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Part Number LTC2909

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LTC2909
1
2909f
SEL Pin Connection for Input Polarity
Combinations
POLARITY
ADJ1
ADJ2
SEL PIN
+
+
V
CC
+
­
OPEN
­
­
GND
Precision Triple/Dual Input
UV, OV and Negative
Voltage Monitor
Desktop and Notebook Computers
Handheld Devices
Network Servers
Core, I/O Monitor
Automotive
Two Low Voltage Adjustable Inputs (0.5V)
Pin Selectable Input Polarity Allows Negative
and OV Monitoring
Guaranteed Threshold Accuracy: ±1.5%
6.5V Shunt Regulator for High Voltage Operation
Low 50µA Quiescent Current
Buffered 1V Reference for Negative Supply Offset
Input Glitch Rejection
Adjustable Reset Timeout Period
Selectable Internal Timeout Saves Components
Open-Drain RST Output
Accurate UVLO for 2.5V, 3.3V, 5V Systems
Ultralow Voltage Reset: V
CC
= 0.5V Guaranteed
Space Saving 8-Lead TSOT-23 and 3mm × 2mm DFN
Packages
3.3V UV/OV (Window) Monitor Application with
200ms Internal Timeout (3.3V Logic Out)
V
CC
ADJ1
LTC2909-2.5
REF
ADJ2
RST
SEL
R
PU
10k
FAULT
OUTPUT
2909 TA01a
R
P6
453k
3.3V
R
P5
10.7k
R
P4
76.8k
C
BYP
100nF
TMR
GND
The LTC
®
2909 is a dual input monitor intended for a variety
of system monitoring applications. Polarity selection and
a buffered reference output allow the LTC2909 to monitor
positive and negative supplies for undervoltage (UV) and
overvoltage (OV) conditions.
The two inputs have a nominal 0.5V threshold, featuring
tight 1.5% threshold accuracy over the entire operating
temperature range. Glitch fi ltering ensures reliable reset
operation without false triggering. A third fi xed-threshold
UVLO monitor on the part's V
CC
(also 1.5% accuracy) is
available for standard logic supplies.
The common reset output has a timeout that may use
a preset 200ms, be set by an external capacitor or be
disabled. A three-state input pin sets the input polarity
of each adjustable input without requiring any external
components.
The LTC2909 provides a highly versatile, precise, space-
conscious, micropower solution for supply monitoring.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
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LTC2909
2
2909f
Terminal Voltages
V
CC
(Note 3) ............................................. ­0.3V to 6V
SEL, RST .............................................. ­0.3V to 7.5V
ADJ1, ADJ2 .......................................... ­0.3V to 7.5V
TMR .......................................... ­0.3V to (V
CC
+ 0.3V)
Terminal Currents
I
VCC
(Note 3) ....................................................±10mA
I
REF
....................................................................±1mA
ORDER PART
NUMBER
T
JMAX
= 125°C,
JA
= 76°C/W
EXPOSED PAD (PIN 9) MAY BE LEFT OPEN OR TIED TO GND
(PCB CONNECTION REQUIRED FOR STATED
JA
)
*The temperature grade is identifi ed by a label on the shipping container. Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
LBXG
LBXG
LBZS
LBZS
LBZT
LBZT
LTC2909CDDB-2.5
LTC2909IDDB-2.5
LTC2909CDDB-3.3
LTC2909IDDB-3.3
LTC2909CDDB-5
LTC2909IDDB-5
(Notes 1, 2)
ABSOLUTE AXI U
RATI GS
W
W
W
U
Operating Temperature Range
LTC2909C ................................................ 0°C to 70°C
LTC2909I .............................................­ 40°C to 85°C
Storage Temperature Range
DFN ....................................................­ 65°C to 125°C
TSOT-23 .............................................­ 65°C to 150°C
Lead Temperature (Soldering, 10 sec)
TSOT-23
............................................................ 300°C
TOP VIEW
9
DDB PACKAGE
8-LEAD (3mm
´ 2mm) PLASTIC DFN
5
6
7
8
4
3
2
1
SEL
TMR
V
CC
RST
ADJ1
ADJ2
REF
GND
LTBXF
LTBXF
LTBZV
LTBZV
LTBZW
LTBZW
LTC2909CTS8-2.5
LTC2909ITS8-2.5
LTC2909CTS8-3.3
LTC2909ITS8-3.3
LTC2909CTS8-5
LTC2909ITS8-5
ADJ1 1
ADJ2 2
REF 3
GND 4
8 SEL
7 TMR
6 V
CC
5 RST
TOP VIEW
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
T
JMAX
= 125°C,
JA
= 250°C/W
DDB PART*
MARKING
ORDER PART
NUMBER
TS8 PART*
MARKING
PACKAGE/ORDER I FOR ATIO
U
U
W
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/
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LTC2909
3
2909f
The
denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
CC
= 2.5V (LTC2909-2.5), V
CC
= 3.3V (LTC2909-3.3), V
CC
= 5V
(LTC2909-5), ADJ1 = ADJ2 = 0.55V, SEL = fl oating, unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
CC(MIN)
Operating Supply Voltage
RST in Correct State
0.5
V
V
CC(SHUNT)
V
CC
Shunt Regulation Voltage
I
VCC
= 1mA, I
VREF
= 0
6.0
6.5
6.9
V
I
CC
V
CC
Input Current
2.175 < V
CC
< 6V
50
150
µA
V
RT
ADJ Input Threshold
0.492
0.500
0.508
V
V
RT
ADJ Hysteresis (Note 4)
TMR = V
CC
1.5
3.5
10.0
mV
I
ADJ
ADJ Input Current
V
ADJ
= 0.55V
±15
nA
V
CC(UVLO)
V
CC
UVLO Threshold
LTC2909-2.5
LTC2909-3.3
LTC2909-5


2.175
2.871
4.350
2.213
2.921
4.425
2.250
2.970
4.500
V
V
V
V
CC(UVLO)
UVLO Hysteresis (Note 4)
TMR = V
CC
0.3
0.7
2.0
%
V
REF
Buffered Reference Voltage
V
CC
> 2.175V, I
VREF
= ±1mA
0.985
1.000
1.015
V
I
TMR(UP)
TMR Pull-Up Current
V
TMR
= 1V
­1.5
­2.1
­2.7
µA
I
TMR(DOWN)
TMR Pull-Down Current
V
TMR
= 1V
1.5
2.1
2.7
µA
t
RST(EXT)
Reset Timeout Period, External
C
TMR
= 2.2nF
16
20
25
ms
t
RST(INT)
Reset Timeout Period, Internal
V
TMR
= 0V
150
200
260
ms
V
TMR(DIS)
Timer Disable Voltage
V
TMR
Rising
V
CC
­ 0.36
V
CC
­ 0.25
V
CC
­ 0.16
V
V
TMR(DIS)
Timer Disable Hysteresis
V
TMR
Falling
60
110
150
mV
V
TMR(INT)
Timer Internal Mode Voltage
V
TMR
Falling
0.14
0.21
0.27
V
V
TMR(INT)
Timer Internal Mode Hysteresis
V
TMR
Rising
40
70
110
mV
t
PROP
ADJx Comparator Propagation Delay
to RST
ADJx Driven Beyond Reset Threshold
(V
RTX
) by 5mV
50
150
500
µs
t
UV
V
CC
Undervoltage Detect to RST
V
CC
Less Than UVLO Threshold
(V
CC(UVLO)
) by 1%
50
150
500
µs
V
OL(RST)
RST Output Voltage Low
V
CC
= 0.5V, I = 5µA
V
CC
= 1V, I = 100µA
V
CC
= 3V, I = 2500µA


0.01
0.01
0.10
0.15
0.15
0.30
V
V
V
I
OH(RST)
RST Output Voltage High Leakage
RST = V
CC
±1
µA
Three-State Input SEL
V
IL
Low Level Input Voltage
0.4
V
V
IH
High Level Input Voltage
1.4
V
V
Z
Pin Voltage when Left in Open State
I
SEL
= 0µA
0.9
V
I
SEL(Z)
Allowable Leakage in Open State
±5
±10
µA
µA
I
SEL
SEL Input Current
SEL = V
CC
or SEL = GND
±25
µA
ELECTRICAL CHARACTERISTICS
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: All currents into pins are positive; all voltages are referenced to
GND unless otherwise noted.
Note 3: V
CC
maximum pin voltage is limited by input current. Since the
V
CC
pin has an internal 6.5V shunt regulator, a low impedance supply
which exceeds 6V may exceed the rated terminal current. Operation
from higher voltage supplies requires a series dropping resistor. See
Applications Information.
Note 4: Threshold voltages have no hysteresis unless the part is in
comparator mode. Hysteresis is one-sided, affecting only invalid-to-valid
transitions. See Applications Information.
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LTC2909
4
2909f
ADJ Threshold Voltage
vs Temperature
V
CC
UVLO Threshold Variation
vs Temperature
REF Output Voltage
vs Temperature
REF Output Load Regulation
Quiescent Supply Current
vs Temperature
Allowable Glitch Duration
vs Magnitude
External Timeout Period
vs Capacitance
Reset Timeout Period
vs Temperature
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
T
A
= 25°C unless otherwise noted
TEMPERATURE (
°C)
­50
THRESHOLD VOLTAGE, V
RT
(mV)
506
25
2909 G01
500
496
­25
0
50
494
492
508
504
502
498
75
100
125
TEMPERATURE (
°C)
­50
THRESHOLD VOLTAGE VARIATION (% OF 25
°
C VALUE)
0.5
1.0
1.5
25
75
2909 G02
0
­0.5
­25
0
50
100
125
­1.0
­1.5
TEMPERATURE (
°C)
­50
REF VOLTAGE, V
REF
(V)
1.005
1.010
0.015
25
75
2909 G03
1.000
0.995
­25
0
50
100
125
0.990
0.985
I
REF
= 0A
LOAD CURRENT, I
REF
(mA)
­1
0.985
REF VOLTAGE, V
REF
(V)
0.990
0.995
1.000
1.005
1.010
1.015
V
CC
= 2.5V
­0.5
0
0.5
1
2909 G04
T
A
= 125
°C
T
A
= 25
°C
T
A
= ­40
°C
REF Output Line Regulation
SUPPLY VOLTAGE, V
CC
(V)
2
0.985
REF VOLTAGE, V
REF
(V)
0.990
0.995
1.000
1.005
3
4
5
6
2909 G05
1.010
1.015
2.5
3.5
4.5
5.5
T
A
= 125
°C
I
REF
= 0A
T
A
= 25
°C
T
A
= ­40
°C
GLITCH PERCENTAGE PAST THRESHOLD (%)
0.1
400
MAXIMUM ALLOWABLE
GLITCH DURATION (ms)
500
600
700
1
10
100
2909 G07
300
200
100
0
RESET OCCURS
ABOVE CURVE
TMR PIN CAPACITANCE, C
TMR
(nF)
10
RESET TIMEOUT PERIOD, t
RST
(ms)
100
1000
10000
0.1
10
100
1000
2909 G08
1
1
TEMPERATURE (
°C)
­50
RESET TIMEOUT PERIOD, t
RST
(ms)
220
240
260
25
75
2909 G09
200
180
­25
0
50
100
125
160
140
INTERNAL
EXTERNAL WITH
22nF CAPACITOR
TEMPERATURE (
°C)
­50
QUIESCENT SUPPLY CURRENT, I
CC
(
µ
A)
55
25
2909 G06
40
30
­25
0
50
25
20
60
50
45
35
75
100
125
ADJ1 = 0.55V
ADJ2 = 0.45V
SEL = OPEN
V
CC
= 5V
V
CC
= 3.3V
V
CC
= 2.5V
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LTC2909
5
2909f
Shunt Regulation Voltage
vs Temperature
RST Output Voltage vs V
CC
RST Pull-Down Current vs V
CC
RST V
OL
vs I
RST
I
SEL
vs Temperature
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
T
A
= 25°C unless otherwise noted
TEMPERATURE (
°C)
­50
6.0
SHUNT REGULATION VOLTAGE, V
CC(SHUNT)
(V)
6.4
7.0
0
50
75
2909 G10
6.2
6.8
6.6
­25
25
100
125
I
CC
= 10mA
I
CC
= 1mA
I
CC
= 100
µA
RST Output Voltage vs V
CC
Shunt Regulation Voltage
vs Supply Current
SUPPLY CURRENT, I
CC
(mA)
SHUNT REGULATION VOLTAGE, V
CC(SHUNT)
(V)
7.0
6.2
6.8
6.6
6.4
0.01
1
10
100
2909 G11
6.0
0.1
T
A
= 25
°C
SUPPLY VOLTAGE, V
CC
(V)
0
RST VOLTAGE (V)
3
4
5
4
2909 G12
2
1
0
1
2
3
5
LTC2909-2.5
LTC2909-5
LTC2909-3.3
ADJ1 = 0.55
ADJ2 = 0.45
SEL = OPEN
10k PULL-UP R TO V
CC
SUPPLY VOLTAGE, V
CC
(V)
0
0
RST VOLTAGE (V)
0.1
0.2
0.3
0.4
0.1
0.2
0.3
0.4
2909 G13
0.5
0.6
0.7
0.8
RST WITH 10k PULL-UP
RST WITH 100k PULL-UP
V
CC
SUPPLY VOLTAGE, V
CC
(V)
0
0
PULL-DOWN CURRENT, I
RST
(mA)
1
2
3
4
5
6
1
2
3
4
2909 G14
5
ADJ1 = 0.55
ADJ2 = 0.55
SEL = OPEN
RST AT 150mV
RST AT 50mV
RST Pull-Down Current vs V
CC
SUPPLY VOLTAGE, V
CC
(V)
0.01
PULL-DOWN CURRENT, I
RST
(mA)
0.1
1
0
0.4
0.6
0.8
0.001
0.0001
0.2
1
2909 G15
RST AT 150mV
RST AT 50mV
I
SEL
vs Temperature
I
RST
(mA)
0
0
RST V
OL
(V)
0.2
0.4
0.6
0.8
1.0
5
10
15
20
1635 G07
25
30
V
CC
= 3V
NO PULL-UP R
T
A
= 125
°C
T
A
= ­40
°C
T
A
= 25
°C
TEMPERATURE (
°C)
­50
­25
­10
I
SEL
(
µ
A)
­14
­20
0
50
75
2909 G17
­12
­18
­16
25
100
125
SEL = GND
TEMPERATURE (
°C)
­50
­25
10
I
SEL
(
µ
A)
14
20
0
50
75
2909 G18
12
18
16
25
100
125
SEL = V
CC