ISSI ® IS23SC4442 256 BYTE EEPROM WITH WRITE PROTECT FUNCTION AND PROGRAMMABLE SECURITY FEATURES • Standard CMOS process • 256 x 8 bits EEPROM organization • Byte-wise addressing • Irreversible byte-wise write protection of lowest 32 address (Byte 0..31) • 3-byte Programmable Security Code (PSC) for memory write/erase protection • 2.7-5.5V power supply for read and write/erase • Low power operation: 3 mA typical active current • 2.5 ms programming time • 2-wire serial interface • End of processing indication • ISO standard 7816 compatible • High reliability: – 1,000,000 erase/write cycles guaranteed – 10 years data retention PRELIMINARY INFORMATION August 2003 DESCRIPTION IS23SC4442 contains 256 x 8 bits of EEPROM main memory and a 32 x 1 bit protection PROM memory. The main memory can be randomly accessed byte by byte. During memory erase, all 8 bits of a byte are set to logical one. During memory write, individual bit(s) are set to logical zeros depend on the data value to be written. Normally, a data change may consists of an erase and a write operation. The write or erase operation takes at least 2.5 ms to complete. The first 32 bytes (Address: 0 to 31) in memory are irreversibly protected by the corresponding 32 protect bits in the 32 x 1 bit protection memory. The 32 protect bits are onetime programmable, and they cannot be erased once they are set to logical zero. IS23SC4442 provides a 3-bit Error Counter (EC), and three bytes Programmable Security Code (PSC) to prevent unauthorized erase/write operation to the memory. All the memory, except the PSC, can be read after the chip is powered on. But, the memory can be written or erased only after the PSC is entered and verified correct. After three successive unsuccessful verifications of PSC, the Error Counter locks the chip from a further attempt, and the memory can never be erased or written. • Wide operating temperature range –30oC to 75oC Copyright © 2003 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised to obtain the latest version of this device specification before relying on any published information and before placing orders for products. Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 1 ISSI IS23SC4442 ® PIN CONFIGURATION C5 C1 C2 C6 C3 C7 C4 C8 Definitions and Functions Card Contact C1 C2 C3 C4 C5 C6 C7 C8 Symbol VCC RST CLK NC GND NC I/O NC Description Supply Voltage Reset Clock Input No Connect Ground No Connect Bidirectional Data I/O (Open drain) No Connect Note: An external pull up resistor is needed to be connected to the I/O pin. 2 Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 ISSI IS23SC4442 ® MEMORY OVERVIEW Main Memory VCC Reset, Blockade Logic Sequencer and Security Logic RST CLK High-Volt Generator 225 224 Byte Unprotected Data Memory Protection Memory (PROM) 32 31 Interface I/O Decoder 0 GND 32 Byte Protectable Data Memory Manufacturer Code Functional Description Reset and Answer-to-Reset The IS23SC4442 works on a 2-wire serial transmission protocol. Data is input or output from the chip through the I/O pin at the falling edge of CLK. The following are the four modes of operations: – Reset and Answer-to-Reset – Command Mode – Outgoing Data Mode – Processing Mode The Answer-to-Reset operation conforms to ISO 7816-3 ATR standard. The reset action can be invoked at any time during the operation to terminate any active command operation. With RST High, the internal address counter is set to zero by the CLK pulse. The LSB of the first byte data in the memory will be output from I/O when RST goes from High to Low. By continuing to send pluses to CLK, the contents of the first four bytes will be output from I/O pin. After the ATR process completes, the I/O pin will be set to high impedance. Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 3 ISSI IS23SC4442 ® FUNCTIONAL DESCRIPTION Block Diagram Security memory Protection memory Main memory 255 31 EEPROM 256X8 3 Reference data PSC 2 Reference data 32 31 Erase with 1 Reference data write 0 protection addr. data addr. 8 0 0 5 data EC addr. data 2LSB memory High-voltage generator Bias current generator Reset VCC 4 GND Vecoder Column sampling Addr. & data register comparator Timing security Programming Control Interface I/O RSTCLK Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 ISSI IS23SC4442 ® Functional Description The IS23SC4442 contains 256 bytes of EEPROM main memory (see block diagram) and a 32 bit protection memory. The main memory is byte-wise erased and written. When the memory is erased, 8 bits of the data byte are all set to logic 1. When the memory is written, a data byte can be programmed bit by bit, and it is set to logic 0 according to the logic between the old and new data. Generally, updating data includes an erase and write procedure. When updated, new input data and the contents of the old data are compared. If none of the 8 bits requires a logic 0 to 1 change, the erase operation will be skipped. On the contrary, the write operation will be skipped if no logic 1 to 0 change is necessary. The write and erase operation takes at least 2.5 ms each. TRANSMISSION PROTOCOL Transmission Mode The first 32 bytes can be protected individually by writing the corresponding bit in the protection memory. Each data byte in the address range and its assigned bit in the protection memory have the same address. Once the protection bit is written it cannot be erased. The security memory of IS23SC4442 contains an error counter (bit 0-bit 2) and 3 bytes reference data. The three bytes reference data are as a whole called programmable security code (PSC). After power on, except for the PSC, the whole memory can always be read. The error counter can always be written. After three successive unsuccessful PSC verifications, the error counter will block the chip, and write and erase operation to the memory will be forbidden. Reset and Answer-To-Reset The transmission protocol is a two-wire link protocol between the interface device IFD and IC. The protocol type is "S = 10". All data changes on I/O are triggered by the falling edge on CLK. The transmission protocol is composed of the following four modes: – Reset and answer- to-reset – Command mode – Data output mode – Processing mode According to IS07816-3, Answer-To-Reset takes place during operation. The reset can be implemented at any time. During reset, the address counter is set to zero. When RST is set from high level to low level, the lowest bit of the first byte is read on the I/O. Under continuous 31 clock pulses, the contents of the first 4 byte EEPROM addresses can be read out. The 33rd clock pulse sets the I/O to high impedance. During Answer-To-Reset, any start and stop condition is ignored. Vcc RST 1 2 31 3 IC sets I/O high impedance 32 CLK I/O 1 2 3 31 32 Figure: Reset and Answer-To-Reset Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 5 ISSI IS23SC4442 ® Command Mode After Answer-To-Reset, IS23SC4442 waits for a command entry. Each command begins with a start condition, which includes a three bytes command entry, and it ends with a stop condition. – Start condition: during CLK in high level, a falling edge on I/O – Stop condition: during CLK in high level, a rising edge on I/O – After receiving a command, there are two possible modes: – Processing mode for writing and erasing IFD sets I/O To L-level Command 1 2 24 23 3 CLK I/O 1 2 23 3 24 Stop from IFD Start from IFD Figure: Command Mode Data Output Mode When reading, the chip sends the data to IFD. The figure shows the timing diagram. After the first falling edge on CLK, the first bit on the I/O is valid. After the last data bit, an additional CLK pulse is necessary to set the I/O to a high level for receiving a new command. During this mode, any start and stop condition is ignored. IC set I/O to high-level Command CLK n-1 1 2 1 n 3 2 3 n-1 n I/O Start of output data Figure: Data Output Mode 6 Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 ISSI IS23SC4442 ® Processing Mode During processing, the chip processes internally. The following Figure shows the timing diagram. The IFD sends clock to the chip continuously until the I/O us set to the high level that has been set to low level on the first falling edge of CLK. During this mode any start and stop condition is ignored. IFD sets I/O to level L Outgoing Data IC sets I/O To level Z Command RST is low level 0 1 0 24 1 n 2 .. .. CLK I/O DI0 .. DI23 DO0 .. Don-1 Start from IFD Stop From IFD Start of Outgoing Data DOn IC sets I/O To level Z Processing CLK 0 1 I/O DI: Data In DO: Data Out Start of Processing End of Processing Figure : Sector Trailer (Block 3) Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 7 ISSI IS23SC4442 ® COMMANDS Command Format IS23SC4442 provide seven commands that are listed on Table 1. Every command consists of three bytes. MSB CONTROL LSB MSD ADDRESS LSB B7 B6 B5 B4 B3 B2 B1 B0 A7 A6 A5 A4 A3 A2 A1 A0 Note: Command transmission begins with the control byte LSB. MSB DATA D7 D6 D5 D4 D3 D2 LSB D1 D0 Table 1 Control of Byte 1 B7 B6 B5 B4 B3 B2 B1 B0 Address of Byte 2 A7 ~ A0 Address Address Data of Byte 3 D7 ~ D0 0 0 0 0 1 1 1 1 0 1 0 0 0 0 0 0 0 0 1 1 0 1 0 0 0 0 1 1 1 1 0 0 Address Input Data 0 0 0 0 1 1 1 1 0 1 0 0 0 0 1 1 Address Input Data 0 0 1 1 0 0 1 1 Address Input Data Input Data Operation Mode Read Main Memory Update Main Memory Read Protection Memory Write Protection Memory Read Main Memory Update Main Memory Compare Data Data Output Processing Output Data Output Data Data Output Processing Processing Command Mode IFD sets I/O To Level L Command 0 24 1 ... CLK I/O B0 Start from IFD 8 .. B7 A0 .. A7 D07 .. D7 Stop from IFD Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 ISSI IS23SC4442 ® Read Main Memory The command reads out the memory contents from the given address (N) to the last address of the memory (with LSB first). After the command entry, the IFD has to provide sufficient clock pluses. The number of clock pulse = (256 - N) x 8+1. The main memory can always be read. Address (decimal) Main Memory Protection Memory Security Memory 255 Data Byte 255 (D7 ...D0) — — : : —- — 32 Data Byte 32 (D7 ... D0) — — 31 Data Byte 31(D7 ... D0) Protection Bit 31 (D31) — : : : — 1 Data Byte 1 (D7 ... D0) Protection Bit 1 (D1) Reference Data Byte 1 (D7...D0) 0 Data Byte 0 (D7 ... D0) Protection Bit 0 (D0) Error Counter Address Control B7 0 Binary B6 B5 B4 B3 B2 B1 B0 A7... A0 D7... D0 0 1 1 0 0 0 0 Address No Effect Hexadecimal 00 30 H IFD set I/O to level L Command 0 24 1 H ... FF H No Effect Outgoing Data 0 IC sets I/O To Level Z 10 1 ... CLK Data ... I/O B0 Start from IFD .. D0 B7 D1 Data of Startaddress Stop from IFD .. D0 D1 Data of Startaddress +1 .. D0 .. D7 Data of Startaddress 255 Start of Outgoing Data Figure: Read Main Memory Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 9 ISSI IS23SC4442 ® Read Protection Memory The command reads out 32 bits to I/O on continuous 32 clock pulses. By an additional clock pulse, the I/O is set to high level. The protection memory can always be read. Address (decimal) Main Memory Protection Memory Security Memory 255 Data Byte 255 (D7 ...D0) — — : : — — 32 Data Byte 32 (D7 ... D0) — — 31 Data Byte 31 (D7...D0) Protection Bit 31 (D31) — : : : — 1 Data Byte 1 (D7 ... D0) Protection Bit 1 (D1) Reference Data Byte 1 (D7...D0) 0 Data Byte 0 (D7 ... D0) Protection Bit 0 (D0) Error Counter Address Control B7 B6 B5 B4 B3 B2 B1 B0 A7... A0 D7... D0 0 1 1 0 1 0 0 No Effect No Effect No Effect No Effect 0 Binary Data Hexadecimal 34 IFD set I/O to level L Command 0 H 24 24 1 IC sets I/O To Level Z Outgoing Data 0 32 1 ... CLK ... I/O B0 Start from IFD .. B7 D0 Data of Byte 1 Stop from IFD D1 .. D8 Data of Byte 2 D9 .. D24 .. D31 Data of byte 4 Start of Outgoing Data Figure: Read Protection Memory 10 Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 ISSI IS23SC4442 ® Read Security Memory level. The error counter can always be read. The read out four bytes security memory requires 32 clock pulses, I/O is set to the high level by an additional pulse. The three bytes of reference data can only be read after successful PSC verification; otherwise, the output of the PSC will be suppressed and the I/O will be set to the low Address (decimal) Main Memory Protection Memory Security Memory 255 Data Byte 255 (D7 ...D0) — — : : — — 32 Data Byte 32 (D7 ... D0) — — 31 Data Byte 31(D7 ... D0) Protection Bit 31 (D31) — : : : — 1 Data Byte 1 (D7 ... D0) Protection Bit 1 (D1) Reference Data Byte 1 (D7...D0) 0 Data Byte 0 (D7 ... D0) Protection Bit 0 (D0) Error Counter Address Control Binary Data B7 B6 B5 B4 B3 B2 B1 B0 A7... A0 D7... D0 0 No Effect No Effect No Effect No Effect 0 1 1 Hexadecimal 0 0 0 1 31 H IFD set I/O to level L Command 0 24 24 1 Outgoing Data IC sets I/O To Level Z 0 32 1 ... CLK ... I/O B0 Start from IFD .. X D0 D1 .. Data of Error Counter Stop from IFD D8 Reference Data Byte 1 D9 .. D24 .. D31 Reference Data byte 3 Start of Outgoing Data Figure: Read Security Memory Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 11 ISSI IS23SC4442 Update Main Memory – Write only (2.5 ms) corresponding to m=124 clock The command programs the addressed EEPROM byte with the given data byte. Depending on the old and the new data, one of the following operations will take place during processing mode. – Erase and write (5 ms) corresponding to m = 255 clock pulses pulses – Erase only (2.5ms) corresponding to m=124 clock pulses (frequency of clock = 50 kHz) Command 3 2 1 Processing 2 1 24 m 3 .. CLK m-2 I/O ® 1 .. 2 ... m-1 ... 24 RST Figure: Update Main Memory Address (decimal) Main Memory Protection Memory Security Memory 255 Data Byte 255 (D7 ...D0) — — : : — — 32 Data Byte 32 (D7 ... D0) — — 31 Data Byte 31(D7 ... D0) Protection Bit 31 (D31) — : : : — 1 Data Byte 1 (D7 ... D0) Protection Bit 1 (D1) Reference Data Byte 1 (D7...D0) 0 Data Byte 0 (D7 ... D0) Protection Bit 0 (D0) Error Counter Address Control Binary Hexadecimal 12 Data B7 B6 B5 B4 B3 B2 B1 B0 A7... A0 D7... D0 0 Address Input Data 00 ...FF H H Input Data 0 1 1 38 1 H 0 0 0 Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 ISSI IS23SC4442 ® Erase or Write Main Memory IFD set I/O to level L Command 0 24 24 1 CLK IC sets I/O To Level Z Processing 0 254 1 ... ... I/O .. B0 X Start from IFD Stop from IFD Start of Processing Figure 1 IFD set I/O to level L Command 0 24 24 1 CLK 0 B0 Start from IFD .. 123 1 ... I/O IC sets I/O To Level Z Processing ... X Stop from IFD Start of Processing Figure 2 Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 13 ISSI IS23SC4442 ® Update Security Memory After the successful PSC verification, the reference data can be updated. Otherwise, only the error counter can be written. The processing time and the required clock pulses are the same as that of the update main memory. Address Control Binary Data B7 B6 B5 B4 B3 B2 B1 B0 A7... A0 D7... D0 0 Address Input Data 00 ...03 H H Input Data 0 1 1 1 0 0 1 39 H Hexadecimal Write Protection Memory The execution of this command includes a comparison of the given data byte and the assigned byte in the main memory. If the result is data identity, the protection bit is written so the corresponding data byte in the main memory is unchangeable. If the result is differences, the protection bit cannot be written. The execution time and clock pulses are the same as that of the update main memory. Address (decimal) Main Memory Protection Memory Security Memory 255 Data Byte 255 (D7 ...D0) — — : : — — 32 Data Byte 32 (D7 ... D0) — — 31 Data Byte 31(D7 ... D0) Protection Bit 31 (D31) — : : : — 1 Data Byte 1 (D7 ... D0) Protection Bit 1 (D1) Reference Data Byte 1 (D7...D0) 0 Data Byte 0 (D7 ... D0) Protection Bit 0 (D0) Error Counter Address Control Binary Hexadecimal 14 Data B7 B6 B5 B4 B3 B2 B1 B0 A7... A0 D7... D0 0 Address Input Data 00 ...1F H H Input Data 0 1 1 1 3C H 1 0 0 Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 ISSI IS23SC4442 ® Compare Verification Data Only after the error counter has written one bit, can the procedure and compare verification data be executed. The command compares the given verification data byte with the corresponding reference data byte. Address Control B7 B6 B5 B4 B3 B2 B1 B0 A7... A0 D7... D0 0 1 1 0 0 1 1 Address Input Data 00 ...03 H H Input Data 0 Binary Data 33 Hexadecimal H IFD set I/O to level L IC sets I/O To Level Z Command 0 0 24 2 1 CLK 1 2 ... I/O B0 Start from IFD .. A0 .. D0 .. D7 Address1 Byte1 Address2 Byte2 Address3 Byte3 Stop from IFD Start of Processing Figure: Compare Verification data Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 15 ISSI IS23SC4442 Usage of the Compare Command The following procedure must be completed exactly as described. Any variation to the procedure can results in a failure, so that a write and erase can not be accessed. If the procedure cannot successful complete, only the error counter can be written that means one to zero but it cannot be erased. First of all, an error counter bit has to be written to zero by an update security memory command. Thereafter, a successful execution of three compare verification Command ® commands from byte 1 to byte 3 makes erasing the error counter possible. Write and erase access to all memory areas is possible; as long as, the operation voltage is applied. If an error takes place, the whole reference data can be updated like any other information in the main memory. As transported, the PSC is coded with the individual agreement with the customer. Knowing the code is indispensable to alter data. Control Address Data Remark B7....B0 A7...A0 D7...D0 Read Security Memory 31H No Effect Not Effect Check Error Counter Update Security Memory 39H 00H Input Data Write Free Bit in Error Counter Input Data 0000 0dd Binary 16 Compare Verification Data 33H 01H Input Data Reference Data Byte 1 Compare Verification Data 33H 02H Input Data Reference Data Byte 2 Compare Verification Data 33H 03H Input Data reference Data Byte 3 Update Security Memory 39H 00H FFH Erase Error Counter Read Security Memory 31H No Effect No Effect Check Error Counter Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 ISSI IS23SC4442 ® Verification Procedure Verification Procedure Read EC Comparison Blocked ... . (EC) =000? N Compare VD,ref, D Erase EC Read EC Update SM Address Data Compare VD Address Byte 1 Compare VD Address Byte 2 Compare VD Address Byte 3 Update SM Addr. 0 Read SM (EC) =111? Y Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 ... . Y write one bit of EC to "0" Number of comparision unsuccessful "1" = number of posible retries N Read SM ... . 111111111 .... EC = error counter SM = security memory VD = verification data 17 ISSI IS23SC4442 ® RESET MODE Break Reset and Answer-To-Reset If RST is set on the high level while CLK is set on the low level, the operation is aborted and the I/O is switched to the high level. To trigger a defined valid reset, the necessary minimum duration is tRES = 5 ms. After break, the IC is ready for further operations. Power on Reset After power on, the I/O is set to the high level. A read operation or an Answer-To-Reset command must be carried out before any data can be altered. RST tRES CLK I/O Figure: Break Failures Coding of the Chip Behavior of failures: In case of one of the following failures, the chip sets the I/O to the high level after 8 clock pulses. For security purposes, every chip is irreversibly coded by a scheme. This way fraud and misuse is excluded. For example, Figure a and Figure b show ATR and Directory Data of Structure 1. When transported, the ATR header, ICM and ICT are programmed. Shanghai Belling Microelectronics Mfg. CO., Ltd. programs the IC manufacturer identifier (ICM), IC type (ICT)... Belling programs other code depending on the customer agreement. Possible failures: - Comparison unsuccessful - Wrong number of command clock pulses - Write/erase access to already protected bytes - Rewrite and erase a protection bit 18 Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 ISSI IS23SC4442 ® Synchronous Transmission ATR and Directory Data ATR head 1 1 1 ATR data 1 1 1 1 5 1 4 1 1 H1 H2 H3 H4 TM LM ICM ICT ICCF ICCSN TT LT DIR data 6 1 1 1 1 1 Application file TA LA AID TD LD AP LD LA LM LT Figure a AID Application identifier ICCF Card Fabricator id. LM Length of manufacture data AP Appl. personalizer identifier ICCSN Card serial number LT Length of application template ICM ICT LA LD IC manufacturer IC manufacturer Length of AID Length of data TA TD TM TT Tag of AZD Tag of discretionary data Tag of manufacturer data Tag of application data ATR Answer-to-Reset DIR Directory H1, H2 Protocol bytes H3, H4 ATR historical bytes Output Mode protocol bytes acc. to ISO7816-3 protocol type H1 protocol parameter H2 Historical bytes acc. to ISO7816-4 category indicator H3 DIR data referemce b8 b7 b6 b5 b4 b3 b2 b1 b8 b7 b6 b5 b4 b3 b2 b1 b8 b7 b6 b5 b4 b3 b2 b1 b8 b7 b6 b5 b4 b3 b2 b1 1 0 1 0 0 0 1 0 0 0 0 1 0 0 1 1 0 0 0 1 0 0 0 0 1 0 0 1 0 0 0 1 Protocol typeS RFU structure id 0-7 = defined by ISO 8-E =not def.by ISO 8 =serial data access protocol 9=3 wire bus protocol A=2 wire bus protocol F=RFU number of data units Length of data units in bits (2xx) category indicator acc. to ISO 786-4 RFU 00 = definee by ISO 10 = structure 1 01 = structure 2 not def. by ISO 11 = structure 3 000 = no indication 001 = 128 010 = 256 100 = 1024 101 = 2048 111 = RFU 0: read to end 1: read with defined length b8 = 1 b7-b1 = reference of DIR data b8 = 0 b7-b1 = out of ISO7816-4 1: specify DIR data ref. 0: not specify DIR data ref. Figure b Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 19 ISSI IS23SC4442 ® ELECTRICAL CHARACTERISTICS Absolute Maximum Ratings Parameter Supply Input voltage Storage temperature Power Dissipation Temperature Symbol VCC V1 TSTG TTOT Ta Limits Typ. — — — — — Min. -0.3 -0.3 -40 0 -30 Unit Max. 6 6 125 70 75 V V O C mW O C Absolute Maximum Ratings Parameter Symbol Min. Supply Supply Voltage Supply Current Data Input H input Voltage (I/O, CLK, RST, SELECT) L input Voltage (I/O, CLK RST, SELECT) H input current (I/O, CLK, RST) Data Output (I/O) L output current H current leakage Capacitance Input capacitance 20 Limits Typ. Unit Max VCC ICC 2.7 — 5 3 5.5 10 V mA VH VL IH VCC-1 VGND-0.2 — — — — VCC+0.3 VGND+0.8 50 V V µA IL IH 1 — — — — 50 mA µA CI — — 10 pF Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 ISSI IS23SC4442 ® AC Characteristics Parameter Clock frequency Clock High period Clock Low period Rise Time Full Time Start Condition hold time Delay Time Stop condition, setup time Data hold time Data setup time Start condition, setup time Reset Delay Time Erase Time Write Time Interval before new start condition Notes: *f = 50kHz Symbol CLK tH tL tR tF td1 td2 td3 td5 td7 td8 tRES td9 tER Twr tbuf Limits Min. 7 9 9 1 1 4 2.5 4 1 1 4 5 2.5 2.5* 2.5* 10 Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774 Rev. 00B 08/01/03 Unit Max 50 kHz µs µs µs µs µs µs µs µs µs µs µs µs ms ms µs 21