ADVANCED
LINEAR
DEVICES, INC.
TM
e
®
EPAD
D
LE
AB
EN
ALD2721E/ALD2721
DUAL EPAD® MICROPOWER CMOS OPERATIONAL AMPLIFIER
KEY FEATURES
BENEFITS
•
•
•
•
•
•
•
•
•
•
•
•
• Eliminates manual and elaborate
system trimming procedures
• Remote controlled automated trimming
• In-System Programming capability
• No external components
• No internal clocking noise source
• Simple and cost effective
• Small package size
• Extremely small total functional
volume size
• Low system implementation cost
• Micropower and Low Voltage
EPAD (Electrically Programmable Analog Device)
User programmable VOS trimmer
Computer-assisted trimming
Rail-to-rail input/output
Compatible with standard EPAD Programmer
Each amplifier VOS can be trimmed to a different VOS level
High precision through in-system circuit precision trimming
Reduces or eliminates VOS, PSRR, CMRR and TCVOS 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 35µV input offset
voltage simultaneously
• Low voltage operation
GENERAL DESCRIPTION
The ALD2721E/ALD2721 is a dual monolithic rail-to-rail precision CMOS
operational amplifier with integrated user programmable EPAD (Electrically Programmable Analog Device) based offset voltage adjustment. The
ALD2721E/ALD2721 is a dual version of the ALD1721E/ALD2721 operational amplifier. Each ALD2721E/ALD2721 operational amplifier features
individual user-programming 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 performance.
The ALD2721E/ALD2721 dual 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 200µA for both amplifiers.
ORDERING INFORMATION
Operating Temperature Range
0°C to +70°C
0°C to +70°C
-55°C to +125°C
14-Pin
Small Outline
Package (SOIC)
14-Pin
Plastic Dip
Package
14-Pin
CERDIP
Package
ALD2721ESB
ALD2721SB
ALD2721EPB
ALD2721PB
ALD2721EDB
ALD2721DB
* Contact factory for high temperature versions.
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
-IN A
1
14
VE 2A
+IN A
2
13
VE 1A
V-
3
12
OUT A
N/C
4
11
V+
N/C
5
10
OUT B
+IN B
6
9
VE 1B
-IN B
7
8
VE 2B
TOP VIEW
SB, PB, DB PACKAGES
* N/C Pins are internally connected. Do not connect externally.
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
FUNCTIONAL DESCRIPTION
Functional Description of ALD2721
The ALD2721E/ALD2721 uses EPADs as in-circuit elements for trimming of offset voltage bias characteristics.
Each ALD2721E/ALD2721 has a pair of EPAD-based circuits connected such that one circuit is used to adjust VOS in
one direction and the other circuit is used to adjust VOS in the
other direction. While each of the EPAD devices is a
monotonically adjustable programmable device, the VOS of
the ALD2721E can be adjusted many times in both directions. Once programmed, the set VOS levels are stored
permanently, even when the device power is removed.
The ALD2721 is pre-programmed at the factory under standard operating conditions for minimum equivalent input offset voltage. The ALD2721 offers similar programmable
features as the ALD2721E, but with a more limited offset
voltage program range. In is intended for standard operational amplifier applications, where little or no electrical
porggramming by the user is necessary.
Functional Description of ALD2721E
The ALD2721E is pre-programmed at the factory under
standard operating conditions for minimum equivalent input
offset voltage. It also has a guaranteed offset voltage
program range, which is ideal for applications that require
electrical offset voltage programming.
The ALD2721E is an operational amplifier that can be
trimmed with user application-specific programming or insystem programming conditions. User application-specific
circuit programming refers to the situation where the Total
Input Offset Voltage of the ALD2721E can be trimmed with
the actual intended operating conditions.
For example, an application circuit may have +1V and -1V
power supplies, and the operational amplifier input is biased
at +1V, and an average operating temperature at +85°C.
The circuit can be wired up to these conditions within an
environmental chamber with the ALD2721E inserted into a
test socket connected to this circuit while it is being electrically trimmed. Any error in VOS due to these bias conditions
can be automatically zeroed out. The Total VOS error is now
limited only by the adjustable range and the stability of VOS,
and the input noise voltage of the operational amplifier.
Therefore, this Total VOS error now includes VOS as VOS is
traditionally specified; plus the VOS error contributions from
PSRR, CMRR, TCVOS, and noise. Typically this total VOS
error (VOST) is approximately ±35µV for the ALD2721E.
In-System Programming refers to the condition where the
EPAD adjustment is made after the ALD2721E has been
inserted into a circuit board. In this case, the circuit design
must provide for the ALD2721E to operate in normal mode
and in programming mode. One of the benefits of in-system
programming is that not only is the ALD2721E offset voltage
from operating bias conditions accounted for, any residual
errors introduced by other circuit components, such as
resistor or sensor induced voltage errors, can also be corrected. In this way, the “in-system” circuit output can be
adjusted to a desired level, eliminating the need for another
trimming function.
ALD2721E/ALD2721
USER PROGRAMMABLE VOS FEATURE
Each ALD2721E/ALD2721 has four additional pins, compared to a conventional dual operational amplifier which has
eight pins. These four additional pins are named VE1A,
VE2A for op amp A and VE1B, VE2B for op amp B. Each of
these pins VE1A, VE2A, VE1B, VE2B (represented by VExx)
are connected to a separate, internal offset bias circuit. VExx
pins have initial internal bias voltage values of approximately
1V to 2V. The voltage on these pins can be programmed
using the ALD E100 EPAD Programmer and the appropriate
Adapter Module. The useful programming range of voltages
on VExx pins are 1V to 3V.
VExx pins are programming pins, used during electrical
programming mode to inject charge into the internal EPADs.
Increasing voltage on VE1A/VE1B increases the offset voltage whereas increasing voltage on VE2A/VE2B decreases
the offset voltage of op amp A and op amp B, respectively.
The injected charge is then permanently stored. After
programming, VExx pins must be left open in order for these
voltages to remain at the programmed levels.
During programming, voltages on VExx pins are increased
incrementally to program the offset voltage of the operational
amplifier to the desired VOS. Note that desired VOS can be
any value within the offset voltage programmable ranges,
and can be equal zero, a positive value or a negative value.
This VOS value can also be reprogrammed to a different
value at a later time, provided that the useful VE1x or VE2x
programming voltage range has not been exceeded. VExx
pins can also serve as capacitively coupled input pins.
Internally, VE1 and VE2 are programmed and connected
differentially. Temperature drift effects between the two
internal offset bias circuits cancel each other and introduce
less net temperature drift coefficient change than offset
voltage trimming techniques such as offset adjustment with
an external trimmer potentiometer.
While programming, V+, VE1 and VE2 pins may be alternately pulsed with 12V (approximately) pulses generated by
the EPAD Programmer. In-system programming requires
the ALD2721E application circuit to accommodate these
programming pulses. This can be accomplished by adding
resistors at certain appropriate circuit nodes. For more
information, see Application Note AN1700.
Advanced Linear Devices
2 of 13
ABSOLUTE MAXIMUM RATINGS
Supply voltage, V+
Differential input voltage range
Power dissipation
Operating temperature range SB, PB packages
DB package
Storage temperature range
Lead temperature, 10 seconds
CAUTION: ESD Sensitive Device. Use static control procedures in ESD controlled environment.
10.6V
-0.3V to V+ +0.3V
600 mW
0°C to +70°C
-55°C to +125°C
-65°C to +150°C
+260°C
OPERATING ELECTRICAL CHARACTERISTICS
TA = 25oC VS = ±2.5V unless otherwise specified
Parameter
Symbol
Supply Voltage
VS
V+
Initial Input Offset Voltage1
VOS i
Offset Voltage Program Range 2
∆VOS
Programmed Input Offset
Voltage Error 3
VOS
Total Input Offset Voltage 4
VOST
Input Offset Current 5
Min
2721E
Typ
±1.0
2.0
Max
±5.0
10.0
35
±5
2721
Typ
±1.0
2.0
100
±7
50
Min
50
±0.5
100
Max
Unit
Test Conditions
±5.0
10.0
V
V
Dual Supply
Single Supply
150
µV
RS ≤ 100KΩ
±2
50
mV
150
µV
At user specified
target offset voltage
50
100
50
150
µV
At user specified
target offset voltage
IOS
0.01
10
240
0.01
10
240
pA
pA
TA = 25°C
0°C ≤ TA ≤ +70°C
Input Bias Current 5
IB
0.01
10
240
0.01
10
240
pA
pA
TA = 25°C
0°C ≤ TA ≤ +70°C
Input Voltage Range 6
VIR
5.3
+2.8
V
V
V+ = +5V
VS = ±2.5V
Input Resistance
RIN
Input Offset Voltage Drift 7
-0.3
-2.8
5.3
+2.8
-0.3
-2.8
1014
1014
TCVOS
7
7
Initial Power Supply
Rejection Ratio 8
PSRR i
90
Initial Common Mode
CMRR i
90
Ω
µV/°C
RS ≤ 100KΩ
90
dB
RS ≤ 100KΩ
90
dB
RS ≤ 100KΩ
V/mV
V/mV
RL =100KΩ
0°C ≤ TA ≤ +70°C
V
V
RL =1MΩ V =5V
0°C ≤ TA ≤ +70°C
V
V
RL =100KΩ
0°C ≤ TA ≤ +70°C
Rejection Ratio 8
Large Signal Voltage Gain
AV
Output Voltage Range
Output Short Circuit Current
15
10
100
VO low
VO high
4.99
4.999
VO low
VO high
2.40
-2.48
2.48
0.001
ISC
15
10
100
4.99
4.999
2.40
-2.48
2.48
0.01
0.001
-2.40
1
1
0.01
-2.40
mA
* NOTES 1 through 9, see section titled "Definitions and Design Notes".
ALD2721E/ALD2721
Advanced Linear Devices
3 of 13
OPERATING ELECTRICAL CHARACTERISTICS (cont'd)
TA = 25oC VS = ±2.5V unless otherwise specified
2721E
Typ
Max
IS
200
Power Dissipation
PD
1.00
Input Capacitance
CIN
1
1
pF
Maximum Load Capacitance
CL
50
50
pF
Equivalent Input Noise Voltage
en
55
55
nV/√Hz
f = 1KHz
Equivalent Input Noise Current
in
0.6
0.6
fA/√Hz
f =10Hz
Bandwidth
BW
700
700
KHz
Slew Rate
SR
0.7
0.7
V/µs
AV = +1
RL = 100KΩ
Rise time
tr
0.2
0.2
µs
RL = 100KΩ
20
20
%
RL=100KΩ
CL=50pF
Parameter
Symbol
Supply Current
Min
Overshoot Factor
2721
Typ
Max
400
200
400
µA
VIN = 0V
No Load
2.00
1.00
2.00
mW
VS = ±2.5V
Min
Unit
Test Conditions
Settling Time
tS
10
10
µs
0.1% AV = -1
RL= 100KΩ
CL = 50pF
Channel Separation
CS
140
140
dB
AV =100
TA = 25oC VS = ±2.5V unless otherwise specified
2721E
Parameter
Symbol
Average Long Term Input Offset
Voltage Stability 9
∆ VOS
∆ time
Initial VE Voltage
VE1 i, VE2 i
Programmable Change of
VE Range
∆VE1, ∆VE2
Programmed VE Voltage Error
e(VE1-VE2)
VE Pin Leakage Current
ieb
Min
Typ
2721
Max
Min
0.02
Typ
0.02
Max
Unit
Test Conditions
µV/
1000 hrs
1.5
1.2
1.7
V
2.5
1.0
V
0.1
0.1
%
-5
-5
µA
* NOTES 1 through 9, see section titled "Definitions and Design Notes".
ALD2721E/ALD2721
Advanced Linear Devices
4 of 13
OPERATING ELECTRICAL CHARACTERISTICS (cont'd)
VS = ±2.5V -55°C ≤ TA ≤ +125°C unless otherwise specified
2721E
Min
Typ
2721
Parameter
Symbol
Max
Min
Initial Input offset Voltage
VOS i
Input Offset Current
IOS
2.0
2.0
nA
Input Bias Current
IB
2.0
2.0
nA
Initial Power Supply
PSRR i
85
85
dB
RS ≤ 100KΩ
Initial Common Mode
Rejection Ratio 8
CMRR i
83
83
dB
RS ≤ 100KΩ
Large Signal Voltage Gain
AV
15
50
V/mV
RL = 100KΩ
Output Voltage Range
VO low
VO high
2.35
V
V
RL = 100KΩ
Unit
Test Conditions
0.7
Typ
Max
0.7
Unit
Test Conditions
mV
RS ≤ 100KΩ
Rejection Ratio 8
50
-2.47
2.45
15
-2.40
2.35
-2.47
2.45
-2.40
TA = 25oC VS = ±5.0V unless otherwise specified
2721E
Min
Symbol
Initial Power Supply
8
Rejection Ratio
PSRR i
85
85
dB
RS ≤ 100KΩ
Initial Common Mode
8
Rejection Ratio
CMRRi
83
83
dB
RS ≤ 100KΩ
Large Signal Voltage Gain
AV
250
250
V/mV
RL = 100KΩ
Output Voltage Range
VO low
VO high
V
RL = 100KΩ
4.90
Typ
2721
Parameter
-4.98
4.98
Max
Min
-4.90
4.90
Typ
-4.98
4.98
Max
-4.90
Bandwidth
BW
1.0
1.0
MHz
Slew Rate
SR
1.0
1.0
V/µs
ALD2721E/ALD2721
Advanced Linear Devices
AV = +1, CL = 50pF
5 of 13
DEFINITIONS AND DESIGN NOTES:
ADDITIONAL DESIGN NOTES:
1. Initial Input Offset Voltage is the initial offset voltage of the
ALD2721E/ALD2721 operational amplifier when shipped from
the factory. The device has been pre-programmed and tested
for programmability.
A. The ALD2721E/ALD2721 is internally compensated for
unity gain stability using a novel scheme which produces a single
pole role off in the gain characteristics while providing more than
70 degrees of phase margin at unity gain frequency. A unity gain
buffer using the ALD2721E/ALD2721 will typically drive 50pF
of external load capacitance.
2. Offset Voltage Program Range is the range of adjustment of
user specified target offset voltage. This is typically an adjustment in either the positive or the negative direction of the input
offset voltage from an initial input offset voltage. The input offset
programming pins, VE1A/VE1B or VE2A/VE2B, change the
input offset voltage in the negative or positive direction, for each
of the amplifiers, A or B respectively. User specified target offset
voltage can be any offset voltage within this programming
range.
3. Programmed Input Offset Voltage Error is the final offset
voltage error after programming when the Input Offset Voltage
is at target Offset Voltage. This parameter is sample tested.
4. Total Input Offset Voltage is the same as Programmed Input
Offset Voltage, corrected for system offset voltage error. Usually this is an all inclusive system offset voltage, which also
includes offset voltage contributions from input offset voltage,
PSRR, CMRR, TCVOS and noise. It can also include errors
introduced by external components, at a system level. Programmed Input Offset Voltage and Total Input Offset Voltage is
not necessarily zero offset voltage, but an offset voltage set to
compensate for other system errors as well. This parameter is
sample tested.
5. The Input Offset and Bias Currents are essentially input
protection diode reverse bias leakage currents. This low input
bias current assures that the analog signal from the source will
not be distorted by it. For applications where source impedance
is very high, it may be necessary to limit noise and hum pickup
through proper shielding.
6. Input Voltage Range is determined by two parallel complementary input stages that are summed internally, each stage
having a separate input offset voltage. While Total Input Offset
Voltage can be trimmed to a desired target value, it is essential
to note that this trimming occurs at only one user selected input
bias voltage. Depending on the selected input bias voltage
relative to the power supply voltages, offset voltage trimming
may affect one or both input stages. For the ALD2721E/
ALD2721, the switching point between the two stages occurs at
approximately 1.5V below the positive supply voltage.
7. Input Offset Voltage Drift is the average change in Total Input
Offset Voltage as a function of ambient temperature. This
parameter is sample tested.
8. Initial PSRR and initial CMRR specifications are provided as
reference information. After programming, error contribution to
the offset voltage from PSRR and CMRR is set to zero under the
specific power supply and common mode conditions, and
becomes part of the Programmed Input Offset Voltage Error.
9. Average Long Term Input Offset Voltage Stability is based on
input offset voltage shift through operating life test at 125°C
extrapolated to TA = 25°C, assuming activation energy of 1.0eV.
This parameter is sample tested.
ALD2721E/ALD2721
B. The ALD2721E/ALD2721 has complementary p-channel
and n-channel input differential stages connected in parallel to
accomplish rail-to-rail input common mode voltage range. The
switching point between the two differential stages is 1.5V below
positive supply voltage. For applications such as inverting
amplifiers or non-inverting amplifiers with a gain larger than 2.5
(5V operation), the common mode voltage does not make
excursions below this switching point. However, this switching
does take place if the operational amplifier is connected as a railto-rail unity gain buffer and the design must allow for input offset
voltage variations.
C. The output stage consists of class AB complementary output
drivers. The oscillation resistant feature, combined with the railto-rail input and output feature, makes the ALD2721E/
ALD2721 an effective analog signal buffer for high source
impedance sensors, transducers, and other circuit networks.
D. The ALD2721E/ALD2721 has static discharge protection.
However, care must be exercised when handling the device to
avoid strong static fields that may degrade a diode junction,
causing increased input leakage currents. The user is advised
to power up the circuit before, or simultaneously with, any input
voltages applied and to limit input voltages not to exceed 0.3V of
the power supply voltage levels.
E. VExx are high impedance terminals, as the internal bias
currents are set very low to a few microamperes to conserve
power. For some applications, these terminals may need to be
shielded from external coupling sources. For example, digital
signals running nearby may cause unwanted offset voltage
fluctuations. Care during the printed circuit board layout, to
place ground traces around these pins and to isolate them from
digital lines, will generally eliminate such coupling effects. In
addition, optional decoupling capacitors of 1000pF or greater
value can be added to VExx terminals.
F. The ALD2721E/ALD2721 is designed for use in low voltage,
micropower circuits. The maximum operating voltage during
normal operation should remain below 10V at all times. Care
should be taken to insure that the application in which the device
is used does not experience any positive or negative transient
voltages that will cause any of the terminal voltages to exceed
this limit.
G. All inputs or unused pins except VExx pins should be
connected to a supply voltage such as Ground so that they do not
become floating pins, since input impedance at these pins is very
high. If any of these pins are left undefined, they may cause
unwanted oscillation or intermittent excessive current drain. As
these devices are built with CMOS technology, normal operating
and storage temperature limits, ESD and latchup handling
precautions pertaining to CMOS device handling should be
observed.
Advanced Linear Devices
6 of 13
TYPICAL PERFORMANCE CHARACTERISTICS
OPEN LOOP VOLTAGE GAIN AS A FUNCTION
OF SUPPLY VOLTAGE AND TEMPERATURE
OUTPUT VOLTAGE SWING (V)
OPEN LOOP VOLTAGE
GAIN (V/mV)
1000
OUTPUT VOLTAGE SWING AS A FUNCTION
OF SUPPLY VOLTAGE
100
10
-55°C ≤ TA ≤ +125°C
RL = 100KΩ
±2
±4
±6
-55°C ≤ TA ≤ +125°C
RL = 100KΩ
±5
±4
±3
±2
±1
1
0
±6
0
±8
±1
1000
±4
±5
±6
±7
500
VS = ±2.5V
100
SUPPLY CURRENT (µA)
INPUT BIAS CURRENT (pA)
±3
SUPPLY CURRENT AS A FUNCTION
OF SUPPLY VOLTAGE
INPUT BIAS CURRENT AS A FUNCTION
OF AMBIENT TEMPERATURE
10
1.0
0.1
0.01
INPUTS GROUNDED
OUTPUT UNLOADED
400
+25°C
-25°C
300
TA = -55°C
200
+125°C
100
+70°C
0
-50
-25
0
25
50
75
100
125
0
±1
±2
±3
±4
±5
AMBIENT TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
ADJUSTMENT IN INPUT OFFSET VOLTAGE
AS A FUNCTION OF CHANGE IN VE1 AND VE2
OPEN LOOP VOLTAGE GAIN
AS A FUNCTION OF FREQUENCY
±6
120
OPEN LOOP VOLTAGE
GAIN (dB)
10
8
6
VE1
4
2
0
-2
-4
-6
-8
VE2
-10
VS = ±2.5V
TA = 25°C
100
80
60
0
40
45
20
90
0
135
180
-20
0.50
0.75
1.00
1.25
1.50
1.75
2.00
CHANGE IN VE1 AND VE2 (V)
ALD2721E/ALD2721
Advanced Linear Devices
1
10
100
1K
10K 100K
FREQUENCY (Hz)
1M
PHASE SHIFT IN DEGREES
ADJUSTMENT IN INPUT OFFSET
VOLTAGE ∆VOS (mV)
±2
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
10M
7 of 13
TYPICAL PERFORMANCE CHARACTERISTICS (cont'd)
COMMON MODE INPUT VOLTAGE RANGE
AS A FUNCTION OF SUPPLY VOLTAGE
OPEN LOOP VOLTAGE GAIN AS A
FUNCTION OF LOAD RESISTANCE
±7
1000
OPEN LOOP VOLTAGE
GAIN (V/mV)
COMMON MODE INPUT
VOLTAGE RANGE (V)
±6
TA = 25°C
±5
±4
±3
±2
±1
100
10
VS = ±2.5V
TA = 25°C
0
1
0
±1
±2
±3
±4
±5
±6
±7
10K
100K
SUPPLY VOLTAGE (V)
1M
10M
LOAD RESISTANCE (Ω)
LARGE - SIGNAL TRANSIENT
RESPONSE
LARGE - SIGNAL TRANSIENT
RESPONSE
5V/div
VS = ±2.5V
TA = 25°C
RL = 100KΩ
CL = 50pF
2V/div
VS = ±1.0V
TA = 25°C
RL = 100KΩ
CL = 50pF
2V/div
5µs/div
500mV/div
5µs/div
SMALL - SIGNAL TRANSIENT
RESPONSE
DISTRIBUTION OF TOTAL INPUT OFFSET VOLTAGE
BEFORE AND AFTER EPAD PROGRAMMING
100mV/div
VS = ±2.5V
TA = 25°C
RL = 100KΩ
CL = 50pF
PERCENTAGE OF UNITS (%)
100
80
EXAMPLE A:
VOST AFTER EPAD
PROGRAMMING
VOST TARGET = 0.0µV
EXAMPLE B:
VOST AFTER EPAD
PROGRAMMING
VOST TARGET = -750µV
60
VOST BEFORE EPAD
PROGRAMMING
40
20
20mV/div
2µs/div
0
-2500
-2000
-1500
-1000
-500
0
500
1000
1500
2000
2500
TOTAL INPUT OFFSET VOLTAGE (µV)
ALD2721E/ALD2721
Advanced Linear Devices
8 of 13
EQUIVALENT INPUT OFFSET VOLTAGE DUE TO
CHANGE IN SUPPLY VOLTAGE (µV)
TYPICAL PERFORMANCE CHARACTERISTICS (cont'd)
TWO EXAMPLES OF EQUIVALENT INPUT OFFSET VOLTAGE DUE TO
CHANGE IN SUPPLY VOLTAGE vs. SUPPLY VOLTAGE
500
PSRR = 80 dB
400
EXAMPLE A:
VOS EPAD PROGRAMMED
AT VSUPPLY = +5V
300
EXAMPLE B:
VOS EPAD
PROGRAMMED
AT VSUPPLY = +8V
200
100
0
1
0
2
3
4
5
6
7
8
9
10
EQUIVALENT INPUT OFFSET VOLTAGE DUE TO
CHANGE IN COMMON MODE VOLTAGE (µV)
SUPPLY VOLTAGE (V)
THREE EXAMPLES OF EQUIVALENT INPUT OFFSET VOLTAGE DUE TO
CHANGE IN COMMON MODE VOLTAGE vs. COMMON MODE VOLTAGE
500
VSUPPLY = ±5V
CMRR = 80dB
400
300
EXAMPLE B:
VOS EPAD
PROGRAMMED
AT VIN = -4.3V
200
EXAMPLE A:
VOS EPAD PROGRAMMED
AT VIN = 0V
100
EXAMPLE C:
VOS EPAD PROGRAMMED
AT VIN = +5V
0
-5
-4
-3
-1
-2
0
1
2
3
4
5
EQUIVALENT INPUT OFFSET VOLTAGE DUE TO
CHANGE IN COMMON MODE VOLTAGE (µV)
COMMON MODE VOLTAGE (V)
EXAMPLE OF MINIMIZING EQUIVALENT INPUT OFFSET VOLTAGE
FOR A COMMON MODE VOLTAGE RANGE OF 0.5V
50
COMMON MODE VOLTAGE RANGE OF 0.5V
40
30
VOS EPAD
PROGRAMMED
AT COMMON MODE
VOLTAGE OF 0.25V
20
CMRR = 80dB
10
0
-0.5
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
COMMON MODE VOLTAGE (V)
ALD2721E/ALD2721
Advanced Linear Devices
9 of 13
TYPICAL PERFORMANCE CHARACTERISTICS (cont'd)
APPLICATION SPECIFIC / IN-SYSTEM PROGRAMMING
2500
2500
2000
2000
TOTAL INPUT OFFSET VOLTAGE (µV)
TOTAL INPUT OFFSET VOLTAGE (µV)
Examples of applications where accumulated total input offset voltage from various
contributing sources is minimized under different sets of user-specified operating conditions
1500
1000
VOS BUDGET AFTER
EPAD PROGRAMMING
500
0
-500
+
X
-1000
-1500
-2000
VOS BUDGET BEFORE
EPAD PROGRAMMING
1500
VOS BUDGET AFTER
EPAD PROGRAMMING
1000
500
+
0
X
-500
-1000
VOS BUDGET BEFORE
EPAD PROGRAMMING
-1500
-2000
-2500
-2500
EXAMPLE B
2500
2500
2000
2000
TOTAL INPUT OFFSET VOLTAGE (µV)
TOTAL INPUT OFFSET VOLTAGE (µV)
EXAMPLE A
1500
1000
VOS BUDGET BEFORE
EPAD PROGRAMMING
500
0
-500
-1000
+
X
-1500
-2000
VOS BUDGET AFTER
EPAD PROGRAMMING
1500
1000
500
+
0
X
-500
-1000
-1500
-2000
-2500
VOS BUDGET AFTER
EPAD PROGRAMMING
VOS BUDGET BEFORE
EPAD PROGRAMMING
-2500
EXAMPLE C
EXAMPLE D
Device input VOS
PSRR equivalent VOS
+
Total Input VOS
after EPAD
Programming
CMRR equivalent VOS
TA equivalent VOS
X
Noise equivalent VOS
External Error equivalent VOS
ALD2721E/ALD2721
Advanced Linear Devices
10 of 13
SOIC-14 PACKAGE DRAWING
14 Pin Plastic SOIC Package
Millimeters
E
S (45°)
Dim
A
Min
1.35
Max
1.75
Min
0.053
Max
0.069
A1
0.10
0.25
0.004
0.010
b
0.35
0.45
0.014
0.018
C
0.18
0.25
0.007
0.010
D-14
8.55
8.75
0.336
0.345
E
3.50
4.05
0.140
0.160
1.27 BSC
e
D
A
Inches
0.050 BSC
H
5.70
6.30
0.224
0.248
L
0.60
0.937
0.024
0.037
ø
0°
8°
0°
8°
S
0.25
0.50
0.010
0.020
A1
e
b
S (45°)
H
L
ALD2721E/ALD2721
C
ø
Advanced Linear Devices
11 of 13
PDIP-14 PACKAGE DRAWING
14 Pin Plastic DIP Package
Millimeters
E
E1
D
S
A2
A1
A
L
Inches
Dim
A
Min
Max
Min
3.81
5.08
0.105
Max
0.200
A1
0.38
1.27
0.015
0.050
A2
1.27
2.03
0.050
0.080
b
0.89
1.65
0.035
0.065
b1
0.38
0.51
0.015
0.020
c
0.20
0.30
0.008
0.012
D-14
17.27
19.30
0.680
0.760
E
5.59
7.11
0.220
0.280
E1
7.62
8.26
0.300
0.325
e
2.29
2.79
0.090
0.110
e1
7.37
7.87
0.290
0.310
L
2.79
3.81
0.110
0.150
S-14
1.02
2.03
0.040
0.080
ø
0°
15°
0°
15°
e
b
b1
c
e1
ALD2721E/ALD2721
ø
Advanced Linear Devices
12 of 13
CERDIP-14 PACKAGE DRAWING
14 Pin CERDIP Package
Millimeters
E E1
D
A1
s
A
L
L1
L2
b
b1
e
Inches
Dim
A
Min
Max
Min
Max
3.55
5.08
0.140
0.200
A1
1.27
2.16
0.050
0.085
b
0.97
1.65
0.038
0.065
b1
0.36
0.58
0.014
0.023
C
0.20
0.38
0.008
0.015
D-14
--
19.94
--
0.785
E
5.59
7.87
0.220
0.310
E1
7.73
8.26
0.290
0.325
e
2.54 BSC
0.100 BSC
e1
7.62 BSC
0.300 BSC
L
3.81
5.08
0.150
0.200
L1
3.18
--
0.125
--
L2
0.38
1.78
0.015
0.070
S
--
2.49
--
0.098
Ø
0°
15°
0°
15°
C
e1
ALD2721E/ALD2721
ø
Advanced Linear Devices
13 of 13
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