CY7C245A-45WMB Cypress Semiconductor Corp, CY7C245A-45WMB Datasheet - Page 4

• Manufacturer Part Number: CY7C245A-45WMB
• Manufacturer: Cypress Semiconductor Corp

Specifications of CY7C245A-45WMB

• Density: 16Kb
• Organization: 2Kx8
• Access Time (max): 25ns
• Operating Current: 120mA
• Interface Type: Parallel
• Package Type: Windowed CDIP
• Operating Temperature Classification: Military
• Operating Supply Voltage (typ): 5V
• Operating Temp Range: -55C to 125C
• Pin Count: 24
• Mounting: Through Hole
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / RoHS Status: Not Compliant

Operating Modes
System timing is simplified in that the on-chip edge triggered
register allows the PROM clock to be derived directly from the
system clock without introducing race conditions. The on-chip
register timing requirements are similar to those of discrete
registers available in the market.
The CY7C245A has an asynchronous initialize input (INIT). The
initialize function is useful during power-up and time-out sequences
and can facilitate implementation of other sophisticated functions
such as a built-in “jump start” address. When activated, the initialize
control input causes the contents of a user-programmed 2049th 8-bit
Switching Waveforms
Erasure Characteristics
Wavelengths of light less than 4000 Angstroms begin to erase
the 7C245A. For this reason, an opaque label should be
placed over the window if the PROM is exposed to sunlight or
fluorescent lighting for extended periods of time.
The recommended dose for erasure is ultraviolet light with a
wavelength of 2537 Angstroms for a minimum dose (UV inten-
sity multiplied by exposure time) of 25 Wsec/cm2. For an ultra-
violet lamp with a 12 mW/cm
be approximately 35 minutes. The 7C245A needs to be within 1 inch
of the lamp during erasure. Permanent damage may result if the
PROM is exposed to high-intensity UV light for an extended period of
time. 7258 Wsec/cm
Programming Information
Programming support is available from Cypress as well as
from a number of third-party software vendors. For detailed
programming information, including a listing of software pack-
A
O
0
0
INIT
A
CP
O
E
10
E
S
7
2
is the recommended maximum dosage.
t
CO
t
(Continued)
t
PWI
DI
2
power rating the exposure time would
t
t
PWC
[4]
SES
t
t
PWC
HES
t
t
RI
HZC
t
PWC
t
SES
t
PWC
t
t
HES
t
HA
COS
4
word to be loaded into the on-chip register. Each bit is programmable
and the initialize function can be used to load any desired combina-
tion of 1s and 0s into the register. In the unprogrammed state, activat-
ing INIT will generate a register CLEAR (all outputs LOW). If all the
bits of the initialize word are programmed, activating INIT performs a
register PRESET (all outputs HIGH).
Applying a LOW to the INIT input causes an immediate load of the
programmed initialize word into the master and slave flip-flops of the
register, independent of all other inputs, including the clock (CP). The
initialize data will appear at the device outputs after the outputs are
enabled by bringing the asynchronous enable (E) LOW.
ages, please see the PROM Programming Information located
at the end of this section. Programming algorithms can be ob-
tained from any Cypress representative.
Bit Map Data
Control Byte
t
Decimal
PWC
t
t
SES
SA
00 ............ Asynchronous output enable (default state)
01 ..................................... Synchronous output enable
Programmer Address
2047
2048
2049
0
.
.
.
t
PWC
t
t
HES
HA
t
CO
Hex
7FF
800
801
0
.
.
.
t
HZE
Control Byte
CY7C245A
RAM Data
Contents
Init Byte
Data
Data
.
.
.
t
DOE
C245A-7