DS2437 Datasheet, PDF (1/31 Pages) Dallas Semiconductor – Smart Battery Monitor

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DS2437
Smart Battery Monitor
FEATURES
Unique 1-Wire^® interface requires only one
PIN ASSIGNMENT
port pin for communication
Provides unique 64-bit serial number to
battery packs
Eliminates thermistors by sensing battery
temperature on-chip
On-board A/D converter allows monitoring of
battery voltage for end-of-charge and end-of-
discharge determination
On-board integrated current accumulator
DQ
1
NC
2
VAD
3
NC
4
VSENS+
5
VSENS-
6
NC
7
AGND
8
16 VDD
15 NC
14 NC
13 X1
12 ^NC
11 X2
10 NC
9 GND
16-PIN SSOP
See Mech. Drawings Section
facilitates gas gauging
Real-time clock in binary format
40-byte nonvolatile user memory available for
storage of user data such as gas gauge and
manufacturing information
Operating range -40°C to +85°C
Applications include portable computers,
portable/cellular phones, consumer
electronics, and handheld instrumentation
PIN DESCRIPTION
DQ
- Data In/Out
VAD
- General A/D input
VSENS+ - Battery current monitor input (+)
VSENS- - Battery current monitor input (-)
NC
- No connect
GND
- Digital Ground
AGND - Analog Ground
X2
- Connection for 32.768 kHz XTAL
X1
- Connection for 32.768 kHz XTAL
V_DD
- Power Supply (2.7V to 10.0V)
DESCRIPTION
The DS2437 Smart Battery Monitor provides several functions that are desirable to carry in a battery
pack: a means of tagging a battery pack with a unique serial number; a direct-to-digital temperature
sensor which eliminates the need for thermistors in the battery pack; an A/D converter which measures
the battery voltage and current; an integrated current accumulator, which keeps a running total of all
current going into and out of the battery; a real-time clock; and 40 bytes of nonvolatile EEPROM
memory for storage of important parameters such as battery capacity, capacity remaining, and indication
of battery cycling.
Information is sent to/from the DS2437 over a 1-Wire interface, so that only one wire (and ground) needs
to be connected from a central microprocessor to a DS2437. This means that battery packs need only
have three output connectors: battery power, ground, and the 1-Wire interface.
Because each DS2437 contains a unique silicon serial number, multiple DS2437s can exist on the same
1-Wire bus. This allows multiple battery packs to be charged or used in the system simultaneously.
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