M27W512_08 Datasheet, PDF (7/22 Pages) STMicroelectronics – 512 Kbit (64 Kbit x8) low-voltage OTP EPROM

M27W512
2
Device operation
Device operation
The modes of operations of the M27W512 are listed in Table 2: Operating modes. A single
power supply is required in the read mode. All inputs are TTL levels except for GV_PP and
12V on A9 for Electronic Signature.
2.1
2.2
Read mode
The M27W512 has two control functions, both of which must be logically active in order to
obtain data at the outputs. Chip Enable (E) is the power control and should be used for
device selection. Output Enable (G) is the output control and should be used to gate data to
the output pins, independent of device selection. Assuming that the addresses are stable,
the address access time (t_AVQV) is equal to the delay from E to output (t_ELQV). Data is
available at the output after a delay of t_GLQV from the falling edge of G, assuming that E has
been low and the addresses have been stable for at least t_AVQV-t_GLQV.
Standby mode
The M27W512 has a standby mode which reduces the supply current from 15mA to 15µA
with low voltage operation V_CC ≤ 3.6V, see Table 7: Read mode DC characteristics.
Characteristics table for details. The M27W512 is placed in the standby mode by applying a
CMOS high signal to the E input. When in the standby mode, the outputs are in a high
impedance state, independent of the GV_PP input.
Table 2. Operating modes⁽¹⁾
Mode
E
GV_PP
A9
Q7-Q0
Read
V_IL
V_IL
Output Disable
V_IL
V_IH
Program
V_IL Pulse
V_PP
Program Inhibit
V_IH
V_PP
Standby
V_IH
X
Electronic Signature
V_IL
V_IL
1. X = V_IH or V_IL, V_ID = 12V ± 0.5V.
X
Data Out
X
Hi-Z
X
Data In
X
Hi-Z
X
Hi-Z
V_ID
Codes
Table 3. Electronic signature
Identifier
A0 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 Hex data
Manufacturer code V_IL
0
0
1
0
0
0
0
0
20h
Device code
V_IH
0
0
1
1
1
1
0
1
3Dh
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