Linear Technology LTC1998IS6, LTC1998CS6 Datasheet

SOT-23 Comparator and Voltage

Reference for Battery Monitoring

FEATURES

■

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

■

Low Profile (1mm) ThinSOT

BATT

TM

Package

≥ 1.5V

LTC1998

2.5µA, 1% Accurate

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DESCRIPTIO

The LTC®1998 is a micropower comparator and a preci­sion 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.

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APPLICATIO S

■

Lithium-Ion Battery-Powered Equipment

PDAs
Cell Phones
Handheld Instruments
Battery Packs
Pagers
Palm Top Computers
POS Terminals

, LTC and LT are registered trademarks of Linear Technology Corporation.

ThinSOT is a trademark of Linear Technology Corporation.

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BLOCK DIAGRA

BATT

1.1R

V

HYST.A

V

TH.A

THRESHOLD

ADJUST

R

1.2V

A proprietary internal architecture maintains 1% thresh­old voltage accuracy over temperature with low cost 1%
external resistors.

A separate power supply pin, V

, allows the battery-

LOGIC

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.

Threshold Voltage Error vs Temperature

1.0

0.9
V

SET BY 1%

V

LOGIC

BATTLO

1998 BD

0.8

0.7

0.6

V

0.5

% ERROR

0.4

0.3

0.2

0.1

0

–45 15 55

1V

TH.A =

THRESHOLD = 3V

–25 –5

TEMPERATURE (°C)

TH.A

EXTERNAL R,
THRESHOLD = 3V

V

SHORTED

TH.A

TO GROUND,
THRESHOLD = 2.5V

35 75 95

1998 G05

1998f

1

LTC1998

WW

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ABSOLUTE AXI U RATI GS

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UUW

PACKAGE/ORDER I FOR ATIO

(Note 1)

ORDER PART

Total Supply Voltage (BATT or V

to GND) ......... 6V

LOGIC

Voltage

V

, V

TH.A

...........................

H.A

BATTLO ........................ V

BATT + 0.3V to GND – 0.3V

+ 0.3V to GND – 0.3V

LOGIC

Operating Temperature Range (Note 3) ...–40°C to 85°C
Specified Temperature Range (Note 4)

LTC1998C ...........................................–40°C to 85°C

BATT 1

GND 2

V

TH.A

TOP VIEW

3

S6 PACKAGE

6-LEAD PLASTIC SOT-23

T

= 150°C, θJA = 250°C/W

JMAX

6 BATTLO
5 V

LOGIC

4 V

H.A

NUMBER

LTC1998CS6
LTC1998IS6

S6 PART MARKING*

LTTY

LTC1998I.............................................–40°C to 85°C

Storage Temperature Range ................. –65°C to 150°C

Lead Temperature (Soldering, 10 sec).................. 300°C

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at TA = 25°C. V

PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply

Supply Voltage Range-BATT ● 1.5 5.5 V
Supply Voltage Range-V
Supply Current, V

V

= 1.5V LTC1998CS6 ● 4.2 µA

TH.A

Supply Current, V
V

= 1.5V LTC1998CS6 ● 5.2 µA

TH.A

Monitor

Threshold Accuracy V

Hysteresis Accuracy V

Allowable Hysteresis Range (Note 2) ● 10 750 mV
Propagation Delay C

Threshold Adjust Pin Leakage, I
Hysteresis Adjust Pin Leakage, I

Output

BATTLO High Voltage I
BATTLO Low Voltage I
BATTLO Low Voltage I

LOGIC

= 3V, TA = 25°C 2.5 3.5 µA

BATT

LTC1998IS6 ● 4.5 µA

= 5.5V, TA = 25°C 3 4.3 µA

BATT

LTC1998IS6 ● 5.5 µA

= 2.5V, Pin 3 Shorted to Ground 0.6 0.85 %

BATT.Th

V

= 3V, Pin 3 Driven by Precision LTC1998C ● 0.5 0.61 %

BATT.Th

Voltage Source to 1V LTC1998I
V

= 3V, V

BATT.Th

Programmed with 1% Max External Resistors LTC1998I ● 0.9 1.1 %
V

BATT.Th

Voltage Source to 1.5V LTC1998I ● 0.7 0.85 %
V

BATT.Th

Programmed with1% Max External Resistors LTC1998I

≤ 250mV ● –5 5 mV

HYST

250mV ≤ V

= 100pF, Overdrive = 10mV 350 µs

OUT

TH.AVTH.A

H.AVH.A

≤ 1.5V ● 0.01 1 nA

≤ 1.5V ● 0.01 1 nA

= –1mA ● V

OUT

= 1mA, V

OUT

= 0.25mA, V

OUT

TH.A

= 3.25V, Pin 3 Diven by Precision LTC1998C ● 0.6 0.65 %

= 3.25V, V

TH.A

≤ 750mV ● ±5mV

HYST

Overdrive = 100mV 150 µs

≥ 2V ● 0.2 V

BATT

BATT

The ● denotes the specifications which apply over the full operating

= 1V (Note 5) LTC1998C ● 0.8 1 %

= 1.5V (Note 5) LTC1998C ● 0.9 1.1 %

= 1V ● 0.3 V

*The temperature grades are indentified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.

= 0V, unless otherwise noted.

GND

● 1V

● 0.8 1 %

● 0.6 0.71 %

● 1 1.3 %

– 0.3 V

LOGIC

BATT

1998f

V

2

ELECTRICAL CHARACTERISTICS

LTC1998

Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.

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
specified performance from –40°C to 85°C.

Note 5: This parameter is not 100% tested.

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TYPICAL PERFOR A CE CHARACTERISTICS

Quiescent Supply Current vs
Supply Voltage

3.5
TA = 25°C

= V

V

LOGIC

3.0

2.5

2.0

1.5

1.0

SUPPLY CURRENT (µA)

0.5

BATT

V

= 1.5V

TH.A

V

TH.A

= 0V

Quiescent Supply Current vs
Temperature

3.5
V

= V

LOGIC

= 3V

V

BATT

3.0

2.5

2.0

1.5

1.0

SUPPLY CURRENT (µA)

0.5

TH.A

= 1.5V

Threshold Voltage vs Threshold
Adjust Voltage

3.5

3.0

THRESHOLD VOLTAGE (V)

0

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
SUPPLY VOLTAGE (V)

Available Hysteresis vs
Threshold Voltage

750

500

250

AVAILABLE HYSTERESIS (mV)

0

2.5

2.75 3.0

LOW BATTERY THRESHOLD VOLTAGE (V)

1998 G01

1998 G04

3.25

0

–50 –30 –10 10 30 50 70 90

TEMPERATURE (°C)

Threshold Voltage Error vs
Temperature

1.0

0.9
V

SET BY 1%

0.8

0.7

0.6

V

0.5

% ERROR

0.4

0.3

0.2

0.1

0

–45 15 55

1V

TH.A =

THRESHOLD = 3V

–25 –5

TEMPERATURE (°C)

TH.A

EXTERNAL R,
THRESHOLD = 3V

V

SHORTED

TH.A

TO GROUND,
THRESHOLD = 2.5V

35 75 95

1998 G02

1998 G05

2.5
0

0.5 1.0

THRESHOLD ADJUST VOLTAGE (V)

Input Current vs Temperature

10000

1000

(pA)

H.A

, V

100

TH.A

10

1

INPUT CURRENT V

0.1

45 65

35

55

75

TEMPERATURE (°C)

1.5

1998 G03

VIN = 1.5V

VIN = 1V

VIN = 0.5V

105

85 125

115

95

1998 G06

1998f

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