M24256-A STMICROELECTRONICS | Alldatasheet
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Technical content
This is information on a product still in production but not recommended for new designs. M24256-A
256 Kbit Serial I²C Bus EEPROM
With Two Chip Enable Lines This device is now designated as “Not for New De- sign”. Please use the M24256-B in all future de- signs (as described in application note AN1470). ■ Compatible with I2C Extended Addressing ■ Two Wire I2C Serial Interface Supports 400 kHz Protocol ■ Single Supply Voltage: – 4.5V to 5.5V for M24256-A – 2.5V to 5.5V for M24256-AW ■ 2 Chip Enable Inputs: up to four memories can be connected to the same I2C bus ■ Hardware Write Control ■ BYTE and PAGE WRITE (up to 64 Bytes) ■ RANDOM and SEQUENTIAL READ Modes ■ Self-Timed Programming Cycle ■ Automatic Address Incrementing ■ Enhanced ESD/Latch-Up Behavior ■ More than 100,000 Erase/Write Cycles ■ More than 40 Year Data Retention
DESCRIPTION
These I2C-compatible electrically erasable pro- grammable memory (EEPROM) devices are orga- nized as 32Kx8 bits, and operate down to 2.5 V (for the M24256-AW). The M24256-A is available in Plastic Dual-in-Line, Plastic Small Outline and Thin Shrink Small Out- Figure 1. Logic Diagram Table 1. Signal Names
a chip-scale (SBGA) package. Table 3), terminated by an acknowledge bit. following the bus master’s 8-bit transmission. must be applied before applying any logic signal. a push-pull (rather than open drain) output. pull-up resistor can be calculated). Figure 3. Maximum RL Value versus Bus Capacitance (CBUS ) for an I2C Bus
VIL, and write operations are allowed. detailed description of the Write Control feature. The memory device supports the I2C protocol. tion, and will not respond unless one is given. the internal EEPROM write cycle. Figure 4. I
acknowledge the receipt of the eight data bits. and a 3-bit Chip Enable “Address” (0, E1, E0). bus, and goes into stand-by mode. There are two modes both for read and write. the slave is ended with a STOP condition. Care bits on the M24256-A memory. Table 3. Device Select Code 1 Note: 1. The most significant bit, b7, is sent first. Table 4. Most Significant Byte Note: 1.b15 is treated as Don’t Care on the M24256-A series. Table 5. Least Significant Byte Table 6. Operating Modes
1 X reSTART, Device Select, RW = 1
Figure 6. Write Mode Sequences with WC=0 (data write enabled) write, the internal memory write cycle is triggered. ger the internal write cycle. polling sequence can be used by the master. – Initial condition: a Write is in progress. into the address counter, as shown in Figure 8. the Device Select Code, with the RW bit set to ‘1’. the transfer with a STOP condition.
data transfer and switches to its stand-by state. out acknowledging the byte output. byte output, and must generate a STOP condition. Figure 7. Write Cycle Polling Flowchart using ACK
Figure 8. Read Mode Sequences Note: 1. The seven most significant bits of the Device Select Code of a Random Read (in the 1st and 4th bytes) must be identical.
Table 7. DC Characteristics Table 8. Input Parameters1 (TA = 25 °C, f = 400 kHz) Note: 1. Sampled only, not 100% tested.
Table 9. AC Characteristics Note: 1. For a reSTART condition, or following a write cycle.
- Sampled only, not 100% tested.
- To avoid spurious START and STOP conditions, a minimum delay is placed between SCL=1 and the falling or rising edge of SDA.
Table 10. AC Measurement Conditions Figure 9. AC Testing Input Output Waveforms
Figure 10. AC Waveforms
Table 11. Ordering Information Scheme
ORDERING INFORMATION
Devices are shipped from the factory with the memory content set at all 1s (FFh). The notation used for the device number is as shown in Table 11. For a list of available options (speed, package, etc.) or for further information on any aspect of this device, please contact your nearest ST Sales Office.
PDIP8 – 8 pin Plastic DIP, 0.25mm lead frame Note: 1. Drawing is not to scale. PDIP-B A L be D c eA eB E PDIP8 – 8 pin Plastic DIP, 0.25mm lead frame Symb. mm inches A 5.33 0.210 A1 0.38 0.015 eB 10.92 0.430
SO8 narrow – 8 lead Plastic Small Outline, 150 mils body width Note: Drawing is not to scale. SO-a E N CP B e A D C LA1 α H h x 45˚ SO8 narrow – 8 lead Plastic Small Outline, 150 mils body width Symb. mm inches A 1.35 1.75 0.053 0.069 A1 0.10 0.25 0.004 0.010 B 0.33 0.51 0.013 0.020 C 0.19 0.25 0.007 0.010 D 4.80 5.00 0.189 0.197 E 3.80 4.00 0.150 0.157 H 5.80 6.20 0.228 0.244 h 0.25 0.50 0.010 0.020 L 0.40 0.90 0.016 0.035 α 0° 8° 0° 8° N8 8 CP 0.10 0.004
SO8 wide – 8 lead Plastic Small Outline, 200 mils body width Note: Drawing is not to scale. SO-b E N CP B e D C LA1 α H A SO8 wide – 8 lead Plastic Small Outline, 200 mils body width Symb. mm inches A 2.03 0.080 A1 0.10 0.25 0.004 0.010 A2 1.78 0.070 B 0.35 0.45 0.014 0.018 D 5.15 5.35 0.203 0.211 E 5.20 5.40 0.205 0.213 H 7.70 8.10 0.303 0.319 L 0.50 0.80 0.020 0.031 α 0° 10° 0° 10° N8 8 CP 0.10 0.004
TSSOP14 - 14 lead Thin Shrink Small Outline Note: 1. Drawing is not to scale. TSSOP14-M CP c L EE1 D A2A a eb TSSOP14 - 14 lead Thin Shrink Small Outline Symbol mm inches A 1.200 0.0472 A1 0.050 0.150 0.0020 0.0059 b 0.190 0.300 0.0075 0.0118 c 0.090 0.200 0.0035 0.0079 CP 0.100 0.0039 L1 1.000 0.0394 α 0° 8° 0° 8°
SBGA7 – 7 ball Shell Ball Grid Array – Underside view (ball side) Note: 1. Drawing is not to scale. A SBGA-01 BALL "1" b D E FE FD SBGA7 – 7 ball Shell Ball Grid Array Note: 1. No ball is closer than D2 to any other ball, thus giving an arrangement of equilateral triangles in which: E1 = D2/2 ; E2 = D2 ; E3 = 3xD2/2 D3 = √3xD2/2 ; D1 = D2 + √3xD2/2 Symb. mm inches N7 7
Table 12. Revision History
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is registered trademark of STMicroelectronics All other names are the property of their respective owners © November 2001 STMicroelectronics - All Rights Reserved STMicroelectronics group of companies Austalia - Brazil - Canada - China - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States.