1
LTC1440/LTC1441/LTC1442
144012fd
APPLICATIO S
U
Ultralow Power Single/Dual
Comparator with Reference
V+
R1
1.65M
1%
R2
1.13M
1%
3.3V
V–
21
7
8
GND
OUT
LTC1440
1440 TA01
IN+
IN–
HYST
REF
3
4
5
6
–
+
TEMPERATURE (°C)
–40
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
20 60
1440/1/2 TA02
–20 0 40 80 100
SUPPLY CURRENT (µA)
V
+
= 5V
V
–
= GND = 0V
Micropower 2.9V VCC Threshold Detector LTC1440 Supply Current vs Temperature
The LTC
®
1440/LTC1441/LTC1442 are ultralow power
single and dual comparators with built-in references. The
comparators feature less than 3.7µA supply current over
temperature (LTC1440), a 1.182V ±1% reference, pro-
grammable hysteresis (LTC1440/LTC1442) and TTL/CMOS
outputs that sink and source current. The reference output
can drive a bypass capacitor of up to 0.01µF without
oscillation.
The comparators operate from a single 2V to 11V supply
or a dual ±1V to ±5.5V supply (LTC1440). Comparator
hysteresis is easily programmed by using two resistors
and the HYST pin (LTC1440/LTC1442). Each comparator’s
input operates from the negative supply to within 1.3V of
the positive supply. The comparator output stage can
continuously source up to 40mA. By eliminating the
cross-conducting current that normally happens when the
comparator changes logic states, the power supply glitches
are eliminated.
The LTC1440 is available in 8-pin PDIP, SO, MSOP and
DFN packages. The LTC1441/LTC1442 are available in
8-pin PDIP and SO packages.
■
Battery-Powered System Monitoring
■
Threshold Detectors
■
Window Comparators
■
Oscillator Circuits
■
Ultralow Quiescent Current: 2.1
µ
A Typ (LTC1440)
■
Reference Output Drives 0.01
µ
F Capacitor
■
Adjustable Hysteresis (LTC1440/LTC1442)
■
Wide Supply Range:
Single: 2V to 11V
Dual: ±1V to ±5.5V
■
Input Voltage Range Includes the Negative Supply
■
TTL/CMOS Compatible Outputs
■
12µs Propagation Delay with 10mV Overdrive
■
No Crowbar Current
■
40mA Continuous Source Current
■
Pin Compatible Upgrades for MAX921/922/923
■
3mm x 3mm x 0.75mm DFN Package (LTC1440)
FEATURES
DESCRIPTIO
U
TYPICAL APPLICATIO
U
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
2
LTC1440/LTC1441/LTC1442
144012fd
S8 PART
MARKING
Voltage
V
+
to V
–
, V
+
to GND, GND to V
–
...........12V to –0.3V
IN
+
, IN
–
, HYST ................. (V
+
+ 0.3V) to (V
–
– 0.3V)
REF ................................... (V
+
+ 0.3V) to (V
–
– 0.3V)
OUT (LTC1440) .............. (V
+
+ 0.3V) to (GND – 0.3V)
OUT (LTC1441/LTC1442) ... (V
+
+ 0.3V) to (V
–
– 0.3V)
Current
IN
+
, IN
–
, HYST ................................................. 20mA
REF ................................................................... 20mA
OUT .................................................................. 50mA
ABSOLUTE MAXIMUM RATINGS
W
WW
U
OUT Short-Circuit Duration (V
+
≤ 5.5V) .......Continuous
Power Dissipation.............................................. 500mW
Operating Temperature Range
LTC144XC ............................................... 0°C to 70°C
LTC144XI ........................................... – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Storage Temperature Range
(DD Package) ................................... –65°C to 125°C
Junction Temperature........................................... 150°C
Junction Temperature (DD Package) .................... 125°C
Lead Temperature (Soldering, 10 sec).................. 300°C
PACKAGE/ORDER INFORMATION
W
UU
Consult LTC Marketing for parts specified with wider operating temperature ranges.
* The temperature grade is identified by a label on the shipping container.
(Note 1)
T
JMAX
= 150°C, θ
JA
= 130°C/ W (N8)
T
JMAX
= 150°C, θ
JA
= 175°C/ W (S8)
T
JMAX
= 150°C, θ
JA
= 250°C/ W
ORDER PART
NUMBER
LTC1440CDD
LTC1440IDD
DD8 PART
MARKING*
LBTH
ORDER PART
NUMBER
LTC1440CMS8
LTC1440IMS8
MS8 PART
MARKING*
LTBX
ORDER PART
NUMBER
LTC1440CN8
LTC1440CS8
LTC1440IN8
LTC1440IS8
S8 PART
MARKING
1440
1440
1440I
1440I
T
JMAX
= 125°C, θ
JA
= 160°C/ W (DD)
UNDERSIDE METAL CONNECTED TO V
–
(PCB CONNECTION OPTIONAL)
1
2
3
4
8
7
6
5
TOP VIEW
GND
V–
IN+
IN–
OUT
V+
REF
HYST
S8 PACKAGE
8-LEAD PLASTIC SO
N8 PACKAGE
8-LEAD PDIP
ORDER PART
NUMBER
ORDER PART
NUMBER
S8 PART
MARKING
1441
1441I
T
JMAX
= 150°C, θ
JA
= 130°C/ W (N8)
T
JMAX
= 150°C, θ
JA
= 175°C/ W (S8)
T
JMAX
= 150°C, θ
JA
= 130°C/ W (N8)
T
JMAX
= 150°C, θ
JA
= 175°C/ W (S8)
1
2
3
4
8
7
6
5
TOP VIEW
OUT A
V
–
IN A
+
IN A
–
OUT B
V
+
IN B
+
IN B
–
S8 PACKAGE
8-LEAD PLASTIC SO
N8 PACKAGE
8-LEAD PDIP
1
2
3
4
8
7
6
5
TOP VIEW
OUT A
V
–
IN A
+
IN B
–
OUT B
V
+
REF
HYST
S8 PACKAGE
8-LEAD PLASTIC SO
N8 PACKAGE
8-LEAD PDIP
LTC1441CN8
LTC1441CS8
LTC1441IN8
LTC1441IS8
LTC1442CN8
LTC1442CS8
LTC1442IN8
LTC1442IS8
1442
1442I
1
2
3
4
GND
V
–
IN
+
IN
–
8
7
6
5
OUT
V
+
REF
HYST
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TOP VIEW
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
5
6
7
8
4
3
2
1GND
V–
IN+
IN–
OUT
V+
REF
HYST
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/
3
LTC1440/LTC1441/LTC1442
144012fd
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25
°
C. V+ = 5V and V– = GND = 0V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply
V
+
Supply Voltage Range ●2.0 11.0 V
I
CC
Supply Current IN
+
= IN
–
+ 80mV LTC1440 0°C ≤ T
A
≤ 70°C●2.1 4.0 µA
HYST = REF (LTC1440/LTC1442) –40°C ≤ T
A
≤ 85°C●4.4 µA
LTC1441 ●3.5 5.7 µA
LTC1442 ●3.5 5.7 µA
Comparator
V
OS
Comparator Input Offset Voltage V
CM
= 2.5V ●±3±10 mV
I
IN
Input Leakage Current (IN
+
, IN
–
)V
IN+
= V
IN–
= 2.5V ●±0.01 ±1.0 nA
Input Leakage Current (HYST) ●±0.02 ±1.0 nA
V
CM
Comparator Input Common ●V
–
V
+
– 1.3V V
Mode Range
CMRR Common Mode Rejection Ratio V
–
to V
+
– 1.3V 0.1 1 mV/V
PSRR Power Supply Rejection Ratio V
+
= 2V to 11V (LTC1441) 0.1 1 mV/V
V
+
= 2.5V to 11V (LTC1440/LTC1442) 0.1 1 mV/V
NOISE Voltage Noise 100Hz to 100kHz 100 µV
RMS
V
HYST
Hysteresis Input Voltage Range LTC1440/LTC1442 ●REF – 50mV REF V
t
PD
Propagation Delay C
OUT
= 100pF Overdrive = 10mV 15 µs
Overdrive = 100mV 8 µs
V
OH
Output High Voltage I
O
= – 13mA ●V
+
– 0.4V V
V
OL
Output Low Voltage I
O
= 1.8mA LTC1440 ●GND + 0.4V V
LTC1441/LTC1442 ●V
–
+ 0.4V V
Reference
V
REF
Reference Voltage No Load LTC1440/LTC1442
0°C ≤ T
A
≤ 70°C●1.170 1.194 V
–40°C ≤ T
A
≤ 85°C●1.164 1.200 V
LTC1440 (MSOP, DFN) ●1.164 1.200 V
I
SOURCE
Reference Output Source Current ∆V
REF
≤ 1mV (LTC1442) ●100 µA
I
SINK
Reference Output Sink Current ∆V
REF
≤ 2.5mV (LTC1442) 10 20 µA
∆V
REF
Reference Source Current 0 ≤ I
SOURCE
≤ 2mA (LTC1440) ●0.8 5 mV
Reference Sink Current 0 ≤ I
SINK
≤ 10µA (LTC1440) 0.5 1.5 mV
●5mV
NOISE Voltage Noise 100Hz to 100kHz 100 µV
RMS
4
LTC1440/LTC1441/LTC1442
144012fd
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25
°
C. V+ = 3V and V– = GND = 0V unless otherwise noted.
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply
V
+
Supply Voltage Range ●211V
I
CC
Supply Current IN
+
= IN
–
+ 80mV LTC1440 0°C ≤ T
A
≤ 70°C●2 3.9 µA
HYST = REF (LTC1440/LTC1442) –40°C ≤ T
A
≤ 85°C●4.3 µA
LTC1441 ●3.5 5.7 µA
LTC1442 ●3.5 5.7 µA
Comparator
V
OS
Comparator Input Offset Voltage V
CM
= 1.5V ●±3±10 mV
I
IN
Input Leakage Current (IN
+
, IN
–
)V
IN+
= V
IN –
= 1.5V ●±0.01 ±1nA
Input Leakage Current (HYST) ●±0.02 ±1nA
V
CM
Comparator Input Common ●V
–
V
+
– 1.3V V
Mode Range
CMRR Common Mode Rejection Ratio V
–
to V
+
– 1.3V 0.1 1 mV/V
PSRR Power Supply Rejection Ratio V
+
= 2V to 11V (LTC1441) 0.1 1 mV/V
V
+
= 2.5V to 11V (LTC1440/LTC1442) 0.1 1 mV/V
NOISE Voltage Noise 100Hz to 100kHz 100 µV
RMS
V
HYST
Hysteresis Input Voltage Range LTC1440/LTC1442 ●REF – 50mV REF V
t
PD
Propagation Delay C
OUT
= 100pF Overdrive = 10mV 14 µs
Overdrive = 100mV 5 µs
V
OH
Output High Voltage I
O
= – 8mA ●V
+
– 0.4V V
Comparator
V
OL
Output Low Voltage I
O
= 0.8mA LTC1440 ●GND + 0.4V V
LTC1441/LTC1442 ●V
–
+ 0.4V V
Reference
V
REF
Reference Voltage No Load LTC1440/LTC1442
0°C ≤ T
A
≤ 70°C●1.170 1.182 1.194 V
–40°C ≤ T
A
≤ 85°C●1.164 1.200 V
LTC1440 (MSOP, DFN) ●1.164 1.200 V
I
SOURCE
Reference Output Source Current ∆V
REF
≤ 1mV (LTC1442) ●60 120 µA
I
SINK
Reference Output Sink Current ∆V
REF
≤ 2.5mV (LTC1442) 10 20 µA
∆V
REF
Reference Source Current 0 ≤ I
SOURCE
≤ 1mA (LTC1440) ●0.8 5.5 mV
Reference Sink Current 0 ≤ I
SINK
≤ 10µA (LTC1440) 0.5 1.5 mV
●5mV
NOISE Voltage Noise 100Hz to 100kHz 100 µV
RMS
5
LTC1440/LTC1441/LTC1442
144012fd
RESPONSE TIME (µs)
–1
INPUT VOLTAGE (mV) OUTPUT VOLTAGE (V)
0
0
1
614 18
5
1440/1/2 G02
100
210
412 16
08
2
3
4
100mV
10mV
50mV
20mV
T
A
= 25°C
RESPONSE TIME (µs)
–1
INPUT VOLTAGE (mV) OUTPUT VOLTAGE (V)
100
0
1
64
5
1440/1/2 G01
0
20108
2
3
4100mV 10mV
50mV 20mV
T
A
= 25°C
SUPPLY VOLTAGE (V)
0
SOURCE CURRENT (mA)
35
1440/1/2 G04
12 4
160
140
120
100
80
60
40
20
0
OUT CONNECTED TO
V
–
= GND = 0V
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Comparator Response Time vs
Input Overdrive
Comparator Short-Circuit Sink
Current vs Supply Voltage
SUPPLY VOLTAGE (V)
0
SINK CURRENT (mA)
200
180
160
140
120
100
80
60
40
20
08
1440/1/2 G03
213579
4610
OUT CONNECTED TO V
+
T
A
= 25°C
Comparator Short-Circuit Source
Current vs Supply Voltage
Comparator Response Time vs
Input Overdrive
6
LTC1440/LTC1441/LTC1442
144012fd
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Comparator Response Time vs
Load Capacitance with 100mV
Input Overdrive Comparator Response Time at
Low Supply Voltage
Comparator Output Voltage High
vs Load Current
LOAD CAPACITANCE (nF)
0
RESPONSE TIME (µs)
12
10
8
6
4
280
1440/1/2 G05
20 40 60 100
t
PHL
t
PLH
SUPPLY VOLTAGE (V)
1.0
RESPONSE TIME (µs)
10000
1000
100
10
1
1.2 1.4 1.61.1 1.3 1.5
1440/1/2 G06
20mV OVERDRIVE
100mV OVERDRIVE
LOAD CURRENT (mA)
0
1
OUTPUT VOLTAGE HIGH (V)
2
3
4
5
10 20 30 40
1440/1/2 G07
50 60
V
+
= 5V
V
+
= 3V
V
+
= 2V
T
A
= 25°C
7
LTC1440/LTC1441/LTC1442
144012fd
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Comparator Output Voltage Low
vs Load Current
LTC1440/LTC1442
Hysteresis Control
V
REF
– V
HYST
(mV)
0
POSITIVE-TO-NEGATIVE INPUT VOLTAGE (mV)
30 50
1440/1/2 G09
10 20 40
80
60
40
20
0
–20
–40
–60
–80
OUTPUT HIGH
OUTPUT LOW
TEMPERATURE (°C)
–60
SUPPLY CURRENT (µA)
6
5
4
3
2
1100
1440/1/2 G10
–20–40 20 40 80 1200 60 140
V
+
= 5V
V
–
= –5V
V
+
= 5V
V
–
= GND = 0V
V
+
= 3V
V
–
= GND = 0V
LTC1440
Supply Current vs Temperature
LOAD CURRENT (mA)
0
OUTPUT VOLTAGE LOW (V)
1.5
2.0
2.5
30 50 80
1440/1/2 G08
1.0
0.5
010 20 40 60 70
V
+
= 2V
V
+
= 3V
V
+
= 5V
T
A
= 25°C
8
LTC1440/LTC1441/LTC1442
144012fd
OUTPUT LOAD CURRENT (mA)
0
1.190
1.185
1.180
1.175
1.170
1.165
1.160
1.155
1.5 2.5
1440/1/2 G11
0.5 1.0 2.0 3.0 3.5
REFERENCE OUTPUT VOLTAGE (V)
V
CC
= 5V
SOURCE
Reference Output Voltage vs
Output Load Current
Reference Voltage vs
Temperature
TEMPERATURE (°C)
–60
REFERENCE VOLTAGE (V)
1.186
1.184
1.182
1.180
1.178
1.176
1.174
1.172
1.170
100
1440/1/2 G13
–20–40 20 40 80 1200 60 140
OUTPUT LOAD CURRENT (µA)
0
REFERENCE OUTPUT VOLTAGE (V)
1.200
1.195
1.190
1.185
1.180
1.175
1.170 510 15 20
1440/1/2 G12
25 30
V
CC
= 5V
SINK
V
CC
= 2V
Reference Output Voltage vs
Output Load Current (Sink)
TYPICAL PERFOR A CE CHARACTERISTICS
UW
9
LTC1440/LTC1441/LTC1442
144012fd
PIN FUNCTIONS
UUU
V
–
V
+
OUT A LTC14411
2
3
4
8
7
6
5
IN A
+
IN A
–
IN B
+
IN B
–
OUT B
1440/1/2 PD
–
+
A
–+
B
V
–
V
–
V
+
OUT A LTC1442
1
2
3
4
8
7
6
5
IN A
+
IN B
–
REF
HYST
OUT B
1
2
3
4
8
7
6
5
IN
+
IN
–
HYST
REF
V
+
OUT
–
+
V
–
GND LTC1440
–
+–+
AB
LTC1440
GND (Pin 1): Ground. Connect to V
–
for single supply
operation.
V
–
(Pin 2): Negative Supply. Connect to ground for single
supply operation. Potential should be more negative than
GND.
IN
+
(Pin 3): Noninverting Comparator Input. Input com-
mon mode range from V
–
to V
+
–1.3V. Input current
typically 10pA at 25°C.
IN
–
(Pin 4): Inverting Comparator Input. Input common
mode range from V
–
to V
+
–1.3V. Input current typically
10pA at 25°C.
HYST (Pin 5): Hysteresis Input. Connect to REF if not
used. Input voltage range is from V
REF
to V
REF
– 50mV.
REF (Pin 6): Reference Output. 1.182V with respect
to V
–
. Can source up to 200µA and sink 15µA at 25°C.
Drive 0.01µF bypass capacitor without oscillation.
V
+
(Pin 7): Positive Supply. 2V to 11V.
OUT (Pin 8): Comparator CMOS Output. Swings from
GND to V
+
. Output can source up to 40mA and sink 5mA.
LTC1441
OUT A (Pin 1): Comparator A CMOS Output. Swings from
V
–
to V
+
. Output can source up to 40mA and sink 5mA.
V
–
(Pin 2): Negative Supply.
IN A
+
(Pin 3): Noninverting Input of Comparator A. Input
common mode range from V
–
to V
+
–1.3V. Input current
typically 10pA at 25°C.
IN A
–
(Pin 4): Inverting Input of Comparator A. Input
common mode range from V
–
to V
+
–1.3V. Input current
typically 10pA at 25°C.
IN B
–
(Pin 5): Inverting Input of Comparator B. Input
common mode range from V
–
to V
+
–1.3V. Input current
typically 10pA at 25°C.
IN B
+
(Pin 6): Noninverting Input of Comparator B. Input
common mode range from V
–
to V
+
–1.3V. Input current
typically 10pA at 25°C.
V
+
(Pin 7): Positive Supply. 2V to 11V.
OUT B (Pin 8): Comparator B CMOS Output. Swings from
V
–
to V
+
. Output can source up to 40mA and sink 5mA.
LTC1442
OUT A (Pin 1): Comparator A CMOS Output. Swings from
V
–
to V
+
. Output can source up to 40mA and sink 5mA.
V
–
(Pin 2): Negative Supply.
IN A
+
(Pin 3): Noninverting Input of Comparator A. Input
common mode range from V
–
to V
+
–1.3V. Input current
typically 10pA at 25°C.
IN B
–
(Pin 4): Inverting Input of Comparator B. Input
common mode range from V
–
to V
+
–1.3V. Input current
typically 10pA at 25°C.
HYST (Pin 5): Hysteresis Input. Connect to REF if not
used. Input voltage range is from V
REF
to V
REF
– 50mV.
REF (Pin 6): Reference Output. 1.182V with respect
to V
–
. Can source up to 200µA and sink 15µA at 25°C.
Drive 0.01µF bypass capacitor without oscillation.
V
+
(Pin 7): Positive Supply. 2V to 11V.
OUT B (Pin 8): Comparator B CMOS Output. Swings from
V
–
to V
+
. Output can source up to 40mA and sink 5mA.
10
LTC1440/LTC1441/LTC1442
144012fd
LTC1440/LTC1441/LTC1442 are a family of micropower
comparators with built-in 1.182V reference. Features
include programmable hysteresis (LTC1440/LTC1442),
wide supply voltage range (2V to 11V) and the ability of the
reference to drive up to a 0.01µF capacitor without oscil-
lation. The comparators’ CMOS outputs can source up to
40mA and the supply current glitches, that normally occur
when switching logic states, have been eliminated.
Power Supplies
The comparator family operates from a single 2V to 11V
supply. The LTC1440 includes a separate ground for the
comparator output stage, allowing a split supply ranging
from ±1V to ±5.5V. Connecting V
–
to GND on the LTC1440
will allow single supply operation. If the comparator out-
put is required to source more than 1mA, or the supply
source impedance is high, V
+
should be bypassed with a
0.1µF capacitor.
Comparator Inputs
The comparator inputs can swing from the negative sup-
ply V
–
to within 1.3V max of the positive supply V
+
. The
inputs can be forced 300mV below V
–
or above V
+
without
damage and the typical input leakage current is only
±10pA.
Comparator Outputs
The LTC1440 comparator output swings between GND
and V
+
to assure TTL compatibility with a split supply. The
LTC1441 and LTC1442 outputs swing between V
–
and V
+
.
The outputs are capable of sourcing up to 40mA and
sinking up to 5mA while still maintaining microampere
quiescent currents. The output stage does not generate
crowbar switching currents during transitions which helps
minimize parasitic feedback through the supply pins.
Voltage Reference
The internal bandgap reference has a voltage of 1.182V
referenced to V
–
. The reference accuracy is 1.5% from
–40°C to 85°C. It can source up to 200µA and sink up to
20µA with a 5V supply. The reference can drive a bypass
capacitor of up to 0.01µF without oscillation and by
inserting a series resistor, capacitance values up to 100µF
can be used (Figure 1).
Figure 2 shows the resistor value required for different
capacitor values to achieve critical damping. Bypassing
the reference can help prevent false tripping of the com-
parators by preventing glitches on V
+
or reference load
transients from disturbing the reference output voltage.
Figure 3 shows the bypassed reference output with a
square wave applied to the V
+
pin. Resistors R2 and R3 set
10mV of hysteresis voltage band while R1 damps the
reference response. Note that the comparator output
doesn’t trip.
APPLICATIONS INFORMATION
WUUU
LTC144X
V
–
REF
R1
C1
REFERENCE
OUTPUT
1440/1/2 F01
Figure 1. Damping the Reference Output
CAPACITOR VALUE (µF)
0.001
0.1
RESISTOR VALUE (kΩ)
10
1000
0.01 0.1 101
1440/1/2 F02
1
100
Figure 2. Damping Resistance vs Bypass Capacitor Value
11
LTC1440/LTC1441/LTC1442
144012fd
APPLICATIONS INFORMATION
WUUU
V
+
R1
430Ω
R2
10k
C1
1µF
5V
TO
8V
OUT
V
–
21
7
8
GND
LTC1440
1440/1/2 F03a
IN
+
IN
–
HYST
REF
3
4
5
6
R3
2.4M
–
+
Figure 3a. Reference Transient Response Test Circuit
2ms/DIV 1440/1/2 F03b
8V
V +
5V
VREF
OUT
Hysteresis
Hysteresis can be added to the LTC1440 by connecting a
resistor (R1) between the REF and HYST pins and a
second resistor (R2) from HYST to V
–
(Figure 4).
The difference between the upper and lower threshold
voltages, or hysteresis voltage band (V
HB
), is equal to twice
the voltage difference between the REF and HYST pins.
When more hysteresis is added, the upper threshold
increases the same amount as the low threshold de-
creases. The maximum voltage allowed between REF and
HYST pins is 50mV, producing a maximum hysteresis
voltage band of 100mV. The hysteresis band could vary by
2mV/DIV
up to 15%. If hysteresis is not wanted, the HYST pin
should be shorted to REF. Acceptable values for I
REF
range
from 0.1µA to 5µA. If 2.4M is chosen for R2, then the value
of R1 is equal to the value of V
HB
.
Figure 5. Glitch-Free Level Detector with Hysteresis
V+
R5
430Ω
5%
R3
15k
1%
C1
1µF
OUT
V–
21
7
5V
VIN
8
GND
LTC1440
1440/1/2 F05
IN+
IN–
HYST
REF
3
4
5
6
–
+
R2
3.4M
1%
R1
1.18M
1%
R4
2.4M
1%
6
R2
HYST
V–
REF
5
R1
1440/1/2 F04
LTC1440
2
IREF
R1 = VHB
(2)(IREF)
R2 = IREF
1.182V –
( )
VHB
2
Figure 4. Programmable Hysteresis
Level Detector
The LTC1440 is ideal for use as a micropower level
detector as shown in Figure 5. R1 and R2 form a voltage
divider from V
IN
to the noninverting comparator input. R3
and R4 set the hysteresis voltage, and R5 and C1 bypass
the reference output. The following design procedure can
be used to select the component values:
1. Choose the V
IN
voltage trip level, in this example 4.65V.
Figure 3b. Reference and Comparator Output
Transient Response
12
LTC1440/LTC1441/LTC1442
144012fd
APPLICATIONS INFORMATION
WUUU
2. Calculate the required resistive divider ratio.
Ratio = V
REF
/V
IN
Ratio = 1.182V/4.65V = 0.254
3. Choose the required hysteresis voltage band at the
input V
HBIN
, in this example 60mV. Calculate the hyster-
esis voltage band referred to the comparator input V
HB
.
V
HB
= (V
HBIN
)(Ratio)
V
HB
= (60mV)(0.254)
V
HB
= 15.24mV
4. Choose the values for R3 and R4 to set the hysteresis.
R4 = 2.4M
R3(kΩ) = V
HB
= 15k
5. Choose the values for R1 and R2 to set the trip point.
RV
I
V
AM
RR V
VV
REF
BIAS
IN
REF HB
11 182
1118
21
2
1
== =
=
+
−
⎡
⎣
⎢
⎢
⎢
⎢
⎤
⎦
⎥
⎥
⎥
⎥
..
µ
RM V
VmV
RM
2118 465
1 182 15
2
1
2340
=
+
−
⎡
⎣
⎢
⎢
⎢
⎢
⎤
⎦
⎥
⎥
⎥
⎥
=
..
.
.
Low Voltage Operation
It is important to note that the voltage references internal
to the LTC1440 and LTC1442 can exceed the common
mode range of the comparators at low supply voltages.
The input common mode range of the LTC1440/LTC1441/
LTC1442 comparators is guaranteed to extend up to (V
+
-
1.3V). Therefore, if one of the comparator inputs is at the
1.182V reference voltage, the minimum supply voltage is
2.5V for a valid output reading.
The guaranteed minimum operating voltage for the
LTC1440/LTC1441/LTC1442 is 2V (or ±1V). However,
both the reference and comparator(s) will function with a
supply voltage as low as 1.5V, but performance will
degrade as the voltage goes below 2V. The voltage refer-
ence temperature coefficient will degrade slightly, and the
comparators will have less output drive with an increase in
propagation delay. At the reduced supply voltages, the
input common mode range of the comparator(s) will still
typically extend from the negative supply to approximately
1.1V below the positive supply.
13
LTC1440/LTC1441/LTC1442
144012fd
10-Bit 30µA A/D Converter
–
+
5V
5V
2N3809
1N914
32.768kHz
VN2222LL
10pF
100k
EIN
0V TO 3V
365k*
470k
1M
10M
150k
0.033µF
POLYSTYRENE
C1
1/2 LTC1441
LT®1034
1.2V
Q
D CLK
74C74
CONV
COMMAND
DATA
OUT
STATUS
1440/1/2 TA03
Q
1.2M
–
+C2
1/2 LTC1441
74C00
74C00 74C00 74C00
*TRW-IRC MRT–5/+120ppm/°C
TYPICAL APPLICATIONS
U
32.768kHz “Watch Crystal” Oscillator
+V
32.768kHz
10pF
470k
1M
OUT
1440/1/2 TA05
1.2M
–
+
1/2
LTC1441
14
LTC1440/LTC1441/LTC1442
144012fd
3.00 ±0.10
(4 SIDES)
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON TOP AND BOTTOM OF PACKAGE
0.38 ± 0.10
BOTTOM VIEW—EXPOSED PAD
1.65 ± 0.10
(2 SIDES)
0.75 ±0.05
R = 0.115
TYP
2.38 ±0.10
(2 SIDES)
14
85
PIN 1
TOP MARK
(NOTE 6)
0.200 REF
0.00 – 0.05
(DD8) DFN 1203
0.25 ± 0.05
2.38 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
1.65 ±0.05
(2 SIDES)2.15 ±0.05
0.50
BSC
0.675 ±0.05
3.5 ±0.05
PACKAGE
OUTLINE
0.25 ± 0.05
0.50 BSC
MSOP (MS8) 0204
0.53 ± 0.152
(.021 ± .006)
SEATING
PLANE
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
0.18
(.007)
0.254
(.010)
1.10
(.043)
MAX
0.22 – 0.38
(.009 – .015)
TYP
0.127 ± 0.076
(.005 ± .003)
0.86
(.034)
REF
0.65
(.0256)
BSC
0° – 6° TYP
DETAIL “A”
DETAIL “A”
GAUGE PLANE
12
34
4.90 ± 0.152
(.193 ± .006)
8765
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
3.00 ± 0.102
(.118 ± .004)
(NOTE 4)
0.52
(.0205)
REF
5.23
(.206)
MIN
3.20 – 3.45
(.126 – .136)
0.889 ± 0.127
(.035 ± .005)
RECOMMENDED SOLDER PAD LAYOUT
0.42 ± 0.038
(.0165 ± .0015)
TYP
0.65
(.0256)
BSC
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698)
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660)
U
PACKAGE DESCRIPTIO
15
LTC1440/LTC1441/LTC1442
144012fd
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
PACKAGE DESCRIPTION
U
N8 Package
8-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
N8 1002
.065
(1.651)
TYP
.045 – .065
(1.143 – 1.651)
.130 ± .005
(3.302 ± 0.127)
.020
(0.508)
MIN
.018 ± .003
(0.457 ± 0.076)
.120
(3.048)
MIN
12 34
87 65
.255 ± .015*
(6.477 ± 0.381)
.400*
(10.160)
MAX
.008 – .015
(0.203 – 0.381)
.300 – .325
(7.620 – 8.255)
.325 +.035
–.015
+0.889
–0.381
8.255
()
NOTE:
1. DIMENSIONS ARE INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
.100
(2.54)
BSC
.016 – .050
(0.406 – 1.270)
.010 – .020
(0.254 – 0.508)× 45°
0°– 8° TYP
.008 – .010
(0.203 – 0.254)
SO8 0303
.053 – .069
(1.346 – 1.752)
.014 – .019
(0.355 – 0.483)
TYP
.004 – .010
(0.101 – 0.254)
.050
(1.270)
BSC
1234
.150 – .157
(3.810 – 3.988)
NOTE 3
8765
.189 – .197
(4.801 – 5.004)
NOTE 3
.228 – .244
(5.791 – 6.197)
.245
MIN .160 ±.005
RECOMMENDED SOLDER PAD LAYOUT
.045 ±.005
.050 BSC
.030 ±.005
TYP
INCHES
(MILLIMETERS)
NOTE:
1. DIMENSIONS IN
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
16
LTC1440/LTC1441/LTC1442
144012fd
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com
LT 0806 REV D • PRINTED IN USA
© LINEAR TECHNOLOGY CORPORATION 1996
10kHz V/F Converter
TYPICAL APPLICATION
U
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
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LTC1444/LTC1445 1.2V Reference with Quad Comparator 1% Accuracy, 8.5µA Maximum Current, Ref Output Drives 0.01µF
with Adjustable Hysteresis
LTC1540 1.182V Reference with Nanopower Comparator DFN Package 0.3µA Quiescent Current (Typical), Reference
with Adjustable Hysteresis Drives 0.01µF
LTC1541 1.2V Reference with Micropower Amplifier and Comparator DFN Package 1.25% Accuracy, Rail-to-Rail Out, Low Offset Amplifier
LTC1842/LTC1843 1.82V Reference with Dual Comparators 1% Accuracy, Open-Drain Out, Reference Drives 0.01µF
with Adjustable Hysteresis
LTC1998 1.2 Reference with Comparator with Adjustable Thesholds Li-Ion Low Battery Monitor, SOT23, 1% Accuracy
LT6700-1 0.4 Reference with Low Voltage Dual Comparators SOT23, 1.4V to 18.5V Supply Range, ±2% Over Temperature
LT6700-2/LT6700-3
–
+
100pF**
50pF
2.2µF
1.2M*
10kHz TRIM
200k
10M
100k
2k*
LM334
+V
6.2V TO 12V
LT1034-1.2
LT1034-1.2
2.7M
C1
1/2 LTC1441
fOUT
0kHz TO 10kHz
74C14
1440/1/2 TA04
0.01µF
0.1µF
INPUT
0V TO 5V
Q5
Q6
15k
2M TYP
100Hz TRIM
–
+
C2
1/2 LTC1441
Q1 Q8
Q2
Q3
Q4
0.47µF
Q7
= HP5082-2810
= 1N4148
= 2N2222
= 1% METAL FILM
= POLYSTYRENE
*
**
+
+
