LTC1540
Nanopower Comparator
with Reference
FEATURES
n
n
n
n
n
n
n
n
n
n
n
n
DESCRIPTION
Ultralow Quiescent Current: 0.3µA Typ
Reference Output Drives 0.01µF Capacitor
Adjustable Hysteresis
Available in 3mm × 3mm × 0.8mm DFN Package
Wide Supply Range: 2V to 11V
Input Voltage Range Includes the Negative Supply
Reference Output Sources Up to 1mA
TTL/CMOS Compatible Outputs
60µs Propagation Delay with 10mV Overdrive
No Crowbar Current
40mA Continuous Source Current
Pin Compatible with LTC1440, MAX921, MAX931
APPLICATIONS
n
n
n
n
Battery-Powered System Monitoring
Threshold Detectors
Window Comparators
Oscillator Circuits
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and C-Load
is a trademark of Analog Devices, Inc. All other trademarks are the property of their respective
owners.
The LTC®1540 is an ultralow power, single comparator with built-in reference. The comparator’s features
include less than 0.6µA supply current over the commercial
temperature range, a 1.182V ± 2% reference, programmable hysteresis 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 comparator operates from a single 2V to 11V supply
or a dual ±1V to ±5.5V supply. Comparator hysteresis is
easily programmed by using two resistors and the HYST
pin. 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
occur when the comparator changes logic states, power
supply glitches are eliminated.
The LTC1540 is available in the 8-pin MSOP and SO
packages. For space limited applications, the LTC1540
is available in a 3mm × 3mm low profile (0.8mm) dual
fine-pitch leadless package (DFN).
TYPICAL APPLICATION
Nanopower 2.9V VCC Threshold Detector
3.3V
R2
3M
1%
7
V+
3 IN +
4 IN–
0.45
LTC1540
+
8
–
5 HYST
6 REF
OUT
SUPPLY CURRENT (µA)
R1
4.32M
1%
LTC1540 Supply Current vs Temperature
0.50
V + = 5V
V – = GND = 0V
0.40
0.35
0.30
0.25
0.20
V–
2
0.15
–40 –20
GND
1
40
20
60
0
TEMPERATURE (°C)
80
100
1540 • TA02
1540 • TA01
1540fb
For more information www.linear.com/LTC1540
1
LTC1540
ABSOLUTE MAXIMUM RATINGS
(Note 1)
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................................ (V + + 0.3V) to (GND – 0.3V)
Current
IN +, IN–, HYST....................................................20mA
REF.....................................................................20mA
OUT....................................................................50mA
OUT Short-Circuit Duration (V + ≤ 5.5V) ...... Continuous
Power Dissipation ............................................. 500mW
Operating Temperature Range
LTC1540C................................................ 0°C to 70°C
LTC1540I..............................................–40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
(DD Package)...................................... –65°C to 125°C
Lead Temperature (Soldering, 10 sec).................... 300°C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
GND
8 OUT
1
V–
2
IN+
3
IN–
4
9
V–
+
GND 1
8
OUT
V– 2
7
V+
IN + 3
6
REF
IN –
5
HYST
7 V
6 REF
5 HYST
S8 PACKAGE
8-LEAD PLASTIC SO
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 160°C/W (NOTE 2) UNDERSIDE METAL
CONNECTED TO V– (PCB CONNECTION OPTIONAL)
ORDER INFORMATION
4
TOP VIEW
GND
V–
IN +
IN –
1
2
3
4
8
7
6
5
OUT
V+
REF
HYST
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 250°C/W
TJMAX = 150°C, θJA = 175°C/W
http://www.linear.com/product/LTC1540#orderinfo
LEAD FREE FINISH
TAPE AND REEL
*PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC1540CDD#PBF
LTC1540CDD#TRPBF
LAAS
8-Lead (3mm × 3mm) Plastic DFN
0°C to 70°C
LTC1540IDD#PBF
LTC1540IDD#TRPBF
LAAS
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 85°C
LTC1540CS8#PBF
LTC1540CS8#TRPBF
1540
8-Lead Plastic SO
0°C to 70°C
LTC1540IS8#PBF
LTC1540IS8#TRPBF
1540I
8-Lead Plastic SO
–40°C to 85°C
LTC1540CMS8#PBF
LTC1540CMS8#TRPBF
LTCE
8-Lead Plastic MSOP
0°C to 70°C
LTC1540IMS8#PBF
LTC1540IMS8#TRPBF
LTADV
8-Lead Plastic MSOP
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/. Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
1540fb
2
For more information www.linear.com/LTC1540
LTC1540
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. V+ = 5V, V– = GND = 0V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
11.0
V
0.3
0.68
0.71
µA
µA
±12
±15
±16
mV
mV
mV
±1.0
±1.0
nA
nA
V+ – 1.3V
V
Power Supply
V+
Supply Voltage Range
ICC
Supply Current
l
IN– – IN+ = 80mV, HYST = REF, C-Grade
IN– – IN+ = 80mV, HYST = REF, I-Grade
2.0
l
l
Comparator
VOS
Comparator Input Offset Voltage
VCM = 2.5V
LTC1540CMS8/IMS8
IIN
VCM
Input Leakage Current (IN+, IN–)
Input Leakage Current (HYST)
VIN+ = VIN– = 2.5V
l
l
Comparator Input Common Mode Range
l
Common Mode Rejection Ratio
V– to V+ – 1.3V
PSRR
Power Supply Rejection Ratio
V+ = 2V to 11V
VHYST
Hysteresis Input Voltage Range
tPD
Propagation Delay
COUT = 100pF
VOH
Output High Voltage
IO = – 13mA
l
VOL
Output Low Voltage
IO = 1.8mA
l
VREF
Reference Voltage
No Load
∆VREF
Load Regulation
0 ≤ ISOURCE ≤ 100µA
CMRR
±0.01
±0.02
l
l
V–
0.1
0.1
l REF – 50mV
Overdrive = 10mV
Overdrive = 100mV
1
mV/V
1
mV/V
REF
60
50
V
µs
µs
V+ – 0.4V
V
GND + 0.4V
V
1.182
1.182
1.182
1.206
1.208
1.212
V
V
V
0.5
2.5
mV
0.5
1.5
5
mV
mV
Reference
(SO-8)/(DFN) Commercial
MS8 Commercial
(SO-8)/(MS8)/(DFN) Industrial
l
l
l
l
0 ≤ ISINK ≤ 10µA
l
1.158
1.156
1.152
1540fb
For more information www.linear.com/LTC1540
3
LTC1540
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. V+ = 3V, V– = GND = 0V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Power Supply
V+
ICC
Supply Voltage Range
Supply Current
l
IN– – IN + = 80mV, HYST = REF, C-Grade
IN – – IN + = 80mV, HYST = REF, I-Grade
2
0.28
l
l
11
V
0.61
0.64
µA
µA
±12
±15
±16
mV
mV
mV
±1
±1
nA
nA
V+ – 1.3V
V
Comparator
VOS
Comparator Input Offset Voltage
VCM = 2.5V
l
l
LTC1540CMS8/IMS8
IIN
Input Leakage Current (IN+, IN–)
Input Leakage Current (HYST)
VCM
Comparator Input Common 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
0.1
1
mV/V
VHYST
Hysteresis Input Voltage Range
tPD
Propagation Delay
COUT = 100pF
VOH
Output High Voltage
IO = –8mA
l
VOL
Output Low Voltage
IO = 0.8mA
l
VREF
Reference Voltage
No Load
∆VREF
Load Regulation
0 ≤ ISOURCE ≤ 100µA
VIN+ = VIN– = 1.5V
±0.01
±0.02
l
l
l
l
V–
REF – 50mV
Overdrive = 10mV
Overdrive = 100mV
REF
V
70
60
µs
µs
V+ – 0.4V
V
GND + 0.4V
V
1.182
1.182
1.182
1.206
1.208
1.212
V
V
V
0.75
3.5
mV
0.5
1.5
5
mV
mV
Reference
(SO-8)/(DFN) Commercial
MS8 Commercial
(SO-8)/(MS8)/(DFN) Industrial
l
l
l
l
0 ≤ ISINK ≤ 10µA
l
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.
1.158
1.156
1.152
Note 2: The θJA specified for the DD package is with minimal PCB heat
spreading metal. Using expanded metal area on all layers of a board
reduces this value.
1540fb
4
For more information www.linear.com/LTC1540
LTC1540
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Temperature
0.5
1.190
V + = 5V
V – = GND = 0V
0.3
V + = 2V
V – = GND = 0V
0.2
0.1
0
– 60 – 40 –20 0 20 40 60
TEMPERATURE (°C)
80
100
8
1.186
7
1.184
1.182
1.180
1.178
2
1
1.172
20 40 60
– 60 – 40 – 20 0
TEMPERATURE (°C)
0
1
3
2
1
OUTPUT SOURCE CURRENT (mA)
OUTPUT VOLTAGE (V)
V+ = 3V
2
10
20 30 40 50 60
LOAD CURRENT (mA)
40
0
1
2
3 4 5 6 7 8
SUPPLY VOLTAGE (V)
60
55
50
45
tPLH
tPHL
40
9
10
1540 G07
20 30 40 50 60
LOAD CURRENT (mA)
70
30
80
Hysteresis Control
35
0
10
80
65
20
0
1540 G06
DIFFERENTIAL INPUT VOLTAGE (V)
60
V+ = 5V
1.0
0
80
TA = 25°C
75 V + = 5V
V – = GND = 0V
70
OUTPUT
CONNECTED
TO V +; SINK
CURRENT
80
70
80
TIME (µs)
CURRENT (mA)
100
1.5
Comparator Response Time
vs Input Overdrive
TA = 25°C
120
V+ = 3V
V+ = 2V
0.5
V+ = 2V
0
40
TA = 25°C
1540 G05
Comparator Short-Circuit Current
vs Supply Voltage
140
10 15 20 25 30 35
OUTPUT SINK CURRENT (µA)
Comparator Output Voltage (Low)
vs Load Current
2.5
3
0
4
OUTPUT
CONNECTED TO
– = GND = 0V;
V
SOURCE
CURRENT
5
2.0
1540 G04
160
0
1540 G03
V+ = 5V
1
180
100
TA = 25°C
4
OUTPUT VOLTAGE (V)
∆VREF (mV)
5
2
200
80
1540 G02
V + = 5V
V – = GND = 0V
TA = 25°C
0
4
Comparator Output Voltage (High)
vs Load Current
3
0
5
1.174
Reference Voltage
Load Regulation (Source)
4
6
3
1.176
1540 G01
5
V + = 5V
V – = GND = 0V
TA = 25°C
9
∆VREF (mV)
V + = 3V
V – = GND = 0V
10
V + = 5V
V – = GND = 0V
1.188
REFERENCE VOLTAGE (V)
SUPPLY CURRENT (µA)
0.4
Reference Voltage
Load Regulation (Sink)
Reference Voltage vs Temperature
10 20 30 40 50 60 70 80 90 100 110
INPUT VOLTAGE (mV)
1540 G08
60
40
20
0
– 20
– 40
– 60
– 80
0
10
20
30
VREF – VHYST (mV)
40
50
1540 G09
1540fb
For more information www.linear.com/LTC1540
5
LTC1540
PIN FUNCTIONS
GND (Pin 1): Ground. Connect to V – for single supply
operation.
V+ (Pin 7): Positive Supply operating voltage is from 2V
to 11V.
V– (Pin 2): Negative Supply. Potential should be more
negative than GND. Connect to ground for single supply
operation.
OUT (Pin 8): Comparator CMOS Output. Swings from
GND to V+. Output can source up to 40mA and sink 5mA.
IN+ (Pin 3): Noninverting Comparator Input. Input common
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 VREF to VREF – 50mV.
1
GND
LTC1540
–
2 V
OUT 8
V+
7
+
3 IN+
–
4 IN
REF (Pin 6): Reference Output. 1.182V with respect
to V –. Can source up to 1mA and sink 10µA at 25°C. Drive
0.01µF bypass capacitor without oscillation.
–
REF 6
HYST
5
1540 • PD
APPLICATIONS INFORMATION
The LTC1540 is a nanopower comparator with a built-in
1.182V reference. Features include programmable hysteresis, wide supply voltage range (2V to 11V) and the ability
of the reference to drive up to a 0.01µF capacitor without
oscillation. The comparator’s CMOS outputs can source
up to 40mA while supply current glitches that normally
occur when switching logic states, have been eliminated.
Power Supplies
The comparator operates from a single 2V to 11V supply.
The LTC1540 includes a separate ground for the comparator output stage, allowing a split supply ranging from ± 1V
to ±5.5V. Connecting V– to GND will allow single supply
operation. If the comparator output 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 supply,
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 Output
The comparator output swings between GND and V + to
assure TTL compatibility with a split supply. The output
is capable of sourcing up to 40mA and sinking up to 5mA
while still maintaining nanoampere 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 ±2.0% from
0°C to 70°C. It can source up to 1mA and sink up to 10µA
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 10µF 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 comparators by preventing glitches on V+ or reference load
transients from disturbing the reference output voltage.
1540fb
6
For more information www.linear.com/LTC1540
LTC1540
APPLICATIONS INFORMATION
REFERENCE
OUTPUT
7
REF
R1
C1
3 IN +
LTC1540
4
5V
TO
8V
LTC1540
+
IN–
8
OUT
–
V–
1540 • F01
5 HYST
R2
10k
Figure 1. Damping the Reference Output
R3
2.4M
6 REF
R1
430Ω
1000
RESISTOR VALUE (kΩ)
V+
C1
1µF
V–
GND
2
1
1540 • F03a
100
Figure 3a. Power Supply Transient Test Circuit
10
1
8V
V+
0.01
0.1
1
CAPACITOR VALUE (µF)
10
1540 • F02
5V
2mV/DIV
0.1
0.001
VREF
Figure 2. Damping Resistance vs Bypass Capacitor Value
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.
OUT
2ms/DIV
1540 F03b
Figure 3b. Power Supply Transient Rejection
Low Voltage Operation: V + = 1.6V
5
V – = GND = 0V
IN+ = 0V
IN – = REF = HYST
TA = 25°C
4
SUPPLY CURRENT (µA)
The guaranteed minimum operating voltage is 2V (or
±1V). As the total supply voltage is reduced below 2V,
the performance degrades and the supply current falls.
At low supply voltages, the comparator’s output drive is
reduced and the propagation delay increases. The VREF
and VOS are also slightly worse. The useful input voltage
range extends from the negative supply to 0.9V below
the positive supply. Test your prototype over the full
temperature and supply voltage range if operation below 2V is anticipated. Because of the increase in supply current, operation below 1.5V is not recommended
(Figure 4).
3
2
1
0
0
0.5
1.5
2.0
1.0
SUPPLY VOLTAGE (V)
2.5
1540 F04
Figure 4. Supply Current vs Supply Voltage
1540fb
For more information www.linear.com/LTC1540
7
LTC1540
APPLICATIONS INFORMATION
Hysteresis
Hysteresis can be added to the LTC1540 by connecting a
resistor (R1) between the REF and HYST pins and a second
resistor (R2) from HYST to V – (Figure 5).
15%. If hysteresis is not wanted, the HYST pin should
be shorted to REF. Acceptable values for IREF range from
0.1µA to 5µA. If 2.4M is chosen for R2, then the value of
R1 (kΩ) is equal to the value of VHB (mV).
The difference between the upper and lower threshold voltages, or hysteresis voltage band (VHB), is equal to twice
the voltage difference between the REF and HYST pins.
6
IREF
LTC1540
R1
5
When more hysteresis is added, the upper threshold increases the same amount as the low threshold decreases.
The maximum voltage allowed between REF and HYST
pins is 50mV, producing a maximum hysteresis voltage
band of 100mV. The hysteresis band may vary by up to
R1 =
REF
HYST
R2 =
VHB
(2)(IREF)
(
1.182V –
V–
2
R2
IREF
VHB
2
)
1540 • F05
Figure 5. Programmable Hysteresis
TYPICAL APPLICATIONS
Level Detector
The LTC1540 is ideal for use as a nanopower level detector
as shown in Figure 6. R1 and R2 form a voltage divider
from VIN 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 VIN voltage trip level, in this example 4.65V.
2. Calculate the required resistive divider ratio.
Ratio = VREF / VIN
Ratio = 1.182V/4.65V = 0.254
R1 =
VREF 1.182V
=
= 1.18M
IBIAS
1µA
R2 = R1
VIN
V
VREF + HB
2
R2 = 1.18M
–1
4.65V
–1
15mV
1.182V +
2
R2 = 3.40M
VIN
3. Choose the required hysteresis voltage band at the input
VHBIN, in this example 60mV. Calculate the hysteresis
voltage band referred to the comparator input VHB.
VHB = (VHBIN)(Ratio)
5V
7
R2
3.4M
1%
V+
3 IN +
R1
1.18M
1%
4 IN–
VHB = (60mV)(0.254)
LTC1540
+
8
OUT
–
5 HYST
VHB = 15.24mV
4. Choose the values for R3 and R4 to set the hysteresis.
R4 = 2.4M
R3
15k
1%
R4
2.4M
1%
R3 (kΩ) = 15k, VHB (mV) = 15mV
5. Choose the values for R1 and R2 to set the trip point.
6 REF
R5
430Ω
5%
C1
1µF
V–
2
GND
1
1540 F06
Figure 6. Glitch-Free Level Detector with Hysteresis
1540fb
8
For more information www.linear.com/LTC1540
LTC1540
TYPICAL APPLICATIONS
3.3V Output Low Dropout Linear Regulator
The LTC1540 can be connected as a micropower (IQ =
5.5µA at VIN = 5V) low dropout linear regulator (Figure 7).
When the output is low, Q1 turns on, allowing current to
charge output capacitor C1. Local feedback formed by
R4, Q1 and Q2 creates a constant-current source from the
5V input to C1. R4, R1 and Q2’s VBE also provide current
limiting in the case of an output short-circuit to ground. C2
reduces output ripple, while the R2-R3 feedback voltage
divider establishes the output voltage.
is the switched power supply output. With a 10mA load, it
typically provides a voltage of (VBAT – 0.17V). The whole
circuit draws a mere 0.8µA of quiescent current with VBAT
= 5V. The three resistor voltage divider programs 50mV of
hysteresis for the comparator, and sets the IN – voltage at
200mV. This gives an IN+ trip threshold of approximately
150mV
The RC time constant determines the maximum power-on
time of the OUT pin before power down occurs. This period
can be approximated by:
t = 4.6RC (seconds)
Auto Power-Off Source
Figure 8 shows the circuit for a 30mA power supply that
has a timed auto power-off function. The comparator output
The actual time will vary with both the leakage current of
the capacitor and the input current at the IN + pin.
V BAT
V IN = 5V
7
V+
3 IN +
4 IN–
LTC1540
+
R4
10Ω
Q2
2N3906
R1
47k
OUT 8
7
Q1
TP0610L
V OUT
3.3V
6 REF
C3
GND
1
C2
2.2nF
2M
121k
R2
430k
1%
V–
IN +
+
432k
4 IN –
5 HYST
R3
750k
1%
V+
3
MOMENTARY
SWITCH
C
C1
10µF
–
LTC1540
–
(VBAT – 0.17V)
10mA
5 HYST
6 REF
2
V–
2
1540 F07
Figure 7. 3.3V Output Low Dropout Linear Regulator
OUT 8
R
GND
1
1540 F08
Figure 8. Auto Power-Off Switch Operates
on 0.8µA Quiescent Current
1540fb
For more information www.linear.com/LTC1540
9
LTC1540
TYPICAL APPLICATIONS
Low-Battery Detect
down to a supply voltage of 2V, but it is still functional with
the supply as low as 1.6V. Some parameters, such as VREF
and VOS, will be degraded on lower supply voltages. The
input voltage range extends from 0.9V below the positive
supply to the negative supply.
Figure 9 shows how to use the LTC1540 for a low-battery
detect, drawing only 1.4µA at VBAT = 2V. The circuit is powered by a 2-cell NiCd battery. The VBAT pin could be as low
as 1.6V when the batteries are completely depleted. The
electrical specifications of the LTC1540 guarantee operation
VBAT = ~1.6V TO 2.5V
2-CELL
NiCd
7
R1
3M
3 IN +
R2
1.1M
4
IN–
V+
LTC1540
+
OUT
8
LBO
–
6 REF
R3
40k
R4
1.2M
R5
1M
5 HYST
V–
2
GND
1
1540 F09
Figure 9. Low-Battery Detect Works Down to 1.6V
1540fb
10
For more information www.linear.com/LTC1540
LTC1540
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/product/LTC1540#packaging for the most recent package drawings.
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698 Rev C)
R = 0.125
TYP
5
0.40 ±0.10
8
0.70 ±0.05
3.5 ±0.05
1.65 ±0.05
2.10 ±0.05 (2 SIDES)
PACKAGE
OUTLINE
0.25 ±0.05
3.00 ±0.10
(4 SIDES)
PIN 1
TOP MARK
(NOTE 6)
4
0.25 ±0.05
0.75 ±0.05
0.200 REF
0.50
BSC
2.38 ±0.05
1.65 ±0.10
(2 SIDES)
1
(DD8) DFN 0509 REV C
0.50 BSC
2.38 ±0.10
BOTTOM VIEW—EXPOSED PAD
0.00 – 0.05
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
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
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660 Rev G)
3.00 ±0.102
(.118 ±.004)
(NOTE 3)
0.889 ±0.127
(.035 ±.005)
5.10
(.201)
MIN
0.42 ± 0.038
(.0165 ±.0015)
TYP
3.20 – 3.45
(.126 – .136)
0.65
(.0256)
BSC
0.254
(.010)
8
7 6 5
3.00 ±0.102
(.118 ±.004)
(NOTE 4)
4.90 ±0.152
(.193 ±.006)
DETAIL “A”
0.52
(.0205)
REF
0° – 6° TYP
GAUGE PLANE
0.53 ±0.152
(.021 ±.006)
RECOMMENDED SOLDER PAD LAYOUT
DETAIL “A”
1
1.10
(.043)
MAX
2 3
4
0.86
(.034)
REF
0.18
(.007)
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
SEATING
PLANE
0.22 – 0.38
(.009 – .015)
TYP
0.65
(.0256)
BSC
0.1016 ±0.0508
(.004 ±.002)
MSOP (MS8) 0213 REV G
1540fb
For more information www.linear.com/LTC1540
11
LTC1540
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/product/LTC1540#packaging for the most recent package drawings.
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610 Rev G)
.189 – .197
(4.801 – 5.004)
NOTE 3
.045 ±.005
.050 BSC
8
.245
MIN
.160 ±.005
.010 – .020
× 45°
(0.254 – 0.508)
NOTE:
1. DIMENSIONS IN
5
.150 – .157
(3.810 – 3.988)
NOTE 3
1
RECOMMENDED SOLDER PAD LAYOUT
2
.053 – .069
(1.346 – 1.752)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
6
.228 – .244
(5.791 – 6.197)
.030 ±.005
TYP
.008 – .010
(0.203 – 0.254)
7
.014 – .019
(0.355 – 0.483)
TYP
INCHES
(MILLIMETERS)
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)
4. PIN 1 CAN BE BEVEL EDGE OR A DIMPLE
3
4
.004 – .010
(0.101 – 0.254)
.050
(1.270)
BSC
SO8 REV G 0212
1540fb
12
For more information www.linear.com/LTC1540
LTC1540
REVISION HISTORY
(Revision history begins at Rev B)
REV
DATE
DESCRIPTION
B
08/17
Reformatted Order Information.
PAGE NUMBER
2
Added web links.
All Pages
Add Information for analog devices.
All Pages
Corrected test conditions for supply current specification (ICC).
3
1540fb
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 representation that the interconnection
of its circuits
as described
herein will not infringe on existing patent rights.
For more
information
www.linear.com/LTC1540
13
LTC1540
TYPICAL APPLICATION
RF Field Detector
Figure 10 shows the complete circuit for a field detector
which was tested at 445MHz. A transmission line is used to
match the detector diode (1N5712) to a quarter-wave whip
antenna. The 0.23λ wavelength transmission line section
transforms the 1pF (350Ω) diode junction capacitance to
a virtual short at the base of the antenna. At the same time
it converts the received antenna current to a voltage loop
at the diode, giving excellent sensitivity.
The rectified output is monitored by the LTC1540 comparator. The internal reference is used to set up a threshold of
about 18mV at the inverting input. A rising edge at the
comparator output triggers a one shot that temporarily
enables answer back and any other pulsed functions.
The total supply current is 400nA. Among other monolithic
one shots, the CD4047 draws the least amount of transient
current.
2V TO 11V
λ /4
FB
12M
10k
3
10nF
4
0.23λ
10nF
5
+
6
LTC1540
–
180k
2
7
8
CMOS
ONE SHOT
(CD4047)
Q
Q
1
1540 F10
1N5712
Figure 10. Nanopower Field Detector
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT ®1178/LT1179
Dual/Quad 17µA Precision Single Supply Op Amps
70µV Max VOS, 5nA Max IBIAS
LT1351
Single 250µA, 3MHz, 200V/µs Op Amp with Shutdown
C-Load™ Op Amp Stable Driving Any Capacitive Load
LT1352/LT1353
Dual/Quad 250µA, 3MHz, 200V/µs Op Amps
C-Load Op Amps Stable Driving Any Capacitive Load
LTC1440
Micropower Comparator with 1% Reference
1.182V ±1% Reference, ±10mV (Max) Input Offset
LTC1443/LTC1444/
LTC1445
Micropower Quad Comparators with 1% Reference
LTC1443 Has 1.182V Reference, LTC1444/LTC1445 Have 1.221V
Reference and Adjustable Hysteresis
LTC1474
Low Quiescent Current High Efficiency Step-Down Converter
10µA Standby Current, 92% Efficiency, Space Saving 8-Pin
MSOP Package
LT1495
1.5µA Max, Dual Precision Rail-to-Rail
Input and Output Op Amp
375µV Max VOS, 250pA IBIAS, 25pA IOS
LT1521
300mA Low Dropout Regulator with Micropower
Quiescent Current and Shutdown
0.5V Dropout Voltage, 12µA Quiescent Current, Adjustable
Output 3V, 3.3V and 5V Fixed
LT1634
Micropower Precision Shunt Voltage Reference
1.25V, 2.5V, 4.096V, 5V Outputs, 10µA Operating Current,
0.05% Initial Accuracy 25ppm/°C Max Drift, SO-8, MSOP and
TO-92 Packages
1540fb
14
LT 0817 REV B • PRINTED IN USA
For more information www.linear.com/LTC1540
www.linear.com/LTC1540
LINEAR TECHNOLOGY CORPORATION 1997
工商网监
湘ICP备2023018690号
