMOS
www.BDTIC.com/ADI
FEATURES
Supply current: 1 μA maximum/amplifier
Offset voltage: 3 mV maximum
Single-supply or dual-supply operation
Rail-to-rail input and output
No phase reversal
Unity gain stable
APPLICATIONS
Portable equipment
Remote sensors
Low power filters
Threshold detectors
Current sensing
GENERAL DESCRIPTION
The AD8502/AD8504 are low power, precision CMOS operational
amplifiers featuring a maximum supply current of 1 μA. The
AD8502/AD8504 have a maximum offset voltage of 3 mV and a
typical input bias current of 1 pA operating rail-to-rail on both
the input and output. The AD8502/AD8504 can operate from a
single-supply voltage of +1.8 V to +5.5 V or a dual-supply
voltage of ±0.9 V to ±2.75 V.
With its low power consumption, low input bias current, and
il-to-rail input and output, the AD8502/AD8504 are ideally
ra
suited for a variety of battery-powered portable applications.
Potential applications include bedside monitors, pulse monitors,
glucose meters, smoke and fire detectors, vibration monitors,
and backup battery sensors.
Operational Amplifiers
AD8502/AD8504
PIN CONFIGURATIONS
1
OUT A
–IN A
2
AD8502
+IN A
OUT A
–IN A
+IN A
+IN B
–IN B
OUT B
Figure 2. 14-Lead TSSOP (RU-14)
TOP VIEW
3
(Not to Scale)
V–
4
Figure 1. 8-Lead SOT-23
1
2
3
AD8504
TOP VIEW
4
V+
(Not to Scale)
5
6
7
The ability to swing rail-to-rail at both the input and output
ps maximize dynamic range and signal-to-noise ratio in
hel
systems that operate at very low voltages. The low offset voltage
allows use of the AD8502/AD8504 in systems with high gain
without creating excessively large output offset errors. The
AD8502 and AD8504 offer an additional benefit by providing
high accuracy without the need for system calibration.
The AD8502/AD8504 are fully specified over the industrial
emperature range (−40°C to +85°C) and the extended indus-
t
trial temperature range (−40°C to +125°C). The AD8502 is
available in an 8-lead, SOT-23 surface-mount package. The
AD8504 is available in a 14-lead TSSOP surface-mount package.
8
7
6
5
14
13
12
11
10
V+
OUT B
–IN B
+IN B
9
8
OUT D
–IN D
+IN D
V–
+IN C
–IN C
OUT C
06323-001
06323-038
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 www.analog.com
Fax: 781.461.3113 ©2007 Analog Devices, Inc. All rights reserved.
AD8502/AD8504
www.BDTIC.com/ADI
TABLE OF CONTENTS
Features .............................................................................................. 1
Absolute Maximum Ratings ............................................................6
Applications....................................................................................... 1
Pin Configurations ........................................................................... 1
General Description......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Electrical Characteristics............................................................. 3
REVISION HISTORY
1/07—Revision 0: Initial Version
Thermal Resistance .......................................................................6
ESD Caution...................................................................................6
Typical Perf or m an c e Charac t e r istics ..............................................7
Outline Dimensions ....................................................................... 14
Ordering Guide .......................................................................... 14
Rev. 0 | Page 2 of 16
AD8502/AD8504
www.BDTIC.com/ADI
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
@ VS = 5 V, VCM = VS/2, TA = 25°C, unless otherwise noted.
Table 1.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage V
OS
−40°C < TA < +85°C 5 mV
−40°C < TA < +125°C 5.5 mV
Offset Voltage Drift ΔVOS/ΔT −40°C < TA < +85°C 7 μV/°C
−40°C < TA < +125°C 5 μV/°C
Input Bias Current I
B
−40°C < TA < +85°C 100 pA
−40°C < TA < +125°C 600 pA
Input Offset Current I
OS
−40°C < TA < +85°C 50 pA
−40°C < TA < +125°C 100 pA
Input Voltage Range IVR 0 5.0 V
Common-Mode Rejection Ratio CMRR 0 V < VCM < 5 V 67 76 dB
−40°C < TA < +85°C 65 dB
−40°C to +125°C 65 dB
Large Signal Voltage Gain A
VO
0.1 V < V
0.1 V < V
Input Capacitance C
C
DIFF
CM
OUTPUT CHARACTERISTICS
Output Voltage High V
OH
−40°C < TA < +85°C 4.960 V
−40°C to +125°C 4.950 V
R
−40°C < TA < +85°C 4.810 V
−40°C to +125°C 4.650 V
Output Voltage Low V
OL
−40°C < TA < +85°C 7 mV
−40°C to +125°C 7 mV
R
−40°C < TA < +85°C 37 mV
−40°C to +125°C 40 mV
Short-Circuit Current I
SC
POWER SUPPLY
Power Supply Rejection Ratio PSRR 1.8 V < VS < 5 V 85 105 dB
−40°C < TA < +85°C 66 dB
−40°C < TA < +125°C 66 dB
Supply Current/Amplifier I
SY
−40°C < TA < +85°C 1.5 μA
−40°C < TA < +125°C 2 μA
DYNAMIC PERFORMANCE
Slew Rate SR R
Gain Bandwidth Product GBP 7 kHz
Phase Margin Ø
O
0 V < VCM < 5 V 0.5 3 mV
0 V < VCM < 5 V 1 10 pA
0 V < VCM < 5 V 0.5 5 pA
0.1 V < V
< 4.9 V; R
OUT
< 4.9 V; −40°C < TA < +85°C 93 dB
OUT
< 4.9 V; −40°C < TA < +125°C 75 dB
OUT
= 1 MΩ 98 120 dB
LOAD
2 pF
4.5 pF
R
= 100 kΩ to GND 4.970 4.990 V
LOAD
= 10 kΩ to GND 4.900 4.930 V
LOAD
R
= 100 kΩ to V
LOAD
= 10 kΩ to V
LOAD
V
= GND ±5 mA
OUT
S
S
1.6 5 mV
15 20 mV
VO = VS/2 0.75 1 μA
= 1 MΩ 0.004 V/μs
LOAD
60 Degrees
Rev. 0 | Page 3 of 16
AD8502/AD8504
www.BDTIC.com/ADI
Parameter Symbol Conditions Min Typ Max Unit
NOISE PERFORMANCE
Peak-to-Peak Noise 0.1 Hz to 10 Hz 6 μV p-p
Voltage Noise Density e
Current Noise Density i
n
n
@ VS = 1.8 V, VCM = VS/2, TA = 25°C, unless otherwise noted.
Table 2.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage V
OS
−40°C < TA < +85°C 5 mV
−40°C < TA < +125°C 5.5 mV
Offset Voltage Drift ∆VOS/∆T −40°C < TA < +85°C 7 μV/°C
−40°C < TA < +125°C 5 μV/°C
Input Bias Current I
B
−40°C < TA < +85°C 100 pA
−40°C < TA < +125°C 600 pA
Input Offset Current I
OS
−40°C < TA < +85°C 50 pA
−40°C < TA < +125°C 100 pA
Input Voltage Range IVR 0 1.8 V
Common-Mode Rejection Ratio CMRR 0 V < VCM < 1.8 V 59 75 dB
−40°C < TA < +85°C 56 dB
−40°C < TA < +125°C 55 dB
Large Signal Voltage Gain A
VO
0.1 V < V
0.1 V < V
Input Capacitance C
C
DIFF
CM
OUTPUT CHARACTERISTICS
Output Voltage High V
OH
−40°C < TA < +85°C 1.78 V
−40°C to +125°C 1.77 V
R
−40°C < TA < +85°C 1.70
−40°C to +125°C 1.65
Output Voltage Low V
OL
−40°C < TA < +85°C
−40°C to +125°C
R
−40°C < TA < +85°C 28 mV
−40°C to +125°C 29 mV
Short-Circuit Current I
SC
POWER SUPPLY
Power Supply Rejection Ratio PSRR 1.8 V < VS < 5 V 85 105 dB
−40°C < TA < +85°C 66 dB
−40°C < TA < +125°C 66 dB
Supply Current/Amplifier I
SY
−40°C < TA < +85°C 1.5 μA
−40°C < TA < +125°C 2 μA
f = 1 kHz 190 nV/√Hz
f = 1 kHz 0.1 pA/√Hz
0 V < VCM < 1.8 V 0.5 3 mV
0 V < VCM < 1.8 V 1 10 pA
0 V < VCM < 1.8 V 0.5 5 pA
0.1 V < V
< 1.7 V; R
OUT
< 1.7 V; −40°C < TA < +85°C 80 dB
OUT
< 1.7 V; −40°C < TA < +125°C 65 dB
OUT
= 1 MΩ 88 110 dB
LOAD
2 pF
4.5 pF
R
= 100 kΩ to GND 1.79 1.795 V
LOAD
= 10 kΩ to GND 1.75 1.764 V
LOAD
V
V
6 mV
7 mV
R
= 100 kΩ to V
LOAD
= 10 kΩ to V
LOAD
S
1.0 5 mV
S
10 20 mV
±5 mA
VO = VS/2 0.65 1 μA
Rev. 0 | Page 4 of 16
AD8502/AD8504
www.BDTIC.com/ADI
Parameter Symbol Conditions Min Typ Max Unit
DYNAMIC PERFORMANCE
Slew Rate SR R
Gain Bandwidth Product GBP 7 kHz
Phase Margin Ø
NOISE PERFORMANCE
Peak-to-Peak Noise 0.1 Hz to 10 Hz 6 μV p-p
Voltage Noise Density e
Current Noise Density i
O
n
n
= 1 MΩ 0.004 V/μs
LOAD
60 Degrees
f = 1 kHz 190 nV/√Hz
f = 1 kHz 0.1 pA/√Hz
Rev. 0 | Page 5 of 16
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