LTC331, LTC393
P-1
General Description
The LTC331/393 single-/dual- channel comparators are drop-in, pin-for-pin compatible
replacements for the LMV331/LMV393, and low-voltage versions of TL331/LM393. The
devices with open-drain output offer the ultimate combination of high speed (100 ns
propagation delay) and very low power consumption (37 μA), and feature such as rail-torail inputs, low offset voltage (typically 1 mV), large output drive current, and a wide range
of supply voltages from 1.8 V to 5.5 V. The devices are very easy to implement in a wide
variety of applications where require critical response time, power-sensitive, lowvoltage, and/or tight board space.
Advantages of the LTC331/393 also include the added benefit of internal hysteresis
provide noise immunity, preventing output oscillations even with slow-moving input
signals. Designed with the most modern techniques, the LTC331/393 achieve superior
performance over BiCMOS or bipolar versions on the market.
The LTC331 (single) is available in both SOT23-5L and SC70-5L packages. The LTC393
(dual) is offered in DFN-8L, SOIC-8L, MSOP-8L and TSSOP-8L packages. All devices are
rated over −40 ℃ to +85 ℃ industrial temperature range.
Features and Benefits
Micro-power Operating Current (37 μA) Preserves Battery Power
Fast 100 ns Propagation Delay (100-mV Overdrive)
Single 1.8 V to 5.5 V Supply Voltage Range
– Can be Powered From the Same 1.8V/2.5V/3.3V/5V System Rails
Rail-to-Rail Input
Open-Drain Output Current Drive: 30 mA Typically at 5V Supply
Internal Hysteresis for Clean Switching
Internal RF/EMI Filter
Operating Temperature Range: −40 ℃ to +85 ℃
Applications
Consumer Accessories
Portable and Battery-Powered Devices
Alarms and Monitoring Circuits
Threshold Detectors and Discriminators
Logic Level Shifting or Translation
Zero-Crossing Detectors
Window Comparators
IR Receivers
Line Receivers
Pin Configurations (Top View)
LTC331
LTC331R
LTC393
LTC393
SOT23-5L / SC70-5L
SOT23-5L
DFN-8L
SOIC-8L / MSOP-8L / TSSOP-8L
+IN
1
–VS
2
–IN
3
5
4
+VS
OUT
–IN
1
–VS
2
+IN
3
5
4
+VS
OUT
OUTA 1
8 +VS
–INA 2
7 OUTB
OUT A
1
8
+VS
+INA 3
6 –INB
–IN A
2
7
OUT B
–VS 4
5 +INB
+IN A
3
6
–IN B
–VS
4
5
+IN B
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.
A
B
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-2
Pin Description
Symbol
Description
–IN
Negative input. The voltage range is from (VS– – 0.1V) to (VS+ + 0.1V).
+IN
Positive input. This pin has the same voltage range as –IN.
+VS
Positive power supply.
–VS
Negative power supply.
OUT
Comparator output.
Ordering Information (3)
Orderable
Type Number
Package
Name
Package
Quantity
Eco Class (1)
Operating
temperature
Marking
Code (2)
LTC331YT5/R6
SOT23-5L
3 000
Green (RoHS & no Sb/Br)
–40℃ to +85℃
CG7
LTC331YC5/R6
SC70-5L
3 000
Green (RoHS & no Sb/Br)
–40℃ to +85℃
CG7
LTC331RYT5/R6
SOT23-5L
3 000
Green (RoHS & no Sb/Br)
–40℃ to +85℃
CG9
LTC393YS8/R8
SOIC-8L
4 000
Green (RoHS & no Sb/Br)
–40℃ to +85℃
CG8 Y
LTC393YV8/R6
MSOP-8L
3 000
Green (RoHS & no Sb/Br)
–40℃ to +85℃
CG8Y
LTC393YT8/R6
TSSOP-8L
3 000
Green (RoHS & no Sb/Br)
–40℃ to +85℃
CG8Y
LTC393YF8/R6
DFN2x2-8L
3 000
Green (RoHS & no Sb/Br)
–40℃ to +85℃
CG8
(1) Eco Class - The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS & Halogen Free).
(2) 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.
(3) Please contact to your Linearin representative for the latest availability information and product content
details.
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– – 0.3 V to VS+ + 0.3 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
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
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.
Unit
V
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-3
Electrical Characteristics
VS = 5.0V, TA = +25℃, unless otherwise noted.
Boldface limits apply over the specified temperature range, TA = −40 to +85 ℃.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
±5.0
Unit
OFFSET VOLTAGE
VOS
Input offset voltage
VCM = 0
±1
VOS TC
Offset voltage drift
TA = −40 to +85 ℃
±2
PSRR
Power supply
rejection ratio
VS = 1.8 to 5.5 V, VCM < (VS+ − 1V)
70
TA = −40 to +85 ℃
66
Hyst
Input hysteresis
VCM = 0
3
VCM = VS+ /2
5
mV
μV/℃
82
dB
mV
INPUT BIAS CURRENT
IB
Input bias current
IOS
Input offset current
TA = −40 to +85 ℃
30
800
VCM = VS+ /2
10
TA = −40 to +85 ℃
50
1,000
pA
pA
INPUT VOLTAGE RANGE
VCM
CMRR
Common-mode
voltage range
Common-mode
rejection ratio
VS––0.1
VS = 5.5 V, VCM = −0.1 to 5.5 V
61
VCM = 0 to 5.3 V, TA = −40 to +85 ℃
58
VS = 1.8 V, VCM = −0.1 to 1.8 V
58
VCM = 0 to 1.6 V, TA = −40 to +85 ℃
55
VS++0.1
V
78
dB
77
INPUT IMPEDANCE
RIN
CIN
Input resistance
Input capacitance
100
GΩ
Differential
2.0
Common mode
3.5
ISINK = 1 mA
50
pF
OUTPUT
VOL
Low output voltage
swing
ISC
Output short-circuit
current
TA = −40 to +85 ℃
80
90
Sink current
–30
mV
–25
mA
5.5
V
POWER SUPPLY
VS
Operating supply
voltage
1.8
VS = 1.8 V, VCM = 0.5V, IO = 0
IQ
Quiescent current
(per comparator)
32
TA = −40 to +85 ℃
VS = 5.5 V, VCM = 0.5V, IO = 0
40
50
37
TA = −40 to +85 ℃
45
μA
60
SWITCHING CHARACTERISTICS
tPD–
Propagation delay
time, High to low
tF
Fall time
Input overdrive = 20 mV, CL = 15
pF
Input overdrive = 100 mV, CL =
15 pF
Input overdrive = 20 mV, CL = 15
pF
Input overdrive = 100 mV, CL =
15 pF
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.
240
100
20
10
ns
ns
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-4
Electrical Characteristics (continued)
VS = 5.0V, TA = +25℃, unless otherwise noted.
Boldface limits apply over the specified temperature range, TA = −40 to +85 ℃.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Unit
+85
℃
THERMAL CHARACTERISTICS
TA
θJA
Operating
temperature range
Package Thermal
Resistance
-40
SC70-5L
333
SOT23-5L
190
DFN2x2-8L
80
MSOP-8L
216
TSSOP-8L
160
SOIC-8L
125
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
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-5
Typical Performance Characteristics
At TA=+25℃, VS=±2.5V, VCM=VS /2, RL=10kΩ connected to VS /2, and CL=15pF, unless otherwise noted.
60
60
VCM=0.5V
+85℃
40
30
+25℃
–40℃
20
VS = 5V
VOD = 50mV
55
Supply Current (μA)
Supply Current (μA)
50
10
50
Output Low Voltage
45
40
35
Output High Voltage
30
25
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
0
6
1
Supply Current vs. Supply Voltage
4
5
350
VCM = VS / 2
VOD = 100mV
175
Propagation Delay L-H (ns)
Propagation Delay H-L (ns)
3
Supply Current vs. Common-Mode Input
200
150
+85℃
125
100
–40℃
75
+25℃
50
25
0
VCM = VS / 2
VOD = 100mV
RPU = 5.1kΩ
TA = +25℃
300
250
200
150
tPD+ (L-H)
100
50
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
1.5
2
Supply Voltage (V)
500
425
400
375
tPD– (H-L)
350
3.5
4
4.5
5
5.5
900
Propagation Delay L-H (ns)
450
3
Propagation Delay (tPLH) vs. Supply Voltage
VCM = VS / 2
VOD = 10mV
TA = +25℃
475
2.5
Supply Voltage (V)
Propagation Delay (tPHL) vs. Supply Voltage
Propagation Delay H-L (ns)
2
Common-Mode Voltage (V)
Supply Voltage (V)
325
300
VCM = VS / 2
VOD = 10mV
RPU = 5.1kΩ
TA = +25℃
800
700
600
500
tPD+ (L-H)
400
300
1.5
2
2.5
3
3.5
4
4.5
5
5.5
1.5
Supply Voltage (V)
Propagation Delay (tPHL) vs. Supply Voltage
2
2.5
3
3.5
4
4.5
5
Supply Voltage (V)
Propagation Delay (tPLH) vs. Supply Voltage
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.
5.5
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-6
Typical Performance Characteristics
At TA=+25℃, VS=±2.5V, VCM=VS /2, RL=10kΩ connected to VS /2, and CL=15pF, unless otherwise noted.
500
VS = 5.0V
Propagation Delay (ns)
Propagation Delay (ns)
500
400
300
tPD– (H-L)
200
100
VS = 1.8V
400
300
tPD– (H-L)
200
100
0
0
10
100
1000
10
100
Overdrive Voltage (mV)
Propagation Delay (tPHL) vs. Input Overdrive
Propagation Delay (tPHL) vs. Input Overdrive
1000
190
VOD = 50mV
180
Propagation Delay (ns)
Propagation Delay H-L (ns)
1000
Overdrive Voltage (mV)
170
160
150
140
130
VS = 5.0V
VOD = 100mV
100
10
0.01
120
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
tPD– (H-L)
5
0.1
1
Output Capacitive Load (nF)
Common-Mode Voltage (V)
Propagation Delay (tPHL) vs. Input Common-Mode
Propagation Delay (tPHL) vs. Capacitive Load
1000
VS = 1.8V
VOD = 100mV
4
tPD– (H-L)
100
10
0.01
Output Voltage (V)
Propagation Delay (ns)
5
0.1
1
+85℃
2
–40℃
1
0
0
5
Output Capacitive Load (nF)
Propagation Delay (tPHL) vs. Capacitive Load
+25℃
3
10
15
20
25
30
35
40
45
Output Current (mA)
Output Voltage vs. Output Sinking Current
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.
50
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-7
Typical Performance Characteristics
At TA=+25℃, VS=±2.5V, VCM=VS /2, RL=10kΩ connected to VS /2, and CL=15pF, unless otherwise noted.
10
Short-Circuit Current (mA)
Short-Circuit Current (mA)
50
VS = 5.0V
45
40
35
30
VS = 1.8V
8
6
4
2
0
25
-50
-25
0
25
50
75
100
-50
Temperature (℃)
Short Circuit Current vs. Temperature
-25
0
25
50
75
Temperature (℃)
Short Circuit Current vs. 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.
100
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-8
Application Notes
OPERATING VOLTAGE
The LTC331/LTC393 micro-power comparators of
open-drain output are fully specified and ensured for
operation from 1.8 V to 5.5 V and offers an excellent
speed-to-power combination with a propagation
delay of 100 ns and a quiescent supply current of 37
μA. This combination of fast response time at micropower enables power conscious systems to monitor
and respond quickly to fault conditions.
In addition, and many specifications apply over the
industrial temperature range of –40℃ to +85℃.
Parameters that vary significantly with operating
voltages or temperature are illustrated in the Typical
Characteristics graphs.
INPUT VOLTAGE
The input common-mode voltage range of the
LTC331/LTC393 family extends 100mV beyond the
supply rails. This performance is achieved with a
complementary input stage: an N-channel input
differential pair in parallel with a P-channel
differential pair. The N-channel pair is active for
input voltages close to the positive rail, typically VS+–
1.4V to the positive supply, whereas the P-channel
pair is active for inputs from 100mV below the
negative supply to approximately VS+–1.4V. There is a
small transition region, typically VS+–1.2V to VS+–1V, in
which both pairs are on. This 200mV transition region
can vary up to 200mV with process variation. Thus,
the transition region (both stages on) can range from
VS+–1.4V to VS+–1.2V on the low end, up to VS+–1V to
VS+–0.8V 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.
INPUT VOLTAGE
The LTC331/LTC393 comparator family uses CMOS
transistors at the inputs which prevent phase
inversion when the input pins exceed the supply
voltages.
VS+
D1
RS1
500Ω
IN+
D2
D3
CCM1
RS2 CDM
500Ω
IN–
D4
CCM2
VS–
Figure 1. Input EMI Filter and Clamp Circuit
The LTC331/LTC393 comparators 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
300mV beyond the rails to be applied at the input of
either terminal without causing permanent damage.
See the table of Absolute Maximum Ratings for more
information.
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 amplifier must
accurately amplify the input signals. However, all
comparator 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 comparator 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.
Amplifiers do not amplify EMI or RF signals due to
their relatively low bandwidth. However, due to the
nonlinearities of the input devices, comparators can
rectify these out of band signals. When these high
frequency signals are rectified, they appear as a dc
offset at the output.
The LTC331/LTC393 comparators have integrated EMI
filters at their input stage. A mathematical method of
measuring EMIRR is defined as follows:
EMIRR = 20 log (VIN_PEAK / ΔVOS)
INTERNAL HYSTERESIS
Most high-speed comparators oscillate in the linear
region because of noise or undesired parasitic
feedback. This tends to occur when the voltage on
one input is at or equal to the voltage on the other
input. To counter the parasitic effects and noise, the
devices have an internal hysteresis of 3 mV.
The hysteresis in a comparator creates two trip
points: one for the rising input voltage and one for
the falling input voltage. The difference between the
trip points is the hysteresis. The average of the trip
points is the offset voltage. When the comparator’s
input voltages are equal, the hysteresis effectively
causes one comparator input voltage to move quickly
past the other, thus taking the input out of the region
where oscillation occurs. Standard comparators
require hysteresis to be added with external
resistors. To increase hysteresis and noise margin
e v e n
m o r e ,
a d d
Figure 1 shows the input EMI filter and clamp circuit.
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.
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-9
Application Notes
positive feedback with two resistors as a voltage
divider from the output to the non-inverting input.
Figure 2 illustrates the case where IN– is fixed and
IN+ is varied. If the inputs were reversed, the figure
would look the same, except the output would be
inverted.
VTRIP+
VIN+
VHYST
VOS
VIN– = 0
VTRIP–
VOS = (VTRIP+ + VTRIP–)/2
VOH
Comparator
Output
VOL
Figure 2. Input and Output Waveform, Non-inverting
Input Varied
MAXIMIZING PERFORMANCE THROUGH PROPER
LAYOUT
electric 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,
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.
To achieve the maximum performance of the
extremely high input impedance and low offset
voltage of the LTC331/LTC393 devices, 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 comparator inputs further reduces
leakage currents. Figure 3 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 3. Use a guard ring around sensitive pins
Other potential sources of offset error are thermoCAUTION: 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.
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-10
Typical Application Circuits
IR RECEIVER AFE AND WAKE- UP CIRCUIT
Infrared (IR) communication is inherently immune to
RF interference as long as there is a line-of-sight
path between the transmitter and the receiver. It is
also one of the lowest cost communication schemes.
This makes it a good choice for implementing
wireless communications in applications such as
utility metering. A common system topology to
extend battery life is to use a power efficient IR
receiver analog front end (AFE) that is always on and
wakes up the host only when there is a valid IR
signal detected as shown in Figure 1.
IR
LED
IR Receiver
AFE
Digital output
(hardware wake-up
event)
GPIO
MCU
(Low
Power)
through R3. And finally R3 and R4 are used to
introduce additional hysteresis to keep the output
free of spurious toggles.
VREF
3V
Figure 4. Coin Cell Battery Powered IR Receiver
R4
470kΩ
10MΩ
3V
LTC331
Output to MCU
(Also to wake-up MCU)
R1
10MΩ
C1
0.01μF
Figure 5. IR Receiver AFE Using LTC331
USE WINDOW COMPARATOR TO DETECT
UNDER-VOLTAGE AND OVER-VOLTAGE
Window comparators are commonly used to detect
undervoltage (UV) and overvoltage (OV) conditions.
Figure 6 shows a simple window comparator circuit.
Power efficient comparators such as the LTC331
/LTC393 can be used in the IR receiver AFE to
increase battery life. The LTC331/LTC393 device is
responsible for two major tasks:
1. IR signal conditioning,
2. Host system wake-up.
The LTC331/LTC393 device is constantly powered to
always be ready to receive IR signals and wake up
the host microcontroller (MCU) when data is
received. The short working distance (approx 5 cm)
is suitable for a virtual-contact operation where the
IR transmitter and receiver are closely placed with
an optional mechanical alignment guide.
R3
470kΩ
IR
LED
+
10MΩ
R2
3.3V
LTC393
R1
RPU
VS+
+
UV_OV
–
Sensor
VS–
R2
MicroController
VS+
+
–
R3
Figure 1 shows the IR receiver system block diagram.
The host MCU is normally in the shutdown mode
(during which the quiescent current is less than 1 μA)
except when data is being transferred.
VS–
Figure 6. Window Comparator
Figure 2 shows the detailed circuit design. The circuit
establishes a threshold through R2 and C1 which
automatically adapts to the ambient light level. To
further reduce BOM cost, this example uses an IR
LED as the IR receiver. The IR LED is reverse-biased
to function as a photodiode (but at a reduced
sensitivity).
For this design, follow these design requirements:
The low input bias current allows a greater load
resistor value (R1) without sacrificing linearity, which
in turn helps reduce the always-on supply current.
Configure the circuit as shown in Figure 6. Connect
VS+ to a 3.3-V power supply and VS– to ground. Make
R 1, R2 and R3 each 10-MΩ resistors. These three
resistors are used to create the positive and negative
thresholds for the window comparator (VTH+ and VTH–).
With each resistor being equal, VTH+ is 2.2 V and VTH–
The load resistor R1 converts the IR light induced
current into a voltage fed into the inverting input of
the comparator. R2 and C1 establish a reference
voltage VREF which tracks the mean amplitude of the
IR signal. The non-inverting input is connected to VREF
• Alert (logic low output) when an input signal is less
than 1.1 V
• Alert (logic low output) when an input signal is
greater than 2.2 V
• Alert signal is active low
• Operate from a 3.3-V power supply
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.
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-11
Typical Application Circuits
is 1.1 V. Large resistor values such as 10-MΩ are used
to minimize power consumption. The sensor output
voltage is applied to the inverting and non-inverting
inputs of the 2-channel LTC393's. The LTC393 is used
for its open-drain output configuration. Using the
LTC393 allows the two comparator outputs to be
Wire-ORed together. The respective comparator
outputs will be low when the sensor is less than 1.1 V
or greater than 2.2 V. VOUT will be high when the
sensor is in the range of 1.1 V to 2.2 V. See the
application curve in Figure 7.
VIN
VTH+ = 2.2 V
VTH– = 1.1 V
Time
VOUT
Time
Figure 5. Window Comparator Results
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.
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-12
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
LTC331YT5/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.
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-13
Package Outlines
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
1.25
0.04
0.10
1.00
1.20
0.33
0.41
0.15
0.19
2.820
3.02
1.50
1.70
2.60
3.00
0.95 BSC
1.90 BSC
0.60 REF
0.30
0.60
0°
8°
Dimensions
In Inches
Min
Max
0.049
0.002
0.004
0.039
0.047
0.013
0.016
0.006
0.007
0.111
0.119
0.059
0.067
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
)
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-14
Package Outlines (continued)
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
0.025
0.65
0.025
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°
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-15
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
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-16
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
)
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-17
Package Outlines (continued)
DIMENSIONS, TSSOP-8L
A3 A2
A
A1
Symbol
D
b
C
e
L1 L
E
E1
A
A1
A2
A3
b
C
D
E
E1
e
L1
L
θ
Dimensions
In Millimeters
Min
Max
1.200
0.020
0.150
0.900
1.050
0.390
0.490
0.200
0.290
0.130
0.180
2.900
3.100
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
0.001
0.006
0.035
0.041
0.015
0.019
0.008
0.011
0.005
0.007
0.114
0.122
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-8L
8X
(1.45)
MAX
(0.057)
(4.40)
MIN
(0.173)
PITCH
0.65
0.026
8X
5.90
0.232
(0.45)
MAX
(0.018)
mm
( inches
)
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.
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
LTC331, LTC393
P-18
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
)
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
P-19
LTC331, LTC393
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.
FN1617-38G.1a — Data Sheet
General Purpose, 1.8V, RRI, Open-drain Output Comparators
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