PRELIMINARY TECHNICAL DATA
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a
Zero-Drift, Single-Supply,
Rail-to-Rail Input/Output
Low Noise Operational Amplifier
Preliminary Technical Data AD8628
FEATURES
Lowest auto-zero amplifier noise
Low Offset Voltage: 5 µV
Input Offset Drift: 0.03 µV/°C
Rail-to-Rail Input and Output Swing
5 V Single-Supply Operation
High Gain, CMRR, and PSRR: 120 dB
Very Low Input Bias Current: 100 pA
Low Supply Current: 1.3 mA
Overload Recovery Time: 0.2 ms
No External Components Required
APPLICATIONS
Automotive Sensors
Pressure and Position Sensors
Strain Gage Amplifiers
Medical Instrumentation
Thermocouple Amplifiers
GENERAL DESCRIPTION
This new fa mily of amplifiers has ultra-low offset, drift and bias
current. The AD8628 is a wide bandwidth auto-zero amplifier
featuring rail-to -rail input and output swings and low noise.
Operation is fully specified from 2.7 to 5 volts single supply
(±1.35V to ±2.5V dual supply).
The AD8628 family provides the benefits previously found only
in expensive auto-zeroing or chopper-stabilized amplifiers.
Using Analog Devices’ new topology these zero-drift amplifiers
combine low cost, with high accuracy and low noise. (No
external capacitors are required.) In addition, the AD8628
greatly reduces the digital switching noise found in most
chopper stabilized amplifiers.
With an offset voltage of only 1µV, drift less than 0.005 µV/°C
and noise of only 0.5uV P-P (0Hz to 10 Hz) the AD8628 is
perfectly suited for applications where error sources canno t be
tolerated. Po sition and pressure sensors, medical equipment, and
strain gage amplifiers benefit greatly fr om nearly zero drift over
their ope rating temperature range. Many systems may t ake
advantage of the rail-to -rail input and output swings provided by
the AD8628 family to reduce input biasing complexity and
maximize SNR.
The AD8628 family is specified for the extended industrial
(-40° to +125°C) temperature range. The AD8628 amplifier is
available in the tiny SOT23 and the popular 8-pin narrow
SOIC plastic packages.
5-Lead SOT
(RT-5)
8-Lead SO
(R-8)
AD8628
AD8628
REV. PrA 1/29/02
PRELIMINARY TECHNICAL DATA
AD8628
– 2 – REV. PrA 1/29/02
ELECTRICAL SPECIFICATIONS (@ VS=+5.0V, VCM = +2.5V, VO=+2.5V, TA=+25°C unless otherwise specified.)
Parameter Symbol Conditions Min Typ Max Units
INPUT CH ARACTERISTICS
Offse t Volt age VOS 1 5 µV
-40°C ≤ TA ≤ +125°C 10 µV
Input Bias Current IB 30 100 pA
-40°C ≤ TA ≤ +125°C 1.5 nA
Input Offset Current IOS 50 200 pA
-40°C ≤ TA ≤ +125°C 250 pA
Input Voltage Range 0 5 V
Common-Mode Rejection Ratio CMRR VCM = 0V to 5V 120 140 dB
-40°C ≤ TA ≤ +125°C 115 130 dB
Large Signal Voltage Gain (Note 1) AVO R
L = 10 kΩ, Vo=0.3 to 4.7V 125 145 dB
-40°C ≤ TA ≤ +125°C 120 135 dB
Offset Voltage Drift ∆VOS/∆T -40°C ≤ TA ≤ +125°C 0.002 0.03 µV/°C
OUTPUT CH ARACTERISTICS
Output Voltage High VOH R
L = 100kΩ to Ground 4.99 4.996 V
-40°C ≤ TA ≤ +125°C 4.99 4.995 V
R
L = 10kΩ to Ground 4.95 4.98 V
-40°C ≤ TA ≤ +125°C 4.95 4.97 V
Output Voltage Low VOL R
L = 100kΩ to V+ 1 10 mV
-40°C ≤ TA ≤ +125°C 2 10 mV
R
L = 10 kΩ to V+ 10 20 mV
-40°C ≤ TA ≤ +125°C 15 20 mV
Short Circuit Limit ISC ± 25 ± 50 mA
-40°C ≤ TA ≤ +125°C ± 40 mA
Output Current IO ± 30 mA
-40°C ≤ TA ≤ +125°C ± 15 mA
POWER SUPPLY
Power Supply Rejection Ratio PSRR VS = 2.7V to 5.5V 120 130 dB
-40°C ≤ TA ≤ +125°C 115 130 dB
Supply Current/Amplifier ISY V
O = 0V 1.3 1.5 mA
-40°C ≤ TA ≤ +125°C 1.6 1.8 mA
DYNAMIC PERFORMANCE
Slew Rate SR RL =10 kΩ 0.8 V/µs
Overload Recovery Time 0.05 0.2 ms
Gain Bandwidth Product GBP 2.5 MHz
NOISE PERFORMANCE
Voltage Noise en p-p 0.1 to 10 Hz 0.5 µVp-p
Voltage Noise en p-p 0.1 to 1.0 Hz 0.16 µVp-p
Voltage Noise Density en f = 1 kHz 22 nV/√Hz
Current Noise Density in f=10 Hz 5
fA/√Hz
Note 1: G ain test ing is highly dependent up on test bandwidth.
PRELIMINARY TECHNICAL DATA AD8628
– 3 –
ELECTRICAL SPECIFICATIONS (@ VS=+2.7V, VCM = +1.35 V, VO=1.4V, TA=+25°C unless otherwise specified.)
Parameter Symbol Conditions Min Typ Max Units
INPUT CH ARACTERISTICS
Offset Voltage AD8628 VOS 1 5 µV
-40°C ≤ TA ≤ +125°C 10 µV
Input Bias Current IB 30 100 pA
-40°C ≤ TA ≤ +125°C 1.0 1.5 nA
Input Offset Current IOS 50 200 pA
-40°C ≤ TA ≤ +125°C 250 pA
Input Voltage Range 0 5 V
Common-Mode Rejection Ratio CMRR VCM = 0 to 2.9V 115 130 dB
-40°C ≤ TA ≤ +125°C 110 120 dB
Large Signal Voltage Gain AVO R
L = 10 kΩ, Vo=0.3 to 4.7V 110 140 dB
-40°C ≤ TA ≤ +125°C 105 130 dB
Offset Voltage Drift ∆VOS/∆T -40°C ≤ TA ≤ +125°C 0.002 0.03 µV/°C
OUTPUT CH ARACTERISTICS
Output Voltage High VOH R
L = 100kΩ to Ground 2.68 2.695 V
-40°C ≤ TA ≤ +125°C 2.68 2.695 V
R
L = 10kΩ to Ground 2.67 2.68 V
-40°C ≤ TA ≤ +125°C 2.67 2.675 V
Output Voltage Low VOL R
L = 100kΩ to V+ 1 10 mV
-40°C ≤ TA ≤ +125°C 2 10 mV
R
L = 10 kΩ to V+ 10 20 mV
-40°C ≤ TA ≤ +125°C 15 20 mV
Short Circuit Limit ISC ±10 ± 15 mA
-40°C ≤ TA ≤ +125°C ± 10 mA
Output Current IO ± 10 mA
-40°C ≤ TA ≤ +125°C ± 5 mA
POWER SUPPLY
Power Supply Rejection Ratio PSRR VS = 2.7V to 5.5 V 120 130 dB
-40°C ≤ TA ≤ +125°C 115 130 dB
Supply Current/Amplifier ISY V
O = 0V 1.1 1.4 mA
-40°C ≤ TA ≤ +125°C 1.3 1.6 mA
DYNAMIC PERFORMANCE
Slew Rate SR RL =10 kΩ 1 V/µs
Overload Recovery Time 0.05 ms
Gain Bandwidth Product GBP 2 MHz
NOISE PERFORMANCE
Voltage Noise en p-p 0.1 to 10 Hz 0.75 µVp-p
Voltage Noise Density en f = 1 kHz 33 nV/√Hz
Current Noise Density in f=10 Hz 5
fA/√Hz
REV. PrA 1/29/02
PRELIMINARY TECHNICAL DATA
AD8628
– 4 – REV. PrA 1/29/02
ABSOLUTE MAXIMUM RATINGS
Supply Voltage..........................................................................+6V
Input Voltage......................................................GND to Vs + 0.3V
Differential Input Voltage1.....................................................±5.0V
Output Short-Circuit Duration to Gnd...............................Indefinite
Storage Temperature Range
RT, R Package...............................................-65°C to +150°C
Operatin g Temperatu r e Range
AD8628.........................................................-40°C to +125°C
Junction Temperature Range
RT, R Package...............................................-65°C to +150°C
Lead Temperature Range (Soldering, 10 sec).......................+300°C
Package Type θJA2 θJC Units
5-Pin SOT23 (RT) °C/W
8-Pin SOIC (R) 158 43 °C/W
NOTES
1 Differential input voltage is limited to ±5. 0 volts or t h e s upply voltage , w hiche ver is le ss.
2 θJA is specified for the worst case conditions, i.e., θJA is specified for device in socket
for P-DIP packages; θJAis specified for device soldered in circuit board for SOIC and
TSSOP packages.
ORDERING GUIDE
Temperature Package Package
Model Range Description Option
AD8628ART -40°C to +125°C 5-Pin SOT23 RT-5
AD8628AR -40°C to +125°C 8-Pin SOIC SO-8
