Figure 1.  Logic Diagram
M2732A
NMOS 32K (4K x 8) UV EPROM
FAST ACCESS TIME: 200ns
EXTENDED TEMPERATURE RANGE SINGLE 5V SUPPLY VOLTAGE LOW STANDBY CURRENT: 35mA max INPUTS and OUTPUTS TTL COMPATIBLE DURING READ and PROGRAM COMPLETELY STATIC
DESCRIPTION
The M2732A is a 32,768 bit UV erasable and electrically programmable memory EPROM. It is organized  as  4,096  words by  8 bits. The M2732A with its single 5V power supply and with an access time of 200 ns, is ideal suited for applications where fast turn around and pattern experimentation one important requirements.
The M2732A is honsed in a 24 pin Window Ceramic Frit-Seal Dual-in-Line package. The transparent lid allows the user to expose the chip to ultraviolet light to erase the bit pattern. A new pattern can be then written to the clerice by following the programming
procedure.
Table 1.  Signal Names
July 19941/9
Figure 2.  DIP Pin Connections
Note: Except for the rating "Operating Temperature Range", stresses above those listed in the Table "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other conditions above those indicated in the Operating sections of this specification is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Refer also to the SGS-THOMSON SURE Program and other relevant quality documents.
Table 2.  Absolute Maximum Ratings
DEVICE OPERATION
The six modes of operation for the M2732A are listed in the Operating Modes Table. A single 5V power supply is required in the read mode. All inputs are TTL level except for V PP . Read Mode
The M2732A has two control functions, both of which must be logically satisfied 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, inde-
pendent of device selection.
Assuming that the addresses are stable, address access time (t AVAQ ) is equal to the delay from E to output (t ELQV ). Data is available at the outputs after 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 M2732A has a standby mode which reduces the active power current by 70 %, from 125 mA to 35 mA. The M2732A is placed in the standby mode by applying a TTL high signal to E input. When in standby mode, the outputs are in a high impedance state, independent of the GV PP  input.Two Line Output Control
Because M2732A’s are usually used in larger mem-ory arrays, this product features a 2 line control function which accommodates the use of multiple memory connection. The two line control function allows:
a. the lowest possible memory power dissipation,
b. complete assurance that output bus contention will not occur.To most efficiently use these two control lines, it is recommended that E be decoded and used as the be made a common connection to all devices in the array and connected to the READ line from the system control bus.
This ensures that all deselected memory devices are in their low power standby mode and that the output pins are only active when data is required from a particular memory device.
Programming
When delivered, and after each erasure, all bits of the M2732A are in the “1" state. Data is introduced by selectively programming ”0’s" into the desired bit locations. Although only “0’s” will be pro-grammed, both “1’s” and “0’s” can be presented in the data word. The only way to change a “0" to a ”1" is by ultraviolet light erasure.
The M2732A is in the programming mode when the GV PP input is at 21V. A  0.1µF capacitor must be placed across GV PP and ground to suppress spu-rious voltage transients which may damage the device. The data to be programmed is applied, 8 bits in parallel, to the data output pins. The levels required for the address and data inputs are TTL. When the address and data are stable, a 50ms, active low, TTL program pulse is applied to the E input. A program pulse must be applied at e
ach address location to be programmed. Any location can be programmed at any time - either individually, sequentially, or at random. The program pulse has a maximum width of 55ms. The M2732A must not be programmed with a DC signal applied to the E input.
张雨绮美腿现淤青Programming of multiple M2732As in parallel with the same data can be easily accomplished due to the simplicity of the programming requirements. Inputs of the paralleled M2732As may be con-nected together when they are programmed with the same data. A low level TTL pulse applied to the E input programs the paralleled 2732As. Program Inhibit
Programming of multiple M2732As in parallel with different data is also easily accomplished. Except for E, all like inputs (including GV PP) of the parallel M2732As may be common. A TTL level program pulse applied to a M2732A’s E input with GV PP at 21V will program that M2732A. A high level E input inhibits the other M2732As from being pro-grammed.
Program Verify
就当我们从来没爱过是什么歌A verify should be performed on the programmed bits to determine that they were correctly pro-grammed. The verify is carried out with GV PP and E at V IL.
ERASURE OPERATION
The erasure characteristics of the M2732A are such that erasure begins when the cells are ex-posed to light with wavelengths shorter than ap-proximately 4000 Å. It should be noted that sunlight and certain types of fluorescent lamps have wave-lengths in the 3000-4000 Å range. Research shows that constant exposure to room level fluorescent lighting could erase a typical M2732A in approxi-mately 3 years, while it would take approximately 1 week to cause erasure when exposed to the direct sunlight. If the M2732A is to be exposed to these types of lighting conditions for extended pe-riods of time, it is suggested that opaque labels be put over the M2732A window to prevent uninten-tional erasure.
The recommended erasure procedure for the M2732A is exposure to shortwave ultraviolet light which has a wavelength of 2537 Å. The integrated dose (i.e. UV intensity x exposure time) for erasure should be a minimum of 15 W-sec/cm2. The era-sure time with this dosage is approximately 15 to 20 minutes using an ultraviolet lamp with 12000µW/cm2 power rating. The M2732A should be placed within 2.5 cm of the lamp tubes during erasure. Some lamps have a filter on their tubes which should be removed before erasure.
IH IL
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Table 3.  Operating Modes
Figure 3. AC Testing Input Output Waveforms
Input Rise and Fall Times ≤  20ns Input Pulse Voltages
0.45V to 2.4V Input and Output Timing Ref. Voltages
0.8V to 2.0V
AC MEASUREMENT CONDITIONS
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Figure 4.  AC Testing Load Circuit
Note that Output Hi-Z is defined as the point where data is no longer driven.
Note:  1.Sampled only, not 100% tested.
Table 4.  Capacitance (1)  (T A  = 25 °C, f = 1 MHz )
Figure 5.  Read Mode AC Waveforms孩子他爸
CC PP PP 2.Sampled only, not 100% tested.
Table 6.  Read Mode AC Characteristics (1)
(T A  = 0 to 70 °C or –40 to 85 °C; V CC  = 5V ± 5% or 5V ± 10%; V PP  = V CC
)
CC PP PP Table 5.  Read Mode DC Characteristics (1)
(T A  = 0 to 70 °C or –40 to 85 °C; V CC  = 5V ± 5% or 5V ± 10%; V PP  = V CC )