28C256T MAXWELL | Alldatasheet
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All data sheets are subject to change without notice (858) 503-3300 - Fax: (858) 503-3301- www.maxwell.com 256K EEPROM (32K x 8-Bit) 28C256T ©2001 Maxwell Technologies All rights reserved. EEPROM
02.18.02 Rev 5
FEATURES:
- R AD-PAK® radiation-hardened against natural space radia- tion Total dose hardness: - > 100 Krad (Si), dependent upon space mission Excellent Single Event Effects: - SELTH LET: > 120 MeV/mg/cm2 - SEUTH LET (read mode): > 90 MeV/mg/cm2 - SEUTH LET (write mode): > 18 MeV/mg/cm2 Package: - 28 pin RAD-PAK® flat pack - 28 pin RAD-PAK® DIP - JEDEC approved byte wide pinout High Speed: - 120, 150 ns maximum access times available High endurance: - 10,000 erase/write (in Page Mode), 10-year data retention Page Write Mode: - 1 to 64 bytes Low power dissipation: - 15 mA active current (cycle = 1 µ s) - 20 µ A standby current (CE = VCC) DESCRIPTION: Maxwell Technologies’ 28C256T high density 256k-bit EEPROM microcircuit features a greater than 100 krad (Si) total dose tolerance, depending upon space mission. The 28C256T is capable of in-system electrical byte and page pro- grammability. It has a 64-Byte page programming function to make its erase and write operations faster. It also features data polling to indicate the completion of erase and program- ming operations. Maxwell Technologies' patented RAD-PAK® packaging technol- ogy incorporates radiation shielding in the microcircuit pack- age. It eliminates the need for box shielding while providing the required radiation shielding for a lifetime in orbit or space mission. In a GEO orbit, R AD-PAK provides greater than 100 krad (Si) radiation dose toleranc e. This product is available with screening up to Class S. OE, CE, and WE LOGIC Y DECODER X DECODER DATA LATCH INPUT/OUTPUT BUFFERS Y-GATING CELL MATRIX IDENTIFICATION OE WE CE ADDRESS INPUTS VCC GND DATA INPUTS/OUTPUTS I/O0 - I/O7 Logic Diagram
02.18.02 Rev5
*Refer to diagram on Page 1 for pin relationship. TABLE 1. 28C256T PINOUT DESCRIPTION
22 OE Output Enable
20 CE Chip Enable
27 WE Write Enable
28 V CC Power Supply
14 V SS Ground
TABLE 2. 28C256T ABSOLUTE MAXIMUM RATINGS
- V IN = -3.0 V for pulse width > 50 ns.
- Including electrical characteristics and data retention.
TABLE 3. 28C256T DELTA LIMITS
TABLE 4. 28C256T RECOMMENDED OPERATING CONDITIONS
- V IL min= -1.0V for pulse width < 50 ns.
TABLE 5. 28C256T CAPACITANCE1 TABLE 6. 28C256T DC ELECTRICAL CHARACTERISTICS
TABLE 7. 28C256T AC ELECTRICAL CHARACTERISTICS FOR READ OPERATION1
- Test conditions: Input pulse levels - 0V to 3V; input rise and fall times < 20 ns; output load - 1 TTL gate + 100 pF (including scope and jig); ref-
erence levels for measuring timing - 0.8V/1.8V.
- t DF and tDFR are defined as the time at which the output becomes an open circuit and data is no longer driven.
TABLE 8. 28C256T AC ELECTRICAL CHARACTERISTICS FOR PAGE/BYTE ERASE AND WRITE OPERATIONS
- Use this device in a longer cycle than this value.
TABLE 8. 28C256T AC ELECTRICAL CHARACTERISTICS FOR PAGE/BYTE ERASE AND WRITE OPERATIONS
TABLE 9. 28C256T MODE SELECTION 1
FIGURE 1. READ TIMING WAVEFORM FIGURE 2. BYTE WRITE TIMING WAVEFORM (1) (WE CONTROLLED)
FIGURE 3. BYTE WRITE TIMING WAVEFORM (2) (CE CONTROLLED) FIGURE 4. PAGE WRITE TIMING WAVEFORM (1) (WE CONTROLLED)
FIGURE 5. PAGE WRITE TIMING WAVEFORM (2) (CE CONTROLLED) FIGURE 6. DATA POLLING TIMING WAVEFORM
10All data sheets are subject to change without notice ©2001 Maxwell Technologies All rights reserved. 256K EEPROM (32K x 8-Bit) EEPROM 28C256T This application note describes the programming procedures for the EEPROM modules and the details of various techniques to preserve data protection. Automatic Page Write Page-mode write feature allows 1 to 64 bytes of data to be written into the EEPROM in a single write cycle, and allows the undefined data within 64 bytes to be written corresponding to the undefined address (A0 to A5). Loading the first byte of data, the data load window opens 30 µ s for the second byte. In the same manner each additional byte of data can be loaded within 30 µ s. In case CE and WE are kept high for 100(s after data input, EEPROM enters erase and write mode automatically and only the input data are written into the EEPROM. WE CE Pin Operation During a write cycle, addresses are latched by the falling edge of WE or CE, and data is latched by the rising edge of WE or CE. Data Polling Data Polling function allows the status of the EEPROM to be determined. If EEPROM is set to read mode during a write cycle, an inversion of the last byte of data to be loaded outputs from I/O 7 to indicate that the EEPROM is per- forming a write operation. Data Protection To protect the data during operation and power on/off, the EEPROM has the internal functions described below. 1. Data Protection against Noise of Control Pins (CE , OE, WE) during Operation. During readout or standby, noise on the control pins may act as a trigger and turn the EEPROM to programming mode by mis- take. To prevent this phenomenon, the EEPROM has a noise cancellation function that cuts noise if its width is 20ns or less in programming mode. Be careful not to allow noise of a width of more than 20ns on the control pins.
11All data sheets are subject to change without notice ©2001 Maxwell Technologies All rights reserved. 256K EEPROM (32K x 8-Bit) EEPROM 28C256T Note: All dimensions in inches.
28 PIN RAD-PAK® FLAT PACKAGE
A 0.165 0.177 0.189 b 0.015 0.017 0.022 c 0.003 0.005 0.009 D -- 0.720 0.740 E 0.380 0.410 0.420 E1 -- -- 0.440 E2 0.180 0.240 -- E3 0.030 0.085 -- e 0.050 BSC L 0.390 0.400 0.410 Q 0.040 0.050 0.053 S1 0.005 0.027 -- N2 8
12All data sheets are subject to change without notice ©2001 Maxwell Technologies All rights reserved. 256K EEPROM (32K x 8-Bit) EEPROM 28C256T Note: All dimensions in inches.
28 PIN RAD-PAK® DUAL IN LINE PACKAGE
A -- 0.177 0.225 b 0.014 0.018 0.026 b2 0.045 0.050 0.065 c 0.008 0.010 0.018 D -- 1.400 1.485 E 0.510 0.595 0.620 eA 0.600 BSC eA/2 0.300 BSC e 0.100 BSC L 0.140 0.150 0.160 Q 0.015 0.040 0.060 S1 0.005 0.025 -- S2 0.005 -- -- N2 8
13All data sheets are subject to change without notice ©2001 Maxwell Technologies All rights reserved. 256K EEPROM (32K x 8-Bit) EEPROM 28C256T Important Notice: These data sheets are created using the chip manufacturer’s published specifications. Maxwell Technologies verifies functionality by testing key parameters either by 100% testing, sample testing or characterization. The specifications presented within these data sheets represent the latest and most accurate information available to date. However, these specifications are subject to change without notice and Maxwell Technologies assumes no responsibility for the use of this information. Maxwell Technologies’ products are not authorized for use as critical components in life support devices or systems without express written approval from Maxwell Technologies. Any claim against Maxwell Technologies must be made within 90 days from the date of shipment from Maxwell Tech- nologies. Maxwell Technologies’ liability shall be limited to replacement of defective parts.
14All data sheets are subject to change without notice ©2001 Maxwell Technologies All rights reserved. 256K EEPROM (32K x 8-Bit) EEPROM 28C256T Feature Option Details28C256T XX X X -XX Access Time Screening Flow Package Radiation Feature Base Product Nomenclature 12 = 120 ns 15 = 150 ns Monolithic S = Maxwell Class S B = Maxwell Class B E = Engineering (testing @ +25° I = Industrial (testing @ -55°C, +25°C, +125°C) D = Dual In-line Package (DIP) F = Flat Pack RP = R AD-PAK® package RT1 = Guaranteed to 10 krad at die level RT2 = Guaranteed to 25 krad at die level RT4 = Guaranteed to 40 krad at die level 256K EEPROM (32K x 8-Bit) EEPROM