FEATURES
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LTC2934
Ultra-Low Power
Adjustable Supervisor with
Power-Fail Output
DESCRIPTION
The LTC
®
2934 ultra-low power voltage monitor provides
system initialization, power-fail warning and reset gen-
eration functions. Low quiescent current (500nA typical)
makes the LTC2934 an ideal choice for battery-operated
applications.
Precision power-fail and reset voltages can be configured
independently. Early warning of an impending low volt-
age condition is provided at the power-fail output (PFO)
when the PFI input falls below 0.4V. Supervisory circuits
monitor the ADJ input and pull
RST
low when ADJ falls
below 0.4V. When ADJ is rising from an under-threshold
condition, an internal reset timer is started after exceeding
the ADJ threshold by 5%. The reset timeout delays the
return of the
RST
output to a high state. A pushbutton
switch connected to the
MR
input is typically used to
force a manual reset. Outputs
RST
and
PFO
are available
with open-drain (LTC2934-1) or active pull-up circuits
(LTC2934-2). Operating temperature range is from –40ºC
to 85ºC.
500nA Quiescent Current
±1.5% (Max) Accuracy over Temperature
Operates Down to 1.6V Supply
Adjustable Reset Threshold
Adjustable Power-Fail Threshold
Early Warning Power-Fail Output
Selectable 15ms or 200ms Reset Timeout
Manual Reset Input
Compact 8-Lead, 2mm
×
2mm DFN and TSOT-23
(ThinSOT™) Packages
APPLICATIONS
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Portable Equipment
Battery-Powered Equipment
Security Systems
Point-of-Sale Devices
Wireless Systems
, LT, LTC, LTM are registered trademarks of Linear Technology Corporation. ThinSOT is
a trademark of Linear Technology Corporation. All other trademarks are the property of
their respective owners.
TYPICAL APPLICATION
Configurable Low Power Voltage Supervisor
Selectable Reset Timeout Period
V
IN
750k
0.1μF
11.8k
PFI
237k
MR
RT
GND
2934 TA01a
V
CC
ADJ
LTC2934-2
PFO
BATTERY
POWERED
SYSTEM
LOGIC
RST
V
CC
15ms
RST, RT = GND
200ms
2934 TA01b
RST, RT = V
CC
POWER FAIL FALLING THRESHOLD = 1.686V
RESET FALLING THRESHOLD = 1.606V
2934f
1
LTC2934
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Input Voltages
V
CC
........................................................... –0.3V to 6V
ADJ, PFI ................................................... –0.3V to 6V
RT,
MR
......................................–0.3V to (V
CC
+ 0.3V)
Output Voltages
PFO, RST
(LTC2934-1)............................. –0.3V to 6V
PFO, RST
(LTC2934-2)..............–0.3V to (V
CC
+ 0.3V)
RMS Currents
PFO, RST
..........................................................±5mA
Operating Ambient Temperature Range
LTC2934C ................................................ 0°C to 70°C
LTC2934I.............................................. –40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
TSOT-23 Package.............................................. 300°C
PIN CONFIGURATION
TOP VIEW
V
CC
1
MR 2
RST 3
PFO 4
9
8 ADJ
7 PFI
6 RT
5 GND
ADJ 1
PFI 2
RT 3
GND 4
TOP VIEW
8 V
CC
7 MR
6 RST
5 PFO
DC PACKAGE
8-LEAD (2mm
×
2mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 102°C/W
EXPOSED PAD (PIN 9) PCB GND CONNECTION OPTIONAL
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
T
JMAX
= 125°C,
θ
JA
= 195°C/W
ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI)
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
LTC2934CTS8-1#TRMPBF
LTC2934CTS8-1#TRPBF
LTDKR
8-Lead Plastic TSOT-23
LTC2934ITS8-1#TRMPBF
LTC2934ITS8-1#TRPBF
LTDKR
8-Lead Plastic TSOT-23
LTC2934CTS8-2#TRMPBF
LTC2934CTS8-2#TRPBF
LTDKS
8-Lead Plastic TSOT-23
LTC2934ITS8-2#TRMPBF
LTC2934ITS8-2#TRPBF
LTDKS
8-Lead Plastic TSOT-23
LTC2934CDC-1#TRMPBF
LTC2934CDC-1#TRPBF
LDKT
8-Lead (2mm
×
2mm) Plastic DFN
LTC2934IDC-1#TRMPBF
LTC2934IDC-1#TRPBF
LDKT
8-Lead (2mm
×
2mm) Plastic DFN
LTC2934CDC-2#TRMPBF
LTC2934CDC-2#TRPBF
LDKV
8-Lead (2mm
×
2mm) Plastic DFN
LTC2934IDC-2#TRMPBF
LTC2934IDC-2#TRPBF
LDKV
8-Lead (2mm
×
2mm) Plastic DFN
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
2934f
2
LTC2934
ELECTRICAL CHARACTERISTICS
SYMBOL
V
CC
I
CC
V
TH
V
THM
V
ADJ(HYST)
V
PFI(HYST)
t
UV
I
TH(LKG)
V
IN(TH)
t
PW
t
PD
R
PU
I
LK
V
OL
V
OH
I
OH
t
RST
PARAMETER
V
CC
Input Supply Voltage
V
CC
Input Supply Current
Input Threshold (Monitored Voltage Falling)
ADJ to PFI Threshold Matching
Reset Threshold Hysteresis
(Monitored Voltage Rising)
Power-Fail Threshold Hysteresis
(Monitored Voltage Rising)
Undervoltage Detect to
RST
or
PFO
Falling
Threshold Adjustment Input Leakage Current
Control Input Threshold
Input Pulse Width
Propagation Delay to
RST
Falling
Internal Pull-Up Resistance
Input Leakage Current (RT Input)
Voltage Output Low
Voltage Output High (LTC2934-2)
Leakage Current, Output High (LTC2934-1)
Reset Timeout Period
V
ADJ
or V
PFI
= V
TH
– 4mV (Note 3)
V
ADJ
or V
PFI
= 420mV
RT
MR
MR
Manual Reset Falling
MR
RT = V
CC
or GND
V
CC
= 1V, 200μA Pull-Up Current
V
CC
= 3V, 3mA Pull-Up Current
–200μA Pull-Down Current
V
RST
, V
PFO
= 3.6V
RT Input High
RT Input Low
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
CC
= 3.6V, unless otherwise noted. (Note 2)
CONDITIONS
l
l
MIN
1.6
225
394
18
8
TYP
500
400
±2
20
10
1
0.1
MAX
5.5
1000
406
±8
25
15
UNITS
V
nA
mV
mV
mV
mV
ms
Threshold Adjustment Inputs: ADJ, PFI
l
l
l
l
±1
0.7 • V
CC
1.4
nA
V
V
μs
μs
kΩ
nA
mV
mV
V
nA
ms
ms
Control Inputs:
MR,
RT
0.3 • V
CC
0.4
20
2
600
5
900
±1
25
50
0.7 • V
CC
±1
140
10
200
15
±10
260
25
20
1200
±10
100
150
Reset and Power Fail Outputs:
RST, PFO
l
l
l
l
l
l
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 2.
All currents into pins are positive, all voltages are referenced to
GND unless otherwise noted.
Note 3.
Guaranteed by design. Characterized, but not production tested.
2934f
3
LTC2934
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage
1000
EXTERNALLY CONFIGURED
FOR 3V FALLING THRESHOLDS
85°C
402
25°C
400
–40°C
V
TH
(mV)
I
CC
(nA)
600
400
398
396
394
–50
406
404
T
A
= 25°C, unless otherwise noted.
ADJ, PFI Threshold vs Temperature
800
200
0
0
1
2
3
V
CC
(V)
4
5
6
2934 G01
–25
0
25
50
TEMPERATURE (°C)
75
100
2934 G02
Comparator Undervoltage
Glitch Immunity
3.0
2.5
2.0
1.5
1.0
0.5
0
0.1
V
CC
= 3.6V
260
240
220
t
RST
(ms)
200
180
160
Reset Timeout Period
vs Temperature
V
CC
= RT = 3.6V
GLITCH DURATION, t
UV
(ms)
COMPARATORS PULL DOWN
ABOVE CURVE
1
10
COMPARATOR OVERDRIVE (%)
100
2934 G03
140
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
2934 G04
Voltage Output Low vs Pull-Up
Current (RST,
PFO)
100
V
CC
= 3V
3.6
85°C
3.5
25°C
V
OL
(mV)
V
OH
(mV)
60
–40°C
40
Voltage Output High vs Pull-Down
Current (RST,
PFO)
LTC2934-2
V
CC
= 3.6V
80
–40°C
3.4
25°C
3.3
85°C
20
0
0
1
2
3
4
PULL-UP CURRENT (mA)
5
2934 G05
3.2
0
–0.4
–0.6
–0.8
–0.2
PULL-DOWN CURRENT (mA)
–1
2934 G06
2934f
4
LTC2934
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs RT
Input Voltage
250
V
CC
= 3.6V
5
T
A
= 25°C, unless otherwise noted.
Supply Current vs
MR
Input Voltage
V
CC
= 3.6V
200
4
I
CC
(μA)
100
I
CC
(μA)
0
0.5
1
1.5
2
2.5
3
3.5
4
2934 G07
150
3
2
50
1
0
RT INPUT VOLTAGE (V)
0
0
0.5
1
1.5
2
2.5
3
3.5
4
2934 G08
MR
INPUT VOLTAGE (V)
PIN FUNCTIONS
ADJ:
Reset Threshold Adjustment Input. Tie to resistive
divider between monitored voltage and GND to configure
desired reset threshold. See the Applications Information
section for details. Tie to V
CC
if unused.
Exposed Pad (DFN Only):
Exposed Pad may be left floating
or connected to device ground.
GND:
Device Ground.
MR:
Manual Reset Input. Attach a push-button switch
between this input and ground. A logic low on this input
pulls
RST
low. When the
MR
input returns to logic high,
RST
returns high after the reset timer has expired. Tie to
V
CC
if unused.
PFI:
Power-Fail Threshold Adjustment Input. Tie to
resistive divider between monitored voltage and GND
to configure desired power-fail threshold. See the
Applications Information section for details. Tie to V
CC
or
GND if unused.
PFO:
Power-Fail Output.
PFO
pulls low when monitored
voltage falls below the power-fail (PFI) threshold.
PFO
is released when the PFI voltage rises above the power-
fail threshold by 2.5%.
PFO
is available with open-drain
(LTC2934-1) or active pull-up (LTC2934-2) outputs. Leave
open if unused.
RST:
Reset Output.
RST
pulls low when monitored volt-
age falls below the reset threshold.
RST
is released after
monitored voltage exceeds the reset threshold plus 5%
hysteresis and after reset timer has expired.
RST
is available
with open-drain (LTC2934-1) or active pull-up (LTC2934-2)
outputs. Leave open if unused.
RT:
Reset Timeout Selection Input. Tie to GND or V
CC
for
desired reset timeout. Tie low for 15ms delay or high for
200ms delay.
V
CC
:
Power Supply Input. Bypass V
CC
with 0.1μF to
GND.
2934f
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Microcontroller MCU
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