DS2480B Datasheet, PDF (1/32 Pages) Dallas Semiconductor – Serial 1-Wire Line Driver with Load Sensor

19-5047; 5/10
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DS2480B
Serial to 1-Wire Line
Driver
FEATURES
 Universal, Common-Ground Serial Port to 1-
Wire^® Line Driver
 Works with All iButton^® and 1-Wire Slave
Devices
 Communicates at Standard and Overdrive 1-
Wire speed and Serial Port Data Rates of
9600 (default), 19200, 57600, and 115200 bps
 Supports 12V EPROM Programming and
Stiff 5V Pullup for Sensors and EEPROM
 Self-Calibrating Time Base with 5%
Tolerance for Serial and 1-Wire
Communication
 Slew Rate Controlled 1-Wire Pulldown and
Active Pullup to Accommodate Long Lines
and Reduce Radiation
 User-Selectable RXD/TXD Polarity
Minimizes Component Count When
Interfacing to 5V Based RS232 Systems or
Directly to UARTs
 Programmable 1-Wire Timing and Driver
Characteristics Accommodate a Wide Range
of Slave Device Configurations at Standard
Speed
 Smart Protocol Combines Data and Control
Information Without Requiring Extra Pins
 Compatible with Optical, IR, and RF to
RS232 Converters
 Low-Cost 8-Pin SO Surface-Mount Package
 Operates Over 4.5V to 5.5V from -40°C to
+85°C
PIN ASSIGNMENT
GND
1
8
RXD
1-W
2
7
TXD
NC
3
6
POL
VDD
4
5
VPP
8-Pin SO (150 mil)
PIN DESCRIPTION
GND
- Ground
1-W
- 1-Wire Input/Output
NC
- No Connection
V_DD
- 4.5V to 5.5V
V_PP
- Optional EPROM
Programming Voltage
POL
- RXD/TXD Polarity Select
TXD
- Serial Data from UART
RXD
- Serial Data to UART
ORDERING INFORMATION
PART
TEMP
RANGE
PIN-
PACKAGE
DS2480B+
-40°C to +85°C 8 SO
DS2480B+T&R -40°C to +85°C 8 SO
+ Denotes a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
DESCRIPTION
The DS2480B is a serial port to 1-Wire interface chip that supports standard and overdrive speeds. It con-
nects directly to UARTs and 5V RS232 systems. Interfacing to RS232C (±12V levels) requires a passive
clamping circuit and one 5V to ±12V level translator. Internal timers relieve the host of the burden of
generating the time-critical 1-Wire communication waveforms. In contrast to the DS9097(E) where a full
character must be sent by the host for each 1-Wire time slot, the DS2480B can translate each character
into eight 1-Wire time slots, thereby increasing the data throughput significantly. In addition, the
DS2480B can be set to communicate at four different data rates, including 115.2kbps, 57.6kbps, and
19.2kbps, with 9.6kbps being the power-on default. Command codes received from the host’s crystal
controlled UART serve as a reference to continuously calibrate the on-chip timing generator. The
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