LTC2932IF-TRPBF [Linear]
Confi gurable Six Supply Monitor with Adjustable Reset Timer and Supply Tolerance; 置信可配置六个电源监视器具有可调复位定时器和电源容限
| 型号： | LTC2932IF-TRPBF |
| 厂家： | 
Linear |
| 描述： | Confi gurable Six Supply Monitor with Adjustable Reset Timer and Supply Tolerance |
| 文件： | 总16页 (文件大小：243K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC2932
Configurable Six Supply
Monitor with Adjustable Reset
Timer and Supply Tolerance
DESCRIPTION
FEATURES
The LTC®2932 is a configurable supply monitor for sys-
tems with up to six supply voltages. One of 16 preset or
adjustable voltage monitor combinations can be selected
using an external resistive divider connected to the mode
select pin. The preset voltage thresholds are digitally
configurable to 5%, 7.5%, 10%, or 12.5% below the
nominal operating voltage. The LTC2932 also features
adjustable inputs with a 0.5V nominal threshold. All six
open-drain voltage comparator outputs are connected to
separate pins for individual supply monitoring.
■
Simultaneously Monitors Six Supplies
16 User Selectable Combinations of
■
5V, 3.3V, 3V, 2.5V, 1.8V, 1.5V and
Adꢀustable Voltage Thresholds
■
Guaranteed Threshold Accuracy: 1.5ꢁ
■
Selectable Supply Tolerances: 5ꢁ, 7.5ꢁ, 10ꢁ,
12.5ꢁ Below Monitored Voltage
■
Reset Disable Pin for Margining Applications
■
Low Supply Current: 52μA
■
Power Supply Glitch Immunity
■
Guaranteed RST for V ≥ 1V
CC
The reset timeout period is adjustable using an external
■
■
High Temperature Operation to 125°C
20-Lead TSSOP Package
capacitor. The RST output is guaranteed to be in the
correct state for V down to 1V and may be disabled
CC
during supply margin testing. Each status output has a
weak internal pull-up and may be externally pulled up to
an external voltage.
APPLICATIONS
■
Desktop and Notebook Computers
■
Multivoltage Systems
The 52μA supply current makes the LTC2932 ideal for
power conscious systems and the part may be configured
to monitor less than six inputs.
L, 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 6967591, 7119714, 7239251.
■
Telecom Equipment
■
Portable Battery-Powered Equipment
■
Network Servers
■
Automotive
TYPICAL APPLICATION
Six Supply Monitor 12V (ADJ),
Voltage Threshold Configuration Table
5V, 3.3V, 2.5V, 1.8V, 1.2V (ADJ)
V1 (V)
V2 (V)
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3
V3 (V)
V4 (V)
V5 (V)
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
V6 (V)
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
12V
5
2.5
1.8
5V
3.3V
2.5V
5
2.5
1.5
SYSTEM
LOGIC
5
2.5
ADJ
ADJ
–ADJ
ADJ
–ADJ
ADJ
ADJ
ADJ
1.5
1.8V
1.2V
5
1.8
5
1.8
10k
5
ADJ
ADJ
2.5
POWER
GOOD
2150k 124k
1%
1%
5
V1
5
V2
5
3
1.8
V3
0.1μF
V4
5
3
ADJ
1.8
LTC2932
0.1μF
V5
3.3
3.3
3.3
3.3
3.3
3.3
2.5
2.5
2.5
2.5
2.5
2.5
RDIS
V6
100k
1%
100k
1%
59k
1%
1.8
ADJ
–ADJ
ADJ
ADJ
–ADJ
VREF
R1
RST
1.8
2932 TA01
VPG
t
= 94ms
1.5
RST
T0
T1
CRT
GND
R2
40.2k
1%
ADJ
ADJ
C
RT
47nF
2932fb
1
LTC2932
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Notes 1, 2, 3)
TOP VIEW
V1, V2, V3, V4, V5, V6, VPG ........................–0.3V to 7V
COMP5
V5
1
2
3
4
5
6
7
8
9
20
19
18
17
16
15
14
13
12
COMP6
V6
RST, COMP1-6, T0, T1.................................–0.3V to 7V
CRT, VREF, RDIS............................–0.3V to (V + 0.3V)
CC
COMP3
COMP1
V3
COMP2
COMP4
V2
Reference Load Current (I
).............................. 1mA
VREF
V4 Input Current (–ADJ Mode) ..............................–1mA
RST, COMP1-6 Currents...................................... 10mA
Operating Temperature Range
LTC2932C ................................................ 0°C to 70°C
LTC2932I..............................................–40°C to 85°C
LTC2932H ..........................................–40°C to 125°C
Storage Temperature Range...................–65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
V1
V4
CRT
VREF
VPG
RST
T0
GND
RDIS 10
11 T1
F PACKAGE
20-LEAD PLASTIC TSSOP
T
= 130°C, θ = 90°C/W
JA
JMAX
ORDER INFORMATION
LEAD FREE FINISH
LTC2932F#PBF
LTC2932F#PBF
LTC2932F#PBF
TAPE AND REEL
PART MARKING*
LTC2932F
PACKAGE DESCRIPTION
20-Lead Plastic TSSOP
20-Lead Plastic TSSOP
20-Lead Plastic TSSOP
TEMPERATURE RANGE
LTC2932CF#TRPBF
LTC2932IF#TRPBF
LTC2932HF#TRPBF
0°C to 70°C
LTC2932F
–40°C to 85°C
–40°C to 125°C
LTC2932F
Consult LTC Marketing for information on non-standard lead based finish parts. *Temperature grades are identified by a label on the shipping container.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
This product is only offered in trays. For more information go to: http://www.linear.com/packaging/
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise specified. (Note 3)
SYMBOL
PARAMETER
CONDITIONS
RST, COMP in Correct Logic State
MIN
TYP
MAX
1
UNITS
●
●
●
V
V
V
V
Minimum Internal Operating Voltage
Minimum Required for Mode Selection
Minimum Required for Comparators
V
V
V
CC
n
V
CC
V
CC
Rising
Falling
2.4
2.3
CCMINP
CCMINC
RT50
●
●
●
●
5V, 5% Reset Threshold
5V, 7.5% Reset Threshold
5V, 10% Reset Threshold
5V, 12.5% Reset Threshold
V1 Input Threshold
V1, V2 Input Threshold
V2 Input Threshold
4.600
4.475
4.350
4.225
4.675
4.550
4.425
4.300
4.750
4.625
4.500
4.375
V
V
V
V
●
●
●
●
V
3.3V, 5% Reset Threshold
3.3V, 7.5% Reset Threshold
3.3V, 10% Reset Threshold
3.3V, 12.5% Reset Threshold
3.036
2.954
2.871
2.789
3.086
3.003
2.921
2.838
3.135
3.053
2.970
2.888
V
V
V
V
RT33
RT30
●
●
●
●
V
3V, 5% Reset Threshold
3V, 7.5% Reset Threshold
3V, 10% Reset Threshold
3V, 12.5% Reset Threshold
2.760
2.685
2.610
2.535
2.805
2.730
2.655
2.580
2.850
2.775
2.700
2.625
V
V
V
V
2932fb
2
LTC2932
The ● denotes the specifications which apply over the full operating
ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise specified. (Note 3)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
●
●
●
●
V
V
V
V
2.5V, 5% Reset Threshold
2.5V, 7.5% Reset Threshold
2.5V, 10% Reset Threshold
2.5V, 12.5% Reset Threshold
V2, V3 Input Threshold
2.300
2.238
2.175
2.113
2.338
2.275
2.213
2.150
2.375
2.313
2.250
2.188
V
V
V
V
RT25
RT18
RT15
RTA
●
●
●
●
1.8V, 5% Reset Threshold
1.8V, 7.5% Reset Threshold
1.8V, 10% Reset Threshold
1.8V, 12.5% Reset Threshold
V3, V4 Input Threshold
V3, V4 Input Threshold
V3, V4, V5, V6 Input Threshold
V4 Input Threshold
1.656
1.611
1.566
1.521
1.683
1.638
1.593
1.548
1.710
1.665
1.620
1.575
V
V
V
V
●
●
●
●
1.5V, 5% Reset Threshold
1.5V, 7.5% Reset Threshold
1.5V, 10% Reset Threshold
1.5V, 12.5% Reset Threshold
1.380
1.343
1.305
1.268
1.403
1.365
1.328
1.290
1.425
1.388
1.350
1.313
V
V
V
V
●
●
●
●
ADJ, 5% Reset Threshold
ADJ, 7.5% Reset Threshold
ADJ, 10% Reset Threshold
ADJ, 12.5% Reset Threshold
492.5
479.4
466.3
453.1
500.0
486.6
473.3
459.9
507.5
494
480.4
466.8
mV
mV
mV
mV
●
V
V
–ADJ Reset Threshold
Reference Voltage
–18
0
18
mV
RTAN
V
CC
≥ 2.3V, I
= 1mA, C ≤ 1000pF
VREF REF
REF
●
●
●
●
T0 Low, T1 Low
T0 Low, T1 High
T0 High, T1 Low
T0 High, T1 High
1.192
1.160
1.128
1.096
1.210
1.178
1.146
1.113
1.228
1.195
1.163
1.130
V
V
V
V
●
●
●
●
V
Mode Selection Voltage Range
VPG Input Current
V1 Input Current
V
V
≥ V
= V
0
V
V
nA
μA
μA
PG
VPG
V1
CC
CCMINP
REF
I
I
I
I
20
PG
REF
V1 = 5V, I
= 12μA (Note 4)
52
0.8
75
2
VREF
V2 Input Current
V2 = 3.3V
V2
●
●
V3 Input Current
V3 = 2.5V
V3 = 0.55V (ADJ Mode)
0.52
1.2
15
μA
nA
V3
●
●
●
I
V4
V4 Input Current
V4 = 1.8V
V4 = 0.55V (ADJ Mode)
V4 = –0.02V (–ADJ Mode)
0.34
0.8
15
15
μA
nA
nA
●
●
●
●
●
I
I
I
I
t
t
, I
V5, V6 Input Current
CRT Pull-Up Current
CRT Pull-Down Current
V5, V6 = 0.55V
15
–2.6
30
nA
μA
μA
μA
ms
μs
V5 V6
V
V
V
C
= GND
= 1.3V
–1.4
10
–2
2
–2
20
–6
3
CRT(UP)
CRT(DN)
COMPn
RST
CRT
CRT
COMP Pull-Up Current
= GND
COMPn
–12
4
n
Reset Timeout Period
= 1500pF
RT
V Undervoltage Detect to RST or
V Less Than Reset Threshold by More
150
UV
n
n
COMP
than 1%
n
●
●
V
Voltage Output Low RST, COMP
I
I
= 3mA, V = 3V
0.15
0.05
0.4
0.3
V
V
OL
OH
n
SINK
SINK
CC
= 100μA, V = 1V
CC
●
V
Voltage Output High RST, COMP
(Note 5)
I
= –1μA
V2-1
V
n
SOURCE
2932fb
3
LTC2932
The ● denotes the specifications which apply over the full operating
ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise specified. (Note 3)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Digital Inputs T0, T1, RDIS
●
●
●
●
●
●
V
V
T0, T1 Low Level Input Voltage
T0, T1 High Level Input Voltage
T0, T1 Input Current
V
V
= 3.3V to 5.5V
= 3.3V to 5.5V
0.3V
V
V
IL
CC
CC
0.7V
IH
CC
CC
I
T0, T1 = 2V
0.1
1
μA
V
INTOL
V
V
RDIS Input Threshold Low
RDIS Input Threshold High
RDIS Pull-Up Current
V
V
V
= 3.3V to 5.5V
= 3.3V to 5.5V
0.4
IL
CC
1.6
–4
V
IH
CC
I
= 1V
–10
–16
μA
RDIS
RDIS
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 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 2: All currents into pins are positive, all voltages are referenced to GND
unless otherwise noted.
Note5:TheoutputpinsRSTandCOMP havediodeprotectedinternalpull-ups
to V2 of typically 6μA. However, external pull-up resistors may be used when
n
faster rise times are required or for V voltages greater than V2.
OH
Note 3: The greater of V1, V2 is the internal supply voltage (V ).
CC
TIMING DIAGRAM
Vn Monitor Timing
V
RT
V
n
t
RST
t
UV
RST
2932 TD
COMP
n
2932fb
4
LTC2932
TYPICAL PERFORMANCE CHARACTERISTICS
Normalized Threshold Voltages
vs Temperature
–ADJ Threshold Voltage
vs Temperature
V
REF vs Temperature
1.015
1.010
1.005
1.000
18
12
6
1.228
1.222
1.216
1.210
0
0.995
0.990
0.985
–6
–12
–18
1.204
1.198
1.192
50
TEMPERATURE (°C)
100 125
50
TEMPERATURE (°C)
100 125
–50 –25
0
25
75
–50 –25
0
25
75
50
TEMPERATURE (°C)
100 125
–50 –25
0
25
75
2932 G01
2932 G02
2932 G03
Transient Duration vs Comparator
Overdrive (V1,V2)
I(V4) vs V4 in Negative
Adꢀust Mode
Supply Current vs Temperature
70
65
60
55
–100μ
–10μ
–1μ
300
250
200
150
100
50
V1 = 5V
T
= 25°C
A
V2 = 3.3V
V3 = 2.5V
V4 = 1.8V
V5 = V6 = 1V
125°C
90°C
RESET OCCURS ABOVE CURVE
–100n
–10n
–1n
50
45
40
25°C
–100p
0
50
TEMPERATURE (°C)
100 125
–50 –25
0
25
75
–300 –250 –200 –150 –100 –50
V4 (mV)
0
0.1
1
10
100
RESET COMPARATOR OVERDRIVE (% OF V
)
RTX
2932 G05
2932 G04
2932 G06
Reset Timeout Period
vs Temperature
Transient Duration vs Comparator
Overdrive (V3, V4, V5, V6)
RST Output Voltage
vs V1, VPG = GND
450
375
300
225
150
75
6
5
C
= 1500pF
T
= 25°C
T = 25°C
A
10k PULL-UP FROM RST TO V1
RT
A
(SILVER MICA)
5
4
3
2
4
3
RESET OCCURS ABOVE CURVE
2
1
0
0
1
0.1
1
10
100
)
–50 –25
0
25
50
75 100 125
0
1
2
3
4
5
RESET COMPARATOR OVERDRIVE (% OF V
TEMPERATURE (°C)
V1 (V)
RTX
2932 G07
2932 G09
2932 G08
2932fb
5
LTC2932
TYPICAL PERFORMANCE CHARACTERISTICS
ISINK vs Supply Voltage
(RST, COMPn)
Voltage Output Low vs Output
Sink Current (RST, COMPn)
Reset Timeout Period vs CRT
10
1
500
400
300
200
100
0
15
12
9
V1 = 5V
V2 = 3V
T
= 25°C
T
= 25°C
A
A
125°C
V
= 0.4V
OL
85°C
100m
10m
1m
25°C
V
= 0.2V
OL
6
3
0
–40°C
100μ
10μ
10p
100p
1n
C
10n
(F)
100n
1μ
0
2
6
8
10
0
1
2
3
4
5
4
I
(mA)
V1 OR V2 (V)
RT
SINK
2932 G10
2932 G11
2932 G12
COMPn Propagation Delay vs
Input Overdrive Above Threshold
COMPn Pull-Up Current vs V2
RST Pull-Up Current vs V2
18
15
250
200
150
100
50
18
15
12
9
T
= 25°C
T
= 25°C
T = 25°C
A
A
A
COMPn = GND
12
9
V1, V2
V
6
3
0
6
RT33
3.0
V
RT30
V3, V4, V5, V6
100
V
3
RT25
0
0
1
2
3
4
5
1000
2.0
2.5
3.5
4.0
4.5
5.0
10
V2 (V)
V2 (V)
INPUT OVERDRIVE ABOVE THRESHOLD (mV)
2932 G14
2932 G13
2932 G15
2932fb
6
LTC2932
PIN FUNCTIONS
COMP5 (Pin 1): Comparator Output 5. Real-time logic
output with weak 6μA pull-up to V2. Pulls high when V5
is above reset threshold. May be pulled greater than V2
using external pull-up. Leave open if unused.
RDIS (Pin 10): Digital Input for RST Disable. A low input
on this pin forces RST to V2 (or to the pull-up voltage).
Useful for determining supply margins without issuing a
reset. A weak internal pull-up allows pin to be left open
for normal monitor operation.
V5 (Pin 2): Adjustable Voltage Input 5. High impedance
comparator input with 0.5V typical threshold. See
Applications Information for details. Tie to V1 if unused.
T1 (Pin 11): Supply Tolerance Selection Input. Used in
conjunction with T0 (Pin 9). See Applications Information
for tolerance selection chart (Table 2). Choose from 5%,
7.5%, 10% or 12.5%.
COMP3 (Pin 3): Comparator Output 3. Real-time logic
output with weak 6μA pull-up to V2. Pulls high when V3
is above reset threshold. May be pulled greater than V2
using external pull-up. Leave open if unused.
GND (Pin 12): Ground.
VPG (Pin 13): Threshold Select Input. Connect to an
external 1% resistive divider between VREF and GND to
select 1 of 16 combinations and/or adjustable voltage
thresholds (see Table 1). Do not add capacitance on the
VPG pin.
COMP1 (Pin 4): Comparator Output 1. Real-time logic
output with weak 6μA pull-up to V2. Pulls high when V1
is above reset threshold. May be pulled greater than V2
using external pull-up. Leave open if unused.
V3 (Pin 5): Voltage Input 3. Select from 2.5V, 1.8V, 1.5V,
or ADJ. See Applications Information for details. Tie to
V1 if unused.
VREF (Pin 14): Buffered Reference Voltage Output. A
1.210V nominal reference used for the mode selection
voltage (V ) and for the offset of negative adjustable
PG
applications. The buffered reference can source and sink
up to 1mA. The reference can drive a bypass capacitor of
up to 1000pF without oscillation.
V1 (Pin 6): Voltage Input 1. Select from 5V or 3.3V. See
Applications Information for details. The greater of V1 or
V2 is also V for the device. Bypass this pin to ground
CC
with a 0.1μF (or greater) capacitor.
V4 (Pin 15): Voltage Input 4. Select from 1.8V, 1.5V, ADJ
or –ADJ. See Applications Information for details. Tie to
V1 if unused and configured for positive voltage.
CRT (Pin 7): Reset Timeout Capacitor. Attach an external
capacitor (C ) to GND to set a reset timeout of 2ms/nF.
RT
Leaving the pin open generates a minimum delay of
approximately 25μs. A 47nF capacitor generates a 94ms
reset delay time.
V2 (Pin 16): Voltage Input 2. Select from 3.3V, 3V or 2.5V.
SeeApplicationsInformationfordetails.ThegreaterofV1,
V2 is also V for the device. Bypass this pin to ground
CC
with a 0.1μF (or greater) capacitor. All status outputs are
RST (Pin 8): Reset Output. Logic output with weak 6μA
pull-up to V2. Pulls low when any voltage input is below
the reset threshold and held low for the configured delay
time after all voltage inputs are above threshold. May be
pulled greater than V2 using external pull-up. Leave open
if unused.
weakly pulled up to V2.
COMP4 (Pin 17): Comparator Output 4. Real-time logic
output with weak 6μA pull-up to V2. Pulls high when V4
is above reset threshold. May be pulled greater than V2
using external pull-up. Leave open if unused.
T0 (Pin 9): Supply Tolerance Selection Input. Used in
conjunction with T1 (Pin 11). See Applications Informa-
tion for tolerance selection chart (Table 2). Choose from
5%, 7.5%, 10% or 12.5%.
COMP2 (Pin 18): Comparator Output 2. Real-time logic
output with weak 6μA pull-up to V2. Pulls high when V2
is above reset threshold. May be pulled greater than V2
using external pull-up. Leave open if unused.
2932fb
7
LTC2932
PIN FUNCTIONS
V6 (Pin 19): Adjustable Voltage Input 6. High impedance
comparator input with 0.5V typical threshold. See
Applications Information for details. Tie to V1 if unused.
COMP6 (Pin 20): Comparator Output 6. Real-time logic
output with weak 6μA pull-up to V2. Pulls high when V6
is above reset threshold. May be pulled greater than V2
using external pull-up. Leave open if unused.
BLOCK DIAGRAM
T0
V1
9
BUFFER GAIN
ADJUST
T1
11
POWER
DETECT
V
CC
BUFFER
V2
VREF
14
6μA
μA
6μA
V2
BANDGAP
REFERENCE
V
RTA
COMP1
4
VPG
13
A/D
4
COMP2
18
COMP3
3
μA
V1
6
COMP4
17
V2
16
–
V2
4
4
RESISTIVE
DIVIDER
MATRIX
4
6μA
CMP1-4
V3
5
+
V2
COMP5
1
V4
15
6μA
V5
2
–
+
COMP6
20
V2
CMP5
6μA
V
RTA
RST
8
4
ADJUSTABLE
RESET PULSE
GENERATOR
+
–
CMP6
V6
19
2μA
V
CC
22μA
CRT
7
10μA
RDIS
10
V
CC
C
RT
2932 BD
GND
12
2932fb
8
LTC2932
APPLICATIONS INFORMATION
Supply Monitoring
NOMINAL
SUPPLY
VOLTAGE
5V
SUPPLY TOLERANCE
The LTC2932 is a low power, high accuracy configurable
six supply monitoring circuit with six real-time monitor
outputs, a common reset output, a reset disable function
and selectable supply thresholds. An external capacitor
sets the reset timeout period. An external resistive divider
betweenVREF, VPGandGNDselects1of16possibleinput
voltage monitor combinations. All six voltage inputs must
beabovetheirpredeterminedthresholdsfortheresetnotto
be activated. The LTC2932 asserts the reset and compara-
tor outputs during power-up, power-down and brownout
conditions on any one of the voltage inputs.
MINIMUM
RELIABLE
SYSTEM
IDEAL
SUPERVISOR
VOLTAGE
THRESHOLD
4.75V
–5%
1.5%
THRESHOLD 4.675V
BAND
–6.5%
4.6V
–8%
REGION OF POTENTIAL MALFUNCTION
Power-Up
Figure 1. 1.5ꢁ Threshold Accuracy Improves System Reliability
The greater of V1 and V2 serves as the internal supply
The LTC2932 has a 1.5% reset threshold accuracy, so a
“5%” threshold is typically set to 6.5% below the nominal
input voltage. Therefore, a typical 5V, “5%” threshold is
4.675V. The threshold is guaranteed to lie in the band be-
tween4.750Vand4.600Vovertemperature.Thepowered
system must work reliably down to the low end of the
threshold band, or risk malfunction before a reset signal
is properly issued.
voltage (V ). On power-up, V powers the drive circuits
CC
CC
for the RST pin. This ensures that the RST output will be
low as soon as either V1 or V2 reaches 1V. The RST output
remains low until the part is configured. Once the voltage
thresholds are set, if any of the supply monitor inputs is
below its configured threshold, RST will be a logic low.
Once all the monitor inputs rise above their thresholds,
an internal timer is started and RST is released after the
delay time. If V < (V3 – 1.0V) and V < 2.4V, the V3
CC
CC
A less accurate supervisor increases the required system
voltage margin and increases the probability of system
malfunction.TheLTC2932’s 1.5%specificationimproves
the reliability of the system over supervisors with wider
threshold tolerances.
input impedance will be low (10kΩ typical).
Threshold Accuracy
Consider a 5V system with 5% tolerance. The 5V supply
may vary between 4.75V to 5.25V. System ICs powered by
thissupplymustoperatereliablywithinthisband(andalittle
moreasexplainedbelow). Aperfectlyaccuratesupervisor
for this supply generates a reset at exactly 4.75V, however
no supervisor is this perfect. The actual reset threshold
of a supervisor varies over a specified band; the LTC2932
varies 1.5% around its nominal threshold voltage (see
Figure 1) over temperature.
Monitor Configuration and Tolerance Selection
Select the LTC2932 input voltage combination by placing
therecommendedresistivedividerfromVREFtoGNDand
connecting the tap point to VPG, as shown in Figure 2.
Table 1 offers recommended 1% resistor values for each
of the 16 modes. The last column in Table 1 specifies
optimum V /V ratios ( 0.01), when configuring with
PG REF
a ratiometric DAC.
The reset threshold band and the power supply tolerance
bands should not overlap. This prevents false or nuisance
resets when the power supply is actually within its speci-
fied tolerance band.
R1
1%
LTC2932
VREF
VPG
GND
R2
1%
2932 F02
Figure 2. Mode Selection
2932fb
9
LTC2932
APPLICATIONS INFORMATION
Table 1. Voltage Threshold Modes*
Table 2. Tolerance Selection
V
T0
T1
TOLERANCE (ꢁ)
V
(V)
REF
PG
V
REF
MODE V1 (V) V2 (V) V3 (V) V4 (V) R1 (kΩ) R2 (kΩ)
Low
Low
High
High
Low
High
Low
High
5
1.210
1.178
1.146
1.113
0
1
5
5
3.3
3.3
2.5
2.5
2.5
3.3
3.3
3.3
3
ADJ
ADJ
ADJ
ADJ
1.5
2.5
2.5
2.5
2.5
ADJ
1.8
1.8
1.8
1.8
1.8
1.8
ADJ
–ADJ
ADJ
–ADJ
ADJ
ADJ
1.8
Open
93.1
86.6
78.7
71.5
66.5
59
Short
9.53
16.2
22.1
28
0.000
0.094
0.156
0.219
0.281
0.344
0.406
0.469
0.531
0.594
0.656
0.719
0.781
0.844
0.906
1
7.5
10
2
3.3
3.3
3.3
5
12.5
3
Table 3. Suggested 1ꢁ Resistor Values for the ADJ Inputs
4
5
34.8
40.2
47.5
53.6
59
V
(V)
V
(V)
R3 (kΩ)
2150
1780
1400
1300
1020
845
R4 (kΩ)
100
100
100
100
100
100
100
100
100
100
100
100
100
100
SUPPLY
TRIP
12
11.25
9.4
6
5
10
8
7
5
1.5
53.6
47.5
40.2
34.8
28
7.5
8
5
ADJ
ADJ
1.5
7.5
6
7
9
5
3
5.6
10
11
12
13
14
15
3.3
3.3
3.3
5
2.5
2.5
2.5
3.3
3.3
3
66.5
71.5
78.7
86.6
93.1
Open
5
4.725
3.055
2.82
2.325
1.685
1.410
1.120
0.933
0.840
ADJ
–ADJ
–ADJ
ADJ
ADJ
3.3
3
511
22.1
16.2
9.53
Short
464
2.5
1.8
1.5
1.2
1
365
5
237
5
182
*V5 and V6 are always adjustable (ADJ).
124
At power-up, once V1 or V2 reaches 2.4V, the monitor
enters a setup period of approximately 150μs. During the
setup time, the voltage on the VPG pin is sampled and the
monitorisconfiguredtothedesiredinputcombination.The
comparators are enabled and supply monitoring begins.
Do not add capacitance to the VPG pin.
86.6
68.1
0.9
*See Figure 3.
Table 4. Suggested 1ꢁ Resistor Values for the –ADJ Inputs
V
(V)
V
(V)
R3 (kΩ)
187
R4 (kΩ)
121
SUPPLY
TRIP
–2
–1.87
–4.64
–4.87
–9.31
–11.30
The two supply tolerance inputs, T0 and T1, configure the
global supply tolerance. Larger tolerances provide more
headroom by lowering the trip thresholds. Table 2 lists the
input combinations for each of the tolerance modes.
–5
464
121
–5.2
–10
–12
487
121
931
121
1130
121
*See Figure 4.
V
TRIP
LTC2932
R3
1%
LTC2932
VREF
V4
V3, V4, V5 OR V6
R4
1%
R4
1%
R3
1%
0.5V
+
–
5% TOLERANCE MODE
V
TRIP
2932 F03
2932 F04
Figure 3. Setting the Positive Adꢀustable Trip Point
Figure 4. Setting the Negative Adꢀustable Trip Point
2932fb
10
LTC2932
APPLICATIONS INFORMATION
Using the Adꢀustable Thresholds
Although all six supply monitor comparators have built-
in glitch immunity, bypass capacitors on V1 and V2 are
recommended because the greater of V1 or V2 is also the
The reference inputs on the V3 and/or V4 comparators
are set to 0.5V when the positive adjustable modes are
selected (Figure 3). The reference inputs on the V5 and V6
comparators are always set to 0.5V. The tap point on an
external resistive divider, connected between the positive
voltage being sensed and ground, is connected to the high
impedance, adjustable inputs (V3, V4, V5, V6). Calculate
the trip voltage from:
V
for the device. Filter capacitors on the V3, V4, V5 and
CC
V6 inputs are allowed.
Power-Down
On power-down, once any of the monitor inputs drops
below its threshold, RST is held at a logic low. A logic low
of 0.4V is guaranteed until both V1 and V2 drop below
R3
R4
ꢀ
ꢁ
ꢃ
ꢄ
1V. If the bandgap reference becomes invalid (V < 2V
VTRIP = 0.5V • 1+
CC
ꢂ
ꢅ
typical), the LTC2932 will enter the 150μs setup period
when V rises above 2.4V (max).
CC
In the negative adjustable mode, the reference level on the
V4 comparator is connected to ground (Figure 4). The tap
point on an external resistive divider, connected between
the negative voltage being sensed and the VREF pin, is
connected to the high impedance adjustable input (V4).
Selecting the Reset Timing Capacitor
The reset timeout period is adjustable in order to
accommodate a variety of microprocessor applications.
The reset timeout period, t , is adjusted by connecting
RST
V
provides the necessary level shift required to operate
REF
a capacitor, C , between the CRT pin and ground. The
RT
at ground. The negative trip voltage is calculated from:
value of this capacitor is determined by:
R3
R4
; V = 1.210V Nominal
REF
VTRIP = −VREF
•
tRST
2MΩ
CRT =
= 500 pF /ms • t
RST
[
]
T0, T1 Low (5% Tolerance Mode)
Leaving the CRT pin unconnected generates a minimum
reset timeout of approximately 25μs. Maximum reset
timeout is limited by the largest available low leakage
capacitor. The accuracy of the timeout period is affected
bycapacitorleakage(thenominalchargingcurrentis2μA)
and capacitor tolerance. A low leakage ceramic capacitor
is recommended.
Once the resistor divider is set in the 5% tolerance mode,
there is no need to change the divider for the other toler-
ance modes (7.5%, 10%, 12.5%) because V is scaled
REF
accordingly, moving the trip point in –2.5% increments.
Inanegativeadjustableapplication,theminimumvaluefor
R4 is limited by the sourcing capability of VREF ( 1mA).
With no other load on VREF, R4 (minimum) is:
Reset Disable
1.210V
=1.210kΩ
1mA
Underconventionaloperation,RSTandCOMP willgolow
n
when V is below its threshold. At any time, the RDIS pin
n
canbepulledlow,overridingtheresetoperationandforcing
the RST pin high. This feature is useful when determining
supply margins under processor control since the reset
command will not be invoked. The RDIS pin is connected
Tables 3 and 4 offer suggested 1% resistor values for vari-
ous positive and negative supply adjustable applications
assuming 5% monitor thresholds.
to a weak internal pull-up to V (10μA typical), allowing
CC
the pin to be left open if unused.
2932fb
11
LTC2932
APPLICATIONS INFORMATION
Six Supply Monitor with Hysteresis
The LTC2932 is configured to mode 13 and a 12.5%
threshold (see Tables 1 and 2). When the threshold is
reached on V1, COMP1 pulls high. COMP1 then enables
the 3.3V converter first. When the threshold is reached
on V2, COMP2 pulls high and enables the 1.8V converter
next. When all the converters have been enabled and are
good, COMP5 pulls high. RST pulls high 9.4ms after
COMP5. Figure 7 shows the power-up sequence of the
five supplies and the DONE and RST outputs.
TheLTC2932monitorssixsupplyvoltagesinFigure5and
is configured to mode 6 (see Table 1). Supply tolerance
inputs T0 and T1 are tied to RST. As the LTC2932 powers
up, RST is low, which keeps the tolerance at 5%. After all
six inputs exceed their 5% threshold voltages, RST pulls
high.Thischangesthesupplytoleranceto12.5%.Ifanyof
the input voltages drop below the 12.5% threshold level,
reset is asserted. The push button on V6 also allows for
a manual reset when pressed.
If the KILL input on the LTC2950-1 does not receive a logic
highfromtheRSToutputwithin512msofinitialpower-up,
EN pulls low and the LTM4600 is powered down.
Five Supply Power-up Sequencer
In Figure 6, the LTC2932’s real-time COMP outputs are
usedtoenableDC/DCconverterssequentially.Thesystem
is powered by a 12V source.
In the event that the external 12V supply drops below 9.6V,
COMP6 and RST pull low. The LTC2950-1 then receives
a logic low on the KILL input, which powers down the
LTM4600 and the sequencing circuit.
Thesystemisstartedwhenthepush-buttonispressedand
the LTC2950-1 brings the RUN pin of the LTM4600 high.
Subsequently, the LTM4600 generates a 5V output which
applies power to each of the 4 DC/DC converters.
5V
10k 10k 10k 10k 10k 10k 10k
0.1μF
LTC2932
V1
V2
V3
V4
V5
V6
COMP1
COMP2
COMP3
3.3V
2.5V
1.8V
12V
SYSTEM
LOGIC
COMP4
2150k 1%
COMP5
124k 1%
1.2V
COMP6
VREF
RST
R1
59k
1%
T0
2932 F05
T1
VPG
GND CRT
RDIS
10k*
C
RT
47nF
R2
40.2k
1%
100k
1%
100k
1%
PUSHBUTTON
t
= 94ms
*OPTIONAL FOR EXTENDED ESD TOLERANCE
RST
Figure 5. Six Supply Monitor with Hysteresis
5ꢁ Tolerance (Supplies Rising)
12.5ꢁ Tolerance (After RST Goes High)
2932fb
12
LTC2932
APPLICATIONS INFORMATION
12V (9.6V THRESHOLD)
LTM4600
V
IN
5V
5V
V
OUT
10k
10k
LT3028
RUN
3.3V
3.3V
1.8V
–5.2V
2.5V
V
V
V
V
V
IN
OUT
OUT
SHDN
10k
10k
10k
10k
LT3028
1.8V
EN
V
IN
LTC2950-1
SYSTEM
LOGIC
SHDN
V
INT
IN
PB
KILL
LTC3704
–5.2V
V
IN
OUT
RUN/UVLO
LT3028
2.5V
V
IN
OUT
SHDN
DONE
12V
SUPPLY
STATUS
COMP1 COMP2 COMP3 COMP4 COMP5 COMP6
V1
2932 F06
V2
V3
V4
V5
V6
RST
T0
T1
365k
1%
487k
1%
10k
0.1μF
1820k
1%
LTC2932
RDIS
100k
1%
100k
1%
121k
1%
VREF
R1
16.2k
1%
VPG
CRT
4.7nF
GND
t
= 9.4ms
R2
86.6k
1%
RST
Figure 6. Five Supply 12.5ꢁ Tolerance Power-Up Sequencer with Pushbutton
2932fb
13
LTC2932
APPLICATIONS INFORMATION
PB
5V
3.3V
2.5V
1.8V
–5.2V
DONE
RST
2932 FO7
Figure 7. Five Supply Power-Up Sequencing (Based on Circuit in Figure 6)
2932fb
14
LTC2932
PACKAGE DESCRIPTION
F Package
20-Lead Plastic TSSOP (4.4mm)
(Reference LTC DWG # 05-08-1650)
6.40 – 6.60*
(.252 – .260)
1.05 p0.10
4.50 p0.10
20 19 18 17 16 15 14 13 12 11
6.60 p0.10
6.40
(.252)
BSC
0.45 p0.05
RECOMMENDED SOLDER PAD LAYOUT
0.65 BSC
5
7
8
1
2
3
4
6
9 10
1.10
(.0433)
MAX
4.30 – 4.50**
(.169 – .177)
0.25
REF
0o – 8o
0.65
(.0256)
BSC
0.09 – 0.20
0.50 – 0.75
0.05 – 0.15
(.0035 – .0079)
(.020 – .030)
(.002 – .006)
0.19 – 0.30
(.0075 – .0118)
TYP
F20 TSSOP 0204
NOTE:
1. CONTROLLING DIMENSION: MILLIMETERS
3. DRAWING NOT TO SCALE
MILLIMETERS
2. DIMENSIONS ARE IN
(INCHES)
*DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED .152mm (.006") PER SIDE
**DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED .254mm (.010") PER SIDE
2932fb
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LTC2932
TYPICAL APPLICATION
Five Supply Adꢀustable Threshold Monitor with LED Indicators
5V
0.1μF
1k
1k
1k
1k
1k
LTC2932
V1
V2
V3
V4
V5
V6
COMP1
COMP2
COMP3
COMP4
COMP5
COMP6
3.3V
12V
1.2V
1V
2150k 1%
86.6k 1%
124k 1%
2932 TA02
TO SYSTEM RESET
VREF
RST
RDIS
CRT
VPG GND T0
T1
100k
1%
100k
1%
100k
1%
C
RT
47nF
t
= 94ms
RST
RELATED PARTS
PART NUMBER
LTC1326
DESCRIPTION
COMMENTS
Micropower Triple Supply Monitor for 5V/2.5V, 3.3V and ADJ
Micropower Triple Supply Monitor with Open-Drain Reset
Programmable Quad Supply Monitor
4.725V, 3.118V, 1V Threshold ( 0.75%) and ADJ
5-Lead SOT-23 Package
LTC1728
LTC2900
Adjustable Reset, 10-Lead MSOP and DFN Packages
Adjustable Reset and Watchdog Timer
Adjustable Reset and Tolerance (5%, 7.5%, 10%, or 12.5%)
6-Lead SOT-23 Package
LTC2901
Programmable Quad Supply Monitor
LTC2902
Programmable Quad Supply Monitor
LTC2903
Precision Quad Supply Monitor
LTC2904-LTC2907
LTC2908
Three-State Programmable Precision Dual Supply Monitor
Precision Six Supply Monitor (Four Fixed & Two Adjustable)
8-Lead SOT-23 and DFN Packages
8-Lead TSOT-23 and DFN Packages
LTC2909
Precision Triple/Dual Input UV, OV and Negative Voltage Monitor Shunt Regulated V Pin, Adjustable Threshold and Reset,
CC
8-Lead SOT-23 and DFN Packages
LTC2910
Precision Octal Positive/Negative Voltage Supply Monitor
Single/Dual/Quad UV and OV Voltage Monitors
16-Lead SSOP and 5mm × 3mm DFN Packages, H-Grade
Temperature Range
LTC2912-LTC2914
LTC2915-LTC2918
LTC2928
Separate V Pin, Adjustable Reset Timer,
CC
H-Grade Temperature Range
Single Supply Monitor with 27 Pin-Selectable Thresholds
Quad Power Supply Sequencer and Supervisor
Manual Reset, Watchdog, TSOT-8/MSOP-10 and
3mm × 2mm DFN Packages, H-Grade Temperature Range
Easily Configure Power Management without Software,
36-Lead 5mm × 7mm QFN and SSOP Packages
LTC2930
Configurable Six Supply Monitor with Adjustable Reset Timer,
Manual Reset
3mm × 3mm DFN-12 Package, H-Grade Temperature Range
LTC2931
Configurable Six Supply Monitor with Adjustable Reset and
Watchdog Timers
TSSOP-20 Package, H-Grade Temperature Range,
Individual Supply Comparator Outputs
2932fb
LT 0408 REV B • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
16
●
●
© LINEAR TECHNOLOGY CORPORATION 2008
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
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