Fuel-Gauge. DS2788 Datasheet


DS2788 Datasheet PDF


DS2788


Stand-Alone Fuel-Gauge
DS2788

19-4639; Rev 2; 5/09

Stand-Alone Fuel-Gauge IC with LED Display Drivers

General Description
The DS2788 measures voltage, temperature, and current, and estimates available capacity for rechargeable lithium-ion (Li+) and Li+ polymer batteries. Cell characteristics and application parameters used in the calculations are stored in on-chip EEPROM. The available capacity registers report a conservative estimate of the amount of charge that can be removed given the current temperature, discharge rate, stored charge, and application parameters. Capacity estimation is reported in mAh remaining and percentage of full.
LED display drivers and a debounced input make display of the capacity information easy. The LED pins can directly sink current, requiring only a resistor for setting the current in the LED display, thus reducing space and cost.
Applications
Power Tools
Electric Bicycles
Electric Vehicles
Uninterruptible Power Supply
Digital Cameras

TOP VIEW

LED2 LED1 DVSS VDD OVD
VSS DQ

1 2 3 4 5 6 7

+

Pin Configuration

DS2788 TSSOP

14 LED3 13 LED4 12 LED5 11 PIO 10 VIN 9 SNS 8 VMA

Features
♦ Five 30mA Open-Drain Drivers for Driving LED Fuel-Gauge Display
♦ Debounced Fuel-Gauge Display Enable
♦ Internal Voltage Measurement Gain Register for Trimming External Voltage-Divider
♦ Pin for Driving FETs to Enable Voltage-Divider Only During Voltage Measurement, Conserving Power
...



DS2788
19-4639; Rev 2; 5/09
Stand-Alone Fuel-Gauge IC with
LED Display Drivers
General Description
The DS2788 measures voltage, temperature, and cur-
rent, and estimates available capacity for rechargeable
lithium-ion (Li+) and Li+ polymer batteries. Cell charac-
teristics and application parameters used in the calcu-
lations are stored in on-chip EEPROM. The available
capacity registers report a conservative estimate of the
amount of charge that can be removed given the cur-
rent temperature, discharge rate, stored charge, and
application parameters. Capacity estimation is reported
in mAh remaining and percentage of full.
LED display drivers and a debounced input make dis-
play of the capacity information easy. The LED pins can
directly sink current, requiring only a resistor for setting
the current in the LED display, thus reducing space and
cost.
Applications
Power Tools
Electric Bicycles
Electric Vehicles
Uninterruptible Power Supply
Digital Cameras
TOP VIEW
LED2
LED1
DVSS
VDD
OVD
VSS
DQ
1
2
3
4
5
6
7
+
Pin Configuration
DS2788
TSSOP
14 LED3
13 LED4
12 LED5
11 PIO
10 VIN
9 SNS
8 VMA
Features
Five 30mA Open-Drain Drivers for Driving LED
Fuel-Gauge Display
Debounced Fuel-Gauge Display Enable
Internal Voltage Measurement Gain Register for
Trimming External Voltage-Divider
Pin for Driving FETs to Enable Voltage-Divider
Only During Voltage Measurement, Conserving
Power
Precision Voltage, Temperature, and Current
Measurement System
Accurate, Temperature-Stable, Internal Time Base
Absolute and Relative Capacity Estimated from
Coulomb Count, Discharge Rate, Temperature,
and Battery Cell Characteristics
Accurate Warning of Low Battery Conditions
Automatic Backup of Coulomb Count and Age
Estimation to Nonvolatile (NV) EEPROM
Gain and Tempco Calibration Allows the Use of
Low-Cost Sense Resistors
24-Byte Battery/Application Parameter EEPROM
16-Byte User EEPROM
Unique ID and Multidrop 1-Wire® Interface
14-Pin TSSOP Package
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
DS2788E+
-25°C to +70°C 14 TSSOP
DS2788E+T&R -25°C to +70°C 14 TSSOP
+Denotes a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
Typical Operating Circuit appears at end of data sheet.
1-Wire is a registered trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

DS2788
Stand-Alone Fuel-Gauge IC with
LED Display Drivers
ABSOLUTE MAXIMUM RATINGS
Voltage Range on Any Pin Relative to VSS..............-0.3V to +6.0V
Voltage Range on VIN, VMA Relative to VSS ...-0.3V to VDD + 0.3V
DVSS to VSS .....................................................................-0.3V to +0.3V
LED1–5.................................................................60mA each pin
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-55°C to +125°C
Soldering Temperature (10s) ................Refer to IPC/JEDEC-020
Specification.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
RECOMMENDED DC OPERATING CHARACTERISTICS
(VDD = 2.5V to 4.5V, TA = -25°C to +70°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
Supply Voltage
VIN, VMA Voltage Range
DQ, PIO, OVD, LED1–LED5
Voltage Range
SYMBOL
VDD
(Note 1)
(Note 1)
(Note 1)
CONDITIONS
MIN
+2.5
0
0
TYP
MAX
+4.5
VDD
+5.5
UNITS
V
V
V
DC ELECTRICAL CHARACTERISTICS
(VDD = 2.5V to 4.5V, TA = -25°C to +70°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
ACTIVE Current
SYMBOL
IACTIVE
CONDITIONS
2.5V  VDD  4.2V
MIN
SLEEP Mode Current
Input Logic-High: DQ, PIO
Input Logic-Low: DQ, PIO
Output Logic-Low: DQ, PIO, VMA
Output Logic-High: VMA
VMA Precharge Time
Pulldown Current: DQ, PIO
Output Logic-Low: LED1–LED5
Input Logic-High: OVD
ISLEEP
VIH
VIL
VOL
VOH
tPRE
IPD
VOL
VIH
(Note 1)
(Note 1)
IOL = 4mA (Note 1)
IOH = 1mA (Note 1)
VDQ, VPIO = 0.4V
IOL = -30mA (Note 1)
(Note 1)
1.5
VDD -
0.5
13.3
VDD -
0.2
Input Logic-Low: OVD
VIN Input Resistance
DQ SLEEP Timeout
Undervoltage SLEEP Threshold
PIO Switch Debounce
LED1 Display Blink Rate
LED Display-On Time
VIL
RIN
tSLEEP
VSLEEP
(Note 1)
DQ < VIL
(Note 1)
50% duty cycle
15
1.8
2.40
100
0.9
3.6
TYP
70
1
MAX
95
105
3
0.6
0.4
UNITS
μA
μA
V
V
V
V
14.2
0.2 5
1
ms
μA
V
V
VSS +
0.2
2.0
2.45
1.0
4.0
2.2
2.50
130
1.1
4.4
V
M
s
V
ms
Hz
s
2 _______________________________________________________________________________________

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