LTC1326/LTC1326-2.5 Triple Supply Monitor Datasheet

1
LTC1326/LTC1326-2.5
132625fc
TYPICAL APPLICATIO
U
APPLICATIO S
U
FEATURES
DESCRIPTIO
U
Micropower Precision
Triple Supply Monitors
RST Output Voltage vs Supply Voltage (LTC1326-2.5)
■
Simultaneously Monitors Three Supplies
LTC1326: 5V, 3.3V and ADJ
LTC1326-2.5: 2.5V, 3.3V and ADJ
■
Guaranteed Threshold Accuracy: ±0.75%
■
Low Supply Current: 20µA
■
Internal Reset Time Delay: 200ms
■
Manual Push-Button Reset Input
■
Active Low and Active High Reset Outputs
■
Active Low “Soft” Reset Output
■
Power Supply Glitch Immunity
■
Guaranteed RESET for V
CC3
≥ 1V or V
CC5
≥ 1V
or V
CC25
≥ 1V
■
8-Pin SO and MSOP Packages
The LTC
®
1326/LTC1326-2.5 are triple supply monitors
intended for systems with multiple supply voltages. They
provide micropower operation, small size and high accu-
racy supply monitoring.
Tight 0.75% threshold accuracy and glitch immunity
ensure reliable reset operation without false triggering.
The 20µA typical supply current makes the LTC1326/
LTC1326-2.5 ideal for power-conscious systems.
The RST output is guaranteed to be in the correct state for
V
CC3
, V
CC5
or V
CC25
down to 1V. The LTC1326/LTC1326-2.5
can be configured to monitor one, two or three inputs,
depending on system requirements.
A manual push-button reset input provides the ability to
generate a very narrow “soft” reset pulse (100µs typ) or a
200ms reset pulse equivalent to a power-on reset. Both
SRST and RST outputs are open-drain and can be OR-tied
with other reset sources.
■
Desktop Computers
■
Notebook Computers
■
Intelligent Instruments
■
Portable Battery-Powered Equipment
VCC3 (V)
0
2.0
2.5
3.5
1.5 2.5
1326/2.5 TA02
1.5
1.0
0.5 1.0 2.0 3.0 3.5
0.5
0
3.0
RST OUTPUT VOLTAGE (V)
VCC25 = VCCA = VCC3
4.7k PULL-UP FROM RST TO VCC3
TA = 25°C
PUSH-BUTTON
RESET
1326/2.5 TA01
V
CC3
V
CC25
0.1µF
V
CCA
GND
RST
PBR SRST
LTC1326-2.5
V
CORE
3.3V
2.5V
DC/DC
CONVERTER
SYSTEM
LOGIC
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 4843302.

2
LTC1326/LTC1326-2.5
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A
U
G
W
A
W
U
W
ARBSOLUTEXI T
IS
Terminal Voltage
V
CC3
, V
CC5
, V
CC25
, V
CCA
......................... – 0.5V to 7V
RST, SRST ............................................ – 0.5V to 7V
RST ...................................... –0.5V to (V
CC3
+ 0.3V)
PBR .......................................................... –7V to 7V
Operating Temperature Range
LTC1326C/LTC1326C-2.5....................... 0°C to 70°C
LTC1326I/LTC1326I-2.5 ..................... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
WU
U
PACKAGE/ORDER I FOR ATIO
ORDER PART NUMBER
1326
1326I
LTBA
LTUH
LTC1326CS8
LTC1326IS8
LTC1326CMS8
LTC1326IMS8
MS8 PART NUMBER
LTC1326CS8-2.5
LTC1326IS8-2.5
LTC1326CMS8-2.5
LTC1326IMS8-2.5
132625
326I25
LTEK
LTUJ
Consult factory for parts specified with wider operating temperature ranges.
1
2
3
4
8
7
6
5
TOP VIEW
S8 PACKAGE
8-LEAD PLASTIC SO
VCC3
VCC5
VCCA
GND
PBR
SRST
RST
RST
T
JMAX
= 125°C, θ
JA
= 150°C/W
1
2
3
4
VCC3
VCC5
VCCA
GND
8
7
6
5
PBR
SRST
RST
RST
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 125°C, θ
JA
= 250°C/W
1
2
3
4
8
7
6
5
TOP VIEW
S8 PACKAGE
8-LEAD PLASTIC SO
V
CC3
V
CC25
V
CCA
GND
PBR
SRST
RST
RST
T
JMAX
= 125°C, θ
JA
= 150°C/W
1
2
3
4
V
CC3
V
CC25
V
CCA
GND
8
7
6
5
PBR
SRST
RST
RST
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 125°C, θ
JA
= 250°C/W
ORDER PART NUMBER S8 PART NUMBER
ORDER PART NUMBER MS8 PART NUMBER ORDER PART NUMBER S8 PART NUMBER
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/
(Notes 1, 2)

3
LTC1326/LTC1326-2.5
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V
RT3
Reset Threshold V
CC3
0°C ≤ T
A
≤ 70°C●3.094 3.118 3.135 V
–40°C ≤ T
A
≤ 85°C●3.052 3.118 3.143 V
V
RT5
Reset Threshold V
CC5
(LTC1326) 0°C ≤ T
A
≤ 70°C●4.687 4.725 4.750 V
–40°C ≤ T
A
≤ 85°C●4.625 4.725 4.762 V
V
RT25
Reset Threshold V
CC25
(LTC1326-2.5) 0°C ≤ T
A
≤ 70°C●2.344 2.363 2.375 V
–40°C ≤ T
A
≤ 85°C●2.312 2.363 2.381 V
V
RTA
Reset Threshold V
CCA
0°C ≤ T
A
≤ 70°C●0.992 1.000 1.007 V
–40°C ≤ T
A
≤ 85°C●0.980 1.000 1.007 V
V
CC
V
CC3
Operating Voltage RST in Correct Logic State ●17V
I
VCC3
V
CC3
Supply Current PBR = V
CC3
●20 40 µA
I
VCC5
V
CC5
Input Current (LTC1326) V
CC5
= 5V ●410 µA
I
VCC25
V
CC25
Input Current (LTC1326-2.5) V
CC25
= 2.5V ●2.8 7 µA
I
VCCA
V
CCA
Input Current V
CCA
= 1V ●–15 0 15 nA
t
RST
Reset Pulse Width RST Low with 10kΩ Pull-Up to V
CC3
0°C ≤ T
A
≤ 70°C●140 200 280 ms
–40°C ≤ T
A
≤ 85°C●140 200 300 ms
t
SRST
Soft Reset Pulse Width SRST Low with 10kΩ Pull-Up to V
CC3
●50 100 200 µs
t
UV
V
CC
Undervoltage Detect to RST V
CC25
, V
CC3
or V
CCA
Less Than Reset 13 µs
Threshold V
RT
by More Than 1%
I
PBR
PBR Pull-Up Current PBR = 0V
0°C ≤ T
A
≤ 70°C●3710 µA
–40°C ≤ T
A
≤ 85°C●3715 µA
V
IL
PBR, RST Input Low Voltage ●0.8 V
V
IH
PBR, RST Input High Voltage ●2V
t
PW
PBR Min Pulse Width ●40 ns
t
DB
PBR Debounce Deassertion of PBR Input to SRST ●20 35 ms
Output (PBR Pulse Width = 1µs)
t
PB
PBR Assertion Time for Transition PBR Held Less Than V
IL
from Soft to Hard Reset Mode 0°C ≤ T
A
≤ 70°C●1.4 2.0 2.8 s
–40°C ≤ T
A
≤ 85°C●1.4 2.0 3.0 s
V
OL
RST Output Voltage Low I
SINK
= 5mA ●0.15 0.4 V
I
SINK
= 100µA, V
CC3
= 1V, V
CC5
= 0V ●0.05 0.4 V
0°C ≤ T
A
≤ 70°CV
CC3
= 0V, V
CC5
= 1V ●0.05 0.4 V
V
CC3
= 1V, V
CC5
= 1V ●0.05 0.4 V
I
SINK
= 100µA, V
CC3
= 1.1V, V
CC5
= 0V ●0.05 0.4 V
–40°C ≤ T
A
≤ 85°CV
CC3
= 0V, V
CC5
= 1.1V ●0.05 0.4 V
V
CC3
= 1.1V, V
CC5
= 1.1V ●0.05 0.4 V
I
SINK
= 100µA, V
CC3
= 1V, V
CC25
= 0V ●0.05 0.4 V
0°C ≤ T
A
≤ 70°CV
CC3
= 0V, V
CC25
= 1V ●0.05 0.4 V
V
CC3
= 1V, V
CC25
= 1V ●0.05 0.4 V
I
SINK
= 100µA, V
CC3
= 1.1V, V
CC25
= 0V ●0.05 0.4 V
–40°C ≤ T
A
≤ 85°CV
CC3
= 0V, V
CC25
= 1.1V ●0.05 0.4 V
V
CC3
= 1.1V, V
CC25
= 1.1V ●0.05 0.4 V
SRST Output Voltage Low I
SINK
= 2.5mA ●0.15 0.4 V
RST Output Voltage Low I
SINK
= 2.5mA ●0.15 0.4 V
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC3 = 3.3V, VCC5 = 5V (for LTC1326),VCC25 = 2.5V (for LTC1326-2.5),
VCCA = VCC3, TA = 25°C unless otherwise noted.

4
LTC1326/LTC1326-2.5
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ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OH
RST Output Voltage High (Note 3) I
SOURCE
= 1µA●V
CC3
– 1 V
SRST Output Voltage High (Note 3) I
SOURCE
= 1µA●V
CC3
– 1 V
RST Output Voltage High I
SOURCE
= 600µA●V
CC3
– 1 V
t
PHL
Prop Delay RST to RST C
RST
= 20pF 25 ns
High Input to Low Output
t
PLH
Prop Delay RST to RST C
RST
= 20pF 45 ns
Low Input to High Output
V
OVR
V
CC5
Reset Override Voltage Override V
CC5
Ability to Assert RST (Note 4) V
CC3
±0.025 V
Note 3: The output pins SRST and RST have weak internal pull-ups to
V
CC3
of 6µA typ. However, external pull-up resistors may be used when
faster rise times are required.
Note 4: The V
CC5
reset override voltage is valid for an operating range less
than approximately 4.15V. Above this point the override is turned off and
the V
CC5
pin functions normally.
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.
Note 2: All voltage values are with respect to GND.
TYPICAL PERFOR A CE CHARACTERISTICS
UW
TEMPERATURE (°C)
15
IVCC3 (µA)
16
18
19
20
25
22
1326/2.5 G01
17
23
24
21
–60 –20 20 40
–40 0 60 80 100
IVCC3 vs Temperature
TEMPERATURE (°C)
2.50
IVCC25 (µA)
2.55
2.65
2.70
2.75
3.00
2.85
1326/2.5 G03
2.60
2.90
2.95
2.80
–60 –20 20 40
–40 0 60 80 100
IVCC25 vs Temperature
(LTC1326-2.5)
TEMPERATURE (°C)
IVCC5 (µA)
5.0
4.8
4.6
4.4
4.2
4.0
3.8
3.6
3.4
3.2
3.0
1326/2.5 G02
–60 –20 20 40
–40 0 60 80 100
IVCC5 vs Temperature
(LTC1326)
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. LTC1326 Only VCC3 = 3.3V, VCC5 = 5V, VCCA = VCC3, TA = 25°C unless
otherwise noted.

5
LTC1326/LTC1326-2.5
132625fc
TYPICAL PERFOR A CE CHARACTERISTICS
UW
TEMPERATURE (°C)
–60
V
CC25
THRESHOLD VOLTAGE, V
RT25
(V)
2.375
2.370
2.365
2.360
2.355
2.350
–20 20 40
1326/2.5 G10
–40 0 60 80 100
VCC25 Threshold Voltage
vs Temperature (LTC1326-2.5)
TEMPERATURE (°C)
–60
VCCA THRESHOLD VOLTAGE, VRTA (V)
1.005
1.004
1.003
1.002
1.001
1.000
0.999
0.998
0.997
0.996
0.995
–20 20 40
1326/2.5 G12
–40 0 60 80 100
VCCA Threshold Voltage
vs Temperature
VCC3 Threshold Voltage
vs Temperature
TEMPERATURE (°C)
–60
VCC3 THRESHOLD VOLTAGE, VRT3 (V)
60
1326/2.5 G11
–20 20
–40 80
0 40 100
3.135
3.130
3.125
3.120
3.115
3.110
3.105
3.100
VCCA Transient Immunity
V
CCA
RESET COMPARATOR OVERDRIVE (V)
0.001
20
TRANSIENT DURATION (µs)
30
40
0.01 0.1 1
1326/2.5 G07
10
0
25
35
15
5
RESET OCCURS
ABOVE CURVE
T
A
= 25°C
VCC3 RESET COMPARATOR OVERDRIVE (V)
0.001
20
TRANSIENT DURATION (µs)
30
40
0.01 0.1 1
1326/2.5 G08
10
0
25
35
15
5
RESET OCCURS
ABOVE CURVE
TA = 25°C
VCC3 Transient Immunity
TEMPERATURE (°C)
–60
VCC5 THRESHOLD VOLTAGE, VRT5 (V)
4.750
4.745
4.740
4.735
4.730
4.725
4.720
4.715
4.710
4.705
4.700
–20 20 40
1326/2.5 G09
–40 0 60 80 100
VCC5 Threshold Voltage
vs Temperature (LTC1326)
VCC5 Transient Immunity
(LTC1326)
VCC5 RESET COMPARATOR OVERDRIVE (V)
0.001
20
TRANSIENT DURATION (µs)
25
30
35
40
0.01 0.1 1
1326/2.5 G05
15
10
5
0
45
50
RESET OCCURS
ABOVE CURVE
TA = 25°C
VCCA Input Current vs Input Voltage
INPUT VOLTAGE (V)
0.8
–3
INPUT CURRENT (nA)
–2
–1
0
1
0.9 1.0 1.1 1.2
1326/2.5 G04
2
3
0.85 0.95 1.05 1.15
TA = 25°C
VCC25 Transient Immunity
(LTC1326-2.5)
V
CC25
RESET COMPARATOR OVERDRIVE (V)
0.001
TRANSIENT DURATION (µs)
0.01 0.1 1
1326/2.5 G06
45
40
35
30
25
20
15
10
5
0
RESET OCCURS
ABOVE CURVE
T
A
= 25°C