24LC22A

Specifications

Parameter Name	Value
Density	2k bits (x8)
Max. Clock Freq.	400 kHz
Page Size (bytes)	8
Endurance	1,000,000
Op. Volt Range (V)	2.5 to 5.5
Temp Range (°C)	-40°C to +85°C

Description

The Microchip Technology Inc. 24LC22A is a 256 x 8-bit dual-mode Electrically Erasable PROM. 24LC22A is designed for use in applications requiring storageand serial transmission of configuration and controlinformation. Two modes of operation have been implemented:Transmit-Only mode (1 Kbit) and Bidirectionalmode (2 Kbit). Upon power-up, the device will be in theTransmit-Only mode, sending a serial bit stream of thememory array from 00h to 7Fh, clocked by the VCLKpin. A valid high-to-low transition on the SCL pin willcause the device to enter the Transition mode, and lookfor a valid control byte on the I²C?Compatible bus. If it detects avalid control byte from the master, it will switch intoBidirectional mode, with byte selectable read/writecapability of the entire 2K memory array using SCL. Ifno control byte is received, 24LC22A will revert to theTransmit-Only mode after it receives 128 consecutiveVCLK pulses while the SCL pin is idle. The 24LC22A isavailable in standard 8-pin PDIP and SOIC packages.

The 24LC22A is a 256 x 8- bit dual-mode Electrically Erasable PROM. This device is designed for use in applications requiring storage and serial transmission of configuration and control information. Two modes of operation have been implemented: Transmit-Only Mode (1 Kbit) and Bi-directional Mode (2Kbit). Upon power-up, the device will be in the Transmit-Only Mode, sending a serial bit stream of the memory array from OOh to 7Fh, clocked by the VCLK pin.

Features of the 24LC22A are:(1)single supply with operation down to 2.5V; (2)supports enhanced EDIDTM (E-EDIDTM)1.3; (3)completely implements DDC1/DDC27M interface for monitor identification, including recovery to DDC1; (4)100 kHz (2.5V) and 400 kHz (5V) compatibility; (5)self timed write cycle (including auto-erase); (6)page-write buffer for up to eight bytes; (7)1,000,000 erase write cycles guaranteed; (8)data retention>200 years; (9)ESD protection>4000V; (10)8-pin DIP and SOIC packages.

The absolute maximum ratings of the 24LC22A can be summarized as:(1)Vcc:7V;(2)storage temperature range:-65 to +150;(3)ambient temperature with power applied:-65 to 125;(4)all inputs and outputs:-0.6 to Vcc+1.0V;(5)soldering temperature of leads:+240.The 24LC22A is designed to comply to the DDC Standard proposed by VESA (Figure 3-3) with the exception that it is not Access.bus capable. It operates in two modes, the Transmit-Only Mode (1Kbit) and the Bidirectional Mode (2Kbit). There is a separate 2-wire protocol to support each mode, each having a separate clock input but sharing a common data line (SDA). The device enters the Transmit-Only Mode upon power-up.In this mode, the device transmits data bits on the SDA pin in response to a clock signal on the VCLK pin. The device will remain in this mode until a valid high to low transition is placed on the SCL input. When a valid transition on SCL is recognized, the device will switch into the Bi-directional Mode and look for its control byte to be sent by the master. If it detects its control byte, 24LC22A will stay in the Bi-directional Mode. Otherwise, it will revert to the Transmit-Only Mode after it sees 128 VCLK pulses.