LTC321, LTC358, LTC324
P-1
General Description
The LTC321/LTC358/LTC324 family of single-, dual-, and quad- channel operational
amplifiers is specifically designed for general-purpose cost-sensitive systems and
applications. Featuring rail-to-rail input and output (RRIO) swings, and low quiescent
current (typical 85 µA) combined with a wide bandwidth (1.2 MHz) and low noise (30
nV/√Hz at 1 kHz) makes this family very attractive for a variety of battery-powered
applications that require a good balance between cost and performance, such as audio
outputs, consumer electronics, smoke detectors, portable medical devices and white
goods. The low input bias current supports these amplifiers to be used in applications
with mega-ohm source impedances.
The robust design of the LTC321/LTC358/LTC324 family provides ease-of-use to the
circuit designer: unity-gain stability with capacitive loads of up to 500 pF, integrated
RF/EMI rejection filter, no phase reversal in overdrive conditions, and high electro-static
discharge (ESD) protection (5-kV HBM). The LTC321/LTC358/LTC324 amplifiers are
optimized for operation at voltages as low as +1.8 V (±0.9 V) and up to +5.5 V (±2.75 V),
and over the extended temperature range of −40 ℃ to +125 ℃.
The LTC321 (single) is available in both SOT23-5L and SC70-5L packages. The LTC358
(dual) is offered in SOIC-8L, DFN-8L and MSOP-8L packages. The quad-channel LTC324
is offered in SOIC-14L, TSSOP-14L and QFN-16L packages.
Features and Benefits
General Purpose Amplifiers for Cost-Sensitive Systems
1.2 MHz GBW for Unity-Gain Stable
Micro-Power: 85 μA Supply Current Per Amplifier
Low Input Offset Voltage: ±3.0 mV Maximum
Low Noise: 30 nV/√Hz at 1 kHz
Single 1.8 V to 5.5 V Supply Voltage Range
Rail-to-Rail Input and Output
Internal RF/EMI Filter
Extended Temperature Range: −40℃ to +125℃
Applications
Battery-Powered Instruments:
– Consumer, Industrial, Medical, Notebooks
Audio Outputs
Wireless Sensors:
– Home Security, Remote Sensing, Wireless Metering
Sensor Signal Conditioning:
– Sensor Interfaces, Loop-Powered, Active Filters
Pin Configurations (Top View)
3
4 OUT
OUTA 1
8
+VS
–INA 2
7
OUTB
+INA 3
6
–INB
–VS 4
5
+INB
SOIC-8L / MSOP-8L
OUTA
–INA
1
2
+INA
3
–VS
4
8
7
A
B
+VS
OUTB
6
–INB
5
+INB
16
15
14
13
+INA
1
12
+IND
+VS
2
11
–VS
+INB
3
10
+INC
–INB
4
9
–INC
5
6
7
8
OUTC
–IN
5 +VS
NC
2
NC
1
OUTB
+IN
–VS
–IND
LTC324
SOIC-14L / TSSOP-14L
OUTD
LTC324
QFN3x3-16L
OUTA
LTC358
DFN2x2-8L
–INA
LTC321
SOT23-5L / SC70-5L
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
OUTA
1
14
OUTD
–INA
2
13
–IND
+INA
3
12
+IND
+VS
4
11
–VS
+INB
5
10
+INC
–INB
6
9
–INC
OUTB
7
8
OUTC
A
B
D
C
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-2
Pin Description
Symbol
Description
–IN
Inverting input of the amplifier. The voltage range is from (VS– – 0.1V) to (VS+ + 0.1V).
+IN
Non-inverting input of the amplifier. This pin has the same voltage range as –IN.
+VS
Positive power supply.
–VS
Negative power supply.
OUT
Amplifier output.
Ordering Information
Type Number
Package Name
Package Quantity
Marking Code (1)
LTC321XT5/R6
SOT23-5L
Tape and Reel, 3 000
321, 321I
LTC321XC5/R6
SC70-5L
Tape and Reel, 3 000
321
LTC358XS8/R8
SOIC-8L
Tape and Reel, 4 000
358 x, C42
LTC358XF8/R6
DFN2x2-8L
Tape and Reel, 3 000
358x, C42
LTC358XV8/R6
MSOP-8L
Tape and Reel, 3 000
358x, AG2
LTC324XS14/R5
SOIC-14L
Tape and Reel, 2 500
324 x, C44
LTC324XT14/R6
TSSOP-14L
Tape and Reel, 3 000
324 x, AG4
LTC324XF16/R6
QFN3x3-16L
Tape and Reel, 3 000
AG4x, 324x
(1) There may be multiple device markings, a varied marking character of “x” , or additional marking, which relates to the
logo, the lot trace code information, or the environmental category on the device.
Limiting Value
In accordance with the Absolute Maximum Rating System (IEC 60134).
Parameter
Absolute Maximum Rating
Supply Voltage, VS+ to VS–
10.0 V
Signal Input Terminals: Voltage, Current
VS– – 0.5 V to VS+ + 0.5 V, ±10 mA
Output Short-Circuit
Continuous
Storage Temperature Range, Tstg
–65 ℃ to +150 ℃
Junction Temperature, TJ
150 ℃
Lead Temperature Range (Soldering 10 sec)
260 ℃
ESD Rating
Parameter
Electrostatic
Discharge Voltage
Item
Value
Human body model (HBM), per MIL-STD-883J / Method 3015.9 (1)
±5 000
Charged device model (CDM), per ESDA/JEDEC JS-002-2014 (2)
±2 000
Machine model (MM), per JESD22-A115C
±250
Unit
V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
Manufacturing with less than 500-V HBM is possible if necessary precautions are taken.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
Manufacturing with less than 250-V CDM is possible if necessary precautions are taken.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-3
Electrical Characteristics
VS = 5.0V, TA = +25℃, VCM = VS /2, VO = VS /2, and RL = 10kΩ connected to VS /2, unless otherwise noted.
Boldface limits apply over the specified temperature range, TA = −40 to +125 ℃.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Unit
±0.7
±3.0
mV
±1
3.5
μV/℃
OFFSET VOLTAGE
VOS
Input offset voltage
VOS TC
Offset voltage drift
TA = −40 to +125 ℃
PSRR
Power supply
rejection ratio
VS = 2.0 to 5.5 V, VCM < VS+ − 2V
80
TA = −40 to +125 ℃
75
110
dB
INPUT BIAS CURRENT
5
IB
IOS
Input bias current
50
TA = −40 to +85 ℃
200
TA = −40 to +125 ℃
2000
Input offset current
10
50
pA
pA
NOISE
Vn
Input voltage noise
f = 0.1 to 10 Hz
6
en
Input voltage noise
density
f = 10 kHz
27
f = 1 kHz
30
In
Input current noise
density
f = 1 kHz
5
μVP-P
nV/√Hz
fA/√Hz
INPUT VOLTAGE
VCM
CMRR
Common-mode
voltage range
Common-mode
rejection ratio
VS––0.1
VS = 5.5 V, VCM = −0.1 to 5.6 V
70
VCM = 0 to 5.3 V, TA = −40 to +125 ℃
65
VS = 2.0 V, VCM = −0.1 to 2.1 V
65
VCM = 0 to 1.8 V, TA = −40 to +125 ℃
60
VS++0.1
V
83
77
dB
INPUT IMPEDANCE
CIN
Input capacitance
Differential
2.0
Common mode
3.5
pF
OPEN-LOOP GAIN
AVOL
Open-loop voltage
gain
RL = 50 kΩ, VO = 0.05 to 3.5 V
90
TA = −40 to +125 ℃
85
RL = 2 kΩ, VO = 0.15 to 3.5 V
85
TA = −40 to +125 ℃
80
105
100
dB
FREQUENCY RESPONSE
GBW
Gain bandwidth
product
SR
Slew rate
G = +1, CL = 100 pF, VO = 1.5 to 3.5
V
THD+N
Total harmonic
distortion + noise
G = +1, f = 1 kHz, VO = 1 VRMS
tS
Settling time
tOR
Overload recovery
time
1.2
MHz
1
V/μs
0.003
%
To 0.1%, G = +1, 1V step
1.5
To 0.01%, G = +1, 1V step
1.8
To 0.1%, VIN * Gain > VS
2.5
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
μs
μs
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-4
Electrical Characteristics (continued)
VS = 5.0V, TA = +25℃, VCM = VS /2, VO = VS /2, and RL = 10kΩ connected to VS /2, unless otherwise noted.
Boldface limits apply over the specified temperature range, TA = −40 to +125 ℃.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Unit
OUTPUT
VOH
High output voltage
swing
RL = 50 kΩ
VS+–6
VS+–3
RL = 2 kΩ
VS+–100
VS+–65
VOL
Low output voltage
swing
RL = 50 kΩ
VS–+2
VS–+4
RL = 2 kΩ
VS–+42
VS–+65
ISC
Short-circuit current
Source current through 10Ω
40
Sink current through 10Ω
50
mV
mV
mA
POWER SUPPLY
VS
Operating supply
voltage
IQ
Quiescent current
(per amplifier)
1.8
5.5
85
TA = −40 to +125 ℃
120
150
V
μA
THERMAL CHARACTERISTICS
TA
θJA
Operating
temperature range
Package Thermal
Resistance
–40
+125
SC70-5L
333
SOT23-5L
190
DFN2x2-8L
94
MSOP-8L
201
SOIC-8L
125
QFN3x3-16L
65
TSSOP-14L
112
SOIC-14L
115
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
℃
℃/W
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-5
Typical Performance Characteristics
At TA = +25℃, VCM = VS /2, and RL = 10kΩ connected to VS /2, unless otherwise noted.
100
AOL (dB)
80
60
40
20
0
-20
-40
10
100
1k
10k
100k
1M
1,000
Voltage Noise (nV/√Hz)
140
120
100
80
60
40
20
0
-20
-40
-60
-80
10M
Phase (deg)
120
100
10
1
1
100
Frequency (Hz)
Open-loop Gain and Phase as a function of
Frequency.
140
120
100
100
PSRR (dB)
120
CMRR (dB)
1M
Input Voltage Noise Spectral Density as a function of
Frequency.
140
80
60
80
60
40
40
20
20
0
0
1
100
10k
1M
1
100
Frequency (Hz)
10k
1M
Frequency (Hz)
Common-mode Rejection Ratio as a function of
Frequency.
Power Supply Rejection Ratio as a function of
Frequency.
120
Quiescent Current (μA)
125
Quiescent Current (μA)
10k
Frequency (Hz)
100
75
50
25
100
80
60
40
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
-50
0
25
50
75
100
125
Temperature (℃)
Supply Voltage (V)
Quiescent Current as a function of Supply Voltage.
-25
Quiescent Current as a function of Temperature.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-6
Typical Performance Characteristics (continued)
At TA = +25℃, VCM = VS /2, and RL = 10kΩ connected to VS /2, unless otherwise noted.
350
300
Sourcing Current
4
250
Output Voltage (V)
Distribution (Unit)
5
VCM = –VS
200
150
100
50
–40℃
3
+125℃
+25℃
2
1
Sinking Current
-3
-2.625
-2.25
-1.875
-1.5
-1.125
-0.75
-0.375
0
0.375
0.75
1.125
1.5
1.875
2.25
2.625
3
0
0
0
10
Offset Voltage (mV)
30
40
50
60
70
Output Current (mA)
Output Voltage Swing as a function of Output
Current.
Offset Voltage Production Distribution
80
60
Short-circuit Current (mA)
Short-circuit Current (mA)
20
60
–ISC
40
20
+ISC
0
–ISC
50
40
+ISC
30
20
2
2.5
3
3.5
4
4.5
5
5.5
-50
0
25
50
75
100
125
Temperature (℃)
Supply Voltage (V)
Short-circuit Current as a function of Supply
Voltage.
-25
Short-circuit Current as a function of Temperature.
CL=100pF
1V/div
25mV/div
CL=100pF
5μs/div
Large Signal Step Response.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
2μs/div
Small Signal Step Response.
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
P-7
LTC321, LTC358, LTC324
Application Notes
The LTC321/LTC358/LTC324 is a family of low-power,
rail-to-rail input and output operational amplifiers
specifically designed for portable applications. These
devices operate from 1.8 V to 5.5 V, are unity-gain
stable, and suitable for a wide range of generalpurpose applications. The class AB output stage is
capable of driving ≤ 10-kΩ loads connected to any
point between VS+ and ground. The input commonmode voltage range includes both rails, and allows
the LTC321/LTC358/LTC324 family to be used in
virtually any single-supply application. Rail-to-rail
input and output swing significantly increases
dynamic range, especially in low-supply applications,
and makes them ideal for driving sampling analogto-digital converters (ADCs).
The
LTC321/LTC358/LTC324
features
1.2-MHz
bandwidth and 1-V/μs slew rate with only 85-μA
supply current per amplifier, providing good ac
performance at very low power consumption. DC
applications are also well served with a low input
noise voltage of 30-nV/√Hz at 1-kHz, low input bias
current, and an input offset voltage of ±3.0-mV
maximum. The typical offset voltage drift is 1-μV/℃,
over the full temperature range the input offset
voltage changes only 100-μV (0.7-mV to 0.8-mV).
OPERATING VOLTAGE
The LTC321/LTC358/LTC324 family is optimized for
operation at voltages as low as +1.8 V (±0.9 V) and
up to +5.5 V (±2.75 V). In addition, many
specifications apply from –40 ℃ to +125 ℃.
Parameters that vary significantly with operating
voltages or temperature are illustrated in the Typical
Characteristics graphs.
The typical input bias current of the LTC321/LTC358
/LTC324 during normal operation is approximately 5pA. In overdriven conditions, the bias current can
increase significantly. The most common cause of an
overdriven condition occurs when the operational
amplifier is outside of the linear range of operation.
When the output of the operational amplifier is driven
to one of the supply rails, the feedback loop
requirements cannot be satisfied and a differential
input voltage develops across the input pins. This
differential input voltage results in activation of
parasitic diodes inside the front-end input chopping
switches that combine with electromagnetic
interference (EMI) filter resistors to create the
equivalent circuit. Notice that the input bias current
remains within specification in the linear region.
INPUT EMI FILTER AND CLAMP CIRCUIT
Figure 1 shows the input EMI filter and clamp circuit.
The LTC321/LTC358/LTC324 op-amps have internal
ESD protection diodes (D1, D2, D3, and D4) that are
connected between the inputs and each supply rail.
These diodes protect the input transistors in the
event of electrostatic discharge and are reverse
biased during normal operation. This protection
scheme allows voltages as high as approximately
500-mV beyond the rails to be applied at the input of
either terminal without causing permanent damage.
These ESD protection current-steering diodes also
provide in-circuit, input overdrive protection, as long
as the current is limited to 20-mA as stated in the
Absolute Maximum Ratings.
VS+
NOTE: Supply voltages (VS+ to VS–) higher than +10 V
can permanently damage the device.
RAIL-TO-RAIL INPUT
The input common-mode voltage range of the
LTC321/LTC358/LTC324 extends 100-mV beyond the
negative and positive supply rails. This performance
is achieved with a complementary input stage: an Nchannel input differential pair in parallel with a Pchannel differential pair. The N-channel pair is active
for input voltages close to the positive rail, typically
VS+–1.4 V to the positive supply, whereas the Pchannel pair is active for inputs from 100-mV below
the negative supply to approximately VS+–1.4 V. There
is a small transition region, typically VS+–1.2 V to VS+–1
V, in which both pairs are on. This 200-mV transition
region can vary up to 200-mV with process variation.
Thus, the transition region (both stages on) can range
from VS+–1.4 V to VS+–1.2 V on the low end, up to VS+–1
V to VS+–0.8 V on the high end. Within this transition
region, PSRR, CMRR, offset voltage, offset drift, and
THD can be degraded compared to device operation
outside this region.
D1
RS1
5kΩ
IN+
D2
D3
CCM1
RS2 CDM
5kΩ
IN–
D4
CCM2
VS–
Figure 1. Input EMI Filter and Clamp Circuit
Operational amplifiers vary in susceptibility to EMI. If
conducted EMI enters the operational amplifier, the
dc offset at the amplifier output can shift from its
nominal value when EMI is present. This shift is a
result of signal rectification associated with the
internal semiconductor junctions. Although all
operational amplifier pin functions can be affected by
EMI, the input pins are likely to be the most
susceptible. The EMI filter of the LTC321/358/324
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-8
Application Notes (continued)
is composed of two 5-kΩ input series resistors (RS1
and RS2), two common-mode capacitors (CCM1 and
CCM2), and a differential capacitor (CDM). These RC
networks set the −3 dB low-pass cutoff frequencies
at 35-MHz for common-mode signals, and at 22-MHz
for differential signals.
RAIL-TO-RAIL OUTPUT
Designed as a micro-power, low-noise op-amp, the
LTC321/358/324 delivers a robust output drive
capability. A class AB output stage with common source transistors is used to achieve full rail-to-rail
output swing capability. For resistive loads up to 50kΩ, the output swings typically to within 3-mV of
either supply rail regardless of the power-supply
voltage applied. Different load conditions change the
ability of the amplifier to swing close to the rails. For
resistive loads up to 2-kΩ, the output swings typically
to within 65-mV of the positive supply rail and within
42-mV of the negative supply rail.
provides the DC accuracy by connecting the inverting
signal with the output.
The CF and RISO serve to counteract the loss of phase
margin by feeding the high frequency component of
the output signal back to the amplifier’s inverting
input, thereby preserving phase margin in the overall
feedback loop.
For no-buffer configuration, there are two others
ways to increase the phase margin: (a) by increasing
the amplifier’s gain, or (b) by placing a capacitor in
parallel with the feedback resistor to counteract the
parasitic capacitance associated with inverting node.
CF
VOUT
VIN
CAPACITIVE LOAD AND STABILITY
CL
The LTC321/LTC358/LTC324 family can safely drive
capacitive loads of up to 500-pF in any configuration.
As with most amplifiers, driving larger capacitive
loads than specified may cause excessive overshoot
and ringing, or even oscillation. A heavy capacitive
load reduces the phase margin and causes the
amplifier frequency response to peak. Peaking
corresponds to over-shooting or ringing in the time
domain. Therefore, it is recommended that external
compensation be used if these op-amps must drive a
load exceeding 500-pF. This compensation is
particularly important in the unity-gain configuration,
which is the worst case for stability.
A quick and easy way to stabilize the op-amp for
capacitive load drive is by adding a series resistor,
RISO, between the amplifier output terminal and the
load capacitance, as shown in Figure 2. RISO isolates
the amplifier output and feedback network from the
capacitive load. The bigger the RISO resistor value, the
more stable VOUT will be. Note that this method
results in a loss of gain accuracy because RISO forms
a voltage divider with the RL.
RISO
RF
RISO
VOUT
VIN
CL
Figure 2. Indirectly Driving Heavy Capacitive Load
An improvement circuit is shown in Figure 3. It
provides DC accuracy as well as AC stability. The RF
RL
Figure 3. Indirectly Driving Heavy Capacitive Load
with DC Accuracy
OVERLOAD RECOVERY
Overload recovery is defined as the time required for
the operational amplifier output to recover from a
saturated state to a linear state. The output devices
of the operational amplifier enter a saturation region
when the output voltage exceeds the rated operating
voltage, either because of the high input voltage or
the high gain. After the device enters the saturation
region, the charge carriers in the output devices
require time to return back to the linear state. After
the charge carriers return back to the linear state,
the device begins to slew at the specified slew rate.
Thus, the propagation delay in case of an overload
condition is the sum of the overload recovery time
and the slew time. The overload recovery time for
the LTC321/LTC358/LTC324 is approximately 2.5-μs.
EMI REJECTION RATIO
Circuit performance is often adversely affected by
high frequency EMI. When the signal strength is low
and transmission lines are long, an op-amp must
accurately amplify the input signals. However, all opamp pins — the non-inverting input, inverting input,
positive supply, negative supply, and output pins —
are susceptible to EMI signals. These high frequency
signals are coupled into an op-amp by various
means, such as conduction, near field radiation, or
far field radiation. For example, wires and printed
circuit board (PCB) traces can act as antennas and
pick up high frequency EMI signals.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-9
Application Notes (continued)
Amplifiers do not amplify EMI or RF signals due to
their relatively low bandwidth. However, due to the
nonlinearities of the input devices, op-amps can
rectify these out of band signals. When these high
frequency signals are rectified, they appear as a dc
offset at the output.
The LTC321/LTC358/LTC324 have integrated EMI
filters at their input stage. A mathematical method of
measuring EMIRR is defined as follows:
EMIRR = 20 log (VIN_PEAK / ΔVOS)
resulting in a thermal voltage error.
This thermocouple error can be reduced by using
dummy components to match the thermoelectric
error source. Placing the dummy component as
close as possible to its partner ensures both
Seebeck voltages are equal, thus canceling the
thermocouple error. Maintaining a constant ambient
temperature on the circuit board further reduces this
error. The use of a ground plane helps distribute heat
throughout the board and reduces EMI noise pickup.
INPUT-TO-OUTPUT COUPLING
To minimize capacitive coupling, the input and output
signal traces should not be parallel. This helps
reduce unwanted positive feedback.
MAXIMIZING PERFORMANCE THROUGH PROPER
LAYOUT
To achieve the maximum performance of the
extremely high input impedance and low offset
voltage of the LTC321/LTC358/LTC324, care is needed
in laying out the circuit board. The PCB surface must
remain clean and free of moisture to avoid leakage
currents between adjacent traces. Surface coating of
the circuit board reduces surface moisture and
provides a humidity barrier, reducing parasitic
resistance on the board. The use of guard rings
around the amplifier inputs further reduces leakage
currents. Figure 4 shows proper guard ring
configuration and the top view of a surface-mount
layout. The guard ring does not need to be a specific
width, but it should form a continuous loop around
both inputs. By setting the guard ring voltage equal to
the voltage at the non-inverting input, parasitic
capacitance is minimized as well. For further
reduction of leakage currents, components can be
mounted to the PCB using Teflon standoff insulators.
Guard
Ring
+IN
–IN
+VS
Figure 4. Use a guard ring around sensitive pins
Other potential sources of offset error are
thermoelectric voltages on the circuit board. This
voltage, also called Seebeck voltage, occurs at the
junction of two dissimilar metals and is proportional
to the temperature of the junction. The most common
metallic junctions on a circuit board are solder-toboard trace and solder-to-component lead. If the
temperature of the PCB at one end of the component
is different from the temperature at the other end,
the resulting Seebeck voltages are not equal,
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-10
Tape and Reel Information
REEL DIMENSIONS
TAPE DIMENSIONS
K0
P1
B0 W
Reel
Diameter
A0
Cavity
A0
B0
K0
W
P1
Reel
Width (W1)
Dimension designed to accommodate the component width
Dimension designed to accommodate the component length
Dimension designed to accommodate the component thickness
Overall width of the carrier tape
Pitch between successive cavity centers
QUADRANT ASSIGNMENTS FOR PIN 1 ORIETATION IN TAPE
Sprocket Holes
Q1
Q2
Q1
Q2
Q3
Q4
Q3
Q4
User Direction of Feed
Pocket Quadrants
* All dimensions are nominal
Device
LTC321XT5/R6
Package
Pins
Type
SOT23
5
SPQ
3 000
Reel
Reel
Diameter Width W1
(mm)
(mm)
178
9.0
A0
(mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
(mm)
Pin 1
Quadrant
3.3
3.2
1.5
4.0
8.0
Q3
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-11
Package Outlines (continued)
DIMENSIONS, SOT23-5L
A2
A
A1
D
e1
Symbol
A
A1
A2
b
c
D
E1
E
e
e1
L
L1
θ
θ
L
E
E1
L1
e
b
Dimensions
In Millimeters
Min
Max
1.35
0.00
0.15
1.00
1.20
0.35
0.45
0.14
0.20
2.82
3.02
1.526
1.726
2.60
3.00
0.95 BSC
1.90 BSC
0.60 REF
0.30
0.60
0°
8°
Dimensions
In Inches
Min
Max
0.053
0.000
0.006
0.039
0.047
0.014
0.018
0.006
0.008
0.111
0.119
0.060
0.068
0.102
0.118
0.037 BSC
0.075 BSC
0.024 REF
0.012
0.024
0°
8°
c
RECOMMENDED SOLDERING FOOTPRINT, SOT23-5L
1.0
0.039
0.95
0.037
0.95
0.037
0.7
0.028
2.4
0.094
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
mm
( inches
)
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-12
Package Outlines
DIMENSIONS, SC70-5L (SOT353)
A2
A
Symbol
A1
D
e1
A
A1
A2
b
C
D
E
E1
e
e1
L
L1
θ
θ
e
L
E1
E
L1
b
Dimensions
In Millimeters
Min
Max
0.90
1.10
0.00
0.10
0.90
1.00
0.15
0.35
0.08
0.15
2.00
2.20
1.15
1.35
2.15
2.45
0.65 typ.
1.20
1.40
0.525 ref.
0.26
0.46
0°
8°
C
RECOMMENDED SOLDERING FOOTPRINT, SC70-5L (SOT353)
0.50
0.0197
0.65
0.0256
0.65
0.0256
0.40
0.0157
1.9
0.0748
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
mm
( inches
)
Dimensions
In Inches
Min
Max
0.035
0.043
0.000
0.004
0.035
0.039
0.006
0.014
0.003
0.006
0.079
0.087
0.045
0.053
0.085
0.096
0.026 typ.
0.047
0.055
0.021 ref.
0.010
0.018
0°
8°
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-13
Package Outlines (continued)
DIMENSIONS, SOIC-8L
A2
A
A1
D
b
Symbol
e
A
A1
A2
b
C
D
E
E1
e
L
θ
L
E
E1
θ
Dimensions
In Millimeters
Min
Max
1.370
1.670
0.070
0.170
1.300
1.500
0.306
0.506
0.203 TYP.
4.700
5.100
3.820
4.020
5.800
6.200
1.270 TYP.
0.450
0.750
0°
8°
Dimensions
In Inches
Min
Max
0.054
0.066
0.003
0.007
0.051
0.059
0.012
0.020
0.008 TYP.
0.185
0.201
0.150
0.158
0.228
0.244
0.050 TYP.
0.018
0.030
0°
8°
C
RECOMMENDED SOLDERING FOOTPRINT, SOIC-8L
8X
5.40
0.213
(1.55)
MAX
(0.061)
(3.90)
MIN
(0.154)
1
(0.60)
MAX 8X
(0.024)
PITCH
1.270
0.050
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
mm
( inches
)
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-14
Package Outlines (continued)
DIMENSIONS, DFN2x2-8L
E
A
c
A1
1
Nd
D1
2
D
b1
Exposed Thermal
Pad Zone
L
h
E1
h
2
e
Symbol
Min.
0.70
A
A1
b
b1
c
D
D1
Nd
E
E1
e
L
h
0.20
0.18
1.90
1.10
1.90
0.60
0.30
0.15
Millimeters
Nom.
0.75
0.02
0.25
0.18 REF
0.20
2.00
1.20
1.50BSC
2.00
0.70
0.50BSC
0.35
0.20
1
b
BOTTOM VIEW
RECOMMENDED SOLDERING FOOTPRINT, DFN2x2-8L
1.60
0.0630
PACKAGE
OUTLINE
8X
0.50
0.0197
1.00
0.0394
2.30
0.0906
1
0.50
PITCH
0.0197
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
0.30
8X 0.0118
mm
( inches
)
Max.
0.80
0.05
0.30
0.25
2.10
1.30
2.10
0.80
0.40
0.25
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-15
Package Outlines (continued)
DIMENSIONS, MSOP-8L
A2
A
A1
D
b
Symbol
e
A
A1
A2
b
C
D
E
E1
e
L
θ
L
E1
E
Dimensions
In Millimeters
Min
Max
0.800
1.100
Dimensions
In Inches
Min
Max
0.031
0.043
0.050
0.150
0.750
0.950
0.290
0.380
0.150
0.200
2.900
3.100
2.900
3.100
4.700
5.100
0.650 TYP.
0.400
0.700
0°
8°
0.002
0.006
0.030
0.037
0.011
0.015
0.006
0.008
0.114
0.122
0.114
0.122
0.185
0.201
0.026 TYP.
0.016
0.028
0°
8°
θ
C
RECOMMENDED SOLDERING FOOTPRINT, MSOP-8L
8X
(0.45)
MAX
(0.018)
(1.45)
MAX
(0.057)
8X
4.40
(5.85)
MAX
0.173
(0.230)
(2.95)
MIN
(0.116)
0.65
PITCH
0.026
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
mm
( inches
)
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-16
Package Outlines (continued)
DIMENSIONS, SOIC-14L
A3
A2
A
A1
D
b
C
e
L1 L
E
Symbol
E1
A
A1
A2
A3
b
C
D
E
E1
e
L1
L
θ
Dimensions
In Millimeters
Min
Max
1.450
1.850
0.100
0.300
1.350
1.550
0.550
0.750
0.406 TYP.
0.203 TYP.
8.630
8.830
5.840
6.240
3.850
4.050
1.270 TYP.
1.040 REF.
0.350
0.750
2°
8°
Dimensions
In Inches
Min
Max
0.057
0.073
0.004
0.012
0.053
0.061
0.022
0.030
0.016 TYP.
0.008 TYP.
0.340
0.348
0.230
0.246
0.152
0.159
0.050 TYP.
0.041 REF.
0.014
0.030
2°
8°
θ
RECOMMENDED SOLDERING FOOTPRINT, SOIC-14L
14X
5.40
0.213
(1.50)
MAX
(0.059)
(3.90)
MIN
(0.154)
1
(0.60)
MAX 14X
(0.024)
PITCH
1.270
0.050
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
mm
( inches
)
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-17
Package Outlines
DIMENSIONS, QFN3x3-16L
SIDE VIEW
A
TOP VIEW
Symbol
A3
D
A
A3
b
D
D1
E
E1
e
h
K
L
BOTTOM VIEW
K
9
L
12
8
E
13
E1
e
D1
h
5
16
PIN#1
4
Min.
0.70
0.20
2.90
1.60
2.90
1.60
0.20
0.225
0.35
Millimeters
Nom.
0.75
0.210 REF.
0.25
3.00
1.65
3.00
1.65
0.50 BSC.
0.25
0.275
0.40
1
b
RECOMMENDED SOLDERING FOOTPRINT, QFN3x3-16L
0.65
0.20
3.50
1.70
1.70
1.80
0.30
0.25
0.50
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
Max.
0.80
0.30
3.10
1.70
3.10
1.70
0.30
0.325
0.45
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
LTC321, LTC358, LTC324
P-18
Package Outlines (continued)
DIMENSIONS, TSSOP-14L
A3 A2
A
Symbol
A1
D
b
e
C
L1 L
E
E1
A
A1
A2
A3
b
C
D
E
E1
e
L1
L
θ
Dimensions
In Millimeters
Min
Max
1.200
0.050
0.150
0.900
1.050
0.390
0.490
0.200
0.290
0.130
0.180
4.860
5.060
6.200
6.600
4.300
4.500
0.650 TYP.
1.000 REF.
0.450
0.750
0°
8°
Dimensions
In Inches
Min
Max
0.047
0.002
0.006
0.035
0.041
0.015
0.019
0.008
0.011
0.005
0.007
0.191
0.199
0.244
0.260
0.169
0.177
0.026 TYP.
0.039 REF.
0.018
0.030
0°
8°
θ
RECOMMENDED SOLDERING FOOTPRINT, TSSOP-14L
14X
(1.45)
MAX
(0.057)
(4.40)
MIN
(0.173)
PITCH
0.65
0.026
1
5.90
0.232
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
14X
(0.45)
MAX
(0.018)
mm
( inches
)
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
P-19
LTC321, LTC358, LTC324
IMPORTANT NOTICE
Linearin is a global fabless semiconductor company specializing in advanced high-performance highquality analog/mixed-signal IC products and sensor solutions. The company is devoted to the innovation
of high performance, analog-intensive sensor front-end products and modular sensor solutions, applied
in multi-market of medical & wearable devices, smart home, sensing of IoT, and intelligent industrial &
smart factory (industrie 4.0). Linearin’s product families include widely-used standard catalog products,
solution-based application specific standard products (ASSPs) and sensor modules that help customers
achieve faster time-to-market products. Go to http://www.linearin.com for a complete list of Linearin
product families.
For additional product information, or full datasheet, please contact with the Linearin’s Sales Department
or Representatives.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Linearin and designs are registered trademarks of Linearin Technology Corporation.
© Copyright Linearin Technology Corporation. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
FN1617-33GL.3b — Data Sheet
General Purpose 1.2MHz, RRIO, 1.8V CMOS Amplifiers
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