Programming Instructions:
Before programming, the memory should be submitted to a full ERASE operation to ensure every bit
in the device is in the “1” state (represented by Output High). Data are entered by programming zeros
(Output Low) into the required bits. The words are addressed the same way as in the READ operation.
A programmed “0” can only be changed to a “1” by ultraviolet light erasure.
To set the memory up for Program Mode, the V
PP
input (Pin21) should be raised to +25V. The V
CC
supply voltage is the same as for the Read operation and G is at V
IH
. Programming data is entered
in 8–bit words through the data out (DQ) terminals. Only “0 s” will be programmed when “0 s” and
“1 s” are entered in the 8–bit data word.
After address and data setup, a program pulse (V
IL
to V
IH
) is applied to the E/Progr input. A program
pulse is applied to each address location to be programmed. To minimize programming time, a 2ms
pulse width is recommended. The maximum program pulse width is 55ms; therefore, programming
must not be attempted with a DC signal applied to the E/Progr input.
Multiple NTE2716s may be programmed in parallel by connecting together like inputs and applying
the program pulse to the E/Progr inputs. Different data may be programmed into multiple NTE2716s
connected in parallel by using the PROGRAM INHIBIT mode. Except for the E/Progr pin, all like inputs
(including Output Enable) may be common.
The PROGRAM VERIFY mode with V
PP
at +25V is used to determine that all programmed bits were
correctly programmed.
Read Operation:
After access time, data is valid at the outputs in the READ mode. With stable system addresses, effec-
tively faster access time can be obtained by gating the data onto the bus with Output Enable.
The Standby mode is available to reduce active power dissipation. The outputs are in the high imped-
ance state when the E/Progr input pin is high (V
IH
) independent of the Output Enable input.
Erasing Instructions:
The NTE2716 can be erased by exposure to high intensity shortwave ultraviolet light, with a wave-
length of 2537 angstroms. The recommended integrated dose (i.e. UV–intensity X exposure time)
is 15Ws/cm
2
. As an example, using the “Model 30–000” UV–Eraser (Turner Designs, Mountain View,
CA 94043) the ERASE–time is 36 minutes. The lamps should be used without shortwave filters and
the NTE2716 should be positioned about one inch away from the UV–tubes.
Recommended Operating Procedures:
After erasure and reprogramming of the EPROM, it is recommended that the quartz window be cov-
ered with an opaque self–adhesive cover. It is important that the self–adhesive cover not leave any
residue on the quartz if it is removed to allow another erasure.
NTE [ NTE ELECTRONICS ]
