DS2430A+T&R - Hytronics

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FEATURES

 256-bit Electrically Erasable Programmable

Read Only Memory (EEPROM) plus 64-bit

one-time programmable application register

 Unique, factory-lasered and tested 64-bit

registration number (8-bit family code + 48-bit

serial number + 8-bit CRC tester) assures

absolute identity because no two parts are alike

 Built-in multidrop controller ensures

compatibility with other MicroLAN products

 EEPROM organized as one page of 32 bytes

for random access

 Reduces control, address, data, and power to a

single data pin

 Directly connects to a single port pin of a

microprocessor and communicates at up to

15.3kbits per second

 8-bit family code specifies DS2430A

communication requirements to reader

 Presence detector acknowledges when reader

first applies voltage

 Low cost TO-92 or 6-pin TSOC and UCSP

surface mount package

 Reads and writes over a wide voltage range of

2.8V to 5.25V from -40°C to +85°C

ORDERING INFORMATION

PART

TEMP RANGE

PIN-PACKAGE

DS2430A+

-40°C to +85°C

3 TO-92

DS2430A+T&R

-40°C to +85°C

3 TO-92 (2k pcs)

DS2430AP+

-40°C to +85°C

6 TSOC

DS2430AP+T&R

-40°C to +85°C

6 TSOC (4k pcs)

+Denotes a lead(Pb)-free/RoHS-compliant package.

T&R = Tape and reel.

PIN ASSIGNMENT

NOTE: The leads of TO-92 packages on tape and reel are formed

to approximately 100-mil (2.54mm) spacing. For details see the

Package Information.

PIN DESCRIPTION

TO-92 TSOC

Pin 1 Ground Ground

Pin 2 Data Data

Pin 3 NC NC

Pin 4 –––– NC

Pin 5 –––– NC

Pin 6 –––– NC

DS2430A

256-Bit 1-Wire EEPROM

SIDE VIEW

TOP VIEW

3.7mm x 4.0mm x 1.5mm

TSOC PACKAGE

BOTTOM VIEW

TO-92

DALLAS

DS2430A

1 2 3

19-5236; Rev 2/12

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

2 of 19

DESCRIPTION

The DS2430A 256-bit 1-Wire® EEPROM identifies and stores relevant information about the product to

which it is associated. This lot or product specific information can be accessed with minimal interface, for

example a single port pin of a microcontroller. The DS2430A consists of a factory-lasered registration

number that includes a unique 48-bit serial number, an 8-bit CRC, and an 8-bit Family Code (14h) plus

256 bits of user-programmable EEPROM and a 64-bit one-time programmable application register. The

power to read and write the DS2430A is derived entirely from the 1-Wire communication line. Data is

transferred serially via the 1-Wire protocol, which requires only a single data lead and a ground return.

The 48-bit serial number that is factory-lasered into each DS2430A provides a guaranteed unique identity

that allows for absolute traceability. The TO-92 and TSOC packages provide a compact enclosure that

allows standard assembly equipment to handle the device easily for attachment to printed circuit boards

or wiring. Typical applications include storage of calibration constants, board identification, and product

revision status.

OVERVIEW

The block diagram in Figure 1 shows the relationships between the major control and memory sections of

the DS2430A. The DS2430A has four main data components: 1) 64-bit lasered ROM, 2) 256-bit

EEPROM data memory with scratchpad, 3) 64-bit one-time programmable application register with

scratchpad and 4) 8-bit status memory. The hierarchical structure of the 1-Wire protocol is shown in

Figure 2. The bus master must first provide one of the four ROM Function Commands: 1) Read ROM, 2)

Match ROM, 3) Search ROM, 4) Skip ROM. The protocol required for these ROM Function Commands

is described in Figure 8. After a ROM Function Command is successfully executed, the memory

functions become accessible and the master can provide any one of the four memory function commands.

The protocol for these memory function commands is described in Figure 6. All data is read and written

least significant bit first.

64-BIT LASERED ROM

Each DS2430A contains a unique ROM code that is 64 bits long. The first 8 bits are a 1-Wire family code

(14h). The next 48 bits are a unique serial number. The last 8 bits are a CRC of the first 56 bits. (Figure

3). The 1-Wire CRC is generated using a polynomial generator consisting of a shift register and XOR

gates as shown in Figure 4. The polynomial is X8 + X5 + X4 + 1. Additional information about the

1-Wire CRC is available in Application Note 27. The shift register bits are initialized to 0. Then starting

with the least significant bit of the family code, one bit at a time is shifted in. After the 8th bit of the

family code has been entered, then the serial number is entered. After the 48th bit of the serial number has

been entered, the shift register contains the CRC value. Shifting in the 8 bits of CRC should return the

shift register to all 0s.

1-Wire is a registered trademark of Maxim Integrated Products, Inc.

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

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DS2430A BLOCK DIAGRAM Figure 1

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

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HIERARCHICAL STRUCTURE FOR 1-WIRE PROTOCOL Figure 2

64-BIT LASERED ROM Figure 3

8-Bit CRC Code

48-Bit Serial Number

8-Bit Family Code (14H)

MSB

LSB

MSB

LSB

MSB

LSB

1-WIRE CRC GENERATOR Figure 4

Polynomial = X8 + X5 + X4 + 1

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

5 of 19

MEMORY

The memory of the DS2430A consists of three separate sections, called data memory, application

intermediate storage area called scratchpad that acts as a buffer when writing to the device. The data

memory can be read and written as often as desired. The application register, however, is one-time

programmable only. Once the application register is programmed, it is automatically write protected. The

status register indicates whether the application register is already locked or whether it is still available

for storing data. As long as the application register is unprogrammed, the status register reads FFh.

Copying data from the register scratchpad to the application register clears the 2 least significant bits of

the status register, yielding an FCh the next time one reads the status register.

DS2430A MEMORY MAP Figure 5

MEMORY FUNCTION COMMANDS

The Memory Function Flow Chart (Figure 6) describes the protocols necessary for accessing the different

memory sections of the DS2430A. An example is shown later in this document.

WRITE SCRATCHPAD [0Fh]

After issuing the Write Scratchpad command, the master must first provide a 1-byte address, followed by

the data to be written to the scratchpad for the data memory. The DS2430A automatically increments the

address after every byte it receives. After having received a data byte for address 1Fh, the address counter

wraps around to 00h for the next byte and writing continues until the master sends a Reset Pulse.

READ SCRATCHPAD [AAh]

This command is used to verify data previously written to the scratchpad before it is copied into the final

storage EEPROM memory. After issuing the Read Scratchpad command, the master must provide the 1-

byte starting address from where data is to be read. The DS2430A automatically increments the address

after every byte read by the master. After the data at address 1Fh has been read, the address counter wraps

around to 00h for the next byte and reading continues until the master sends a Reset Pulse.

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

6 of 19

MEMORY FUNCTION FLOW CHART Figure 6

COPY SCRATCHPAD [55h]

After the data stored in the scratchpad has been verified the master may send the Copy Scratchpad

command followed by a validation key of A5h to transfer data from the scratchpad to the EEPROM

memory. This command always copies the data of the entire scratchpad. Therefore, if one desires to

change only a few bytes of the EEPROM data, the scratchpad should contain a copy of the latest

EEPROM data before the Write Scratchpad and Copy Scratchpad commands are issued. After this

command and the validation key are issued, the data line must be held above VPUPmin for at least tPROG.

READ MEMORY [F0h]

The Read Memory command is used to read a portion or all of the EEPROM data memory and to copy

the entire data memory into the scratchpad to prepare for changing a few bytes. To copy data from the

data memory to the scratchpad and to read it, the master must issue the read memory command followed

by the 1-byte starting address of the data to be read from the scratchpad. The DS2430A automatically

increments the address after every byte read by the master. After the data of address 1Fh has been read,

the address counter wraps around to 00h for the next byte and reading continues until the master sends a

Reset Pulse. If one intends to copy the entire data memory to the scratchpad without reading data, a

starting address is not required; the master may send a Reset Pulse immediately following the command

code.

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

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MEMORY FUNCTION FLOW CHART Figure 6 (continued)

WRITE APPLICATION REGISTER [99h]

This command is essentially the same as the Write Scratchpad command, but it addresses the 64-bit

by the data to be written. The DS2430A automatically increments the address after every byte it receives.

After receiving the data byte for address 07h, the address counter wraps around to 00h for the next byte

and writing continues until the master sends a Reset Pulse. The Write Application Register command can

be used as long as the application register has not yet been locked. If issued for a device with the

application register locked, the data written to the register scratchpad will be lost.

READ STATUS REGISTER [66h]

The status register is a means for the master to find out whether the application register has been

programmed and locked. After issuing the read status register command, the master must provide the

validation key 00h before receiving status information. The two least significant bits of the 8-bit status

master may finish the read status command by sending a Reset Pulse at any time.

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

8 of 19

MEMORY FUNCTION FLOW CHART Figure 6 (continued)

READ APPLICATION REGISTER [C3h]

This command is used to read the application register or the register scratchpad. As long as the

application register is not yet locked, the DS2430A transmits data from the register scratchpad. After the

application register is locked the DS2430A transmits data from the application register, making the

received with this command came from. After issuing the Read Application Register command, the

master must provide the 1-byte starting address from where data is to be read. The DS2430A

automatically increments the address after every byte read by the master. After the data at address 07h

has been read, the address counter wraps around to 00h for the next byte and reading continues until the

master sends a Reset Pulse.

COPY & LOCK APPLICATION REGISTER [5Ah]

After the data stored in the register scratchpad has been verified the master may send the Copy & Lock

Application Register command followed by a validation key of A5h to transfer the contents of the entire

cancel this command by sending a Reset Pulse instead of the validation key. After the validation key is

transmitted, the data line must be held above VPUPmin for at least tPROG. Once tPROG has expired, the

application register will contain the data of the register scratchpad. Further write accesses to the

application register will be denied. The Copy & Lock Application Register command can only be

executed once.

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

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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

DS2430A 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). The 1-Wire protocol defines bus transactions in terms of the bus state

during specified time slots that are initiated on the falling edge of sync pulses from the bus master.

Hardware Configuration

The 1-Wire bus has only a single line by definition; it is important that each device on the bus be able to

drive it at the appropriate time. To facilitate this, each device attached to the 1-Wire bus must have open

drain connection or three-state outputs. The 1-Wire port of the DS2430A is open drain with an internal

circuit equivalent to that shown in Figure 7. A multidrop bus consists of a 1-Wire bus with multiple

slaves attached. The DS2430A communicates at regular 1-Wire speed, 15.3kbits per second, and requires

a pullup resistor as shown in Figure 7. The idle state for the 1-Wire bus is high. If for any reason a

transaction needs to be suspended, the bus MUST be left in the idle state if the transaction is to resume. If

this does not occur and the bus is left low for more than 120µs, one or more of the devices on the bus may

be reset.

HARDWARE CONFIGURATION Figure 7

Note: Depending on the 1-Wire communication speed and the bus characteristics, the optimal pullup

resistor value will be in the 0.3kΩ to 2.2kΩ range. To write to a single device, a RPUPmax resistor and

VPUP of at least 4.0V is sufficient. For writing multiple DS2430As simultaneously or operation at low

VPUP, the resistor should be bypassed by a low-impedance pullup to VPUP while the device copies the

scratchpad to EEPROM.

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

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ROM FUNCTIONS FLOW CHART Figure 8

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

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Transaction Sequence

The sequence for accessing the DS2430A via the 1-Wire port is as follows:

 Initialization

 ROM Function Command

 Memory Function Command

 Transaction/Data

INITIALIZATION

All transactions on the 1-Wire bus begin with an initialization sequence. The initialization sequence

consists of a Reset Pulse transmitted by the bus master followed by a Presence Pulse(s) transmitted by the

slave(s).

The Presence Pulse lets the bus master know that the DS2430A is on the bus and is ready to operate. For

more details, see the 1-Wire Signaling section.

ROM FUNCTION COMMANDS

Once the bus master has detected a presence pulse, it can issue one of the four ROM function commands.

All ROM function commands are 8 bits long. A list of these commands follows (refer to flowchart in

Figure 8):

Read ROM [33h]

This command allows the bus master to read the DS2430A’s 8-bit family code, 48-bit serial number, and

8-bit CRC. This command can be used only if there is a single DS2430A on the bus. If more than one

slave is present on the bus, a data collision will occur when all slaves try to transmit at the same time

(open drain produces a wired-AND result). The resultant family code and 48-bit serial number usually

result in a mismatch of the CRC.

Match ROM [55h]

The Match ROM command, followed by a 64-bit ROM sequence, allows the bus master to address a

specific DS2430A on a multidrop bus. Only the DS2430A that exactly matches the 64-bit ROM sequence

will respond to the subsequent memory function command. All slaves that do not match the 64-bit ROM

sequence will wait for a Reset Pulse. This command can be used with a single or multiple devices on the

bus.

Skip ROM [CCh]

This command can save time in a single-drop bus system by allowing the bus master to access the

memory functions without providing the 64-bit ROM code. If more than one slave is present on the bus

and a read command is issued following the Skip ROM command, data collision will occur on the bus as

multiple slaves transmit simultaneously (open drain pulldowns produces a wired-AND result).

Search ROM [F0h]

When a system is initially brought up, the bus master might not know the number of devices on the 1-

Wire bus or their 64-bit ROM codes. The Search ROM command allows the bus master to use a process

of elimination to identify the 64-bit ROM codes of all slave devices on the bus. The Search ROM process

is the repetition of a simple, three-step routine: read a bit, read the complement of the bit, then write the

desired value of that bit. The bus master performs this simple, three-step routine on each bit of the ROM.

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

12 of 19

After one complete pass, the bus master knows the contents of the ROM in one device. The remaining

number of devices and their ROM codes may be identified by additional passes. See Application Note

187 for a comprehensive discussion of a search ROM, including an actual example.

1-Wire Signaling

The DS2430A requires strict protocols to insure data integrity. The protocol consists of four types of

signaling on one line: Reset Sequence with Reset Pulse and Presence Pulse, Write-0, Write-1 and Read-

Data. All these signals (except Presence Pulse) are initiated by the bus master.

To get from idle to active, the voltage on the 1-Wire line needs to fall from VPUP below the threshold VTL.

To get from active to idle, the voltage needs to rise from VILMAX past the threshold VTH. The time it takes

for the voltage to make this rise is seen in Figure 9 as ε, and its duration depends on the pullup resistor

(RPUP) used and the capacitance of the 1-Wire network attached. The voltage VILMAX is relevant for the

DS2430A when determining a logical level, not triggering any events.

Figure 9 shows the initialization sequence required to begin any communication with the DS2430A. A

Reset Pulse followed by a Presence Pulse indicates the DS2430A is ready to receive data, given the

correct ROM and memory function command. If the bus master uses slew-rate control on the falling

edge, it must pull down the line for tRSTL + tF to compensate for the edge.

After the bus master has released the line it goes into Receive mode. Now the 1-Wire bus is pulled to

VPUP through the pullup resistor. When the threshold VTH is crossed, the DS2340A waits for tPDH and then

transmits a Presence Pulse by pulling the line low for tPDL. To detect a Presence Pulse, the master must

test the logical state of the 1-Wire line at tMSP. The tRSTH window must be at least the sum of tPDHMAX,

tPDLMAX, and tRECMIN. Immediately after tRSTH is expired, the DS2430A is ready for data communication.

INITIALIZATION PROCEDURE “RESET AND PRESENCE PULSES” Figure 9

Read/Write Time Slots

Data communication with the DS2430A takes place in time slots, which carry a single bit each. Write

time slots transport data from bus master to slave. Read time slots transfer data from slave to master.

Figure 10 illustrates the definitions of the write and read time slots.

All communication begins with the master pulling the data line low. As the voltage on the 1-Wire line

falls below the threshold VTL, the DS2430A starts its internal timing generator that determines when the

data line is sampled during a write time slot and how long data is valid during a read time slot.

RESISTOR MASTER DS2430A

tRSTL

tPDL

tRSTH

tPDH

MASTER TX “RESET PULSE”

MASTER RX “PRESENCE PULSE”

PUP

VIHMASTER

VTH

VTL

VILMAX

tREC

tMSP

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

13 of 19

Master-to-Slave

For a Write-1 time slot, the voltage on the data line must have crossed the VTH threshold before the

Write-1 low time tW1LMAX is expired. For a Write-0 time slot, the voltage on the data line must stay below

the VTH threshold until the Write-0 low time tW0LMIN is expired. For the most reliable communication, the

voltage on the data line should not exceed VILMAX during the entire tW0L or tW1L window. After the VTH

threshold has been crossed, the DS2430A needs a recovery time tREC before it is ready for the next time

slot.

READ/WRITE TIMING DIAGRAM Figure 10

Write-1 Time Slot

Write-0 Time Slot

Read-data Time Slot

RESISTOR MASTER

tREC

PUP

VIHMASTER

VTH

VTL

VILMAX

tSLOT

tW0L

RESISTOR MASTER

PUP

VIHMASTER

VTH

VTL

VILMAX

tSLOT

tW1L

RESISTOR MASTER DS2430A

tREC

PUP

VIHMASTER

VTH

VTL

VILMAX

Master

Sampling

Window

tSLOT

tRL

tMSR

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

14 of 19

Slave-to-Master

A Read-data time slot begins like a Write-1 time slot. The voltage on the data line must remain below

VTL until the read low time tRL is expired. During the tRL window, when responding with a 0, the

DS2430A starts pulling the data line low; its internal timing generator determines when this pulldown

ends and the voltage starts rising again. When responding with a 1, the DS2430A does not hold the data

line low at all, and the voltage starts rising as soon as tRL is over.

The sum of tRL + δ (rise time) on one side and the internal timing generator of the DS2430A on the other

side define the master sampling window (tMSRMIN to tMSRMAX) in which the master must perform a read

from the data line. For the most reliable communication, tRL should be as short as permissible, and the

master should read close to but no later than tMSRMAX. After reading from the data line, the master must

wait until tSLOT is expired. This guarantees sufficient recovery time tREC for the DS2430A to get ready for

the next time slot. Note that tREC specified herein applies only to a single DS2430A attached to a 1-Wire

line. For multidevice configurations, tREC must be extended to accommodate the additional 1-Wire device

input capacitance. Alternatively, an interface that performs active pullup during the 1-Wire recovery time

such as the DS2482-x00 or DS2480B 1-Wire line drivers can be used.

IMPROVED NETWORK BEHAVIOR (SWITCHPOINT HYSTERESIS)

In a 1-Wire environment, line termination is possible only during transients controlled by the bus master

(1-Wire driver). 1-Wire networks, therefore, are susceptible to noise of various origins. Depending on the

physical size and topology of the network, reflections from end points and branch points can add up, or

cancel each other to some extent. Such reflections are visible as glitches or ringing on the 1-Wire

communication line. Noise coupled onto the 1-Wire line from external sources can also result in signal

glitching. A glitch during the rising edge of a time slot can cause a slave device to lose synchronization

with the master and, consequently, result in a Search ROM command coming to a dead end or cause a

device-specific function command to abort. For better performance in network applications, the

DS2430A uses a new 1-Wire front end, which makes it less sensitive to noise.

The 1-Wire front end of the DS2430A differs from traditional slave devices in three characteristics.

1) There is additional low-pass filtering in the circuit that detects the falling edge at the beginning of a

time slot. This reduces the sensitivity to high-frequency noise.

2) There is a hysteresis at the low-to-high switching threshold VTH. If a negative glitch crosses VTH but

does not go below VTH - VHY, it will not be recognized (Figure 11, Case A)..

3) There is a time window specified by the rising edge hold-off time tREH during which glitches are

ignored, even if they extend below VTH - VHY threshold (Figure 11, Case B, tGL < tREH). Deep voltage

droops or glitches that appear late after crossing the VTH threshold and extend beyond the tREH

window cannot be filtered out and are taken as the beginning of a new time slot (Figure 11, Case C,

tGL ≥ tREH).

Devices that have the parameters VHY, and tREH specified in their electrical characteristics use the

improved 1-Wire front end.

NOISE SUPPRESSION SCHEME Figure 11

PUP

VTH

VHY

tREH

tGL

tREH

tGL

Case A

Case C

Case B

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

15 of 19

MEMORY FUNCTION EXAMPLE

Example: Write 2 data bytes to data memory locations 0006h and 0007h. Read entire data memory.

MASTER MODE

DATA (LSB FIRST)

COMMENTS

Reset

Reset pulse (480µs to 960µs)

Presence

Presence pulse

CCh

Issue “Skip ROM” command

0Fh

Issue “Write Scratchpad” command

06h

Start address = 06h

<2 Data Bytes>

Write 2 bytes of data to scratchpad

Reset

Reset pulse

Presence

Presence pulse

CCh

Issue “Skip ROM” command

AAh

Issue “Read Scratchpad” command

06h

Start address = 06h

<2 Data Bytes>

Read scratchpad data and verify

Reset

Reset pulse

Presence

Presence pulse

CCh

Issue “Skip ROM” command

55h

Issue “Copy Scratchpad” command

A5h

Validation key

Data line must be above VPUPmin for tPROG.

Reset

Reset pulse

Presence

Presence pulse

CCh

Issue “Skip ROM” command

F0h

Issue “Read Memory” command

00h

Start address = 00h

<32 Bytes>

Read EEPROM data page

Reset

Reset pulse

Presence

Presence pulse

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

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ABSOLUTE MAXIMUM RATINGS

Voltage Range on DATA to Ground -0.5V to +6.0V

DATA Sink Current 20mA

Operating Temperature Range -40°C to +85°C

Junction Temperature +150°C

Storage Temperature Range -55°C to +125°C

Lead Temperature (soldering, 10s) +300°C

Soldering Temperature (reflow)

TSOC +260°C

TO-92 +250°C

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 the

absolute maximum rating conditions for extended periods may affect device reliability.

ELECTRICAL CHARACTERISTICS

(TA = -40°C to +85°C, unless otherwise noted.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

DATA PIN GENERAL DATA

1-Wire Pullup Voltage

VPUP

(Notes 2)

2.8

5.25

1-Wire Pullup Resistance

RPUP

(Notes 2, 3)

0.3

2.2

kΩ

Input Capacitance

CIO

(Notes 4, 5)

1000

Input Load Current

DATA pin at VPUP

0.05

µA

High-to-Low Switching

Threshold

VTL (Notes 5, 6, 7) 0.46

PUP

1.8V

Input Low Voltage

VIL

(Notes 2, 8)

0.5

Low-to-High Switching

Threshold

VTH (Notes 5, 6, 9) 1.0

PUP

1.1V

Switching Hysteresis

VHY

(Notes 5, 6, 10)

0.21

1.70

Output Low Voltage

VOL

At 4mA (Note 11)

0.4

Recovery Time

tREC

RPUP = 2.2kΩ (Notes 2,12)

µs

Rising-Edge Hold-off

Time

tREH

(Notes 5, 13)

0.5 5.0 µs

Timeslot Duration

tSLOT

(Notes 2, 14)

µs

DATA PIN, 1-WIRE RESET, PRESENCE DETECT CYCLE

Reset Low Time

tRSTL

(Note 2)

480

960

µs

Presence Detect High

Time

tPDH

15 60 µs

Presence Detect Low

Time

tPDL

60 240 µs

Presence Detect Sample

Time

tMSP

(Notes 2, 15)

60 75 µs

DATA PIN, 1-Wire WRITE

Write-0 Low Time

tW0L

(Notes 2, 16)

120 - ε

µs

Write-1 Low Time

tW1L

(Notes 2, 16)

15 - ε

µs

DATA PIN, 1-Wire READ

Read Low Time

tRL

(Notes 2, 17)

15 - δ

µs

Read Sample Time

tMSR

(Notes 2, 17)

tRL + δ

µs

EEPROM

Programming Current

IPROG

(Notes 5, 18)

0.5

Programming Time

tPROG

(Note 19)

Write/Erase Cycles

(Endurance)

(Notes 20, 21)

NCY

At 25°C

200k



At 85°C (worst case)

50k

Data Retention (Notes 22,

23, 24)

tDR At 85°C (worst case) 40

years

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

17 of 19

ELECTRICAL CHARACTERISTICS (continued)

(TA = -40°C to +85°C, unless otherwise noted.) (Note 1)

Note 1:

Limits are 100% production tested at T

= +25°C and/or T

= +85°C. Limits over the operating temperature

range and relevant supply voltage range are guaranteed by design and characterization. Typical values are not

guaranteed.

Note 2:

System requirement.

Note 3:

Maximum allowable pullup resistance is a function of the number of 1-Wire devices in the system and 1-Wire

recovery times. The specified value here applies to systems with only one device and with the minimum tREC. For

more heavily loaded systems, an active pullup such as that found in the DS2482-x00, DS2480B, or DS2490 may

be required. If longer tREC is used, higher RPUP values may be able to be tolerated.

Note 4:

Maximum value represents the internal parasite capacitance when V

PUP

is first applied. If a 2.2kΩ resistor is used

to pull up the data line, 2.5µs after VPUP has been applied the parasite capacitance will not affect normal

communications.

Note 5:

Guaranteed by design, characterization and/or simulation only. Not production tested.

Note 6:

, V

, and V

are a function of the internal supply voltage which is itself a function of V

PUP

, R

PUP

, 1-Wire

timing, and capacitive loading on DATA. Lower VPUP, higher RPUP, shorter tREC, and heavier capacitive loading

all lead to lower values of VTL, VTH, and VHY.

Note 7:

Voltage below which, during a falling edge on DATA, a logic 0 is detected.

Note 8:

The voltage on DATA needs to be less or equal to V

IL(MAX)

at all times the master is driving DATA to a logic-0

level.

Note 9:

Voltage above which, during a rising edge on DATA, a logic 1 is detected.

Note 10:

After V

is crossed during a rising edge on DATA, the voltage on DATA has to drop by at least V

to be

detected as logic '0'.

Note 11:

The I-V characteristic is linear for voltages less than 1V.

Note 12:

Applies to a single device attached to a 1-Wire line.

Note 13:

The earliest recognition of a negative edge is possible at t

REH

after V

has been reached on the preceding rising

edge.

Note 14:

Defines maximum possible bit rate. Equal to 1/(tW0L(min) + tREC(min)).

Note 15:

Interval after t

RSTL

during which a bus master is guaranteed to sample a logic-0 on DATA if there is a DS2430A

present. Minimum limit is tPDH(max); maximum limit is tPDH(min) + tPDL(min).

Note 16:

ε in Figure 10 represents the time required for the pullup circuitry to pull the voltage on DATA up from V

VTH. The actual maximum duration for the master to pull the line low is tW1Lmax + tF and tW0Lmax + tF respectively.

Note 17:

δ in Figure 10 represents the time required for the pullup circuitry to pull the voltage on DATA up from V

to the

input high threshold of the bus master. The actual maximum duration for the master to pull the line low is

tRLmax + tF.

Note 18:

Current drawn from DATA during the EEPROM programming interval. The pullup circuit on DATA during the

programming interval should be such that the voltage at DATA is greater than or equal to VPUPMIN. If VPUP in the

system is close to VPUPMIN, a low-impedance bypass of RPUP, which can be activated during programming, may

need to be added.

Note 19:

Interval begins t

REHmax

after the trailing rising edge on DATA for the last timeslot of the validation key for a valid

copy sequence. Interval ends once the device's self-timed EEPROM programming cycle is complete and the

current drawn by the device has returned from IPROG to IL.

Note 20:

Write-cycle endurance is degraded as TA increases.

Note 21:

Not 100% production-tested; guaranteed by reliability monitor sampling.

Note 22:

Data retention is degraded as TA increases.

Note 23:

Guaranteed by 100% production test at elevated temperature for a shorter time; equivalence of this production

test to data sheet limit at operating temperature range is established by reliability testing.

Note 24:

EEPROM writes can become nonfunctional after the data-retention time is exceeded. Long-term storage at

elevated temperatures is not rec

ommended; the device can lose its write capability after 10 years at +125°C or 40

years at +85°C.

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

18 of 19

PACKAGE INFORMATION

For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages.

Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a

different suffix character, but the drawing pertains to the package regardless of RoHS status.

PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.

3 TO-92 (Bulk)

Q3+1

21-0248

—

3 TO-92 (T&R) Q3+4 21-0250 —

6 TSOC D6+1 21-0382 90-0321

NOT RECOMMENDED FOR NEW DESIGNS

DS2430A

19 of 19

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim

reserves the right to change the circuitry and specifications without notice at any time.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

REVISION HISTORY

REVISION

DATE

DESCRIPTION

PAGES

CHANGED

4/3/95 Initial release —

8/26/96

Changed “C-lead” package to “TSOC” package. Deleted V

IHmax

specification

value. Note “Under certain low voltage conditions VILMAX may have to be

reduced to as much as 0.5V to always guarantee a presence pulse.” added to

VIL specification, changed VCC to VPUP in Note 6.

Various

3/26/97 Changed “Touch Memory” to “iButton”. Various

12/8/98

Programming time changed from 100ms to 10ms, change V

to V

PUP

, revised

note below Figure 7, programming current changed from 600µA to 500µA, QOP

removed from EC table, deleted from Note 5 “and will remain valid for 14µs

minimum (15µs total from falling edge on 1-wire bus).” Endurance added to EC

table with note “The Copy Scratchpad takes 10 ms maximum, during which the

voltage on the 1-Wire bus must not fall below 2.8V.”

Various

1/20/99 Chip scale package added to ordering information 1

5/20/99 Deleted duplicate tPDL and contradicting tPROG spec from EC table 15

10/21/99

Template conversion, style changes (capitalization of command names, “Write-

one” to “Write-1”, “Write-zero” to “Write-0”)

All

2/2/02

Part number corrections, style corrections, note below figure 7 revised explain-

ing the appropriate RPUP range, corrections in the Memory Functions Example

(removed Read Memory section at the beginning), changed solder spec from

260°C to JEDEC reference, added notes 11, 12, 13 to EC table, changed

tRSTLmax from 5000µs to 960µs, revised text of EC table note 8.

Various

11/1/05 NRFND watermark added All

1/16/07

Lead free part numbers added; added flip chip graphic with bump electrical

assignment, orientation mark and marking; Added flip chip 56-level drawing

number, changed "Chip Scale" name to "Flip Chip"; replaced references to the

Book of iButton Standards with the corresponding application notes.

Various

8/8/07

Note on formed leads for TO-92 TRL and URL to 56-G0006-003 added, I

Lmin

and ILmax spec values added to EC table. Data retention added to EC table.

1, 15

4/10

Ordering information for standard and flip chip versions deleted, pin assignment

for flip chip version deleted, data rate changed from 16.3kbps to 15.3 kbps.

Style corrections and minor text updates for clarification.

New 1-Wire front end, improved EEPROM and related EC table with notes.

Package information section added.

Various

12-14, 16-17

2/12

Reformatted the Ordering Information, deleted the reference to the UCSP

package.

Revised EC table notes 1 and 18; added the Land Pattern No. to the Package

Information section.

17, 18

NOT RECOMMENDED FOR NEW DESIGNS