LTC2908 - Precision Six Supply Monitor

LTC2908
Precision
Six Input Supply Monitor
FEATURES
DESCRIPTION
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The LTC®2908 is a six input supply monitor for systems
requiring a precise and compact monitoring solution
for multiple supply voltages. The inputs can be shorted
together for monitoring systems with fewer than six
supply voltages, and the open drain RST output of two or
more LTC2908s can be wired-OR together for monitoring
systems with more than six supply voltages. The common
reset output remains low until all six inputs have been in
compliance for 200ms.
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Ultralow Voltage Reset: VCC = 0.5V Guaranteed*
Monitors Six Inputs Simultaneously:
5V, 3.3V, 2.5V, 1.8V, ADJ1, ADJ2 (LTC2908-A1)
3.3V, 2.5V, 1.8V, 1.5V, ADJ1, ADJ2 (LTC2908-B1)
2.5V, ADJ1, ADJ2, ADJ3, ADJ4, ADJ5 (LTC2908-C1)
Guaranteed Threshold Accuracy: ±1.5% of
Monitored Voltage Overtemperature
Internal VCC Auto Select
Power Supply Glitch Immunity
200ms Reset Time Delay
Active Low Open-Drain RST Output
Low Profile (1mm) 8-Lead SOT-23 (ThinSOT™) and
Plastic (3mm × 2mm) DFN Packages
APPLICATIONS
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The LTC2908 features a tight 1.5% threshold accuracy over
the entire operating temperature range and glitch immunity
to ensure reliable reset operation without false triggering.
The open-drain RST output state is guaranteed to be in the
correct state as long as V1 and/or V2 is 0.5V or greater.
The LTC2908 also features adjustable inputs with a nominal
threshold level at 0.5V. This product provides a precise,
space-conscious, micropower and general purpose solution for any kind of system requiring supply monitors.
Network Servers
Wireless Base Stations
Optical Networking Systems
Multivoltage Systems
Desktop and Notebook Computers
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other
trademarks are the property of their respective owners. *Patent pending.
TYPICAL APPLICATION
RST Output Voltage vs V1
with 10k Pull-Up Resistor to V1
Six Supply Monitor with 5% Tolerance
(12V, 3.3V, 2.5V, 1.8V, 1.5V, 1.2V)
12V
DC/DC
DC/DC
DC/DC
DC/DC
V3 = V4 = VADJ1 =
VADJ2 = VADJ3 =
VADJ4 = VADJ5 = GND
3.3V
2.5V
SYSTEM
1.8V
1.5V
1.2V
0.1μF 0.1μF
2.15M
100k
124k
100k
RST OUTPUT VOLTAGE (V)
DC/DC
0.4
0.3
V1 INPUT
0.2
V2 = GND
0.1
V2 = V1 (A1/B1)
0
0
0.2
0.4
0.6
0.8
V1 (V)
V1
V2 V3 V4
VADJ1
LTC2908-B1
GND
VADJ2
2908 TA01b
RST
2908 TA01a
2908fd
1
LTC2908
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Terminal Voltages
V1, V2, V3, V4 .........................................– 0.3V to 7V
VADJ1, VADJ2, VADJ3, ..................–0.3V to (VCC + 0.6V)
VADJ4, VADJ5 .............................–0.3V to (VCC + 0.6V)
RST.......................................................... –0.3V to 7V
Operating Temperature Range
LTC2908C ................................................ 0°C to 70°C
LTC2908I..............................................–40°C to 85°C
Storage Temperature Range
DFN Package......................................–65°C to 125°C
TSOT-23 Package...............................–65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
PIN CONFIGURATION
LTC2908CDDB-A1
LTC2908IDDB-A1
LTC2908CDDB-B1
LTC2908IDDB-B1
LTC2908CDDB-C1
LTC2908IDDB-C1
TOP VIEW
LTC2908CTS8-A1
LTC2908ITS8-A1
LTC2908CTS8-B1
LTC2908ITS8-B1
TOP VIEW
GND 1
8 VADJ2
GND 1
8 VADJ4
RST 2
7 V3
RST 2
7 VADJ3
V2 1
6 VADJ2
V4 2
RST 3
GND 4
V4 3
9
V2 4
LTC2908CTS8-C1
LTC2908ITS8-C1
6 VADJ1
5 V1
DDB8 PACKAGE
8-LEAD (3mm × 2mm) PLASTIC DFN
TJMAX = 125°C, θJA = 76°C/W
EXPOSED PAD (PIN 9)
(PCB CONNECTION OPTIONAL)
VADJ5 3
V1 4
9
5 VADJ1
DDB8 PACKAGE
8-LEAD (3mm × 2mm) PLASTIC DFN
TJMAX = 125°C, θJA = 76°C/W
EXPOSED PAD (PIN 9)
(PCB CONNECTION OPTIONAL)
TOP VIEW
TOP VIEW
8 V1
7 VADJ1
6 V3
5 VADJ2
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
TJMAX = 125°C, θJA = 250°C/W
V1 1
VADJ5 2
RST 3
GND 4
8 VADJ1
7 VADJ2
6 VADJ3
5 VADJ4
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
TJMAX = 125°C, θJA = 250°C/W
ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI)
TAPE AND REEL
PART MARKING* PACKAGE DESCRIPTION
LTC2908CDDB-A1#TRMPBF
LTC2908CDDB-A1#TRPBF
LBFD
8-LEAD (3mm × 2mm) PLASTIC DFN
LTC2908IDDB-A1#TRMPBF
LTC2908IDDB-A1#TRPBF
LBFF
8-LEAD (3mm × 2mm) PLASTIC DFN
LTC2908CDDB-B1#TRMPBF
LTC2908CDDB-B1#TRPBF
LBFG
8-LEAD (3mm × 2mm) PLASTIC DFN
LTC2908IDDB-B1#TRMPBF
LTC2908IDDB-B1#TRPBF
LBFH
8-LEAD (3mm × 2mm) PLASTIC DFN
LTC2908CDDB-C1#TRMPBF
LTC2908CDDB-C1#TRPBF
LCFV
8-LEAD (3mm × 2mm) PLASTIC DFN
LTC2908IDDB-C1#TRMPBF
LTC2908IDDB-C1#TRPBF
LCFV
8-LEAD (3mm × 2mm) PLASTIC DFN
LTC2908CTS8-A1#TRMPBF
LTC2908CTS8-A1#TRPBF
LTBFJ
8-LEAD PLASTIC TSOT-23
LTC2908ITS8-A1#TRMPBF
LTC2908ITS8-A1#TRPBF
LTBFK
8-LEAD PLASTIC TSOT-23
LTC2908CTS8-B1#TRMPBF
LTC2908CTS8-B1#TRPBF
LTBFM
8-LEAD PLASTIC TSOT-23
LTC2908ITS8-B1#TRMPBF
LTC2908ITS8-B1#TRPBF
LTBFN
8-LEAD PLASTIC TSOT-23
LTC2908CTS8-C1#TRMPBF
LTC2908CTS8-C1#TRPBF
LTCFT
8-LEAD PLASTIC TSOT-23
LTC2908ITS8-C1#TRMPBF
LTC2908ITS8-C1#TRPBF
LTCFT
8-LEAD PLASTIC TSOT-23
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on lead based finish parts.
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/
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
2908fd
2
LTC2908
ELECTRICAL CHARACTERISTICS
(LTC2908-A1) The l denotes specifications which apply over the full
operating temperature range, otherwise specifications are TA = 25°C, VCC = 5V unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
VRT50
5V, 5% Reset Threshold
V1 Input Threshold
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4.600
4.675
4.750
V
VRT33
3.3V, 5% Reset Threshold
V2 Input Threshold
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3.036
3.086
3.135
V
VRT25
2.5V, 5% Reset Threshold
V3 Input Threshold
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2.300
2.338
2.375
V
VRT18
1.8V, 5% Reset Threshold
V4 Input Threshold
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1.656
1.683
1.710
V
VRTADJ
ADJ, 5% Reset Threshold
VADJ1, VADJ2 Input Threshold
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0.492
0.500
0.508
V
(LTC2908-B1) The l denotes specifications which apply over the full operating temperature range, otherwise specifications are
TA = 25°C, VCC = 3.3V unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
VRT33
3.3V, 5% Reset Threshold
V1 Input Threshold
l
3.036
3.086
3.135
V
VRT25
2.5V, 5% Reset Threshold
V2 Input Threshold
l
2.300
2.338
2.375
V
VRT18
1.8V, 5% Reset Threshold
V3 Input Threshold
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1.656
1.683
1.720
V
VRT15
1.5V, 5% Reset Threshold
V4 Input Threshold
l
1.380
1.403
1.425
V
VRTADJ
ADJ, 5% Reset Threshold
VADJ1, VADJ2 Input Threshold
l
0.492
0.500
0.508
V
(LTC2908-C1) The l denotes specifications which apply over the full operating temperature range, otherwise specifications are
TA = 25°C, VCC = 2.5V unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
VRT25
2.5V, 5% Reset Threshold
V1 Input Threshold
VRTADJ
ADJ, 5% Reset Threshold
VADJ1, VADJ2, VADJ3, VADJ4, VADJ5,
Input Threshold
MIN
TYP
MAX
UNITS
l
2.300
2.338
2.375
V
l
0.492
0.500
0.508
V
The l denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. VCC = 5V
for the LT2908-A1, VCC = 3.3V for the LTC2908-B1or VCC = 2.5V for the LTC2908-C1, unless otherwise noted. (Notes 2, 3)
SYMBOL
PARAMETER
CONDITIONS
MIN
VCC
Internal Supply Voltage
RST in Correct Logic State
l
IV1
V1 Input Current (Note 4)
V1 = 5.0V (LTC2908-A1)
V1 = 3.3V (LTC2908-B1)
V1 = 2.5V (LTC2908-C1)
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l
l
IV2
V2 Input Current (Note 4)
V2 = 3.3V (LTC2908-A1)
V2 = 2.5V (LTC2908-B1)
IV3
V3 Input Current
IV4
IVADJ
TYP
0.5
MAX
UNITS
6
V
26
24
22
70
70
70
μA
μA
μA
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l
10
8
30
30
μA
μA
V3 = 2.5V (LTC2908-A1)
V3 = 1.8V (LTC2908-B1)
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l
2
2
5
5
μA
μA
V4 Input Current
V4 = 1.8V (LTC2908-A1)
V4 = 1.5V (LTC2908-B1)
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l
2
2
5
5
μA
μA
VADJ1, VADJ2, VADJ3, VADJ4, VADJ5
Input Current
VADJ1 = VADJ2 = VADJ3 = VADJ4 = VADJ5 =
0.55V
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±15
nA
2908fd
3
LTC2908
ELECTRICAL CHARACTERISTICS
The l denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. VCC = 5V
for the LT2908-A1, VCC = 3.3V for the LTC2908-B1 or VCC = 2.5V for the LTC2908-C1, unless otherwise noted. (Notes 2, 3)
SYMBOL
PARAMETER
CONDITIONS
tRST
Reset Time-Out Period
tUV
VX Undervoltage Detect to RST
VX Less Than Reset Threshold VRTX by
More Than 1%
VOH
Output Voltage High RST (Note 5)
IRST = –1μA, VCC = 5V (LTC2908-A1)
IRST = –1μA, VCC = 3.3V (LTC2908-B1)
IRST = –1μA, VCC = 2.5V (LTC2908-C1)
l
l
l
VOL
Output Voltage Low RST
VCC = 0.5V, IRST = 5μA
VCC = 1.0V, IRST = 100μA
VCC = 3.0V, IRST = 2500μA
l
l
l
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
reliabilty and lifetime.
Note 2: The greater of V1, V2 is the internal supply voltage (VCC) for the
LTC2908-A1 and the LTC2908-B1. V1 is the internal supply voltage (VCC)
for the LTC2908-C1.
MIN
TYP
MAX
UNITS
160
200
260
ms
250
μs
VCC – 1.5
VCC – 1.0
VCC – 1.0
V
V
V
0.01
0.01
0.10
0.15
0.15
0.30
V
V
V
Note 3: All currents into pins are positive; all voltages are referenced to
GND unless otherwise noted.
Note 4: Under typical operating conditions, most of the quiescent current is drawn from the V1 input. When V2 exceeds V1, V2 supplies most
of the quiescent current.
Note 5: The output pin RST has an internal pull-up to VCC of typically
6μA. However, an external pull-up resistor may be used when a faster
rise time is required or for VOH voltages greater than VCC.
TYPICAL PERFORMANCE CHARACTERISTICS
Specifications are at TA = 25°C unless otherwise noted.
5V Threshold Voltage
vs Temperature
3.3V Threshold Voltage
vs Temperature
3.135
2.375
4.725
THRESHOLD VOLTAGE, VRT25 (V)
THRESHOLD VOLTAGE, VRT50 (V)
THRESHOLD VOLTAGE, VRT33 (V)
4.750
3.115
4.700
2.360
3.095
4.675
2.345
3.075
4.650
2.330
3.055
4.625
4.600
–50
2.5V Threshold Voltage
vs Temperature
–25
50
25
0
TEMPERATURE (°C)
75
100
2908 G01
3.035
–50
2.315
–25
50
25
0
TEMPERATURE (°C)
75
100
2908 G02
2.300
–50
–25
50
25
0
TEMPERATURE (°C)
75
100
2908 G03
2908fd
4
LTC2908
TYPICAL PERFORMANCE CHARACTERISTICS
Specifications are at TA = 25°C unless otherwise noted.
1.8V Threshold Voltage
vs Temperature
1.5V Threshold Voltage
vs Temperature
1.700
1.690
1.680
1.670
1.425
0.5080
1.420
0.5060
THRESHOLD VOLTAGE, VRTADJ (V)
THRESHOLD VOLTAGE, VRT15 (V)
THRESHOLD VOLTAGE, VRT18 (V)
1.710
ADJ Threshold Voltage
vs Temperature
1.415
1.410
1.405
1.400
1.395
1.390
1.385
–25
50
25
0
TEMPERATURE (°C)
75
100
1.380
–50
–25
0
25
50
TEMPERATURE (°C)
75
2908 G04
0.5000
0.4980
0.4960
0.4940
0.4920
–50
IV1 vs Temperature
V1 = 5.0V (A1)/V1 = 3.3V (B1)
2.1 V2 = 3.3V (A1)/V2 = 2.5V (B1)
V3 = 2.5V (A1)/V3 = 1.8V (B1)
2.0 V4 = 1.8V (A1)/V4 = 1.5V (B1)
VADJ1 = VADJ2 = 0.55V
1.9
10
A1
9
B1
8
23
C1
1.8
1.7
7
21
100
2.2
V1 = 5.0V (A1)/V1 = 3.3V (B1)
13 V2 = 3.3V (A1)/V2 = 2.5V (B1)
V3 = 2.5V (A1)/V3 = 1.8V (B1)
12 V4 = 1.8V (A1)/V4 = 1.5V (B1)
11 VADJ1 = VADJ2 = 0.55V
IV2 (μA)
25
75
IV3 vs Temperature
14
V1 = 5.0V (A1)/V1 = 3.3V (B1)/V1 = 2.5V (C1)
31 V2 = 3.3V (A1)/V2 = 2.5V (B1)
V3 = 2.5V (A1)/V3 = 1.8V (B1)
29 V4 = 1.8V (A1)/V1 = 1.5V (B1)
VADJ1 = VADJ2 = VADJ3 =
27 VADJ4 =VADJ5 = 0.55V
B1
0
50
25
TEMPERATURE (°C)
2908 G06
IV2 vs Temperature
A1
–25
2908 G05
33
IV1 (μA)
100
0.5020
IV3 (μA)
1.660
–50
0.5040
1.6
6
19
1.5
5
–25
0
25
50
TEMPERATURE (°C)
75
4
–50
100
–25
0
50
25
TEMPERATURE (°C)
75
2908 G07
700
2.2
TYPICAL TRANSIENT DURATION (μs)
IV4 (μA)
1.9
1.8
1.7
1.6
1.5
–25
0
50
25
TEMPERATURE (°C)
75
100
2908 G10
0
50
25
TEMPERATURE (°C)
75
Reset Time-Out Period (tRST)
vs Temperature
250
TA = 25°C
600
500
100
2908 G09
Typical Transient Duration
vs Comparator Overdrive
V1 = 5.0V (A1)/V1 = 3.3V (B1)
2.1 V2 = 3.3V (A1)/V2 = 2.5V (B1)
V3 = 2.5V (A1)/V3 = 1.8V (B1)
2.0 V4 = 1.8V (A1)/V4 = 1.5V (B1)
VADJ1 = VADJ2 = 0.55V
–25
2908 G08
IV4 vs Temperature
1.4
–50
1.4
–50
100
RESET TIME-OUT PERIOD, tRST (ms)
17
–50
RESET OCCURS
ABOVE CURVE
400
300
200
100
0
0.1
1
10
100
COMPARATOR OVERDRIVE VOLTAGE (% OF VRTX)
2908 G11
240
230
220
210
200
190
180
170
160
150
–50
–25
0
50
25
TEMPERATURE (°C)
75
100
2908 G12
2908fd
5
LTC2908
TYPICAL PERFORMANCE CHARACTERISTICS
Specifications are at TA = 25°C unless otherwise noted.
0.4
V1 = V2 (A1/B1)
V3 = 2.5V (A1)/V3 = 1.8V (B1)
V4 = 1.8V (A1)/V4 = 1.5V (B1)
4.0 V
ADJ1 = VADJ2 = VADJ3 =
VADJ4 = VADJ5 = 0.55V
RST OUTPUT VOLTAGE (V)
3.0
VRT33
LTC2908-B1
2.0
0.3
V1 = INPUT
0.2
V2 = GND
0.1
1.0
V2 = V1
VRT50
LTC2908-A1
0
1
0
3
2
4
5
0
0.4
0.2
RST Pull-Down Current vs
Supply Voltage
LTC2908-C1
10
RST AT 150mV
3.0
2.5
2.0
1.5
RST AT 50mV
0
VRT25
LTC2908-C1
0.5
2.0
1.5
SUPPLY VOLTAGE VCC (V)
0
1.0
1
RST AT 150mV
0.1
RST AT 50mV
2.5
25°C
0.3
0.2
0.1
0
RST AT 50mV
0
2908 G17
1.20
V1 = 3.3V
0.7 V2 = 2.5V
V3 = 1.8V
0.6 V4 = 1.5V
VADJ1 = VADJ2 = 0.4V
2908 G18
1.0
V1 = 2.5V
VADJ1 = VADJ2 = VADJ3 =
VADJ4 = VADJ5 = 0.4V
85°C
25°C
0.80
0.5
85°C
1
0.2
0.4
0.6
0.8
SUPPLY VOLTAGE, VCC (V)
RST Output Voltage Low vs
RST Pull-Down Current
LTC2908-C1
–40°C
0.4
–40°C
0.60
25°C
0.3
0.40
0.2
0.20
0.1
0
25
30
35
20
15
RST PULL-DOWN CURRENT, IRST (mA)
10
RST AT 150mV
0.1
2908 G16
RST OUTPUT VOLTAGE LOW, VOL (V)
RST OUTPUT VOLTAGE LOW, VOL (V)
–40°C
0.4
VCC = V1
V2 = V3 = V4 = VADJ1 = VADJ2 =
VADJ3 = VADJ4 = VADJ5 = GND
1
1
0.2
0.4
0.6
0.8
SUPPLY VOLTAGE, VCC (V)
0.8
0.5
5
2908 G15
RST Output Voltage Low vs
RST Pull-Down Current
LTC2908-B1
V1 = 5.0V
0.7 V2 = 3.3V
V3 = 2.5V
0.6 V4 = 1.8V
VADJ1 = VADJ2 = 0.4V
2
3
4
SUPPLY VOLTAGE, VCC (V)
0.001
0
0.8
5
1
0
RST AT
50mV
VRT50
LTC2908-A1
0.01
0.001
RST Output Voltage Low vs
RST Pull-Down Current
LTC2908-A1
0
VRT33
LTC2908-B1
10
VCC = V1 = V2
V3 = V4 = VADJ1 = VADJ2 = GND
2928 G25
85°C
1
RST Pull-Down Current vs
Supply Voltage with 1 Input
0.01
1.0
0.5
2
RST Pull-Down Current vs
Supply Voltage with 2 Inputs
LTC2908-A1/LTC29089-B1
RST PULL-DOWN CURRENT, IRST (mA)
RST PULL-DOWN CURRENT, IRST (mA)
3.5
3
2908 G14
2908 G13
VCC = V1
VADJ1 = VADJ2 = VADJ3 =
VADJ4 = VADJ5 = 0.55V
RST AT
150mV
4
V1 (V)
V1 (V)
4.0
0.8
0.6
VCC = V1 = V2
V3 = 2.5V (A1)/V3 = 1.8V (B1)
5 V4 = 1.8V (A1)/V4 = 1.5V (B1)
VADJ1 = VADJ2 = 0.55V
0
RST PULL-DOWN CURRENT, IRST (mA)
0
6
V3 = V4 = VADJ1 =
VADJ2 = GND (A1/B1)
VADJ1 = VADJ2 = VADJ3 =
VADJ4 = VADJ5 = GND (C1)
RST OUTPUT VOLTAGE LOW, VOL (V)
RST OUTPUT VOLTAGE (V)
5.0
VRT25
LTC2908-C1
RST Pull-Down Current vs
Supply Voltage
LTC2908-A1/LTC2908-B1
RST Output Voltage vs V1 with
10k Pull-Up Resistor to V1
RST PULL-DOWN CURRENT, IRST (mA)
RST Output Voltage vs V1 with
10k Pull-Up Resistor to V1
0
5
10
20
15
RST PULL-DOWN CURRENT, IRST (mA)
25
2908 G19
0.00
0.0
25.0
5.0
10.0
15.0
20.0
RST PULL-DOWN CURRENT, IRST (mA)
2908 G23
2908fd
6
LTC2908
TYPICAL PERFORMANCE CHARACTERISTICS
Specifications are at TA = 25°C unless otherwise noted.
RST Output Voltage High vs
RST Output Source Current
LTC2908-A1
RST Pull-Up Current vs
Supply Voltage
–25
–20
5
VCC = V1 = V2 (A1/B1), VCC = V1(C1)
V3 = 2.5V (A1)/V3 = 1.8V (B1)
V4 = 1.8V (A1)/V4 = 1.5V (B1)
VADJ1 = VADJ2 = 0.55V (A1/B1)
VADJ1 = VADJ2 = VADJ3 = VADJ4 =
VADJ5 = 0.55V(C1)
RST HELD AT 0V
–15
RST OUTPUT VOLTAGE HIGH, VOH (V)
RST PULL-UP CURRENT, IRST (μA)
–30
VRT25
LTC2908-C1
VRT33
LTC2908-B1
–10
–5
0
1.5
VRT50
LTC2908-A1
2
3.5
4.5
3
4
2.5
SUPPLY VOLTAGE, VCC (V)
4
3
25°C
–40°C
1
5
V1 = 5.0V
V2 = 3.3V
V3 = 2.5V
V4 = 1.8V
VADJ1 = VADJ2 = 0.55V
2
0
2908 G20
–4
–12
–16
–20
–8
OUTPUT SOURCE CURRENT, IRST (μA)
2908 G21
RST Output Voltage High vs
RST Output Source Current
LTC2908-B1
RST Output Voltage High vs
RST Output Source Current
LTC2908-C1
2.0
2.5
2.0
25°C
1.5
85°C
–40°C
V1 = 3.3V
V2 = 2.5V
1.0 V3 = 1.8V
V4 = 1.5V
VADJ1 = VADJ2 = 0.55V
0.5
–4
–6
–8
–10
–12
0
–2
OUTPUT SOURCE CURRENT, IRST (μA)
RST OUTPUT VOLTAGE HIGH VOH (V)
3.0
RST OUTPUT VOLTAGE HIGH, VOH (V)
85°C
1.5
85°C
1.0
0.5
–40°C
V1 = 2.5V
VADJ1 = VADJ2 = VADJ3 =
VADJ4 = VADJ5 = 0.55V
0
25°C
–1 –2 –3 –4 –5 –6 –7
OUTPUT SOURCE CURRENT, IRST (μA)
–8
2908 G22
2908 G24
PIN FUNCTIONS
(TS8 Package/DDB8 Package) LTC2908-A1/LTC2908-B1
V2 (Pin 1/Pin 4): Voltage Input 2. The greater of V1, V2 is
also the internal VCC. The operating voltage on this pin shall
not exceed 6V. When in normal operation (V1 > V2), this pin
draws approximately 8μA. When this pin is acting as the
VCC (V2 > V1), this pin draws an additional 16μA. Bypass
this pin to ground with a 0.1μF (or greater) capacitor.
V4 (Pin 2/Pin 3): Voltage Input 4.
RST (Pin 3/Pin 2): Reset Logic Output. Pulls low when
any voltage input is below the reset threshold and is held
low for 200ms after all voltage inputs are above threshold.
This pin has a weak pull-up to VCC and may be pulled above
VCC using an external pull-up.
GND (Pin 4/Pin 1): Device Ground.
VADJ2 (Pin 5/Pin 8): Adjustable Voltage Input 2. See Table 1
for recommended ADJ resistors values.
V3 (Pin 6/Pin 7): Voltage Input 3.
VADJ1 (Pin 7/Pin 6): Adjustable Voltage Input 1. See Table 1
for recommended ADJ resistors values.
V1 (Pin 8/Pin 5): Voltage Input 1. The greater of V1, V2 is
also the internal VCC. The operating voltage on this pin shall
not exceed 6V. When in normal operation (V1 > V2), this pin
draws approximately 26 μA. When this pin is not acting as
the VCC (V2 > V1), this pin draws approximately 8μA. Bypass
this pin to ground with a 0.1μF (or greater) capacitor.
Exposed Pad (Pin 9, DDB8 Only): Exposed pad may be
left open or connected to device ground.
2908fd
7
LTC2908
PIN FUNCTIONS
(TS8 Package/DDB8 Package) LTC2908-C1
V1 (Pin 1/Pin 4): Voltage Input 1. V1 is the internal VCC.
The operating voltage on this pin shall not exceed 6V.
When in normal operation, this pin draws approximately
22μA. Bypass this pin to ground with a 0.1μF (or greater)
capacitor.
VADJ5 (Pin 2/Pin 3): Adjustable Voltage Input 5. See Table 1
for recommended ADJ resistors values.
RST (Pin 3/Pin 4): Reset Logic Output. Pulls low when
any voltage input is below the reset threshold and is held
low for 200ms after all voltage inputs are above threshold.
This pin has a weak pull-up to VCC and may be pulled above
VCC using an external pull-up.
GND (Pin 4/Pin 1): Device Ground.
VADJ4 (Pin 5/Pin 8): Adjustable Voltage Input 4.
See Table 1 for recommended ADJ resistors values.
VADJ3 (Pin 6/Pin 7): Adjustable Voltage Input 3.
See Table 1 for recommended ADJ resistors values.
VADJ2 (Pin 7/Pin 6): Adjustable Voltage Input 2.
See Table 1 for recommended ADJ resistors values.
VADJ1 (Pin 8/Pin 5): Adjustable Voltage Input 1.
See Table 1 for recommended ADJ resistors values.
Exposed Pad (Pin 9, DDB8 Only): Exposed pad may be
left open or connected to device ground.
BLOCK DIAGRAMS
LTC2908-A1/LTC2908-B1
–
V1
POWER
DETECT
V2
+
C1
VCC
–
+
C2
VCC
V3
–
+
V4
C4
C5
–
+
GND
RST
200ms
RESET PULSE
GENERATOR
–
+
VADJ2
C3
–
+
VADJ1
6μA
C6
BANDGAP
REFERENCE
2908 BD
2908fd
8
LTC2908
BLOCK DIAGRAMS
LTC2908-C1
–
V1
+
C1
–
VADJ1
+
C2
V1
–
VADJ2
+
6μA
C3
RST
200ms
RESET PULSE
GENERATOR
–
VADJ3
+
C4
–
VADJ4
+
C5
–
VADJ5
+
GND
C6
BANDGAP
REFERENCE
2908 BDa
TIMING DIAGRAM
VX Monitor Timing
VX
VRTX
tUV
RST
tRST
1V
2908 TD
2908fd
9
LTC2908
APPLICATIONS INFORMATION
Supply Monitoring
The LTC2908 is a low power, high accuracy, six input
supply monitoring circuit with two adjustable inputs. The
reset delay is set to a nominal of 200ms with an internal
capacitor, eliminating the need for an external timing
capacitor.
All input voltages must be above predetermined thresholds
for the reset not to be invoked. The LTC2908 asserts the
reset output during power-up, power-down and brownout
conditions on any one of the voltage inputs.
Ultralow Voltage Pull-Down on RST
The LTC2908 issues a logic low on the RST output when
any one of the inputs falls below its threshold. Ideally, the
RST logic output would remain low with the input supply
voltage down to zero volts. Most supervisors lack pulldown capability below 1V.
The LTC2908 power supply supervisor incorporates a novel
low voltage pull-down circuit that can hold the RST line low
with as little as 200mV of input supply voltage on V1 and/or
V2 (see Figures 1 and 2). The pull-down circuit helps maintain
a low impedance path to ground, reducing the risk of the
RST node from floating to an indeterminate voltage.
During power-up, RST starts asserting low as soon as
there is at least 200mV on V1 and/or V2. The RST pulldown capability is a function of V1 and V2 as shown in
the Typical Performance Characteristics.
The greater of V1, V2 is the internal supply voltage (VCC)
that powers the other internal circuitry. Once all the V X
inputs rise above their thresholds, an internal timer is
started. After the internal timer counts a 200ms delay
time, RST weakly pulls high to VCC.
Power-Down
On power-down, once any of the V X inputs drop below
their threshold, RST asserts logic low. VCC of at least 0.5V
guarantees a logic low of 0.15V at RST.
10
VCC = V1 = V2
V3 = V4 = VADJ1 = VADJ2 = GND
1
Power-Up
RST PULL-DOWN CURRENT, IRST (mA)
RST PULL-DOWN CURRENT, IRST (mA)
10
Such an indeterminate voltage may trigger external logic
causing erroneous reset operation(s). Furthermore, a
mid-scale voltage level could cause external circuits
to operate in the middle of their voltage transfer
characteristic, consuming more quiescent current than
normal. These conditions could cause serious system
reliability problems.
RST AT 150mV
0.1
RST AT 50mV
0.01
VCC = V1
V2 = V3 = V4 = VADJ1 = VADJ2 =
VADJ3 = VADJ4 = VADJ5 = GND
1
RST AT 150mV
0.1
RST AT 50mV
0.01
0.001
0.001
0
0.2
0.4
0.6
0.8
SUPPLY VOLTAGE, VCC (V)
1
2908 G16
Figure 1. RST Pull-Down Current vs
Supply Voltage with 2 Inputs LTC2908-A1/
LTC2908-B1
0
0.2
0.4
0.6
0.8
SUPPLY VOLTAGE, VCC (V)
1
2908 G17
Figure 2. RST Pull-Down Current vs
Supply Voltage with 1 Input
2908fd
10
LTC2908
APPLICATIONS INFORMATION
The noninverting input on the VADJ comparator is set to
0.5V. And the high impedance inverting input directly ties
to the VADJ pin.
In a typical application, this pin connects to a tap point on an
external resistive divider between the positive voltage being
monitored and ground (see Figure 3). The following formula
derives the value of the R1 resistor in the divider from a
particular value of R2 and the desired trip voltage:
V
R1= TRIP – 1R2
0.5V R2 = 100k is recommended. Table 1 shows suggested
1% resistor values for various adjustable applications and
their corresponding trip thresholds.
Table 1. Suggested 1% Resistor Values for the VADJ Inputs
VSUPPLY (V)
12
10
8
7.5
6
5
3.3
3
2.5
1.8
1.5
1.2
1.0
0.9
0.8
0.7
0.6
VTRIP (V)
11.25
9.4
7.5
7
5.6
4.725
3.055
2.82
2.325
1.685
1.410
1.120
0.933
0.840
0.750
0.655
0.561
R1 (kΩ)
2150
1780
1400
1300
1020
845
511
464
365
237
182
124
86.6
68.1
49.9
30.9
12.1
R2 (kΩ)
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
VTRIP
R1
1%
LTC2908-A1/LTC2908-B1/LTC2908-C1
–
VADJ
R2
1%
+
+
–
0.5V
In an application with less than six supply voltages, the
unused supervisor inputs should be tied to the closest
higher supply voltage available.
Threshold Accuracy
Specifying system voltage margin for worst-case operation
requires the consideration of three factors: power supply
tolerance, IC supply voltage tolerance and supervisor reset
threshold accuracy. Highly accurate supervisors ease the
design challenge by decreasing the overall voltage margin
required for reliable system operation.
Consider a 5V system with a ±5% power supply tolerance
band. System ICs powered by this supply must operate
reliably within this band (and a little more, as explained
below). The bottom of the supply tolerance band, at 4.75V
(5% below 5V), is the exact voltage at which a perfectly
accurate supervisor generates a reset (see Figure 4).
Such a perfectly accurate supervisor does not exist—the
actual reset threshold may vary over a specified band
(±1.5% for the LTC2908 supervisors). Figure 5 shows
the typical relative threshold accuracy for all six inputs
overtemperature.
5.000V
MINIMUM
SUPPLY
IDEAL
RELIABLE TOLERANCE SUPERVISOR
SYSTEM
THRESHOLD
VOLTAGE
4.750V
±1.5%
THRESHOLD 4.675V
BAND
4.600V
–6.5%
REGION OF POTENTIAL MALFUNCTION
WITH 2.5% MONITOR
2908 F04
Figure 3. Setting the Adjustable Trip Point
–8.0%
±2.5%
THRESHOLD
BAND
–10%
Figure 4. Threshold Band Diagram
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–50
2908 F03
NOMINAL
SUPPLY
VOLTAGE
–5.0%
4.500V
TYPICAL THRESHOLD ACCURACY (%)
Adjustable Input
–25
0
25
50
TEMPERATURE (°C)
75
100
2908 F05
Figure 5. Typical Threshold Accuracy vs Temperature
2908fd
11
LTC2908
APPLICATIONS INFORMATION
With this variation of reset threshold in mind, the nominal
reset threshold of the supervisor resides below the
minimum supply voltage; just enough so that the reset
threshold band and the power supply tolerance bands
do not overlap. If the two bands overlap, the supervisor
could generate a false or nuisance reset when the power
supply remains within its specified tolerance band (for
example at 4.8V).
Adding half of the reset threshold accuracy spread (1.5%)
to the ideal 5% thresholds puts the LTC2908 thresholds at
6.5% (typ) below the nominal input voltage. For example,
the 5V typical threshold is 4.675V, or 75mV below the
ideal threshold of 4.750V. The guaranteed threshold lies
in the band between 4.600V (8% below 5V) and 4.750V
(5% below 5V) overtemperature.
The powered system must work reliably down to the lowest
voltage in the threshold band or risk malfunction before
the reset line falls. In the 5V example, using the 1.5%
accurate supervisor, the system ICs must work down to
4.60V (8% below 5V). System ICs working with a ±2.5%
accurate supervisor must operate down to 4.50V (10%
below 5V), increasing the required system voltage margin
and the probability of system malfunction.
In any supervisory application, supply noise riding on
the monitored DC voltage can cause spurious resets,
particularly when the monitored voltage is near the reset
threshold. A less desirable but common solution to this
problem is to introduce hysteresis around the nominal
threshold. Notice however, this hysteresis introduces an
error term in the threshold accuracy. Therefore, a ±2.5%
accurate monitor with ±1% hysteresis is equivalent to a
±3.5% monitor with no hysteresis.
Therefore, the LTC2908 takes a different approach to solving this problem of supply noise causing spurious reset.
The first line of defense against this spurious reset is a
first order lowpass filter at the output of the comparators.
Therefore, each comparator output is integrated over time
before triggering the output logic. Therefore, any kind of
transient at the input of the comparator needs to be of
sufficient magnitude and duration before it can trigger a
change in the output logic.
The second line of defense is the 200ms delay time tRST.
This delay eliminates the effect of any supply noise, whose
frequency is above 1/200ms = 5Hz, on the RST output.
When any one of the supply voltages drops below its
threshold, the RST pin asserts low. When the supply
recovers above its threshold, the reset-pulse-generator
timer starts counting.
If all the supplies remain above their corresponding threshold when the timer finishes counting, the RST pin weakly
pulls high. However, if any of the supplies falls below its
threshold any time during the period when the timer is still
counting, the timer resets and it starts fresh when all the
supplies rise above their corresponding threshold.
Note that this second line of defense is only effective
for a rising supply and does not affect the sensitivity of
the system to a falling supply. Therefore, the first line of
defense that works for both cases of rising and falling is
necessary. These two approaches prevent spurious reset
caused by supply noise without sacrificing the threshold
accuracy.
Although all six comparators for the six inputs have builtin glitch filtering, use bypass capacitors on the V1 and
V2 inputs because the greater of V1 or V2 supplies the
VCC for the part (a 0.1μF ceramic capacitor satisfies most
applications). Apply filter capacitors on the V3, V4, VADJ1,
VADJ2, VADJ3, VADJ4 and VADJ5 inputs in extremely noisy
situations.
2908fd
12
LTC2908
APPLICATIONS INFORMATION
RST Output Characteristics
The DC characteristics of the RST pull-up and pull-down
strength are shown in the Typical Performance Characteristics section. The RST output has a weak internal pull-up
to VCC = Max(V1, V2) and a strong pull-down to ground.
The weak pull-up and strong pull-down arrangement allows
this pin to have open-drain behavior while possessing
several other beneficial characteristics.
The weak pull-up eliminates the need for external pull-up
resistors when the rise time on these pins is not critical.
On the other hand, the open-drain RST behavior allows for
wired-OR connections and can be useful when more than
one signal needs to pull down on the RST line.
As noted in the discussion of power-up and power-down,
the circuits that drive RST are powered by VCC. During
a fault condition, a VCC of at least 0.5V guarantees a
maximum VOL = 0.15V at RST.
Output Rise and Fall Time Estimation
The following formula estimates the output fall time (90% to
10%) for a particular external load capacitance (CLOAD):
tFALL ≈ 2.2 • RPD • CLOAD
where RPD is the on-resistance of the internal pull-
down transistor estimated to be typically 40Ω at room
temperature (25°C) and CLOAD is the external load
capacitance on the pin. Assuming a 150pF load capacitance,
the fall time is about 13ns.
The rise time on the RST pin is limited by a weak internal
pull-up current source to VCC. The following formula estimates the output rise time (10% to 90%) at the RST pin:
tRISE ≈ 2.2 • RPU • CLOAD
where RPU is the on-resistance of the pull-up transistor. Notice that this pull-up transistor is modeled as a
6μA current source in the Block Diagram as a typical
representation.
The on-resistance as a function of the VCC = Max(V1, V2)
voltage (for VCC > 1V) at room temperature is estimated
as follows:
6 • 105
RPU =
Ω
MAX ( V1,V2) – 1V
At VCC = 3.3V, RPU is about 260k. Using 150pF for load
capacitance, the rise time is 86μs. A smaller external
pull-up resistor may be used if the output needs to pull
up faster and/or to a higher voltage. For example, the rise
time reduces to 3.3μs for a 150pF load capacitance when
using a 10k pull-up resistor.
TYPICAL APPLICATIONS
Six Supply Monitor, 5% Tolerance, 12V, 5V, 3.3V, 2.5V, 1.8V, 1V
12V
DC/DC
DC/DC
DC/DC
DC/DC
DC/DC
5V
3.3V
SYSTEM
2.5V
1.8V
1.0V
C1
C2
0.1μF 0.1μF
V1
R1
2.15M
R3
R2
100k 86.6k
VADJ1
V2 V3 V4
LTC2908-A1
GND
R4
100k
VADJ2
RST
2908 TA02
2908fd
13
LTC2908
TYPICAL APPLICATIONS
Quad Supply Monitor with One Adjustable Input, 5% Tolerance, 3.3V, 2.5V, 1.8V, 1.2V
3.3V
DC/DC
DC/DC
DC/DC
2.5V
SYSTEM
1.8V
1.2V
C1
C2
0.1μF 0.1μF
V1
R3
124k
V2
V3 V4
VADJ1
LTC2908-B1
GND
R4
100k
VADJ2
RST
2908 TA03
Pin Programmable Dual Supply Monitor with Possible Future Expansion up to Six Supplies, 5% Tolerance, 3.3V and 2.5V
3.3V
DC/DC
SYSTEM
2.5V
C2
0.1μF
C1
0.1μF
V1
V2 V3 V4
LTC2908-B1
GND
VADJ1 VADJ2
RST
2908 TA05
Six Supply Monitor, 5% Tolerance 12V, 2.5V, 1.8V, 1.5V, 1.2V, 1.0V
12V
DC/DC
DC/DC
DC/DC
DC/DC
DC/DC
2.5V
1.8V
SYSTEM
1.5V
1.2V
1.0V
C1
0.1μF
R1
2.15M
V1
R3
R2
100k 237k
VADJ1
R4
100k
VADJ2
R5
182k
R6
100k
VADJ3
LTC2908-C1
GND
R7
124k
R9
R8
100k 86.6k
VADJ4
R10
100k
VADJ5
RST
2908 TA06
2908fd
14
LTC2908
PACKAGE DESCRIPTION
DDB Package
8-Lead Plastic DFN (3mm × 2mm)
(Reference LTC DWG # 05-08-1702 Rev B)
0.61 ±0.05
(2 SIDES)
3.00 ±0.10
(2 SIDES)
R = 0.115
TYP
5
R = 0.05
TYP
0.40 ± 0.10
8
0.70 ±0.05
2.55 ±0.05
1.15 ±0.05
PACKAGE
OUTLINE
0.25 ± 0.05
0.50 BSC
2.20 ±0.05
(2 SIDES)
PIN 1 BAR
TOP MARK
(SEE NOTE 6)
0.200 REF
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
2.00 ±0.10
(2 SIDES)
0.56 ± 0.05
(2 SIDES)
0.75 ±0.05
0 – 0.05
4
0.25 ± 0.05
1
PIN 1
R = 0.20 OR
0.25 s 45°
CHAMFER
(DDB8) DFN 0905 REV B
0.50 BSC
2.15 ±0.05
(2 SIDES)
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING CONFORMS TO VERSION (WECD-1) IN JEDEC PACKAGE OUTLINE M0-229
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 THE TOP AND BOTTOM OF PACKAGE
2908fd
15
LTC2908
PACKAGE DESCRIPTION
TS8 Package
8-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1637)
0.52
MAX
2.90 BSC
(NOTE 4)
0.65
REF
1.22 REF
1.4 MIN
3.85 MAX 2.62 REF
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.22 – 0.36
8 PLCS (NOTE 3)
0.65 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.30 – 0.50 REF
0.09 – 0.20
(NOTE 3)
1.95 BSC
TS8 TSOT-23 0802
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
2908fd
16
LTC2908
REVISION HISTORY
(Revision history begins at Rev D)
REV
DATE
DESCRIPTION
PAGE NUMBER
D
01/10
Revised Tape and Reel Part Numbers
2
2908fd
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.
17
LTC2908
TYPICAL APPLICATION
Six Supply Monitor with Manual Reset Button, 5% Tolerance, 12V, 5V, 3.3V, 2.5V, 1.8V, 1.5V
12V (VTRIP = 11.25V)
DC/DC
DC/DC
DC/DC
DC/DC
DC/DC
5V (VTRIP = 4.675V)
3.3V (VTRIP = 3.086V)
SYSTEM
2.5V (VTRIP = 2.338V)
1.8V (VTRIP = 1.685V)
1.5V (VTRIP = 1.410V)
C1
C2
0.1μF 0.1μF
R1
182k
R2
100k
R3
MANUAL
2.15M RESET BUTTON
R5* (NORMALLY OPEN)
10k
R4
100k
V1
*OPTIONAL RESISTOR RECOMMENDED
TO EXTEND ESD TOLERANCE
V2 V3 V4
VADJ1
LTC2908-A1
GND
VADJ2
RST
2908 TA04
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
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4.65 Threshold
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3.3V Supply Monitor, Watchdog Timer and Battery Backup
2.9V Threshold
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4.65 Threshold
LTC1232
5V Supply Monitor, Watchdog Timer and Pushbutton Reset
4.37V/4.62V Threshold
LTC1326/LTC1326-2.5
Micropower Precision Triple Supply Monitor for 5V/2.5V, 3.3V and ADJ 4.725V, 3.118V, 1V Threshold (±0.75%)and ADJ
LTC1536
Precision Triple Supply Monitor for PCI Applications
Meets PCI tFAIL Timing Specifications
LTC1726-2.5/LTC1726-5
Micropower Triple Supply Monitor for 2.5V/5V, 3.3V and ADJ
Adjustable Reset and Watchdog Time-Outs
LTC1727-2.5/LTC1727-5
Micropower Triple Supply Monitor with Open-Drain Reset
Individual Monitor Outputs in MSOP
LTC1728-1.8/LTC1728-3.3 Micropower Triple Supply Monitor with Open-Drain Reset
5-Lead SOT-23 Package
LTC1728-2.5/LTC1728-5
Micropower Triple Supply Monitor with Open-Drain Reset
5-Lead SOT-23 Package
LTC1985-1.8
Micropower Triple Supply Monitor with Push-Pull Reset Output
5-Lead SOT-23 Package
LTC2900
Programmable Quad Supply Monitor
Adjustable Reset, 10-Lead MSOP and DFN Packages
LTC2901
Programmable Quad Supply Monitor
Adjustable Reset and Watchdog Timer,
16-Lead SSOP Package
LTC2902
Programmable Quad Supply Monitor
Adjustable Reset and Tolerance,
16-Lead SSOP Package
LTC2903
Precision Quad Supply Monitor
6-Lead SOT-23 Package
LTC2904
Three-State Programmable Precision Dual Supply Monitor
Adjustable Tolerance, 8-Lead SOT-23 and DFN Packages
LTC2905
Three-State Programmable Precision Dual Supply Monitor
Adjustable Reset and Tolerance, 8-Lead SOT-23 and
DFN Packages
LTC2906
Dual Supply Monitor with One Pin Selectable Threshold and
One Adjustable Input
0.5V Adjustable Threshold and Three Supply
Tolerances, 8-Lead SOT-23 and DFN Packages
LTC2907
Dual Supply Monitor with One Pin Selectable Threshold and
One Adjustable Input
0.5V Adjustable Threshold, Reset and Three Supply
Tolerances, 8-Lead SOT-23 and DFN Packages
LTC2909
Precision Triple/Dual Input UV, OV and Negative Voltage Monitor
Shunt Regulated VCC Pin, Adjustable Threshold and
Reset, 8-Lead SOT-23 and DFN Packages
2908fd
18 Linear Technology Corporation
LT 0210 REV D • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2004