M27C2001_06 Просмотр технического описания (PDF) - STMicroelectronics

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производитель

M27C2001_06

2 Mbit (256Kb x 8) UV EPROM and OTP EPROM

STMicroelectronics 

Device operation

M27C2001

be a high frequency capacitor of low inherent inductance and should be placed as close to

the device as possible. In addition, a 4.7µF bulk electrolytic capacitor should be used

between VCC and VSS for every eight devices. The bulk capacitor should be located near the

power supply connection point. The purpose of the bulk capacitor is to overcome the voltage

drop caused by the inductive effects of PCB traces.

2.5

Programming

When delivered (and after each erasure for UV EPROM), all bits of the M27C2001 are in the

'1' state. Data is introduced by selectively programming '0's into the desired bit locations.

Although only '0's will be programmed, both '1's and '0's can be present in the data word.

The only way to change a '0' to a '1' is by die exposure to ultraviolet light (UV EPROM). The

M27C2001 is in the programming mode when VPP input is at 12.75V, E is at VIL and P is

pulsed to VIL. The data to be programmed is applied to 8 bits in parallel to the data output

pins. The levels required for the address and data inputs are TTL. VCC is specified to be

6.25 ± 0.25V.

2.6

PRESTO II Programming Algorithm

PRESTO II Programming Algorithm allows the whole array to be programmed with a

guaranteed margin, in a typical time of 26.5 seconds. Programming with PRESTO II

consists of applying a sequence of 100µs program pulses to each byte until a correct verify

occurs (see Figure 5). During programming and verify operation, a MARGIN MODE circuit is

automatically activated in order to guarantee that each cell is programmed with enough

margin. No overprogram pulse is applied since the verify in MARGIN MODE provides the

necessary margin to each programmed cell.

Figure 5. Programming Flowchart

VCC = 6.25V, VPP = 12.75V

n=0

NO

++n

= 25

YES

P = 100µs Pulse

NO

VERIFY

YES

++ Addr

FAIL

Last NO

Addr

YES

CHECK ALL BYTES

1st: VCC = 6V

2nd: VCC = 4.2V

AI00715C

9/25

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