Linear Technology LTC1728, LTC1727 Datasheet
FEATURES
1
2
3
4
8
7
6
5
LTC1727-2.5
R2
1727/28 TA08
R1
ADJUSTABLE
SUPPLY
3.3V
2.5V
R3
10k
POWER
GOOD
SYSTEM
RESET
R4
10k
V
CC3
V
CC25
V
CCA
GND
COMP3
COMP25
RST
COMPA
■
Monitors Three Inputs Simultaneously
LTC1727-5: 5V, 3.3V and ADJ
LTC1727-2.5: 2.5V, 3.3V and ADJ
LTC1728-5: 5V, 3.3V and ADJ
LTC1728-2.5: 2.5V, 3.3V and ADJ
LTC1728-1.8: 3V, 1.8V and ADJ
■
±1.5% Threshold Accuracy Over Temperature
■
Very Low Supply Current: 10µA Typ
■
200ms Reset Time Delay
■
Active Low RESET Output
■
Power Supply Glitch Immunity
■
Guaranteed RESET for V
or V
■
■
■
CC5/VCC25/VCC18
LTC1727 Includes Monitor Output for Each Supply
LTC1727: 8-Lead MSOP and SO Packages
LTC1728: 5-Lead SOT-23 Package
≥ 1V
CC3
≥ 1V
U
APPLICATIO S
LTC1727/LTC1728
Micropower Precision
Triple Supply Monitors
in 8-Lead MSOP and
5-Lead SOT-23 Packages
U
DESCRIPTIO
The LTC®1727 is a triple supply monitor intended for
systems with multiple supply voltages. Each supply monitor has its own open-drain output for individual supply
monitoring. A common open-drain reset output remains
low until all three supplies have been in compliance for
200ms. Tight 1.5% accuracy specifications and glitch
immunity ensure reliable reset operation without false
triggering.
The LTC1728 is functionally identical to the LTC1727
without the individual monitor outputs.
The RST output is guaranteed to be in the correct state for
V
CC5/VCC25/VCC18
LTC1728 may also be configured to monitor any one or
two VCC inputs instead of three, depending on system
requirements.
Very low (10µA typical) supply current makes the LTC1727/
LTC1728 ideal for power conscious systems.
or V
down to 1V. The LTC1727/
CC3
■
Desktop Computers
■
Notebook Computers
■
Intelligent Instruments
■
Portable Battery-Powered Equipment
■
Network Servers
TYPICAL APPLICATIO
3.3V
5V
1.8V
51
V
4
V
R1
61.9k
1%
R2
100k
1%
3
V
0.1µF
0.1µF
DC/DC
CONVERTER
U
CC3
LTC1728-5
CC5
CCA
RST
GND
1727/28 TA01
SYSTEM
LOGIC
2
The LTC1727 is available in an 8-lead MSOP or SO
package and the LTC1728 is available in a 5-lead SOT-23
package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Triple Supply Monitor with Power Good Output
(3.3V, 2.5V and Adjustable)
1
LTC1727/LTC1728
A
V
O
LUTEXI TIS
S
, V
CC3
CC5/VCC25/VCC18
W
A
, V
WUW
ARB
................... –0.3V to 7V
CCA
U
G
(Notes 1, 2)
RST ........................................................... –0.3V to 7V
COMPA, COMP3, COMP25/COMP5
(MS8 and SO-8 Only) ............................ –0.3V to 7V
WU
/
PACKAGE
V
CC3
V
CC5/VCC25
V
CCA
GND
T
JMAX
ORDER
PART NUMBER
O
RDER I FOR ATIO
TOP VIEW
1
2
3
4
MS8 PACKAGE
8-LEAD PLASTIC MSOP
= 125°C, θ
= 200°C/W
JA
PART MARKING
8
COMP3
7
COMP25/COMP5
6
RST
5
COMPA
MS8
TOP VIEW
1
V
CC3
V
/
CC5
2
V
CC25
V
3
CCA
GND
4
S8 PACKAGE
8-LEAD PLASTIC SO
T
= 125°C, θ
JMAX
ORDER
PART NUMBER
Operating Temperature Range
(Note 3) ............................................. –40°C to 85°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................ 300°C
U
8
COMP3
COMP25/
7
COMP5
RST
6
COMPA
5
= 150°C/W
JA
S8
PART MARKING
RST 1
GND 2
V
ORDER
PART NUMBER
TOP VIEW
3
CCA
S5 PACKAGE
5-LEAD PLASTIC SOT-23
T
= 125°C, θ
JMAX
JA
PART MARKING
5 V
4
= 250°C/W
V
V
V
CC3
CC5
CC25
CC18
S5
/
/
LTC1727EMS8-2.5
LTC1727EMS8-5
LTHY
LTHX
LTC1727ES8-2.5
LTC1727IS8-2.5
LTC1727ES8-5
LTC1727IS8-5
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
full operating temperature range, otherwise specifications are at TA = 25°C. V
All except LTC1728-1.8. The ● denotes specifications which apply over the
172725
727I25
17275
1727I5
= 3.3V, V
CC3
LTC1728ES5-1.8
LTC1728ES5-2.5
LTC1728ES5-5
CC5
= 5V, V
= 2.5V, V
CC25
CCA
LTPH
LTIA
LTHZ
= V
CC3
unless
otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
RT3
V
RT5
V
RT25
V
RTA
V
CCOP
V
CCOPA
I
VCC3
I
VCC25
I
VCC5
I
VCCA
t
RST
Reset Threshold V
Reset Threshold V
Reset Threshold V
Reset Threshold V
V
, V
CC3
CC5/VCC25
V
, V
CC3
CC5/VCC25
V
Supply Current V
CC3
V
Supply Current V
CC25
V
Supply Current V
CC5
V
Input Current V
CCA
Reset Pulse Width RST Low with 10k Pull-Up to V
CC3
CC5
CC25
CCA
Operating Voltage RST, COMP3, COMP5, COMP25 in Correct Logic State ● 17V
Operating Voltage Minimum Supply Voltage to Guarantee COMPA ● 2 2.3 V
V
Input Threshold ● 3.036 3.086 3.135 V
CC3
V
Input Threshold (5V Version) ● 4.600 4.675 4.750 V
CC5
V
Input Threshold (2.5V Version) ● 2.300 2.338 2.375 V
CC25
V
Input Threshold ● 0.985 1.000 1.015 V
CCA
in Correct Logic State
CC5/VCC25
V
CC5/VCC25
CC25
CC5
CCA
> V
CC3
< V
, V
CC3
< V
, V
CC3
= 5V, V
CC3
= 1V ● –15 0 15 nA
= 3.3V (Note 4) ● 10 20 µA
CC3
= 2.5V (Note 4) ● 12 µA
CC25
< V
CC5
● 12 µA
● 10 20 µA
(Note 5) ● 140 200 280 ms
CC3
2
LTC1727/LTC1728
ELECTRICAL CHARACTERISTICS
full operating temperature range, otherwise specifications are at TA = 25°C. V
All except LTC1728-1.8. The ● denotes specifications which apply over the
= 3.3V, V
CC3
CC5
= 5V, V
= 2.5V, V
CC25
CCA
= V
CC3
unless
otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
UV
V
OL
V
OH
VCC Undervoltage Detect to RST V
CC5
, V
CC25
or COMPX Threshold V
Output Voltage Low, RST, COMPX I
Output Voltage High, RST, COMPX (Note 6) I
= 2.5mA, V
SINK
= 100µA, V
I
SINK
= 100µA, V
I
SINK
I
= 100µA, V
SINK
= 1µA ● V
SOURCE
, V
or V
CC3
by More Than 1% (Note 5)
RT
CC3
CC3
CC3
CC3
Less Than Reset 110 µs
CCA
= 3V, V
CC5/VCC25
= 1V, V
CC5/VCC25
= 0V, V
CC5/VCC25
= 1V, V
CC5/VCC25
= 0V ● 0.15 0.4 V
= 0V ● 0.05 0.3 V
= 1V ● 0.05 0.3 V
= 1V ● 0.05 0.3 V
– 1 V
CC3
LTC1727-5/LTC1728-5 Only
V
OVR
V
Reset Override Voltage (Note 7) Override V
CC5
Ability to Assert RST V
CC5
±0.025 V
CC3
LTC1728-1.8 The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at
TA = 25°C. V
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
RT3
V
RT18
V
RTA
V
CCOP
I
VCC3
I
VCC18
I
VCCA
t
RST
t
UV
V
OL
V
OH
= 3V, V
CC3
Reset Threshold V
Reset Threshold V
Reset Threshold V
V
, V
CC3
CC18
V
Supply Current V
CC3
V
Supply Current V
CC18
V
Input Current V
CCA
= 1.8V, V
CC18
CC3
CC18
CCA
CCA
= V
unless otherwise noted.
CC3
V
Input Threshold ● 2.760 2.805 2.850 V
CC3
V
Input Threshold ● 1.656 1.683 1.710 V
CC18
V
Input Threshold ● 0.985 1.000 1.015 V
CCA
Operating Voltage RST in Correct Logic State ● 17V
> V
CC18
V
CC3
< V
, V
CC18
CC3
< V
CC18
CC3
= 1V ● –15 0 15 nA
CCA
= 3V (Note 4) ● 10 20 µA
CC3
, V
= 1.8V (Note 4) ● 12 µA
CC18
● 12 µA
Reset Pulse Width RST Low (Note 5) ● 140 200 280 ms
VCC Undervoltage Detect to RST V
Output Voltage Low, RST I
Output Voltage High, RST I
, V
or V
CC18
CC3
Threshold V
= 2.5mA, V
SINK
I
= 100µA, V
SINK
= 100µA, V
I
SINK
= 100µA, V
I
SINK
= 1µA (Note 6) ● V
SOURCE
Less Than Reset (Note 5) 110 µs
CCA
by More Than 1%
RT
CC3
CC3
CC3
CC3
= 3V, V
= 1V, V
= 0V, V
= 1V, V
= 0V ● 0.15 0.4 V
CC18
= 0V ● 0.05 0.3 V
CC18
= 1V ● 0.05 0.3 V
CC18
= 1V ● 0.05 0.3 V
CC18
– 1 V
CC3
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: All voltage values are with respect to GND.
Note 3: The LTC1727E/LTC1728E are guaranteed to meet specified
performance from 0°C to 70°C and are designed, characterized and
assured to meet the extended temperature limits of –40°C to 85°C
but are not tested at these temperatures.
Note 4: Both V
CC3
and V
CC5/VCC25/VCC18
can act as the supply depending
on which pin has the greatest potential.
Note 5: Measured from when input passes through the input threshold
) until RST or COMPX passes through 1.5V.
(V
RTX
Note 6: The output pins RST and COMPX have internal pull-ups to V
CC3
of
typically 6µA. However, external pull-up resistors may be used when faster
rise times are required or for VOH voltages greater than V
Note 7: The V
reset override voltage is valid for an operating range less
CC5
CC3
.
than approximately 4.15V. Above this point the override is turned off and
the V
pin functions normally.
CC5
3
LTC1727/LTC1728
TEMPERATURE (°C)
–60
0.5
I
VCC25
(µA)
0.6
0.8
0.9
1.0
1.5
1.2
–20
20
40
1727/28 G06
0.7
1.3
1.4
1.1
–40 0
60
80
100
V
CC3
= 3.3V
V
CC25
= 2.5V
V
CCA
= 3.3V
TEMPERATURE (°C)
–60
5
I
VCC5
(µA)
6
8
9
10
15
12
–20
20
40
1727/28 G09
7
13
14
11
–40 0
60
80
100
V
CC5
= 5V
V
CC3
= 3.3V
V
CCA
= 3.3V
UW
TYPICAL PERFOR A CE CHARACTERISTICS
V
V
Input Current
CCA
vs Input Voltage
2.0
TA = 25°C
1.5
1.0
0.5
0
–0.5
INPUT CURRENT (nA)
–1.0
–1.5
–2.0
0.80 0.85 0.95 1.05 1.15
0.90
1
INPUT VOLTAGE (V)
1.10
1727/28 G01
1.015
(V)
1.010
RTA
1.005
1.000
0.995
THRESHOLD VOLTAGE, V
0.990
CCA
V
0.985
1.20
Threshold Voltage
CCA
vs Temperature
–40 0
–60
–20 20
TEMPERATURE (°C)
40
60
80
1727/28 G02
100
Typical Transient Duration
vs Comparator Overdrive
450
400
350
300
250
200
150
100
TYPICAL TRANSIENT DIRATION (µs)
50
0
0.1
RESET COMPARATOR OVERDRIVE VOLTAGE (% OF VCC)
RESET OCCURS
ABOVE CURVE
1 10 100
TA = 25°C
1727/28 G03
280
260
(ms)
240
RST
220
200
180
RESET PULSE WIDTH, t
160
140
–60 –40
15
14
13
12
11
(µA)
10
VCC3
I
9
8
7
6
5
4
–60
Reset Pulse Width
vs Temperature
–20 20 40 800 100
TEMPERATURE (°C)
I
vs Temperature
VCC3
60
(LTC1727-2.5/LT1728-2.5)
V
= 3.3V
CC3
V
= 2.5V
CC25
V
= 3.3V
CCA
–40 0
–20
TEMPERATURE (°C)
20
40
60
1727/28 G04
80
1727/28 G07
100
RST, COMPX I
vs Supply Voltage
10
TA = 25°C
9
8
7
6
(mA)
5
SINK
I
4
3
2
1
0
1
0
I
VCC3
2
V
CC3
vs Temperature
(LTC1727-5/LTC1728-5)
1.5
V
= 5V
CC5
1.4
V
= 3.3V
CC3
V
= 3.3V
CCA
1.3
1.2
1.1
(µA)
1.0
VCC3
I
0.9
0.8
0.7
0.6
0.5
–60
–40 0
–20
TEMPERATURE (°C)
SINK
VOL = 0.2V
34
OR V
(V)
CC5
20
40
VOL = 0.4V
60
5
1727/28 G05
80
1727/28 G08
100
I
vs Temperature
VCC25
(LTC1727-2.5/LT1728-2.5)
6
I
vs Temperature
VCC5
(LTC1727-5/LTC1728-5)
UW
TEMPERATURE (°C)
–60
V
CC5
THESHOLD VOLTAGE, V
RT5
(V)
4.675
4.700
4.750
4.725
0 40 100
1727/28 G12
4.650
4.625
4.600
–40 –20
20
60 80
TYPICAL PERFOR A CE CHARACTERISTICS
V
V
Threshold Voltage
CC25
vs Temperature
(LTC1727-2.5/LTC1728-2.5)
2.3750
2.3675
(V)
2.3600
RT25
2.3525
2.3450
2.3375
2.3300
2.3225
THRESHOLD VOLTAGE, V
2.3150
CC25
2.3075
V
2.3000
–60
–20
–40 0
TEMPERATURE (°C)
1.5
1.4
1.3
1.2
1.1
(µA)
1.0
VCC18
0.9
I
0.8
0.7
0.5
20
40
I
vs Temperature
VCC18
(LTC1728-1.8)
V
= 3V
CC3
= 1.8V
V
CC18
= 3V
V
CCA
0.6
–60
–40 0
80
60
–20
100
1727/28 G10
20
TEMPERATURE (°C)
3.135
3.125
(V)
3.115
RT3
3.105
3.095
3.085
3.075
3.065
THRESHOLD VOLTAGE, V
3.055
CC3
V
3.045
3.035
60
40
Threshold Voltage
CC3
vs Temperature
(All But LTC1728-1.8)
–60
–40 0
80
1727/28 G13
–20
100
20
TEMPERATURE (°C)
40
(µA)
VCC3
I
60
15
14
13
12
11
10
9
8
7
6
5
–60
80
100
1727/28 G11
I
vs Temperature
VCC3
(LTC1728-1.8)
V
= 3V
CC3
= 1.8V
V
CC18
= 3V
V
CCA
–40 0
–20
TEMPERATURE (°C)
LTC1727/LTC1728
V
Threshold Voltage
CC5
vs Temperature
(LTC1727-5/LTC1728-5)
80
20
60
40
100
1727/28 G14
V
CC18
vs Temperature (LTC1728-1.8)
1.710
(V)
1.700
RT18
1.690
1.680
1.670
THRESHOLD VOLTAGE, V
1.660
CC18
V
1.650
–60
–40 0
Threshold Voltage
–20 20
TEMPERATURE (°C)
40
V
Threshold Voltage
CC3
vs Temperature (LTC1728-1.8)
2.845
2.835
(V)
RT3
2.825
2.815
2.805
2.795
2.785
THRESHOLD VOLTAGE, V
CC3
2.775
V
60
80
100
1727/28 G15
2.765
–60
–40 0
–20
20
TEMPERATURE (°C)
40
100
1727/28 G16
80
60
5
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