adjustable reference in a 6-pin SOT-23 package that is
optimized for lithium-ion low battery detection circuits.
The LTC1998 features a voltage detection circuit with an
adjustable threshold voltage and hysteresis. The threshold
voltage can be programmed from 2.5V to 3.25V with two
external resistors. A 10mV to 750mV hysteresis can be
added with a third external resistor.
A proprietary internal architecture maintains 1% thresh-
old voltage accuracy over temperature with low cost 1%
external resistors.
A separate power supply pin, V
LOGIC,
allows the battery-low
logic output to operate below the battery voltage, allowing
compatibility with low voltage microprocessors without a
pull-up resistor. Power supply glitches are eliminated by
preventing the cross-conducting current which occurs
when the output changes state.
The LTC1998 operates with battery or supply voltages
up to 5.5V and its battery-low output is valid for battery
voltages above 1.5V.
High Accuracy Trip Voltage: 1% Max Error Using
External 1% Resistors
Adjustable Threshold Voltage and Hysteresis
Quiescent Current: 2.5μA Typ
Output Swings Rail-to-Rail
Thresholds Programmable from 2.5V to 3.25V
Output State Guaranteed for V
BATT
≥1.5V
Low Profile (1mm) ThinSOT™ Package
APPLICATIONS
n
Lithium-Ion Battery-Powered Equipment
PDAs
Cell Phones
Handheld Instruments
Battery Packs
Pagers
Palm Top Computers
POS Terminals
L,
LT, LTC and 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.
BLOCK DIAGRAM
Threshold Voltage Error vs Temperature
BATT
V
LOGIC
1.1R
V
HYST.A
V
TH.A
1.2V
% ERROR
THRESHOLD
ADJUST
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
1998 BD
V
TH.A
SET BY 1%
EXTERNAL R,
THRESHOLD = 3V
R
BATTLO
V
TH.A
= 1V
THRESHOLD = 3V
V
TH.A
SHORTED
TO GROUND,
THRESHOLD = 2.5V
0
–45 –25
35
15
55
–5
TEMPERATURE (°C)
75
95
1998 TA02
1998fa
1
LTC1998
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
BATT 1
GND 2
V
TH.A
3
6
BATTLO
5 V
LOGIC
4 V
H.A
Total Supply Voltage (BATT or V
LOGIC
to GND)............6V
Voltage
V
TH.A
, V
H.A
....................... BATT + 0.3V to GND – 0.3V
BATTLO
..........................V
LOGIC
+ 0.3V to GND – 0.3V
Operating Temperature Range (Note 3).... –40°C to 85°C
Specified Temperature Range (Note 4)
LTC1998C ............................................ –40°C to 85°C
LTC1998I.............................................. –40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
S6 PACKAGE
6-LEAD PLASTIC SOT-23
T
JMAX
= 150°C,
θ
JA
= 250°C/W
ORDER INFORMATION
LEAD FREE FINISH
LTC1998CS6#PBF
LTC1998IS6#PBF
LEAD BASED FINISH
LTC1998CS6
LTC1998IS6
TAPE AND REEL
LTC1998CS6#TRPBF
LTC1998IS6#TRPBF
TAPE AND REEL
LTC1998CS6#TR
LTC1998IS6#TR
PART MARKING
LTTY
LTTY
PART MARKING
LTTY
LTTY
PACKAGE DESCRIPTION
6-Lead Plastic SOT-23
6-Lead Plastic SOT-23
PACKAGE DESCRIPTION
6-Lead Plastic SOT-23
6-Lead Plastic SOT-23
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
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/
1998fa
2
LTC1998
ELECTRICAL CHARACTERISTICS
PARAMETER
Power Supply
Supply Voltage Range-BATT
Supply Voltage Range-V
LOGIC
Supply Current, V
BATT
= 3V,
V
TH.A
= 1.5V
Supply Current, V
BATT
= 5.5V,
V
TH.A
= 1.5V
Monitor
Threshold Accuracy
V
BATT.Th
= 2.5V, Pin 3 Shorted to Ground
V
BATT.Th
= 3V, Pin 3 Driven by Precision Voltage Source to 1V
LTC1998C
LTC1998I
V
BATT.Th
= 3V, V
TH.A
= 1V (Note 5)
Programmed with 1% Max External Resistors
LTC1998C
LTC1998I
V
BATT.Th
= 3.25V, Pin 3 Driven by Precision Voltage Source to 1.5V
LTC1998C
LTC1998I
V
BATT.Th
= 3.25V, V
TH.A
= 1.5V (Note 5)
Programmed with 1% Max External Resistors
LTC1998C
LTC1998I
Hysteresis Accuracy
Allowable Hysteresis Range (Note 2)
Propagation Delay
C
OUT
= 100pF
Overdrive = 10mV
Overdrive = 100mV
V
TH.A
≤ 1.5V
V
H.A
≤ 1.5V
I
OUT
= –1mA, V
LOGIC
≥ 1.5V
I
OUT
= 1mA, V
BATT
≥ 2V
I
OUT
= 0.25mA, V
BATT
= 1V
l
l
l
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
GND
= 0V, unless otherwise noted.
CONDITIONS
MIN
1.5
1
2.5
TYP
MAX
5.5
V
BATT
3.5
4.2
4.5
4.3
5.2
5.5
0.85
1
0.61
0.71
UNITS
V
V
μA
μA
μA
μA
μA
μA
%
%
%
%
T
A
= 25°C
LTC1998CS6
LTC1998IS6
T
A
= 25°C
LTC1998CS6
LTC1998IS6
l
l
l
l
3
0.6
0.8
0.5
0.6
l
l
l
l
0.8
0.9
0.6
0.7
1
1.1
0.65
0.85
%
%
%
%
l
l
l
l
l
0.9
1
–5
±5
10
350
150
0.01
0.01
V
LOGIC
– 0.3
1.1
1.3
5
750
%
%
mV
mV
mV
μs
μs
V
HYST
≤ 250mV
250mV ≤ V
HYST
≤ 750mV
Threshold Adjust Pin Leakage, I
TH.A
Hysteresis Adjust Pin Leakage, I
H.A
Output
BATTLO
High Voltage
BATTLO
Low Voltage
BATTLO
Low Voltage
1
1
nA
nA
V
0.2
0.3
V
V
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:
Maximum allowable hysteresis depends on desired trip voltages.
See application notes for details.
Note 3:
LTC1998C and LTC1998I are guaranteed functional over the
operating temperature range of –40°C to 85°C.
Note 4:
The LTC1998C is guaranteed to meet specified performance from
0°C to 70°C. The LTC1998C is designed, characterized and expected to
meet specified performance from –40°C to 85°C but is not tested or QA
sampled at these temperatures. The LTC1998I is guaranteed to meet
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