MBM29LV800TE/BE60/70/90
■ FUNCTIONAL DESCRIPTION
Read Mode
The MBM29LV800TE/BE have two control functions which must be satisfied in order to obtain data at the outputs.
CE is the power control and should be used for a device selection. OE is the output control and should be used
to gate data to the output pins if a device is selected.
Address access time (tACC) is equal to delay from stable addresses to valid output data. The chip enable access
time (tCE) is the delay from stable addresses and stable CE to valid data at the output pins. The output enable
access time is the delay from the falling edge of OE to valid data at the output pins (Assuming the addresses
have been stable for at least tACC-tOE time) . When reading out data without changing addresses after power-up,
it is necessary to input hardware reset or change CE pin from “H” or “L”
Standby Mode
There are two ways to implement the standby mode on the MBM29LV800TE/BE devices, one using both the
CE and RESET pins; the other via the RESET pin only.
When using both pins, a CMOS standby mode is achieved with CE and RESET inputs both held at VCC ± 0.3 V.
Under this condition, the current consumed is less than 5 µA. The device can be read with standard access time
(tCE) from either of these standby modes. During Embedded Algorithm operation, VCC active current (ICC2) is
required even CE = “H”.
When using the RESET pin only, a CMOS standby mode is achieved with RESET input held at VSS ± 0.3 V
(CE = “H” or “L”) . Under this condition the current consumed is less than 5 µA. Once the RESET pin is taken
high, the device requires tRH as wake up time for outputs to be valid for read access.
In the standby mode, the outputs are in the high impedance state, independently of the OE input.
Automatic Sleep Mode
There is a function called automatic sleep mode to restrain power consumption during read-out of
MBM29LV800TE/BE data. This mode can be useful in the application such as handy terminal which requires
low power consumption.
To activate this mode, MBM29LV800TE/BE automatically switches themselves to low power mode when
MBM29LV800TE/BE addresses remain stable during access time of 150 ns. It is not necessary to control CE,
WE, and OE on the mode. Under the mode, the current consumed is typically 1 µA (CMOS Level) .
Since the data are latched during this mode, the data are read-out continuously. If the addresses are changed,
the mode is canceled automatically, and MBM29LV800TE/BE read-out the data for changed addresses.
Output Disable
With the OE input at a logic high level (VIH) , the output from the devices is disabled. This will cause the output
pins to be in a high impedance state.
Autoselect
The autoselect mode allows the reading out of a binary code from the devices and will identify its manufacturer
and type. This mode is intended for use by programming equipment for the purpose of automatically matching
the devices to be programmed with its corresponding programming algorithm. This mode is functional over the
entire temperature range of the devices.
To activate this mode, the programming equipment must force VID (11.5 V to 12.5 V) on address pin A9. Two
identifier bytes may then be sequenced from the devices outputs by toggling address A0 from VIL to VIH. All
addresses are DON’T CARES except A0, A1, A6, and A-1. (See “MBM29LV800TE/BE Sector Protection Verify
Autoselect Codes” in “ DEVICE BUS OPERATION”.)
The manufacturer and device codes may also be read via the command register, for instances when the
MBM29LV800TE/BE are erased or programmed in a system without access to high voltage on the A9 pin. The
command sequence is illustrated in “MBM29LV800TE/BE Command Definitions” in “ DEVICE BUS OPERA-
TION”. (Refer to Autoselect Command section.)
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