A
DVANCED
L
INEAR
D
EVICES,
I
NC.
TM
ALD1721E
e
®
EPAD
D
LE
AB
E
N
EPAD® MICROPOWER CMOS OPERATIONAL AMPLIFIER
KEY FEATURES
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EPAD (Electrically Programmable Analog Device)
User programmable V
OS
trimmer
Computer-assisted trimming
Rail-to-rail input/output
Compatible with standard EPAD Programmer
High precision through in-system circuit precision trimming
Reduces or eliminates V
OS
, PSRR, CMRR and TCV
OS
errors
System level “calibration” capability
Application Specific Programming mode
In-System Programming mode
Electrically programmable to compensate for external
component tolerances
• Achieves 0.01pA input bias current and 35
µ
V input offset
voltage simultaneously
• Compatible with industry standard pinout
BENEFITS
• Eliminates manual and elaborate
system trimming procedures
• Remote controlled automated trimming
• In-System Programming capability
• No external components
• No internal chopper clocking noise
• No chopper dynamic power dissipation
• Simple and cost effective
• Small package size
• Extremely small total functional
volume size
• Low system implementation cost
• Micropower and Low Voltage
GENERAL DESCRIPTION
The ALD1721E is a monolithic rail-to-rail precision CMOS operational
amplifier with integrated user programmable EPAD (Electrically Program-
mable Analog Device) based offset voltage adjustment. The ALD1721E
operational amplifier is a direct replacement of the ALD1701 operational
amplifier, with the added feature of user-programmable offset voltage
trimming resulting in significantly enhanced total system performance and
user flexibility. EPAD technology is an exclusive ALD design which has
been refined for analog applications where precision voltage trimming is
necessary to achieve a desired performance. It utilizes CMOS FETs as in-
circuit elements for trimming of offset voltage bias characteristics with the
aid of a personal computer under software control. Once programmed, the
set parameters are stored indefinitely within the device even after power-
down. EPAD offers the circuit designer a convenient and cost-effective
trimming solution for achieving the very highest amplifier/system perfor-
mance.
The ALD1721E operational amplifier features rail-to-rail input and output
voltage ranges, tolerance to over-voltage input spikes of 300mV beyond
supply rails, capacitive loading up to 50pF, extremely low input currents of
0.01pA typical, high open loop voltage gain, useful bandwidth of 700KHz,
slew rate of 0.7V/µs, and low typical supply current of 120µA.
APPLICATIONS
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Sensor interface circuits
Transducer biasing circuits
Capacitive and charge integration circuits
Biochemical probe interface
Signal conditioning
Portable instruments
High source impedance electrode
amplifiers
Precision Sample and Hold amplifiers
Precision current to voltage converter
Error correction circuits
Sensor compensation circuits
Precision gain amplifiers
Periodic In-system calibration
System output level shifter
PIN CONFIGURATION
VE1
1
2
3
4
TOP VIEW
SAL, PAL, DA PACKAGES
* N/C Pin is internally connected. Do not connect externally.
8
2
7
6
5
VE2
V+
OUT
N/C
ORDERING INFORMATION
(“L” suffix denotes lead-free (RoHS))
Operating Temperature Range
0°C to +70°C
8-Pin
Small Outline
Package (SOIC)
ALD1721ESAL
0°C to +70°C
8-Pin
Plastic Dip
Package
ALD1721EPAL
-55°C to +125°C
8-Pin
CERDIP
Package
ALD1721EDA
-IN
+IN
V-
* Contact factory for leaded (non-RoHS) or high temperature versions.
Rev 2.1 ©2011 Advanced Linear Devices, Inc. 415 Tasman Drive, Sunnyvale, CA 94089-1706 Tel: (408) 747-1155 Fax: (408) 747-1286
www.aldinc.com
ALD [ ADVANCED LINEAR DEVICES ]
