NTE21128 Datasheet, PDF (5/6 Pages) NTE Electronics – Integrated Circuit NMOS, 128K (16K x 8) UV EPROM

Device Operation (Cont’d):
Program Inhibit
Programming of multiple NTE21128s in parallel with different data is also easily accomplished. Ex-
cept for E, all like inputs (including G) of the parallel NTE21128 may be common. A TTL low pulse
applied to an NTE21128’s E input, with V_PP = 12.5V, will program that NTE21128> A high level E input
inhibits the other NTE21128s from being programmed.
Program Verify
A verify should be performed on the programmed bits to determine that they were correctly pro-
grammed. The verify is accomplished with G = V_IL, E = V_IL, P = V_IH, and V_PP at 12.5V.
Erasure Operation:
The erasure characteristic of the NTE21128 is such that erasure begins when the cells are exposed
to light with wavelengths shorter than approximately 4000 angstroms. The recommended erasure
procedure for the NTE21128 is exposure to short wave ultraviolet light which has a wavelength of
2537 angstroms. The integrated dose (i.e. UV intensity x exposure time) for erasure should be a mini-
mum of 15 W sec/cm². The erasure time with this dosage is approximately 15 to 20 minutes using
an ultraviolet lamp with 12000 µW/cm² power rating. The NTE21128 should be placed within 2.5cm
(1 inch) of the lamp tubes during the erasure. Some lamps have a filter on their tubes which should
be removed before erasure.
Pin Connection Diagram
V_PP 1
A12 2
A7 3
A6 4
A5 5
A4 6
A3 7
A2 8
A1 9
A0 10
O0 ¹¹
O1 12
O2 13
GND 14
28 V_CC
27 PGM
26 A13
25 A8
24 A9
23 A11
22 OE
21 A10
20 CE
19 O7
18 O6
17 O5
16 O4
15 O3