Rainbow-electronics DS2431 Manuel d'utilisateur télécharger pdf (Page 3)

DS2431: 1024-Bit, 1-Wire EEPROM

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PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

I/O PIN, 1-Wire WRITE

Standard speed 60 120

Write-0 Low Time (Note 1) t

W0L

Overdrive speed (Note 13) 716

µs

Standard speed 5

15 - ε

Write-1 Low Time

(Notes 1, 15)

W1L

Overdrive speed 1

2 - ε

µs

I/O PIN, 1-Wire READ

Standard speed 5

15 - δ

Read Low Time

(Notes 1, 16)

Overdrive speed 1

2 - δ

µs

Standard speed

+ δ

Read Sample Time

(Notes 1, 16)

MSR

Overdrive speed

+ δ

µs

EEPROM

Programming Current I

PROG

(Note 17) 1 mA

Programming Time t

PROG

(Note 18) 12.5 ms

At 25°C 200k

Write/Erase Cycles

(Endurance)

At 85°C (worst case) 50k

---

Data Retention t

At 85°C (worst case) 10 years

Note 1:

System requirement.

Note 2:

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 1-Wire recovery times. For more heavily

loaded systems, an active pullup such as that found in the DS2482-x00, DS2480B, or DS2490 may be required.

Note 3:

Capacitance on the data pin could be 800pF when V

PUP

is first applied. If a 2.2kΩ resistor is used to pull up the data line, 2.5µs

after V

PUP

has been applied the parasite capacitance will not affect normal communications.

Note 4:

Guaranteed by design, simulation only. Not production tested.

Note 5:

, V

, and V

are a function of the internal supply voltage.

Note 6:

Voltage below which, during a falling edge on I/O, a logic 0 is detected.

Note 7:

The voltage on I/O needs to be less or equal to V

ILMAX

whenever the master drives the line low.

Note 8:

Voltage above which, during a rising edge on I/O, a logic 1 is detected.

Note 9:

After V

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

to be detected as logic '0'.

Note 10:

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

Note 11:

Applies to a single DS2431 attached to a 1-Wire line.

Note 12:

The earliest recognition of a negative edge is possible at t

REH

after V

has been previously reached.

Note 13:

Highlighted numbers are NOT in compliance with legacy 1-Wire product standards. See comparison table below.

Note 14:

Interval during the negative edge on I/O at the beginning of a Presence Detect pulse between the time at which the voltage is

80% of V

PUP

and the time at which the voltage is 20% of V

PUP

Note 15:

ε represents the time required for the pullup circuitry to pull the voltage on I/O up from V

to V

Note 16:

δ represents the time required for the pullup circuitry to pull the voltage on I/O up from V

to the input high threshold of the bus

master.

Note 17:

Current drawn from I/O during the EEPROM programming interval. The pullup circuit on I/O during the programming interval

should be such that the voltage at I/O is greater than or equal to Vpup(min). If Vpup in the system is close to Vpup(min) then a

low impedance bypass of Rpup which can be activated during programming may need to be added.

Note 18:

Interval begins t

WiLMIN

after the leading negative edge on IO for the last timeslot of the E/S byte for a valid Copy Scratchpad

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

device has returned from I

PROG

to I

LEGACY VALUES DS2431 VALUES

PARAMETER STANDARD SPEED OVERDRIVE SPEED STANDARD SPEED OVERDRIVE SPEED

MIN MAX MIN MAX MIN MAX MIN MAX

SLOT

(incl. t

REC

) 61µs (undef.) 7µs (undef.) 65µs

(undef.) 9µs (undef.)

RSTL

480µs (undef.) 48µs 80µs 504µs 640µs 53µs 80µs

PDH

15µs 60µs 2µs 6µs 15µs 63µs 2µs 7µs

PDL

60µs 240µs 8µs 24µs 60µs 240µs 8µs 26µs

W0L

60µs 120µs 6µs 16µs 60µs 120µs 7µs 16µs

Intentional change, longer recovery time requirement due to modified 1-Wire front end.

PIN DESCRIPTION

NAME FUNCTION

I/O 1-Wire Bus Interface. Open drain, requires external pullup resistor.

GND Ground Reference

N.C. Not Connected

1 2 3 4 5 6 7 8 ... 22 23

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Rainbow-electronics DS2431 Manuel d'utilisateur Page 3

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