AK6420A Datasheet, PDF (2/15 Pages) Asahi Kasei Microsystems – 2K / 4K / 8Kbit Serial CMOS EEPROM

ASAHI KASEI
[AK6420B/40B/80B]
General Description
The AK6420B/40B/80B is a 2048/4096/8192bit, serial, read/write, non-volatile memory device fabricated using
an advanced CMOS E2PROM technology. The AK6420B has 2048bits of memory organized into 128
registers of 16 bits each. The AK6440B has 4096bits of memory organized into 256 registers of 16 bits each.
The AK6480B has 8192bits of memory organized into 512 registers of 16 bits each. The AK6420B/40B/80B
can operate full function under wide operating voltage range from 1.8V to 5.5V. The charge up circuit is
integrated for high voltage generation that is used for write operation.
The AK6420B/40B/80B can connect to the serial communication port of popular one chip microcomputer
directly (3 line negative clock synchronous interface). At write operation, AK6420B/40B/80B takes in the write
data from data input pin (DI) to a register synchronously with rising edge of input pulse of serial clock pin
(SK). And at read operation, AK6420B/40B/80B takes out the read data from a register to data output pin
(DO) synchronously with falling edge of SK.
The AK6420B/40B/80B has 4 instructions such as READ, WRITE, WREN (write enable) and WRDS (write
disable). Each instruction is organized by op-code block (8bits), address block (8bits) and data (8bits Õ 2).
When input level of SK pin is high level and input level of chip select (CS) pin is changed from high level to low
level, AK6420B/40B/80B can receive the instructions.
Special features of the AK6420B/40B/80B include : automatic write time-out with auto-ERASE, Ready/Busy
status signal output and ultra-low standby power mode when deselected (CS=high).
• Software and Hardware controlled write protection
The AK6420B/40B/80B has 2 (hardware and software) write protection functions.
After power on or after execution of WRDS (write disable) instruction, execution of WRITE instruction will be
disabled. This write protection condition continues until WREN instruction is executed or Vcc is removed from
the part.
Execution of READ instruction is independent of both WREN and WRDS instructions.
Reset pin should be low level when WRITE instruction is executed. When the Reset pin is high level, the
WRITE instruction is not executed.
• Ready/Busy status signal
The DO pin indicates the Busy status. When input level of SK pin is low level and input level of CS pin is
changed from high level to low level, the AK6420B/40B/80B is in the status output mode and the DO pin
indicates the Ready/Busy status. The Ready/ Busy status outputs on DO pin until CS pin is changed from low
level to high level, or first bit ("1") of op-code of next instruction is given to the part. Except when the device is
in the status output mode or outputs data, the DO pin is in the high impedance state.
„ Type of Products
Model
AK6420BH
AK6440BH
AK6480BH
Memory size
2Kbits
4Kbits
8Kbits
Temp.Range
-40°C∼85°C
-40°C∼85°C
-40°C∼85°C
Vcc
1.8V∼5.5V
1.8V∼5.5V
1.8V∼5.5V
Package
8pin Plastic MSOP
8pin Plastic MSOP
8pin Plastic MSOP
DAS03E-00
-2-
1999/05