DS2405Z/T&R Maxim Integrated Products, DS2405Z/T&R Datasheet - Page 2

• Manufacturer Part Number: DS2405Z/T&R
• Description: IC SWITCH ADDRESS NCH O-D SOT223
• Manufacturer: Maxim Integrated Products

Specifications of DS2405Z/T&R

• Interface: 1-Wire
• Voltage - Supply: 2.8 V ~ 6 V
• Package / Case: SOT-223 (3 leads + Tab), SC-73, TO-261
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Applications: -

ORDERING INFORMATION
DS2405
DS2405Z
DS2405P
DS2405/T&R
DS2405Z/T&R
DS2405P/T&R
DESCRIPTION
The DS2405 Addressable Switch is an open drain N-channel transistor that can be turned on or off by
matching the 64-bit factory-lasered registration number within each part. The 64-bit number consists of
an 8-bit family code, a unique 48-bit serial number, and an 8-bit cyclic redundancy check.
Communication with the DS2405 follows the standard Dallas Semiconductor 1-Wire protocol and can be
accomplished with a single port pin of a microcontroller. Multiple DS2405 devices can reside on a
common 1-Wire bus creating a MicroLAN. The network controller circuitry is embedded within the chip
including a search algorithm to determine the identity of each DS2405 on the network. The open drain
output (PIO pin) for each DS2405 on the MicroLan can be independently toggled on or off whether there
is one or many devices sharing the same 1-Wire bus. The logic level of the PIO pin for each device on the
MicroLan can also be individually sensed and reported to the bus master.
OVERVIEW
The DS2405 Addressable Switch provides a means for assigning an electronically readable identification
to a particular node or location with additional control capability provided by an open drain N-channel
MOSFET that can be remotely switched and sensed via communication over the 1-Wire bus. The DS2405
contains a factory-lasered registration number that includes a unique 48-bit serial number, an 8-bit CRC,
and an 8-bit family code (05h). The 64-bit ROM portion of the DS2405 not only creates an absolutely
unique electronic identification for the device itself but also is a means to locate and change or obtain the
state of the switch that is associated with the 64-bit ROM. The structure of the 64-bit ROM is shown in
Figure 1. The device derives its power entirely from the 1-Wire bus by storing energy on an internal
capacitor during periods of time when the signal line is high and continues to operate off of this “parasite”
power source during the low times of the 1-Wire line until it returns high to replenish the parasite
(capacitor) supply. The DS2405 uses the standard Dallas Semiconductor 1-Wire protocol for data
transfers, with all data being read and written least significant bit first. Communication to and from the
DS2405 requires a single bidirectional line that is typically the port pin of the microcontroller. The 1-
Wire bus master (microcontroller) must first issue one of five ROM function commands: 1) Read ROM,
2) Match ROM, 3) Search ROM, 4) Skip ROM, and 5) Active-Only Search ROM. These commands
operate on the 64-bit lasered ROM portion of each device and can singulate a specific device if many are
present on the 1-Wire line as well as indicate to the bus how many and what type of each device is
present. The protocol required for these ROM function commands is described in Figure 4. After a ROM
function command is successfully executed, the open drain output can be toggled or its current status
determined via the 1-Wire bus.
1-WIRE BUS SYSTEM
The 1-Wire bus is a system that has a single bus master and one or more slaves. In all instances, the
DS2405 is a slave device. The bus master is typically a microcontroller. The discussion of this bus system
is broken down into three topics: hardware configuration, transaction sequence, and 1-Wire signaling
(signal type and timing). For a more detailed protocol description, refer to Chapter 4 of the Book of
DS19xx iButton® Standards.
TO-92 package
4-pin SOT-223 package
6-pin TSOC package
Tape & Reel version of DS2405
Tape & Reel version of DS2405Z
Tape & Reel version of DS2405P
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