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LTC2935
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TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
Ultra-Low Power Supervisor
with Power-Fail Output,
Selectable Thresholds
The LTC
®
2935 ultra-low power voltage monitor provides
system initialization, power-fail warning and reset gen-
eration functions. Low quiescent current (500nA typical)
makes the LTC2935 an ideal choice for battery-operated
applications.
Three binary threshold-select inputs confi gure one of
eight integrated reset thresholds, ranging from 1.6V to
3.45V in pre-determined increments. Early warning of an
impending low voltage condition is provided at the power-
fail output (PFO), whose threshold is above the confi gured
reset threshold. Supervisory circuits monitor VCC and
pull RST low when VCC drops below the confi gured reset
threshold. When VCC is rising from an under-threshold
condition, an internal reset timer is started after exceeding
the reset threshold by 5%. A 200ms reset timeout delays
the return of the RST output to a high state. A pushbut-
ton switch connected to the MR input is typically used to
force a manual reset. Outputs RST and PFO are available
with open-drain (LTC2935-1/LTC2935-3) or active pull-up
(LTC2935-2/LTC2935-4) circuits. Operating temperature
range is from –40°C to 85°C.
Confi gurable Low Power Voltage Monitor
n 500nA Quiescent Current
n ±1.5% (Max) Accuracy over Temperature
n Integrated Precision Attenuators
n Eight Pin-Selectable Reset Thresholds
n Eight Pin-Selectable Power-Fail Thresholds
n Early Warning Power-Fail Output
n 200ms Reset Timeout
n Manual Reset Input
n Compact 8-Lead, 2mm × 2mm DFN and
TSOT-23 (ThinSOT™) Packages
n Portable Equipment
n Battery-Powered Equipment
n Security Systems
n Point-of-Sale Devices
n Wireless Systems
Falling Threshold Selection Table
VCC
VIN
BATTERY
POWERED
SYSTEM
LOGIC
2935 TA01a
S2
S1
0.1μF PFO
RST
S0
MR
LTC2935-2
GND
LTC2935-1/LTC2935-2 LTC2935-3/LTC2935-4
RESET
THRESHOLD
(V)
POWER-FAIL
THRESHOLD
(V)
RESET
THRESHOLD
(V)
POWER-FAIL
THRESHOLD
(V) S2S1S0
3.30 3.45 2.44 2.56 Low Low Low
3.15 3.30 2.32 2.44 Low Low High
3.00 3.15 2.20 2.32 Low High High
2.85 3.00 2.08 2.20 Low High Low
2.70 2.85 1.96 2.08 High High Low
2.55 2.70 1.84 1.96 High Low Low
2.40 2.55 1.72 1.84 High Low High
2.25 2.40 1.60 1.72 High High High
L, LT, LTC, LTM, Linear Technology and the Linear logo 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.
[IC2935
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LTC2935
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ABSOLUTE MAXIMUM RATINGS
Input Voltages
V
CC ........................................................... –0.3V to 6V
S2, S1, S0, MR .........................–0.3V to (VCC + 0.3V)
Output Voltages (PFO, RST)
LTC2935-1/LTC2935-3 ............................. –0.3V to 6V
LTC2935-2/LTC2935-4 ..............–0.3V to (VCC + 0.3V)
RMS Currents
PFO, RST ..........................................................±5mA
(Notes 1, 2)
TOP VIEW
VCC
MR
RST
PFO
S2
S1
S0
GND
DC PACKAGE
8-LEAD (2mm s 2mm) PLASTIC DFN
9
4
1
2
36
5
7
8
TJMAX = 125°C, θJA = 102°C/W
EXPOSED PAD (PIN 9), PCB GND CONNECTION OPTIONAL
VCC
MR
RST
PFO
S2 1
S1 2
S0 3
GND 4
8
7
6
5
TOP VIEW
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
TJMAX = 125°C, θJA = 195°C/W
PIN CONFIGURATION
Operating Ambient Temperature Range
LTC2935C ................................................ 0°C to 70°C
LTC2935I.............................................. –40°C to 85°C
Storage Temperature Range ................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
TSOT-23 Package .............................................. 300°C
ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI) TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC2935CTS8-1#TRMPBF LTC2935CTS8-1#TRPBF LTDPW 8-Lead Plastic TSOT-23 0°C to 70°C
LTC2935ITS8-1#TRMPBF LTC2935ITS8-1#TRPBF LTDPW 8-Lead Plastic TSOT-23 –40°C to 85°C
LTC2935CTS8-2#TRMPBF LTC2935CTS8-2#TRPBF LTDQB 8-Lead Plastic TSOT-23 0°C to 70°C
LTC2935ITS8-2#TRMPBF LTC2935ITS8-2#TRPBF LTDQB 8-Lead Plastic TSOT-23 –40°C to 85°C
LTC2935CTS8-3#TRMPBF LTC2935CTS8-3#TRPBF LTFHV 8-Lead Plastic TSOT-23 0°C to 70°C
LTC2935ITS8-3#TRMPBF LTC2935ITS8-3#TRPBF LTFHV 8-Lead Plastic TSOT-23 –40°C to 85°C
LTC2935CTS8-4#TRMPBF LTC2935CTS8-4#TRPBF LTFHX 8-Lead Plastic TSOT-23 0°C to 70°C
LTC2935ITS8-4#TRMPBF LTC2935ITS8-4#TRPBF LTFHX 8-Lead Plastic TSOT-23 –40°C to 85°C
LTC2935CDC-1#TRMPBF LTC2935CDC-1#TRPBF LDPX 8-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C
LTC2935IDC-1#TRMPBF LTC2935IDC-1#TRPBF LDPX 8-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C
LTC2935CDC-2#TRMPBF LTC2935CDC-2#TRPBF LDQC 8-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C
LTC2935IDC-2#TRMPBF LTC2935IDC-2#TRPBF LDQC 8-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C
LTC2935CDC-3#TRMPBF LTC2935CDC-3#TRPBF LFHW 8-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C
LTC2935IDC-3#TRMPBF LTC2935IDC-3#TRPBF LFHW 8-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C
LTC2935CDC-4#TRMPBF LTC2935CDC-4#TRPBF LFHY 8-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C
LTC2935IDC-4#TRMPBF LTC2935IDC-4#TRPBF LFHY 8-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C
TRM = 500 pieces. *Temperature grades are identifi ed by a label on the shipping container.
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
Consult LTC Marketing for information on lead based fi nish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/
LTC2935
L7 LJUW
LTC2935
3
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ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VCC VCC Input Supply Voltage l5.5 V
ICC VCC Input Supply Current l225 500 1000 nA
Reset Thresholds (LTC2935-1/LTC2935-2)
VRTF1 Reset Threshold 1 (VCC Falling) S2 = Low : S1 = Low : S0 = Low l3.251 3.300 3.349 V
VRTF2 Reset Threshold 2 (VCC Falling) S2 = Low : S1 = Low : S0 = High l3.103 3.150 3.197 V
VRTF3 Reset Threshold 3 (VCC Falling) S2 = Low : S1 = High : S0 = High l2.955 3.000 3.045 V
VRTF4 Reset Threshold 4 (VCC Falling) S2 = Low : S1 = High : S0 = Low l2.808 2.850 2.892 V
VRTF5 Reset Threshold 5 (VCC Falling) S2 = High : S1 = High : S0 = Low l2.660 2.700 2.740 V
VRTF6 Reset Threshold 6 (VCC Falling) S2 = High : S1 = Low : S0 = Low l2.512 2.550 2.588 V
VRTF7 Reset Threshold 7 (VCC Falling) S2 = High : S1 = Low : S0 = High l2.364 2.400 2.436 V
VRTF8 Reset Threshold 8 (VCC Falling) S2 = High : S1 = High : S0 = High l2.217 2.250 2.283 V
ΔVRTF Reset Threshold Differential VRTF(N+1) – VRTF(N) (Note 3) l142 150 158 mV
VRT(HYST) Reset Threshold Hysteresis (VCC Rising) Relative to Any Selected Reset Threshold l4.5 5 6 %
tUVR Undervoltage Detect to RST Falling VCC Below Threshold by 1% (Note 3) 1 ms
Reset Thresholds (LTC2935-3/LTC2935-4)
VRTF1 Reset Threshold 1 (VCC Falling) S2 = Low : S1 = Low : S0 = Low l2.404 2.440 2.476 V
VRTF2 Reset Threshold 2 (VCC Falling) S2 = Low : S1 = Low : S0 = High l2.286 2.320 2.354 V
VRTF3 Reset Threshold 3 (VCC Falling) S2 = Low : S1 = High : S0 = High l2.167 2.200 2.233 V
VRTF4 Reset Threshold 4 (VCC Falling) S2 = Low : S1 = High : S0 = Low l2.049 2.080 2.111 V
VRTF5 Reset Threshold 5 (VCC Falling) S2 = High : S1 = High : S0 = Low l1.931 1.960 1.989 V
VRTF6 Reset Threshold 6 (VCC Falling) S2 = High : S1 = Low : S0 = Low l1.813 1.840 1.867 V
VRTF7 Reset Threshold 7 (VCC Falling) S2 = High : S1 = Low : S0 = High l1.695 1.720 1.745 V
VRTF8 Reset Threshold 8 (VCC Falling) S2 = High : S1 = High : S0 = High l1.576 1.600 1.624 V
ΔVRTF Reset Threshold Differential VRTF(N+1) – VRTF(N) (Note 3) l112 120 128 mV
VRT(HYST) Reset Threshold Hysteresis (VCC Rising) Relative to Any Selected Reset Threshold l4.5 5 6 %
tUVR Undervoltage Detect to RST Falling VCC Below Threshold by 1% (Note 3) 1 ms
Power-Fail Thresholds (LTC2935-1/LTC2935-2)
ΔVPFT Power-Fail Threshold Differential VPFT(N) – VRTF(N) Any Selected Reset Threshold (VCC Falling) l100 150 200 mV
VPFT(HYST) Power-Fail Threshold Hysteresis Relative to Any Selected Power-Fail Threshold
(VCC Rising)
l2 2.5 3.5 %
tUVP Undervoltage Detect to PFO Falling VCC Below Threshold by 1% (Note 3) 1 ms
Power-Fail Thresholds (LTC2935-3/LTC2935-4)
ΔVPFT Power-Fail Threshold Differential VPFT(N) – VRTF(N) Any Selected Reset Threshold (VCC Falling) l70 120 170 mV
VPFT(HYST) Power-Fail Threshold Hysteresis Relative to Any Selected Power-Fail Threshold
(VCC Rising)
l2 2.5 3 %
tUVP Undervoltage Detect to PFO Falling VCC Below Threshold by 1% (Note 3) 1 ms
Control Inputs: MR, S2, S1, S0
VIN(TH) Control Input Threshold S2, S1, S0
MR
l
l
0.3 • VCC
0.4
0.7 • VCC
1.4
V
V
tPW Input Pulse Width MR l20 μs
tPD Propagation Delay to RST Falling Manual Reset Falling l2520 μs
RPU Internal Pull-Up Resistance MR l600 900 1200 kΩ
ILK Input Leakage Current S2, S1, S0 = VCC or GND l±1 ±10 nA
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at TA = 25°C, VCC = 3.6V, unless otherwise noted. (Note 2)
LTC2935
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LTC2935
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TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage
Normalized Reset and Power-Fail
Thresholds vs Temperature
Comparator Undervoltage
Glitch Immunity
Reset Timeout Period
vs Temperature
Voltage Output Low vs Pull-Up
Current (RST, PFO)
Voltage Output High vs Pull-Down
Current (RST, PFO)
VCC (V)
0
0
ICC (nA)
200
400
600
800
1000
1234
2935 G01
56
–40°C
25°C
85°C
S0 = S1 = S2 = GND
TEMPERATURE (°C)
–50
0.985
NORMALIZED THRESHOLD (V/ V)
0.990
0.995
1.000
1.005
1.015
–25 02550
2935 G02
75 100
1.010
COMPARATOR OVERDRIVE (%)
0.1
2.0
GLITCH DURATION, tUV (ms)
2.5
1 10 100
1.5
1.0
0.5
0
3.0
2935 G03
VCC = 3.6V
COMPARATORS PULL DOWN
ABOVE CURVE
TEMPERATURE (°C)
–50
140
tRST (ms)
160
180
200
220
260
–25 02550
2935 G04
75 100
240
VCC = 3.6V
PULL-UP CURRENT (mA)
0
0
VOL (mV)
20
40
60
80
100
1234
2935 G05
5
–40°C
25°C
85°C
VCC = 3V
PULL-DOWN CURRENT (mA)
0
3.2
VOH (mV)
3.3
3.4
3.5
3.6
–0.2 –0.4 –0.6 –0.8
2935 G06
–1
–40°C
25°C
85°C
LTC2935-2
VCC = 3.6V
TA = 25°C, unless otherwise noted.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Reset and Power-Fail Outputs: RST, PFO
VOL Voltage Output Low VCC = 1V, 200μA Pull-Up Current
VCC = 3V, 3mA Pull-Up Current
S2, S1, S0 = Low
l
l
25
50
100
150
mV
mV
VOH Voltage Output High (LTC2935-2) –200μA Pull-Down Current l0.7 • VCC V
IOH Current Output High, Leakage (LTC2935-1) VRST, VPFO = 3.6V l±1 ±10 nA
tRST Reset Timeout Period l140 200 260 ms
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at TA = 25°C, VCC = 3.6V, unless otherwise noted. (Note 2)
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.
LTC2935
L7 LJUW
LTC2935
5
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Supply Current vs S0, S1, S2
Input Voltage Supply Current vs MR Input Voltage
PIN FUNCTIONS
Exposed Pad (DFN Only): Exposed Pad may be left fl oating
or connected to device ground.
GND: Device ground.
MR: Manual Reset Input. Attach a pushbutton 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 200ms. Tie to VCC if unused.
PFO: Power-Fail Output. PFO pulls low when VCC falls
below the power-fail threshold. The power-fail thresh-
old is above the confi gured falling reset threshold by a
pre-determined margin. PFO is released when VCC rises
above the power-fail threshold by 2.5%. PFO is available
with open-drain (LTC2935-1/LTC2935-3) or active pull-up
(LTC2935-2/LTC2935-4) outputs. Leave open if unused.
RST: Reset Output. RST pulls low when VCC falls below the
reset threshold. RST is released 200ms after VCC exceeds
the reset threshold plus 5% hysteresis. RST is available
with open-drain (LTC2935-1/LTC2935-3) or active pull-up
(LTC2935-2/LTC2935-4) outputs. Leave open if unused.
S2, S1, S0: Threshold Selection Inputs. Tie to GND or
VCC for required reset threshold. See the Falling Threshold
Selection Table on page 1 for settings.
VCC: Power Supply and Monitored Voltage Input. Bypass
VCC with a 0.1μF capacitor to GND.
TYPICAL PERFORMANCE CHARACTERISTICS
S0, S1, S2 INPUT VOLTAGE (V)
0
ICC (μA)
200
3.5
150
100
12
0.5 1.5 2.5 3 4
50
0
250
2935 G07
VCC = 3.6V
MR INPUT VOLTAGE (V)
0
ICC (μA)
4
3.5
3
2
12
0.5 1.5 2.5 3 4
1
0
5
2935 G08
VCC = 3.6V
TA = 25°C, unless otherwise noted.
LTC2935
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LTC2935
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BLOCK DIAGRAM
TIMING DIAGRAM
900k
LTC2935-2/LTC2935-4
VCC
2935 BD
RC
VCC
RST
PFO
–
+
PC
–
+
0.4V
RESET
DELAY
LTC2935-2/LTC2935-4
VCC
GND
MR
S0
S1
S2
VRTF
VPFT
tRST
2935 TD
VCC
RST
PFO
MR
tRST
tPD
LTC2935
L7 LJUW
LTC2935
7
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APPLICATIONS INFORMATION
VOLTAGE MONITORING
Unmanaged power can cause various system problems.
At power-up, voltage fl uctuation around critical thresholds
can cause improper system or processor initialization.
The LTC2935 provides power management capabilities
for the system power-up phase. The supervisory device
issues a system reset after the monitored voltage has
stabilized. Built-in hysteresis and fi ltering ensures that
fl uctuations due to load transients or supply noise do
not cause chattering of the status outputs. Comparator
undervoltage glitch immunity is shown in the Typical
Performance Characteristics section. The curve dem-
onstrates the transient amplitude and width required to
switch the comparators.
Because many batteries exhibit large series resistance,
load currents can cause signifi cant voltage drops. The
low DC current draw of the LTC2935 (at any input volt-
age) does not add to the loading problem. When voltage
is initially applied to VCC, RST and PFO pull low once there
is enough voltage to turn on the pull-down devices (1V
maximum).
If the monitored supply voltage falls to the power-fail
threshold, the built-in power-fail comparator pulls PFO
low. At this point, there remains a voltage margin before
the RST output pulls low. PFO remains low until VCC rises
above the power-fail threshold plus 2.5% hysteresis. PFO
is typically used in signal preparation for controlled shut-
down. For example, the PFO output may be connected to
a processor nonmaskable interrupt. Upon interrupt, the
processor may begin shutdown procedures. Shutdown
events may include supply sequencing and/or storage/
erasure of system state in nonvolatile memory.
If the monitored voltage drops below the reset threshold,
RST pulls low until VCC rises above the reset threshold plus
5% hysteresis. This may occur through battery charging
or replacement. An internal reset timer delays the return
of the RST output to a high state to provide settling and
initialization time. The RST output is typically connected
to a processor reset input.
Few, if any external components are necessary for reliable
operation. However, a decoupling capacitor between VCC
and ground is recommended (0.01μF minimum).
Threshold Confi guration
The LTC2935 monitors and compares the VCC voltage
against two internal thresholds during operation. The
higher threshold (power-fail) is the level used for early
warning of a low voltage condition, reported on the PFO
output. The lower threshold (reset) is the level at which the
RST output pulls low. Use system requirements to choose
the appropriate reset threshold from Table 1.
Table 1. Falling Threshold Selection
LTC2935-1/LTC2935-2 LTC2935-3/LTC2935-4
RESET
THRESHOLD
(V)
POWER-FAIL
THRESHOLD
(V)
RESET
THRESHOLD
(V)
POWER-FAIL
THRESHOLD
(V) S2 S1 S0
3.30 3.45 2.44 2.56 Low Low Low
3.15 3.30 2.32 2.44 Low Low High
3.00 3.15 2.20 2.32 Low High High
2.85 3.00 2.08 2.20 Low High Low
2.70 2.85 1.96 2.08 High High Low
2.55 2.70 1.84 1.96 High Low Low
2.40 2.55 1.72 1.84 High Low High
2.25 2.40 1.60 1.72 High High High
In the LTC2935-1/LTC2935-2 the power-fail threshold
is always 150mV higher than the confi gured reset
threshold. In the LTC2935-3/LTC2935-4 the power-fail
threshold is always 120mV higher than the confi gured
reset threshold. Set the threshold selection inputs (S2,
S1, S0) accordingly.
LTC2935
L7LJCUEN2
LTC2935
8
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APPLICATIONS INFORMATION
Figure 1. RST vs VCC with 10k Pull-Up
Selecting Output Logic Style
The LTC2935 status outputs are available in two op-
tions: open-drain (LTC2935-1/LTC2935-3) or active
pull-up (LTC2935-2/LTC2935-4). The open-drain options
(LTC2935-1/LTC2935-3) allow the outputs to be pulled up
to a user defi ned voltage with a resistor. The open-drain
pull-up voltage may be greater than VCC (5.5V maximum),
which is not always possible with inferior battery supervi-
sors, due to internal clamps. When the status outputs are
low, power is dissipated in the pull-up resistors. Recom-
mended resistor values lie in the range between 10k and
470k. Figure 1 demonstrates typical LTC2935-1/LTC2935-3
RST output behavior.
The active pull-up options (LTC2935-2/LTC2935-4) elimi-
nate the need for external pull-up resistors on the status
outputs. Integrated pull-up devices pull the outputs up to
VCC. Actively pulled up outputs may not be driven above
VCC.
Some applications require the RST and/or PFO outputs to
be valid with VCC down to ground. Active pull-up handles
this requirement with the addition of an external resistor
from the output to ground. The resistor provides a path
for leakage currents, preventing the output from fl oating to
undetermined voltages when connected to high impedance
(such as CMOS logic inputs). The resistor value should
be small enough to provide effective pull-down without
excessively loading the pull-up circuitry. A 100k resistor
from output to ground is satisfactory for most applications.
When the status outputs are high, power is dissipated in
the pull-down resistors. Figure 2 demonstrates typical
LTC2935-2/LTC2935-4 RST output behavior.
Manual Reset Input
When VCC is above its reset threshold, and the manual
reset input (MR) is pulled low, the RST output is forced low.
RST remains low for 200ms after the manual reset input is
released and pulled high. The manual reset input is pulled
up internally through 900k to VCC. If external leakage cur-
rents have the ability to pull down the manual reset input
below its logic threshold, a lower value pull-up resistor,
placed between VCC and MR will fi x the problem.
Input MR is often pulled down through a pushbutton
switch requiring human contact. If extended ESD toler-
ance is required, series resistance between the switch and
the input is recommended. For most applications, a 10k
resistor provides suffi cient current limiting.
Figure 2. RST vs VCC
VCC (V)
0
RST (V)
2.0
2.5
3.0
1.5
1.0
12
0.5 1.5 2.5 3 3.5
0.5
0
3.5
2935 F01
LTC2935-1
S2 = GND
S1 = S0 = VCC
VCC (V)
0
RST (V)
2.0
2.5
3.0
1.5
1.0
12
0.5 1.5 2.5 3 3.5
0.5
0
3.5
2935 F02
LTC2935-2
S2 = GND
S1 = S0 = VCC
LTC2935
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L7 LJUW
LTC2935
9
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TYPICAL APPLICATIONS
Battery Monitor with Interface to Low Voltage Logic
Alkaline Cell Stack Voltage Monitor
Coin Cell Voltage Monitor
1.18M
1μF
590k 100k 100k
VCC VDD
μP
POWER FAIL FALLING THRESHOLD = 3.15V
RESET FALLING THRESHOLD = 3.00V
MANUAL
RESET
PUSHBUTTON
*OPTIONAL RESISTOR FOR ADDED ESD PROTECTION
2935 TA02
NMI
RST
S0
S1
Li-Ion 0.1μF
SHDN
IN OUT
3μA LDO 1.8V
ADJ
PFO
PB1
RST
S2
MR
LTC2935-1
LT3009
RESD*
10k
GND
GND
+
VCC
2935 TA03
S0
S2
1.5V 0.1μF LOW BATTERY
S1 LTC2935-2
GND
+
1.5V
+
1.5V
+RST
PFO
MR
POWER FAIL FAIL THRESHOLD = 2.55V
RESET THRESHOLD = 2.40V
SYSTEM RESET
VCC
2935 TA04
S2
S1
CR2032 0.1μF PFO
RST
S0
MR
LTC2935-2
GND
+
POWER FAIL FAIL THRESHOLD = 2.70V
RESET THRESHOLD = 2.55V
LOW BATTERY
SYSTEM RESET
LTC2935
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LTC2935
10
2935fa
2.00 ±0.10
(4 SIDES)
NOTE:
1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
0.40 ± 0.10
BOTTOM VIEW—EXPOSED PAD
0.64 ± 0.10
(2 SIDES)
0.75 ±0.05
R = 0.115
TYP
R = 0.05
TYP
1.37 ±0.10
(2 SIDES)
1
4
85
PIN 1 BAR
TOP MARK
(SEE NOTE 6)
0.200 REF
0.00 – 0.05
(DC8) DFN 0106 REVØ
0.23 ± 0.05
0.45 BSC
0.25 ± 0.05
1.37 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
0.64 ±0.05
(2 SIDES)
1.15 ±0.05
0.70 ±0.05
2.55 ±0.05
PACKAGE
OUTLINE
0.45 BSC
PIN 1 NOTCH
R = 0.20 OR
0.25 × 45°
CHAMFER
PACKAGE DESCRIPTION
DC Package
8-Lead Plastic DFN (2mm × 2mm)
(Reference LTC DWG # 05-08-1719 Rev Ø)
LTC2935
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LTC2935
11
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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.
PACKAGE DESCRIPTION
1.50 – 1.75
(NOTE 4)
2.80 BSC
0.22 – 0.36
8 PLCS (NOTE 3)
DATUM ‘A’
0.09 – 0.20
(NOTE 3) TS8 TSOT-23 0802
2.90 BSC
(NOTE 4)
0.65 BSC
1.95 BSC
0.80 – 0.90
1.00 MAX 0.01 – 0.10
0.20 BSC
0.30 – 0.50 REF
PIN ONE ID
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
3.85 MAX
0.52
MAX
0.65
REF
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
1.4 MIN
2.62 REF
1.22 REF
TS8 Package
8-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1637)
LTC2935
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LTC2935
12
2935fa
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2008
LT 0609 REV A • PRINTED IN USA
RELATED PARTS
TYPICAL APPLICATION
PART NUMBER DESCRIPTION COMMENTS
LTC690 5V Supply Monitor, Watchdog Timer and Battery Backup 4.65V Threshold
LTC694-3.3 3.3V Supply Monitor, Watchdog Timer and Battery Backup 2.9V Threshold
LTC1232 5V Supply Monitor, Watchdog Timer and Pushbutton Reset 4.37V/4.62V Threshold
LTC1326 Micropower Triple Supply Monitor for 5V/2.5V, 3.3V and ADJ 4.725V, 3.118V, 1V Threshold (±0.75%) and ADJ
LTC1726 Micropower Triple Supply Monitor for 2.5V/5V, 3.3V and ADJ Adjustable Reset and Watchdog Timeouts
LTC1727 Micropower Triple Supply Monitor with Open-Drain Reset Individual Monitor Outputs in MSOP
LTC1728 Micropower Triple Supply Monitor with Open-Drain Reset 5-Lead SOT-23 Package
LTC1985 Micropower Triple Supply Monitor with Push-Pull Reset Output 5-Lead SOT-23 Package
LTC2900 Programmable Quad Supply Monitor Adjustable Reset, 10-Lead MSOP and DFN Packages
LTC2901 Programmable Quad Supply Monitor Adjustable Reset and Watchdog Timer
LTC2902 Programmable Quad Supply Monitor Adjustable Reset and Tolerance
LTC2903 Precision Quad Supply Monitor 6-Lead SOT-23 Package
LTC2904/LTC2905/
LTC2906/LTC2907
Three-State Programmable Precision Dual Supply Monitor 8-Lead SOT-23 and DFN Packages
LTC2908 Precision Six-Supply Monitor (Four Fixed and Two Adjustable) 8-Lead TSOT-23 and DFN Packages
LTC2909 Precision Triple/Dual Input UV, OV and Negative Voltage Monitor Shunt Regulated VCC Pin, Adjustable Threshold and Reset,
8-Lead SOT-23 and DFN Packages
LTC2910 Octal Positive/Negative Voltage Monitor Separate VCC Pin, Eight Inputs, Up to Two Negative Monitors
Adjustable Reset Timer, 16-Lead SSOP and DFN Packages
LTC2912/LTC2913/
LTC2914
Single/Dual/Quad UV and OV Voltage Monitors Separate VCC Pin, Adjustable Reset Timer
LTC2915/LTC2916/
LTC2917/LTC2918
Single Voltage Supervisors with 27 Pin-Selectable Thresholds Manual Reset and Watchdog Functions
LTC2934 Ultralow Power Supervisor with Power-Fail Output 500nA Quiescent Current, 2mm × 2mm 8-Lead DFN and
TSOT-23 Packages, Adjustable via External Resistors
Portable Device Battery Monitor
1.18M
1μF
590k 100k
100k
VCC
LOW BATTERY
EARLY WARNING
2935 TA05
S0
S1
Li-Ion 0.1μF
SHDN
IN OUT
3μA LDO
1.8V
ADJ
PFO
RST
S2
MR
LTC2935-1
LT3009
GND
GND
+
POWER FAIL FALLING THRESHOLD = 3.15V
RESET FALLING THRESHOLD = 3.00V
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