2902f.pm6
1
LTC2902
2902f
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
Programmable Quad Supply
Monitor with Adjustable Reset Timer
and Supply Tolerance
s
Simultaneously Monitors Four Supplies
s
16 User Selectable Combinations of 5V, 3.3V, 3V,
2.5V, 1.8V, 1.5V and/or
Adjustable Voltage
Thresholds
s
Guaranteed Threshold Accuracy:
1.5% of Monitored
Voltage Over Temperature
s
Selectable Supply Tolerance: 5%, 7.5%,
10%, 12.5% Below Monitored Voltage
s
Low Supply Current: 43
A Typ
s
Adjustable Reset Time
s
RESET Disable Pin for Margining Applications
s
Open-Drain RST Output (LTC2902-1)
s
Push-Pull RST Output (LTC2902-2)
s
Individual Nondelayed Monitor Outputs for Each Supply
s
Power Supply Glitch Immunity
s
Guaranteed RESET for V
CC
1V
The LTC
2902 is a programmable supply monitor for sys-
tems with up to four supply voltages. One of 16 preset or
adjustable voltage monitor combinations can be selected
using an external resistor divider connected to the pro-
gram pin. The preset voltage thresholds are digitally pro-
grammable to 5%, 7.5%, 10% or 12.5% below the nomi-
nal operating voltage, and are accurate to 1.5% over tem-
perature. All four voltage comparator outputs are con-
nected to separate pins for individual supply monitoring.
The reset delay time is adjustable using an external
capacitor. Tight voltage threshold accuracy and glitch
immunity ensure reliable reset operation without false
triggering. The RST output is guaranteed to be in the
correct state for V
CC
down to 1V and may be disabled
during supply margin testing. The LTC2902-1 features
an open-drain RST output, while the LTC2902-2 has a
push-pull RST output.
The 43
A supply current makes the LTC2902 ideal for power
conscious systems and the part may be configured to
monitor less than four inputs. The LTC2902-1/LTC2902-2
are available in the 16-lead narrow SSOP package.
Quad Supply Monitor with Adjustable Tolerance (5V, 3.3V, 2.5V, 1.8V)
s
Desktop and Notebook Computers
s
Multivoltage Systems
s
Telecom Equipment
s
Portable Battery-Powered Equipment
s
Network Servers
, LTC and LT are registered trademarks of Linear Technology Corporation.
V1
V2
V
REF
V
PG
COMP1
COMP2
COMP3
COMP4
RST
RDIS
T0
T1
GND
10
11
R1
59k
1%
R3
10k
POWER
GOOD
R2
40.2k
1%
12
7
9
8
6
15
1
16
2
13
3
14
4
5
C
RT
47nF
C2
0.1
F
C1
0.1
F
V4
V3
LTC2902-2
CRT
t
RST
= 216ms
MARGIN
TOLERANCE = 5%
2902 TA01
DC/DC
CONVERTER
1.8V
2.5V
3.3V
5V
SYSTEM
LOGIC
2
LTC2902
2902f
ORDER PART
NUMBER
GN16 PART MARKING
29021
29022
29021I
29022I
T
JMAX
= 125
C,
JA
= 130
C/W
(Notes 1, 2, 3)
V1, V2, V3, V4, V
PG
..................................... 0.3V to 7V
RST (LTC2902-1)........................................ 0.3V to 7V
RST (LTC2902-2).......................... 0.3V to (V2 + 0.3V)
COMPX, RDIS ............................................. 0.3V to 7V
T0, T1 .......................................... 0.3V to (V
CC
+ 0.3V)
CRT ............................................. 0.3V to (V
CC
+ 0.3V)
V
REF
............................................. 0.3V to (V
CC
+ 0.3V)
Reference Load Current (I
VREF
) ............................
1mA
V4 Input Current ( ADJ Mode) ............................ 1mA
Operating Temperature Range
LTC2902-1C/LTC2902-2C ....................... 0
C to 70
C
LTC2902-1I/LTC2902-2I .................... 40
C to 85
C
Storage Temperature Range .................. 65
C to 150
C
Lead Temperature (Soldering, 10 sec)................... 300
C
LTC2902-1CGN
LTC2902-2CGN
LTC2902-1IGN
LTC2902-2IGN
ABSOLUTE AXI U RATI GS
W
W
W
U
PACKAGE/ORDER I FOR ATIO
U
U
W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
GN PACKAGE
16-LEAD PLASTIC SSOP
1
2
3
4
5
6
7
8
TOP VIEW
16
15
14
13
12
11
10
9
COMP3
COMP1
V3
V1
CRT
RST
T0
RDIS
COMP2
COMP4
V2
V4
V
REF
V
PG
GND
T1
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
RT50
5V, 5% Reset Threshold
V1 Input Threshold
q
4.600
4.675
4.750
V
5V, 7.5% Reset Threshold
q
4.475
4.550
4.625
V
5V, 10% Reset Threshold
q
4.350
4.425
4.500
V
5V, 12.5% Reset Threshold
q
4.225
4.300
4.375
V
V
RT33
3.3V, 5% Reset Threshold
V1, V2 Input Threshold
q
3.036
3.086
3.135
V
3.3V, 7.5% Reset Threshold
q
2.954
3.003
3.053
V
3.3V, 10% Reset Threshold
q
2.871
2.921
2.970
V
3.3V, 12.5% Reset Threshold
q
2.789
2.838
2.888
V
V
RT30
3V, 5% Reset Threshold
V2 Input Threshold
q
2.760
2.805
2.850
V
3V, 7.5% Reset Threshold
q
2.685
2.730
2.775
V
3V, 10% Reset Threshold
q
2.610
2.655
2.700
V
3V, 12.5% Reset Threshold
q
2.535
2.580
2.625
V
V
RT25
2.5V, 5% Reset Threshold
V2, V3 Input Threshold
q
2.300
2.338
2.375
V
2.5V, 7.5% Reset Threshold
q
2.238
2.275
2.313
V
2.5V, 10% Reset Threshold
q
2.175
2.213
2.250
V
2.5V, 12.5% Reset Threshold
q
2.113
2.150
2.188
V
V
RT18
1.8V, 5% Reset Threshold
V3, V4 Input Threshold
q
1.656
1.683
1.710
V
1.8V, 7.5% Reset Threshold
q
1.611
1.638
1.665
V
1.8V, 10% Reset Threshold
q
1.566
1.593
1.620
V
1.8V, 12.5% Reset Threshold
q
1.521
1.548
1.575
V
V
RT15
1.5V, 5% Reset Threshold
V3, V4 Input Threshold
q
1.380
1.403
1.425
V
1.5V, 7.5% Reset Threshold
q
1.343
1.365
1.388
V
1.5V, 10% Reset Threshold
q
1.305
1.328
1.350
V
1.5V, 12.5% Reset Threshold
q
1.268
1.290
1.313
V
V
RTA
ADJ, 5% Reset Threshold
V3, V4 Input Threshold
q
0.492
0.500
0.508
V
ADJ, 7.5% Reset Threshold
q
0.479
0.487
0.494
V
ADJ, 10% Reset Threshold
q
0.466
0.473
0.481
V
ADJ, 12.5% Reset Threshold
q
0.453
0.460
0.467
V
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25
C. V
CC
= 5V, unless otherwise noted. (Note 3)
ELECTRICAL CHARACTERISTICS
3
LTC2902
2902f
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25
C. V
CC
= 5V, unless otherwise noted. (Note 3)
ELECTRICAL CHARACTERISTICS
Note 1: Absolute Maximum Ratings are those values beyond which the life of
a device may be impaired.
Note 2: All voltage values are with respect to GND.
Note 3: The greater of V1, V2 is the internal supply voltage (V
CC
).
Note 4: Under static no-fault conditions, V1 will necessarily supply quiescent
current. If at any time V2 is larger than V1, V2 must be capable of supplying
the quiescent current, programming (transient) current and reference load
current.
Note 5: The output pins RST and COMPX have internal pull-ups to V2 of
typically 6
A. However, external pull-up resistors may be used when faster
rise times are required or for V
OH
voltages greater than V2.
Note 6: The push-pull RST output pin on the LTC2902-2 is
actively pulled up
to V2.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
RTAN
ADJ Reset Threshold
V4 Input Threshold
q
18
0
18
mV
V
CC
Minimum Internal Operating Voltage
RST, COMPX in Correct Logic State;
q
1
V
V
CC
Rising Prior to Program
V
CCMINP
Minimum Required for Programming
V
CC
Rising
q
2.42
V
V
CCMINC
Minimum Required for Comparators
V
CC
Falling
q
2.32
V
V
REF
Reference Voltage
V
CC
2.3V, I
VREF
=
1mA, C
REF
1000pF
T0 Low, T1 Low
q
1.192
1.210
1.228
V
T0 Low, T1 High
q
1.160
1.178
1.195
V
T0 High, T1 Low
q
1.128
1.146
1.163
V
T0 High, T1 High
q
1.096
1.113
1.130
V
V
PG
Programming Voltage Range
V
CC
V
CCMINP
q
0
V
REF
V
I
VPG
V
PG
Input Current
V
PG
= V
REF
q
20
nA
I
V1
V1 Input Current
V1 = 5V, I
VREF
= 12
A, (Note 4)
q
43
75
A
I
V2
V2 Input Current
V2 = 3.3V
q
0.8
2
A
I
V3
V3 Input Current
V3 = 2.5V
q
0.52
1.2
A
V3 = 0.55V (ADJ Mode)
15
15
nA
I
V4
V4 Input Current
V4 = 1.8V
q
0.34
0.8
A
V4 = 0.55V (ADJ Mode)
q
15
15
nA
V4 = 0.05V (ADJ Mode)
q
15
15
nA
I
CRT(UP)
CRT Pull-Up Current
V
CRT
= 0V
q
1.4
2
2.6
A
I
CRT(DN)
CRT Pull-Down Current
V
CRT
= 1.3V
q
10
20
30
A
t
RST
Reset Time-Out Period
C
RT
= 1500pF
q
5
7
9
ms
t
UV
V
X
Undervoltage Detect to RST or COMPX
V
X
Less Than Reset Threshold V
RTX
150
s
by More Than 1%
V
OL
Output Voltage Low RST, COMPX
I
SINK
= 2.5mA; V1 = 3V, V2 = 3V;
q
0.15
0.4
V
V3, V4 = 0V; V
PG
= 0V
I
SINK
= 100
A; V2 = 1V; V1, V3, V4 = 0V
q
0.05
0.3
V
I
SINK
= 100
A; V1 = 1V; V2, V3, V4 = 0V
q
0.05
0.3
V
V
OH
Output Voltage High RST, COMPX (Note 5)
I
SOURCE
= 1
A
q
V2 1
V
V
OH
Output Voltage High RST (LTC2902-2)
I
SOURCE
= 200
A
q
0.8 V2
V
(Note 6)
Digital Inputs T0, T1, RDIS
V
IL
T0, T1 Low Level Input Voltage
V
CC
= 3.3V to 5.5V
q
0.3V
CC
V
V
IH
T0, T1 High Level Input Voltage
V
CC
= 3.3V to 5.5V
q
0.7V
CC
V
I
INTOL
T0, T1 Input Current
T0 = 0V, T1 = V
CC
q
0.1
1
A
V
IL
RDIS Input Threshold Low
V
CC
= 3.3V to 5.5V
q
0.4
V
V
IH
RDIS Input Threshold High
V
CC
= 3.3V to 5.5V
q
1.6
V
I
RDIS
RDIS Pull-Up Current
V
RDIS
= 0V
10
A
4
LTC2902
2902f
TEST CIRCUITS
TI I G DIAGRA
U
W
W
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
V1
V2
V3
V4
2902 F01
LTC2902-1
RST
OR COMPX
I
SOURCE
1
A
V1
V2
V3
V4
2902 F02
LTC2902-1
I
SINK
2.5mA,
100
A
RST
OR COMPX
V1
V2
V3
V4
2902 F03
LTC2902-2
RST
I
SOURCE
200
A
Figure 1. RST, COMPX V
OH
Test
Figure 2. RST, COMPX V
OL
Test
Figure 3. Active Pull-Up RST V
OH
Test
t
RST
2902 TD
V
RTX
V
X
RST
COMPX
t
UV
1.5V
V
X
Monitor Timing
5V Threshold Voltage
vs Temperature
TEMPERATURE (
C)
60
THRESHOLD VOLTAGE, V
RT50
(V)
4.75
4.70
4.65
4.60
4.55
4.50
4.45
4.40
4.35
4.30
4.25
20
20
40
2902 G01
40
0
60
80
100
5%
7.5%
10%
12.5%
TEMPERATURE (
C)
60
THRESHOLD VOLTAGE, V
RT33
(V)
3.135
3.100
3.065
3.030
2.995
2.960
2.925
2.890
2.855
2.820
2.785
20
20
40
2902 G02
40
0
60
80
100
5%
7.5%
10%
12.5%
TEMPERATURE (
C)
60
THRESHOLD VOLTAGE, V
RT30
(V)
2.850
2.815
2.780
2.745
2.710
2.675
2.640
2.605
2.570
2.535
20
20
40
2902 G03
40
0
60
80
100
5%
7.5%
10%
12.5%
3.3V Threshold Voltage
vs Temperature
3V Threshold Voltage
vs Temperature
5
LTC2902
2902f
2.5V Threshold Voltage
vs Temperature
1.8V Threshold Voltage
vs Temperature
1.5V Threshold Voltage
vs Temperature
ADJ Threshold Voltage
vs Temperature
ADJ Threshold Voltage
vs Temperature
I
V1
vs Temperature
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
TEMPERATURE (
C)
60
THRESHOLD VOLTAGE, V
RT25
(V)
2.375
2.350
2.325
2.300
2.275
2.250
2.225
2.200
2.175
2.150
2.125
2.100
20
20
40
2902 G04
40
0
60
80
100
5%
7.5%
10%
12.5%
TEMPERATURE (
C)
60
THRESHOLD VOLTAGE, V
RT18
(V)
1.710
1.685
1.660
1.635
1.610
1.585
1.560
1.535
1.510
20
20
40
2902 G05
40
0
60
80
100
5%
7.5%
10%
12.5%
TEMPERATURE (
C)
60
THRESHOLD VOLTAGE, V
RT15
(V)
1.425
1.405
1.385
1.365
1.345
1.325
1.305
1.285
1.265
20
20
40
2902 G06
40
0
60
80
100
5%
7.5%
10%
12.5%
TEMPERATURE (
C)
60
THRESHOLD VOLTAGE, V
RTA
(V)
0.508
0.503
0.498
0.493
0.488
0.483
0.478
0.473
0.468
0.463
0.458
0.453
20
20
40
2902 G07
40
0
60
80
100
5%
7.5%
10%
12.5%
V
REF
vs Temperature
I
V2
vs Temperature
I
V3
vs Temperature
TEMPERATURE (
C)
60
THRESHOLD VOLTAGE, V
RTAN
(V)
0.018
0.012
0.006
0
0.006
0.012
0.018
20
20
40
2902 G08
40
0
60
80
100
TEMPERATURE (
C)
60
V
REF
(V)
1.228
1.216
1.204
1.192
1.180
1.168
1.156
1.144
1.132
1.112
1.108
1.096
20
20
40
2902 G09
40
0
60
80
100
5%
7.5%
10%
12.5%
TEMPERATURE (
C)
60
0
I
V1
(
A)
10
30
40
50
100
70
20
20
40
2902 G10
20
80
90
60
40
0
60
80
100
V1 = 5V
V2 = 3.3V
V3 = 2.5V
V4 = 1.8V
TEMPERATURE (
C)
60
0.5
I
V2
(
A)
0.6
0.8
0.9
1.0
1.5
1.2
20
20
40
2902 G11
0.7
1.3
1.4
1.1
40
0
60
80
100
V1 = 5V
V2 = 3.3V
V3 = 2.5V
V4 = 1.8V
TEMPERATURE (
C)
60
0.1
I
V3
(
A)
0.2
0.4
0.5
0.6
1.1
0.8
20
20
40
2902 G12
0.3
0.9
1.0
0.7
40
0
60
80
100
V1 = 5V
V2 = 3.3V
V3 = 2.5V
V4 = 1.8V
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