24C322 View Datasheet(PDF) - Catalyst Semiconductor => Onsemi

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Description

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24C322

Supervisory circuits with I2C serial CMOS E2EPROM, precision reset controller and watchdog timer

Catalyst Semiconductor => Onsemi 

CAT24C321/322/641/642

Advanced

Hardware Data Protection

Reset Threshold Voltage

The 24CXXX is designed with the following hardware

data protection features to provide a high degree of data

integrity.

(1) The 24CXXX features a WP pin. When WP pin is tied

high the entire memory array becomes write protected

(read only).

(2) The VCC sense provides write protection when VCC

falls below the reset threshold value (VTH). The VCC lock

out inhibits writes to the serial EEPROM whenever VCC

falls below (power down) VTH or until VCC reaches the

reset threshold (power up) VTH.

From the factory the 24CXXX is offered in five different

variations of reset threshold voltages. They are 4.50-

4.75V, 4.25-4.50V, 3.00-3.15V, 2.85-3.00V and 2.55-

2.70V. To provide added flexibility to design engineers

using this product, the 24CXXX is designed with an

additional feature of programming the reset threshold

voltage. This allows the user to change the existing

reset threshold voltage to one of the other four reset

threshold voltages. Once the reset threshold voltage is

selected it will not change even after cycling the power,

unless the user uses the programmer to change the

reset threshold voltage. However, the programming

function is available only through third party programmer

manufacturers. Please call Catalyst for a list of program-

mer manufacturers who support this function.

Figure 2. Bus Timing

tF

tHIGH

tR

tLOW

tLOW

SCL

tSU:STA

tHD:DAT

tHD:STA

tSU:DAT

SDA IN

SDA OUT

tAA

tDH

tSU:STO

tBUF

Figure 3. Write Cycle Timing

SCL

SDA

8TH BIT

BYTE n

ACK

Figure 4. Start/Stop Timing

tWR

STOP

CONDITION

START

CONDITION

ADDRESS

SDA

SCL

START BIT

Doc. No. 25083-00 12/98

6

STOP BIT

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