DS2408 Datasheet, PDF (1/36 Pages) Maxim Integrated Products – 1-Wire 8-Channel Addressable Switch

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DS2408
1-Wire 8-Channel Addressable Switch
FEATURES
§ Eight Channels of Programmable I/O with
Open-Drain Outputs
§ On-Resistance of PIO Pulldown Transistor
100W (max); Off-Resistance 10MW (typ)
§ Individual Activity Latches Capture
Asynchronous State Changes at PIO Inputs
for Interrogation by the Bus Master
§ Data-Strobe Output to Synchronize PIO
Logic States to External Read/Write Circuitry
§ Built-in Multidrop Controller Ensures
Compatibility with Other Dallas
Semiconductor 1-Wire^® Net Products
§ Supports 1-Wire Conditional Search
Command with Response Controlled by
Programmable PIO Conditions
§ Unique Factory-Lasered 64-Bit Registration
Number Ensures Error-Free Device Selection
and Absolute Part Identity
§ Communicates to Host with a Single Digital
Signal at 15.3kbps or 100kbps using 1-Wire
Protocol
§ Operating Range: 2.8V to 5.25V, -40°C to
+85°C
PIN CONFIGURATION
N.C.
P0
V_CC
I/O
GND
N.C.
P7
P6
1
16
2
15
3
14
4
13
5
12
6
11
7
10
8
9
150-mil SO
N.C.
N.C.
P1
P2
P3
P4
RSTZ
P5
ORDERING INFORMATION
PART
DS2408S
DS2408S
/T&R
TEMP
RANGE
-40°C to +85°C
-40°C to +85°C
PACKAGE
16-Pin SO, 150 mil
Tape-and-Reel of
DS2408S
DESCRIPTION
The DS2408 is an 8-channel, programmable I/O 1-Wire chip. PIO outputs are configured as open-drain
and provide an on resistance of 100W max. A robust PIO channel-access communication protocol ensures
that PIO output-setting changes occur error-free. A data-valid strobe output can be used to latch PIO logic
states into external circuitry such as a D/A converter (DAC) or microcontroller data bus.
DS2408 operation is controlled over the single-conductor 1-Wire bus. Device communication follows the
standard Dallas Semiconductor 1-Wire protocol. Each DS2408 has its own unalterable and unique 64-bit
ROM registration number that is factory lasered into the chip. The registration number guarantees unique
identification and is used to address the device in a multidrop 1-Wire net environment. Multiple DS2408
devices can reside on a common 1-Wire bus and can operate independently of each other. The DS2408
also supports 1-Wire conditional search capability based on PIO conditions or power-on-reset activity;
the conditions to cause participation in the conditional search are programmable. The DS2408 has an
optional V_CC supply connection. When an external supply is absent, device power is supplied parasitically
from the 1-Wire bus. When an external supply is present, PIO states are maintained in the absence of the
1-Wire bus power source. The RSTZ signal is configurable to serve as either a hard-wired reset for the
PIO output or as a strobe for external circuitry to indicate that a PIO write or PIO read has completed.
1-Wire is a registered trademark of Dallas Semiconductor.
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