LTC1326IMS8#TR [ADI]
Power Supply Support Circuit, Fixed, 3 Channel, CMOS, PDSO8;
| 型号： | LTC1326IMS8#TR |
| 厂家： | 
ADI |
| 描述： | Power Supply Support Circuit, Fixed, 3 Channel, CMOS, PDSO8 输入元件 光电二极管 |
| 文件： | 总16页 (文件大小：207K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC1326/LTC1326-2.5
Micropower Precision
Triple Supply Monitors
U
FEATURES
DESCRIPTIO
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.
■
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
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.
■
Internal Reset Time Delay: 200ms
■
Manual Push-Button Reset Input
■
Active Low and Active High Reset Outputs
■
Active Low “Soft” Reset Output
■
■
The RST output is guaranteed to be in the correct state for
CC3,VCC5orVCC25downto1V.TheLTC1326/LTC1326-2.5
can be configured to monitor one, two or three inputs,
depending on system requirements.
Power Supply Glitch Immunity
Guaranteed RESET for VCC3 ≥ 1V or VCC5 ≥ 1V
or VCC25 ≥ 1V
V
■
8-Pin SO and MSOP Packages
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.
U
APPLICATIO S
■
Desktop Computers
■
Notebook Computers
■
Intelligent Instruments
, 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.
■
Portable Battery-Powered Equipment
U
TYPICAL APPLICATIO
RST Output Voltage vs Supply Voltage (LTC1326-2.5)
2.5V
3.5
3.3V
V
V
= V
= V
CCA CC3
DC/DC
CONVERTER
SYSTEM
LOGIC
CC25
3.0
4.7k PULL-UP FROM RST TO V
CORE
CC3
T
= 25°C
A
2.5
2.0
1.5
1.0
0.5
0.1µF
V
V
V
CC25 CC3 CCA
LTC1326-2.5
RST
0
PBR
SRST
GND
2.0
(V)
3.0
3.5
0
0.5
1.0 1.5
2.5
PUSH-BUTTON
RESET
V
CC3
1326/2.5 TA02
1326/2.5 TA01
132625fc
1
LTC1326/LTC1326-2.5
W W W
U
(Notes 1, 2)
ABSOLUTE AXI U RATI GS
Terminal Voltage
Operating Temperature Range
VCC3, VCC5, VCC25, VCCA ......................... –0.5V to 7V
RST, SRST ............................................ –0.5V to 7V
RST ...................................... –0.5V to (VCC3 + 0.3V)
PBR .......................................................... –7V to 7V
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
W U
/O
PACKAGE RDER I FOR ATIO
TOP VIEW
TOP VIEW
1
2
3
4
8
7
6
5
V
V
PBR
SRST
RST
RST
CC3
CC5
CCA
V
V
V
1
2
3
4
8 PBR
7 SRST
6 RST
5 RST
CC3
CC5
CCA
V
GND
GND
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 125°C, θJA = 250°C/W
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 125°C, θJA = 150°C/W
ORDER PART NUMBER
MS8 PART NUMBER
ORDER PART NUMBER
S8 PART NUMBER
LTBA
LTUH
LTC1326CS8
LTC1326IS8
1326
1326I
LTC1326CMS8
LTC1326IMS8
TOP VIEW
TOP VIEW
1
2
3
4
8
7
6
5
V
PBR
SRST
RST
RST
CC3
V
1
2
3
4
8 PBR
7 SRST
6 RST
5 RST
CC3
V
CC25
V
V
CC25
CCA
V
CCA
GND
GND
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 125°C, θJA = 250°C/W
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 125°C, θJA = 150°C/W
ORDER PART NUMBER
MS8 PART NUMBER
ORDER PART NUMBER
S8 PART NUMBER
LTC1326CMS8-2.5
LTC1326IMS8-2.5
132625
326I25
LTEK
LTUJ
LTC1326CS8-2.5
LTC1326IS8-2.5
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/
Consult factory for parts specified with wider operating temperature ranges.
132625fc
2
LTC1326/LTC1326-2.5
ELECTRICAL CHARACTERISTICS The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25°C. V
= 3.3V, V
= 5V (for LTC1326),V
= 2.5V (for LTC1326-2.5),
A
CC3
CC5
CC25
V
CCA
= V , T = 25°C unless otherwise noted.
CC3
A
SYMBOL
PARAMETER
Reset Threshold V
CONDITIONS
0°C ≤ T ≤ 70°C
MIN
TYP
MAX
UNITS
V
V
V
V
V
●
●
3.094
3.052
3.118
3.118
3.135
3.143
V
V
RT3
RT5
RT25
RTA
CC3
CC5
CC25
CCA
A
–40°C ≤ T ≤ 85°C
A
Reset Threshold V
Reset Threshold V
Reset Threshold V
(LTC1326)
0°C ≤ T ≤ 70°C
●
●
4.687
4.625
4.725
4.725
4.750
4.762
V
V
A
–40°C ≤ T ≤ 85°C
A
(LTC1326-2.5) 0°C ≤ T ≤ 70°C
●
●
2.344
2.312
2.363
2.363
2.375
2.381
V
V
A
–40°C ≤ T ≤ 85°C
A
0°C ≤ T ≤ 70°C
●
●
0.992
0.980
1.000
1.000
1.007
1.007
V
V
A
–40°C ≤ T ≤ 85°C
A
V
V
V
V
V
Operating Voltage
Supply Current
RST in Correct Logic State
PBR = V
●
●
●
●
●
1
7
V
µA
µA
µA
nA
CC
CC3
CC3
CC5
CC25
I
I
I
I
t
20
4
40
10
7
VCC3
VCC5
VCC25
VCCA
RST
CC3
Input Current (LTC1326)
V
V
V
= 5V
CC5
Input Current (LTC1326-2.5)
Input Current
= 2.5V
2.8
0
CC25
= 1V
CCA
–15
15
CCA
Reset Pulse Width
RST Low with 10kΩ Pull-Up to V
CC3
0°C ≤ T ≤ 70°C
●
●
140
140
200
200
280
300
ms
ms
A
–40°C ≤ T ≤ 85°C
A
t
t
Soft Reset Pulse Width
SRST Low with 10kΩ Pull-Up to V
●
50
100
13
200
µs
µs
SRST
UV
CC3
V
Undervoltage Detect to RST
V
, V
CC25 CC3
or V
Less Than Reset
CCA
CC
Threshold V by More Than 1%
RT
I
PBR Pull-Up Current
PBR = 0V
PBR
0°C ≤ T ≤ 70°C
●
●
3
3
7
7
10
15
µA
µA
A
–40°C ≤ T ≤ 85°C
A
V
V
PBR, RST Input Low Voltage
PBR, RST Input High Voltage
PBR Min Pulse Width
PBR Debounce
●
●
●
●
0.8
V
V
IL
IH
2
t
t
40
ns
ms
PW
DB
Deassertion of PBR Input to SRST
20
35
Output (PBR Pulse Width = 1µs)
t
PBR Assertion Time for Transition
from Soft to Hard Reset Mode
PBR Held Less Than V
IL
PB
0°C ≤ T ≤ 70°C
●
●
1.4
1.4
2.0
2.0
2.8
3.0
s
s
A
–40°C ≤ T ≤ 85°C
A
V
RST Output Voltage Low
I
= 5mA
●
0.15
0.4
V
OL
SINK
I
= 100µA,
A
V
V
V
= 1V, V
= 0V, V
= 1V, V
= 0V
= 1V
= 1V
●
●
●
0.05
0.05
0.05
0.4
0.4
0.4
V
V
V
SINK
CC3
CC3
CC3
CC5
CC5
CC5
0°C ≤ T ≤ 70°C
I
= 100µA,
V
V
V
= 1.1V, V = 0V
CC5
●
●
●
0.05
0.05
0.05
0.4
0.4
0.4
V
V
V
SINK
CC3
CC3
CC3
–40°C ≤ T ≤ 85°C
= 0V, V
= 1.1V
= 1.1V
A
CC5
= 1.1V, V
CC5
I
= 100µA,
A
V
V
V
= 1V, V
= 0V, V
= 1V, V
= 0V
= 1V
= 1V
●
●
●
0.05
0.05
0.05
0.4
0.4
0.4
V
V
V
SINK
CC3
CC3
CC3
CC25
CC25
CC25
0°C ≤ T ≤ 70°C
I
= 100µA,
V
V
V
= 1.1V, V = 0V
CC25
●
●
●
0.05
0.05
0.05
0.4
0.4
0.4
V
V
V
SINK
CC3
CC3
CC3
–40°C ≤ T ≤ 85°C
= 0V, V
= 1.1V
= 1.1V
A
CC25
= 1.1V, V
CC25
SRST Output Voltage Low
RST Output Voltage Low
I
I
= 2.5mA
= 2.5mA
●
●
0.15
0.15
0.4
0.4
V
V
SINK
SINK
132625fc
3
LTC1326/LTC1326-2.5
ELECTRICAL CHARACTERISTICS The
otherwise noted.
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25°C. LTC1326 Only V
= 3.3V, V
= 5V, V
= V , T = 25°C unless
A
CC3
CC5
CCA
CC3
A
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
RST Output Voltage High (Note 3)
SRST Output Voltage High (Note 3)
RST Output Voltage High
I
I
I
= 1µA
●
●
●
V
CC3
V
CC3
V
CC3
– 1
V
V
OH
SOURCE
SOURCE
SOURCE
= 1µA
– 1
– 1
= 600µA
V
t
t
Prop Delay RST to RST
High Input to Low Output
C
= 20pF
25
45
ns
PHL
PLH
RST
Prop Delay RST to RST
Low Input to High Output
C
= 20pF
ns
V
RST
V
V
Reset Override Voltage
Override V
Ability to Assert RST (Note 4)
V
±0.025
CC3
OVR
CC5
CC5
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 3: The output pins SRST and RST have weak internal pull-ups to
of 6µA typ. However, external pull-up resistors may be used when
V
CC3
faster rise times are required.
Note 4: The V reset override voltage is valid for an operating range less
CC5
Note 2: All voltage values are with respect to GND.
than approximately 4.15V. Above this point the override is turned off and
the V pin functions normally.
CC5
U W
TYPICAL PERFOR A CE CHARACTERISTICS
I
vs Temperature
I
vs Temperature
VCC5
VCC25
I
vs Temperature
(LTC1326)
(LTC1326-2.5)
VCC3
5.0
4.8
4.6
4.4
4.2
4.0
3.8
3.6
3.4
3.2
3.0
25
24
23
22
21
20
19
18
17
16
15
3.00
2.95
2.90
2.85
2.80
2.75
2.70
2.65
2.60
2.55
2.50
–60
20
TEMPERATURE (°C)
60 80
–60
20
TEMPERATURE (°C)
60 80
–40 –20
0
40
100
–60
80
–40 –20
0
40
100
–40 –20
0
20 40 60
TEMPERATURE (°C)
100
1326/2.5 G02
1326/2.5 G01
1326/2.5 G03
132625fc
4
LTC1326/LTC1326-2.5
U W
TYPICAL PERFOR A CE CHARACTERISTICS
V
Transient Immunity
V
Transient Immunity
CC5
CC25
V
CCA
Input Current vs Input Voltage
(LTC1326)
(LTC1326-2.5)
50
45
40
35
30
25
20
15
10
5
45
40
35
30
25
20
15
10
5
3
2
T
A
= 25°C
RESET OCCURS
ABOVE CURVE
A
RESET OCCURS
ABOVE CURVE
A
T
= 25°C
T
= 25°C
1
0
–1
–2
–3
0
0
0.001
0.01
0.1
1
1.05 1.1
0.8 0.85 0.9 0.95 1.0
1.15 1.2
0.001
0.01
0.1
1
INPUT VOLTAGE (V)
V
RESET COMPARATOR OVERDRIVE (V)
V
CC25
RESET COMPARATOR OVERDRIVE (V)
CC5
1326/2.5 G05
1326/2.5 G06
1326/2.5 G04
V
Threshold Voltage
CC5
V
CC3
Transient Immunity
V
Transient Immunity
vs Temperature (LTC1326)
CCA
40
35
30
25
20
15
10
5
40
35
30
25
20
15
10
5
4.750
4.745
4.740
4.735
4.730
4.725
4.720
4.715
4.710
4.705
4.700
RESET OCCURS
ABOVE CURVE
A
RESET OCCURS
ABOVE CURVE
A
T
= 25°C
T = 25°C
0
0
0.001
V
0.01
0.1
1
0.001
V
0.01
0.1
1
–60
20
TEMPERATURE (°C)
60 80
–40 –20
0
40
100
RESET COMPARATOR OVERDRIVE (V)
RESET COMPARATOR OVERDRIVE (V)
CCA
CC3
1326/2.5 G07
1326/2.5 G08
1326/2.5 G09
V
Threshold Voltage
V
Threshold Voltage
V
Threshold Voltage
CC25
CC3
CCA
vs Temperature (LTC1326-2.5)
vs Temperature
vs Temperature
2.375
2.370
2.365
2.360
2.355
2.350
1.005
1.004
1.003
1.002
1.001
1.000
0.999
0.998
0.997
0.996
0.995
3.135
3.130
3.125
3.120
3.115
3.110
3.105
3.100
–60
20
TEMPERATURE (°C)
60 80
–60 –40 –20
TEMPERATURE (°C)
0
20 40 60
80
100
–40 –20
0
40
100
–20
0
20 40
100
–60 –40
60 80
TEMPERATURE (°C)
1326/2.5 G10
1326/2.5 G12
1326/2.5 G11
132625fc
5
LTC1326/LTC1326-2.5
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Reset Pulse Width
vs Temperature
PBR Assertion Time to Reset
vs Temperature
“Soft” Reset Pulse Width
vs Temperature
112.5
110.0
107.5
105.0
102.5
100.0
97.5
2.25
2.20
2.15
2.10
2.05
2.00
1.95
1.90
225
220
215
210
205
200
195
190
95.0
–60
20
TEMPERATURE (°C)
60 80
–60
80
–60
20
60 80
–40 –20
0
40
100
–40 –20
0
20 40 60
100
–40 –20
0
40
100
TEMPERATURE (°C)
TEMPERATURE (°C)
1326/2.5 G14
1326/2.5 G15
1326/2.5 G13
U
U
U
PIN FUNCTIONS
VCC3 (Pin 1): 3.3V Sense Input and Power Supply Pin for RST (Pin 6): Reset Logic Output. Active low, open-drain
the IC. Bypass to ground with ≥ 0.1µF ceramic capacitor. logic output with weak pull-up to VCC3. Can be pulled up
greater than VCC3 when interfacing to 5V logic. Asserted
VCC5 (Pin 2) (LTC1326): 5V Sense Input. Used as gate
when one or more of the supplies are below trip
drive for the RST output FET when the voltage on VCC3 is
thresholds and held for 200ms after all supplies become
less than the voltage on VCC5. If unused, it can be tied to
valid. Also asserted after PBR is held low for more than
VCC3 (see Dual and Single Supply Monitor Operation in
2 seconds and for an additional 200ms after PBR is
the Applications Information section).
released.
VCC25 (Pin 2) (LTC1326-2.5): 2.5V Sense Input. Used as
SRST (Pin 7): Soft Reset. Active low, open-drain logic
gate drive for RST output FET when the voltage on VCC3
output with weak pull-up to VCC3. Can be pulled up
is less than the voltage on VCC25. If unused, it can be tied
greater than VCC3 when interfacing to 5V logic. Asserted
to VCC3
.
for 100µs after PBR is held low for less than 2 seconds
VCCA (Pin 3): 1V Sense, High Impedance Input. Can be
and released.
used as a logic input with a 1V threshold. If unused, it can
PBR (Pin 8): Push-Button Reset. Active low logic input
with weak pull-up to VCC3. Can be pulled up greater than
VCC3 wheninterfacingto5Vlogic. Whenassertedforless
than 2 seconds, outputs a soft reset 100µs pulse on the
SRST pin. When PBR is asserted for greater than 2
seconds, the RST output is forced low and remains low
until 200ms after PBR is released.
be tied to either VCC3 or VCC25
.
GND (Pin 4): Ground.
RST (Pin 5):Reset Logic Output. Active high CMOS logic
output,driveshightoVCC3,bufferedcomplementofRST.
An external pull-down on the RST pin will drive this pin
high.
132625fc
6
LTC1326/LTC1326-2.5
W
BLOCK DIAGRA S
LTC1326
V
CC3
V
CC3
6µA
7µA
7
SRST
SOFT RESET
RESET
PBR
PBR
8
2
TIMER
–
+
TO POWER
DETECT
4.15V
–
+
V
CC5
25mV
25mV
–
+
V
CC3
–
V
CC3
INTERNAL
+
V
1
CC3
V
CC3
V
CC3
6µA
–
+
6
RST
200ms
RESET
GENERATOR
POWER
DETECT/
GATE DRIVE
–
+
V
3
4
CCA
V
CC5
V
CC3
GND
5
RST
REF
1326 BD
LTC1326-2.5
V
CC3
V
CC3
6µA
7µA
7
SRST
SOFT RESET
RESET
PBR
TIMER
PBR
8
TO POWER
DETECT
V
2
CC25
V
CC3
V
CC3
6µA
–
+
6
RST
V
CC3
INTERNAL
200ms
RESET
GENERATOR
POWER
DETECT/
GATE DRIVE
V
1
CC3
V
CC25
V
CC3
–
+
5
RST
–
+
V
3
4
CCA
GND
REF
1326-2.5 BD
132625fc
7
LTC1326/LTC1326-2.5
W U
W
TI I G DIAGRA S
V
Monitor Timing
Push-Button Reset Function Timing
CC
PBR
V
RTX
V
CCX
t < t
PB
t
PB
t
RST
t
RST
t
DB
RST
RST
t
SRST
1326/2.5 TD01
1326/2.5 TD02
SRST
U
W U U
APPLICATIO S I FOR ATIO
Operation
The three internal precision voltage comparators have
response times that are typically 13µs. This slow re-
sponse time helps prevent mistriggering due to tran-
sients on each of the VCC inputs. The part’s ability to
suppress transients can be improved by bypassing each
of the VCC inputs with a 0.1µF capacitor to ground.
The LTC1326/LTC1326-2.5 are micropower, high accu-
racy triple supply monitoring circuits. The parts have two
basic functions: generation of a reset when power sup-
plies are out of range, and generation of reset or a “soft”
reset when the PBR pin is pulled low.
Push-Button Reset
Supply Monitoring
The parts provide a push-button reset input pin. The PBR
inputhasaninternalpull-upcurrentsourcetoVCC3. Ifthe
PBR pin is not used it can be left floating.
All three VCC inputs must be above predetermined
thresholds for 200ms before the reset output is released.
Thepartswillassertresetduringpower-up, power-down
and brownout conditions on any one or more of the VCC
inputs.
When the PBR is pulled low for less than tPB (≈2 sec), a
narrow (100µs typ) soft reset pulse is generated on the
SRST output pin after the button is released. The push-
button circuitry contains an internal debounce counter
whichdelaystheoutputofthesoftresetpulsebytypically
20ms. This pin can be OR-tied to the RST pin and issue
what is called a “soft” reset. The SRST thereby resets the
microprocessor without interrupting the DRAM refresh
cycle. In this manner DRAM information remains undis-
turbed. Alternatively, SRST may be monitored by the
processor to initiate a software-controlled reset.
Onpower-up,eithertheVCC5 orVCC3 pinontheLTC1326,
or the VCC25 or VCC3 pin on the LTC1326-2.5, can power
the drive circuits for the RST pin. This ensures that RST
will be low when VCC5, VCC25 or VCC3 reaches 1V. As long
as any one of the VCC inputs is below its predetermined
threshold, RST will stay a logic low. Once all of the VCC
inputs rise above their thresholds, an internal timer is
started and RST is released after 200ms. The RST pin
outputs the inverted state of what is seen on RST pin.
WhenthePBRpinisheldlowforlongerthantPB (≈2sec),
a standard reset is generated on the RST and RST pins.
Once the 2 second period has elapsed, a reset signal is
produced by the push-button logic, thereby clearing the
reset counter. Once the button is released, the reset
counter begins counting the reset period (200ms nomi-
nal). Consequently, theresetoutputsremainassertedfor
approximately 200ms after the button is released.
RST is reasserted whenever any one of the VCC inputs
drops below its predetermined threshold and remains
asserted until 200ms after all of the VCC inputs are above
their thresholds.
On power-down, once any of the VCC inputs drop below
itsthreshold,RSTisheldatalogiclow.Alogiclowof0.4V
isguaranteeduntilVCC3 andVCC5 ontheLTC1326orVCC3
and VCC25 on the LTC1326-2.5 drop below 1V.
132625fc
8
LTC1326/LTC1326-2.5
U
W U U
APPLICATIO S I FOR ATIO
During a supply induced reset condition, the ability of the
PBR pin to force a soft reset condition on the SRST pin
is disabled. In other words SRST will remain high. If the
PBR pin is held low, both during and after a supply
inducedreset(lowRST),theRSTpinwillremainlowuntil
200ms after the PBR goes high.
appropriate range. The LTC1326 handles this situation as
shown in Figure 2. Above 1V and below VRT3, RST is held
low. From VRT3 to approximately 4.15V, the LTC1326
assumes 3.3V supply monitoring and RST is deasserted.
Aboveapproximately4.15V,theLTC1326operatesasa5V
monitor. Inmostsystems, the5Vsupplywillpassthrough
the 3.1V to 4.15V region in <200ms during power-up, and
theRSToutputwillbehaveasdesired.Table1summarizes
the state of RST and RST at various operating voltages
Power Detect/Gate Drive
The LTC1326/LTC1326-2.5 for the most part are powered
internally from the VCC3 pin. The exception is at the gate
drive of the output FET on the RST pin. On the input to this
FET is power detection circuitry used to detect and drive
the gate from either the 3.3V input pin (VCC3) or the 5V
input pin (VCC5) on the LTC1326 or the 2.5V input pin
(VCC25) on the LTC1326-2.5. The gate drive is derived
from the pin with the highest potential. This ensures the
part pulls the RST pin low as soon as either input pin is
≥ 1V.
with VCC3 = VCC5
.
Table 1. Override Truth Table (V
= V )
CC5
CC3
INPUTS (V
= V
= V )
CC
RST
—
0
RST
—
1
CC3
CC5
0V ≤ V ≤ 1V
CC
1V ≤ V ≤ V
CC
RT3
V
≤ V ≤ 4.15V
1
0
RT3
CC
4.15V ≤ V ≤ V
0
1
CC
RT5
V
≤ V
1
0
RT5
CC
3.3V OR
5V
Dual and Single Supply Monitor Operation
LTC1326
1
2
3
4
8
The VCC3, VCC5 and VCCA inputs may be individually
disabled by the following override techniques which allow
theLTC1326orLTC1326-2.5tobeusedasadualorsingle
supply monitor.
V
V
V
PBR
CC3
CC5
CCA
4.7k
7
6
5
SRST
RST
R1
ADJUSTABLE
SUPPLY
SYSTEM RESET
R2
GND
RST
LTC1326 Override Functions
1326/2.5 F01
The VCCA pin, if unused, can be tied to either VCC3 or VCC5
This is an obvious solution since the trip points for VCC3
andVCC5 willalwaysbegreaterthanthetrippointforVCCA
.
Figure 1
.
5
4
3
V
= V
CC5
= V = 0V TO 5V
CC3 CCA
4.7k PULL-UP FROM RST TO V
The VCC5 input trip point is disabled if its voltage is equal
to the voltage on VCC3 ±25mV and the voltage on VCC5 is
less than 4.15V. In this manner, the part will behave as a
3.3V monitor and the VCC5 reset will be disabled.
CC3
The VCC5 trip point is reenabled when the voltage on VCC5
is equal to the voltage on VCC3 ±25mV and the two inputs
aregreaterthanapproximately4.15V. Inthismanner, the
LTC1326 can function as a 5V monitor with the 3.3V
monitor disabled.
2
1
0
0
1
2
3
4
5
SUPPLY VOLTAGE (V)
When monitoring either 3.3V or 5V with VCC3 strapped to
VCC5 (see Figure 1), the LTC1326 determines which is the
1326/2.5 F02
Figure 2. RST Voltage vs Supply Voltage
132625fc
9
LTC1326/LTC1326-2.5
U
W
U U
APPLICATIO S I FOR ATIO
Figure 3 contains a simple circuit for 5V systems that can’t
risk the RST output going high in the 3.1V to 4.15V range
(possibly due to very slow rise time on the 5V supply).
DiodeD1powerstheLTC1326whiledropping ≈0.6Vfrom
the VCC5 pin to the VCC3 pin. This prevents the part’s
internal override circuit from being activated. Without the
override circuit active, the RST pin stays low until VCC5
reaches VRT5 ≅ 4.725V (See Figure 4).
LTC1326-2.5 Override Functions
TheVCCA pin, ifunused, canbetiedtoeitherVCC3 orVCC25
This is an obvious solution since the trip points for VCC3
and VCC25 will always be greater than the trip point for
.
V
CCA. Likewise, the VCC25, if unused, can be tied to VCC3.
VCC3 must always be used. Tying VCC3 to VCC25 and
operating off of a 2.5V supply will result in the continuous
assertion of RST.
Extending ESD Tolerance on the PBR Input Pin
LTC1326
D1*
1
2
3
4
8
7
6
5
V
V
V
PBR
SRST
RST
CC3
CC5
CCA
4.7k
The PBR pin is susceptible to ESD since it may be brought
out to a front panel in normal applications. The ESD
tolerance of this pin can be increased by adding a resistor
in series with the PBR pin. A 10k resistor can increase the
ESD tolerance of the PBR pin to approximately 10kV. The
PBR’s internal pull-up current of 7µA typical means there
is only 70mV (150mV max) dropped across the resistor.
See Figure 5.
5V
SYSTEM RESET
0.1µF
GND
RST
1326/2.5 F03
*MMBD914 OR EQUIVALENT
Figure 3. LTC1326 Monitoring a Single 5V Supply.
D1 Used to Avoid RST High Near 3.3V to 4V (See
Figure 2).
PUSH-BUTTON
LTC1326-2.5
RESET
10k*
1
2
3
4
8
7
6
5
3.3V
2.5V
V
V
V
PBR
SRST
RST
CC3
5
CC25
CCA
V
= V
= 0V TO 5V
CCA
CC5
4.7k PULL-UP FROM RST TO V
ADJUSTABLE SUPPLY
OR DC/DC FEEDBACK
DIVIDER
R1
CC5
SYSTEM RESET
4
3
2
1
0
T
= 25°C
A
R2
GND
RST
*OPTIONAL RESISTOR EXTENDS ESD TOLERANCE OF PBR INPUT TO APPROXIMATELY 10kV
1326/2.5 F05
Figure 5. Triple Supply Monitor (3.3V, 2.5V
and Adjustable) with Extended ESD Tolerance
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
(V)
V
CC5
1326/2.5 F04
Figure 4. RST Output Voltage
Characteristics of the Circuit in Figure 3
132625fc
10
LTC1326/LTC1326-2.5
U
TYPICAL APPLICATIONS N
Triple Supply Monitor (3.3V, 5V and Adjustable)
LTC1326
1
2
3
4
8
7
6
5
3.3V
5V
V
V
V
PBR
CC3
CC5
CCA
SRST
RST
ADJUSTABLE SUPPLY
OR DC/DC FEEDBACK
DIVIDER
R1
SYSTEM RESET
R2
GND
RST
1326/2.5 TA03
Dual Supply Monitor (3.3V and 5V, Defeat V
Input)
CCA
LTC1326
1
2
3
4
8
7
6
5
3.3V
5V
V
V
V
PBR
SRST
RST
CC3
CC5
CCA
SYSTEM RESET
GND
RST
1326/2.5 TA05
Dual Supply Monitor (3.3V or 5V Plus Adj)
3.3V OR
5V
LTC1326
1
2
3
4
8
7
6
5
V
V
V
PBR
SRST
RST
CC3
CC5
CCA
4.7k
R1
ADJUSTABLE
SUPPLY
SYSTEM RESET
R2
GND
RST
1326/2.5 F01
REFER TO LTC1326 OVERRIDE FUNCTIONS IN
THE APPLICATIONS INFORMATION SECTION.
Dual Supply Monitor (3.3V Plus Adj)
3.3V
LTC1326-2.5
1
2
3
4
8
7
6
5
V
V
V
PBR
SRST
RST
CC3
4.7k
CC25
CCA
R1
ADJUSTABLE
SUPPLY
SYSTEM RESET
R2
GND
RST
1326/2.5 TA07
132625fc
11
LTC1326/LTC1326-2.5
U
TYPICAL APPLICATIONS N
SRST Tied to RST and OR-Tying Other Sources to RST to
Generate Reset and Reset
PUSHBUTTON
8
LTC1326/
LTC1326-2.5
PBR
3.3V
4.7k
6µA
RESET
SRST
RST
7
6
5
6µA
OTHER OPEN DRAIN
RESET SOURCES
OR-TIED TO RESET
V
CC3
RST
RESET
1326/2.5 TA08
Using V
Tied to DC/DC Feedback Divider
CCA
2.9V
35.7k
1%
LTC1326
LTC1435
1
2
3
4
8
7
6
5
6
3.3V
V
V
V
PBR
V
CC3
CC5
CCA
OSENSE
2.8k
1%
5V
SRST
RST
SYSTEM
RESET
22.1k
1%
GND
RST
ADJUSTABLE
RESET TRIP
THRESHOLD 2.74V
1326/2.5 TA09
Using the Short Pulse Width, Push-Button Soft Reset Feature
to Initiate Hard Reset
LTC1326-2.5
1
2
3
4
8
7
6
5
40ns ≤ t ≤ 10µs
P
3.3V
2.5V
V
V
V
PBR
SRST
RST
CC3
CC25
CCA
RESET
GND
RST
PBR
RST
20ms
200ms
1326/2.5 TA11
132625fc
12
LTC1326/LTC1326-2.5
U
TYPICAL APPLICATIONS N
Monitoring a Negative Supply
3.3V
LTC1326
C1
0.1µF
1
2
3
4
8
7
V
V
V
PBR
SRST
RST
CC3
CC5
CCA
5V
R2
150k
1%
R1
150k
1%
6
C2
0.1µF
SYSTEM RESET
5
GND
RST
Q1
2N3906
Q2
2N3906
V
CCA
R3
100k
1%
R4 ≈ (100k)(0.98)(V
+ 0.55)(–1)
TRIP
Q3
2N3904
SUPPLY
–5V
VTRIP
–4.6V
–3V
R4
R4
392k
1%
392k
237k
1M
–3.3V
–12V
–10.8V
1326/2.5 TA12
–5V
Reset Valid for V
Down to 0V
CC3
3.3V
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
LTC1326-2.5
V
= V
= V
CC25 CCA
CC3
1
2
3
4
8
7
6
5
T
= 25°C
V
V
V
PBR
SRST
RST
A
CC3
100k
2.5V
CC25
CCA
R1
RST OUTPUT WITH
100k PULL-UP TO V
ADJUSTABLE
SUPPLY
CC3
SYSTEM RESET
R2
GND
RST
1326/2.5 TA13
RST OUTPUT
WITHOUT
100k PULL-UP.
10M LOAD TO GND
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5
V
(V)
CC3
1326/2.5 TA13a
132625fc
13
LTC1326/LTC1326-2.5
U
PACKAGE DESCRIPTIO
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660)
0.889 ± 0.127
(.035 ± .005)
5.23
(.206)
MIN
3.20 – 3.45
(.126 – .136)
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
0.52
(.0205)
REF
0.65
(.0256)
BSC
0.42 ± 0.038
(.0165 ± .0015)
TYP
8
7 6
5
RECOMMENDED SOLDER PAD LAYOUT
3.00 ± 0.102
(.118 ± .004)
(NOTE 4)
4.90 ± 0.152
(.193 ± .006)
DETAIL “A”
0.254
(.010)
0° – 6° TYP
GAUGE PLANE
1
2
3
4
0.53 ± 0.152
(.021 ± .006)
1.10
(.043)
MAX
0.86
(.034)
REF
DETAIL “A”
0.18
(.007)
SEATING
PLANE
0.22 – 0.38
0.127 ± 0.076
(.009 – .015)
(.005 ± .003)
0.65
(.0256)
BSC
TYP
MSOP (MS8) 0204
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
132625fc
14
LTC1326/LTC1326-2.5
U
PACKAGE DESCRIPTIO
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
.189 – .197
(4.801 – 5.004)
.045 ±.005
NOTE 3
.050 BSC
7
5
8
6
.245
MIN
.160 ±.005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
.030 ±.005
TYP
1
3
4
2
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
(0.254 – 0.508)
× 45°
.053 – .069
(1.346 – 1.752)
.004 – .010
(0.101 – 0.254)
.008 – .010
(0.203 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
.050
(1.270)
BSC
.014 – .019
(0.355 – 0.483)
TYP
NOTE:
INCHES
1. DIMENSIONS IN
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
SO8 0303
132625fc
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 represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LTC1326/LTC1326-2.5
U
TYPICAL APPLICATIO
Triple Supply Monitor with 3.3V and 5V System Resets
3.3V
5V
LTC1326
V
V
V
PBR
CC3
CC5
CCA
SRST
RST
10k
10k
Q1
ADJUSTABLE SUPPLY
OR DC/DC FEEDBACK
DIVIDER
R1
TO 3.3V
SYSTEM RESET
R2
GND
RST
TO 5V
SYSTEM RESET
2N7002
1326/2.5 TA14
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC690
5V Supply Monitor, Watchdog Timer and Battery Backup
3.3V Supply Monitor, Watchdog Timer and Battery Backup
5V Supply Monitor and Watchdog Timer
4.65V Threshold
2.9V Threshold
4.65V Threshold
LTC694-3.3
LTC699
LTC1232
5V Supply Monitor, Watchdog Timer and Push-Button Reset 4.37V/4.62V Threshold
LTC1443/LTC1444/ Micropower Quad Comparators with 1% Reference
LTC1445
LTC1443 has 1.182V Reference, LTC1444/LTC1445
have 1.221V Reference and Adjustable Hysteresis
LTC1536
Precision Triple Supply Monitor for PCI Applications
Nanopower Comparator with 2% Reference
Meets PCI t
Timing Specifications
FAIL
LTC1540
1.182V Reference, 300nA Supply Current, 8-Pin MSOP
Adjustable RESET and Watchdog Time Outs
LTC1726-2.5
LTC1726-5
LTC1727-2.5
LTC1727-5
LTC1728-1.8
LTC1728-2.5
LTC1728-5
LTC1985-1.8
LTC2900
Micropower Triple Supply Monitor for 2.5V, 3.3V and ADJ
Micropower Triple Supply Monitor for 5V, 3.3V and ADJ
Micropower Triple Supply Monitor with Individual Outputs
Micropower Triple Supply Monitor with Individual Outputs
Adjustable RESET and Watchdog Time Outs
2.338V, 3.086V, 1V Thresholds (±1.5%) 2.5, 3.3V, ADJ
4.675V, 3.086V, 1V Thresholds (±1.5%) 5V, 3.3V, ADJ
Micropower Triple Supply Monitor in 5-Pin SOT-23 Package 2.805V, 1.683V,1V Thresholds (±1.5%) 3V, 1.8V, ADJ
Micropower Triple Supply Monitor in 5-Pin SOT-23 Package 2.338V, 3.086V, 1V Thresholds (±1.5%) 2.5, 3.3V, ADJ
Micropower Triple Supply Monitor in 5-Pin SOT-23 Package 4.675V, 3.086V, 1V Thresholds (±1.5%) 5V, 3.3V, ADJ
Micropower Triple Supply Monitor for 3V, 1.8V and ADJ
Programmable Quad Supply Monitor
Push-Pull RESET Output, SOT-23
Adjustable Reset, 10-Lead MSOP and 3mm × 3mm 10-Lead
DFN Package
LTC2901
LTC2902
Programmable Quad Supply Monitor
Programmable Quad Supply Monitor
Adjustable Reset and Watchdog Timer, 16-Lead SSOP Package
Adjustable Reset and Tolerance, 16-Lead SSOP Package,
Margining Functions
LTC2903
Precision Quad Supply Monitor
6-Lead SOT-23 Package, Ultralow Voltage Reset
LTC2904/LTC3905 3-State Programmable Precision Dual Supply Monitor
Adjustable Tolerance and Reset Timer, 8-Lead SOT-23 Package
LTC2906/LTC2907 Precision Dual Supply Monitor 1-Selectable and 1 Adjustable Separate V Pin, RST/RST Outputs/Adjustable Reset Timer
CC
LTC2908
Precision Six Supply Monitor (4 Fixed and 2 Adjustable)
8-Lead SOT-23 and DDB Packages
132625fc
LT 1006 REV C • PRINTED IN THE USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
16
●
●
© LINEAR TECHNOLOGY CORPORATION 2006
(408)432-1900 FAX:(408)434-0507 www.linear-tech.com
相关型号：
LTC1326IMS8-2.5#PBF
LTC1326 - Micropower Precision Triple Supply Monitor; Package: MSOP; Pins: 8; Temperature Range: -40°C to 85°C
Linear
LTC1326IMS8-2.5#TR
LTC1326 - Micropower Precision Triple Supply Monitor; Package: MSOP; Pins: 8; Temperature Range: -40°C to 85°C
Linear
LTC1326IMS8-2.5#TRPBF
LTC1326 - Micropower Precision Triple Supply Monitor; Package: MSOP; Pins: 8; Temperature Range: -40°C to 85°C
Linear
LTC1326IS8#TR
LTC1326 - Micropower Precision Triple Supply Monitor; Package: SO; Pins: 8; Temperature Range: -40°C to 85°C
ADI
LTC1326IS8#TRPBF
LTC1326 - Micropower Precision Triple Supply Monitor; Package: SO; Pins: 8; Temperature Range: -40°C to 85°C
Linear
LTC1326IS8-2.5#PBF
LTC1326 - Micropower Precision Triple Supply Monitor; Package: SO; Pins: 8; Temperature Range: -40°C to 85°C
Linear
LTC1326IS8-2.5#TR
LTC1326 - Micropower Precision Triple Supply Monitor; Package: SO; Pins: 8; Temperature Range: -40°C to 85°C
Linear
©2020 ICPDF网 联系我们和版权申明