Advanced CAT24C161/162(16K), CAT24C081/082(8K) CAT24C041/042(4K), CAT24C021/022(2K) Supervisory Circuits with I2C Serial CMOS E2PROM, Precision Reset Controller and Watchdog Timer FEATURES ■ Active High or Low Reset Outputs ■ Watchdog Timer on SDA for 24CXX1 ■ Programmable Reset Threshold ■ 400 KHz I2C Bus Compatible ■ 2.7 to 6 Volt Operation ■ ■ Low Power CMOS Technology ■ ■ 16 - Byte Page Write Buffer ■ ■ Built-in inadvertent write protection ■ — VCC Lock Out — Precision Power Supply Voltage Monitoring — 5V, 3.3V and 3V options 1,000,000 Program/Erase Cycles 100 Year Data Retention 8-Pin DIP or 8-Pin SOIC Commercial, Industrial and Automotive Temperature Ranges DESCRIPTION The CAT24CXXX is a single chip solution to three popular functions of EEPROM memory, precision reset controller and watchdog timer. The 24C161/162(16K), 24C081/082(8K), 24C041/042(4K) and 24C021/022(2K) feature a I2C Serial CMOS EEPROM. Catalyst's advanced CMOS technology substantially reduces device power requirements. The 24CXXX features a 16-byte page and is available in 8-pin DIP or 8-pin SOIC packages. The reset function of the 24CXXX protects the system during brown out and power up/down conditions. During system failure the watchdog timer feature protects the microcontroller with a reset signal. 24CXXX features active low reset on pin 2 and active high reset on pin 7. 24CXX1 features watchdog timer on the SDA line. 24CXX2 does not feature the watchdog timer function. PIN CONFIGURATION BLOCK DIAGRAM 24CXX1/XX2* DC RESET WP VSS EXTERNAL LOAD SENSE AMPS SHIFT REGISTERS DOUT ACK VCC RESET SCL SDA VCC WORD ADDRESS BUFFERS VSS *All products offered in P and J packages START/STOP LOGIC SDA PIN FUNCTIONS XDEC Pin Name Function SDA Serial Data/Address RESET/RESET Reset I/O SCL Clock Input Vcc Power Supply DC Do Not Connect VSS Ground WP E2PROM CONTROL LOGIC WP DATA IN STORAGE HIGH VOLTAGE/ TIMING CONTROL RESET Controller Only for 24C161 Write Protect WATCHDOG High Precision Vcc Monitor RESET/RESET © 1998 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice COLUMN DECODERS 1 STATE COUNTERS SCL SLAVE ADDRESS COMPARATORS 24C1601 BLOCK Doc. No. 25079-00 1/98 M-1 CAT24CXX1/XX2 Advanced ABSOLUTE MAXIMUM RATINGS* COMMENT Temperature Under Bias....................–55°C to +125°C Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions outside of those listed in the operational sections of this specification is not implied. Exposure to any absolute maximum rating for extended periods may affect device performance and reliability. Storage Temperature........................ –65°C to +150°C Voltage on Any Pin with Respect to Ground(1) ..............–2.0V to +VCC + 2.0V VCC with Respect to Ground..................–2.0V to +7.0V Package Power Dissipation Capability (Ta = 25°C)1.0W.................................1.0W Lead Soldering Temperature (10 secs)...............300°C Output Short Circuit Current(2) ..........................100mA RELIABILITY CHARACTERISTICS Symbol Parameter Min. NEND(3) Endurance TDR (3) VZAP (3) ILTH(3)(4) Max. Units Reference Test Method 1,000,000 Cycles/Byte MIL-STD-883, Test Method 1033 Data Retention 100 Years MIL-STD-883, Test Method 1008 ESD Susceptibility 2000 Volts MIL-STD-883, Test Method 3015 Latch-up 100 mA JEDEC Standard 17 D.C. OPERATING CHARACTERISTICS VCC = +2.7V to +6.0V, unless otherwise specified. Limits Typ. Max. Symbol Parameter Min. Units Test Conditions ICC Power Supply Current 3 mA f SCL = 100 KHz Isb Standby Current 40 µA Vcc=3.3V 50 µA Vcc=5 ILI Input Leakage Current 2 µA VIN=GND or VCC ILO Output Leakage Current 10 µA VIN=GND or VCC VIL Input Low Voltage –1 VCC x 0.3 V VIH Input High Voltage VCC x 0.7 VCC + 0.5 V VOL Output Low Voltage (SDA) 0.4 V IOL = 3 mA ,VCC=3.0V CAPACITANCE TA = 25°C, f = 1.0 MHz, VCC = 5V Symbol Test CI/O(3) CIN (3) Max. Units Conditions Input/Output Capacitance (SDA) 8 pF VI/O = 0V Input Capacitance (SCL) 6 pF VIN = 0V Note: (1) The minimum DC input voltage is –0.5V. During transitions, inputs may undershoot to –2.0V for periods of less than 20 ns. Maximum DC voltage on output pins is VCC +0.5V, which may overshoot to VCC + 2.0V for periods of less than 20ns. (2) Output shorted for no more than one second. No more than one output shorted at a time. (3) This parameter is tested initially and after a design or process change that affects the parameter. (4) Latch-up protection is provided for stresses up to 100 mA on address and data pins from –1V to VCC +1V. Doc. No. 25079-00 1/98 M-1 2 CAT24CXX1/XX2 Advanced A.C. CHARACTERISTICS VCC=2.7V to 6.0V unless otherwise specified. Output Load is 1 TTL Gate and 100pF Read & Write Cycle Limits Symbol Parameter VCC=2.7V - 6V Min. Max. VCC=4.5V - 5.5V Min. Max. Units FSCL Clock Frequency 100 400 kHz TI(1) Noise Suppression Time Constant at SCL, SDA Inputs 200 200 ns tAA SCL Low to SDA Data Out and ACK Out 3.5 1 µs tBUF(1) Time the Bus Must be Free Before a New Transmission Can Start tHD:STA Start Condition Hold Time tLOW 4.7 1.2 µs 4 0.6 µs Clock Low Period 4.7 1.2 µs tHIGH Clock High Period 4 0.6 µs tSU:STA Start Condition Setup Time (for a Repeated Start Condition) 4.7 0.6 µs tHD:DAT Data In Hold Time 0 0 ns tSU:DAT Data In Setup Time 50 50 ns SDA and SCL Rise Time 1 0.3 µs tF(1) SDA and SCL Fall Time 300 300 ns tSU:STO Stop Condition Setup Time tDH Data Out Hold Time tR (1) 4 0.6 µs 100 100 ns Power-Up Timing(1)(2) Symbol Parameter Max. Units tPUR Power-up to Read Operation 1 ms tPUW Power-up to Write Operation 1 ms Note: (1) This parameter is tested initially and after a design or process change that affects the parameter. (2) tPUR and tPUW are the delays required from the time VCC is stable until the specified operation can be initiated. Write Cycle Limits Symbol Parameter tWR Write Cycle Time Min. Typ. Max Units 10 ms The write cycle time is the time from a valid stop condition of a write sequence to the end of the internal program/erase cycle. During the write cycle, the bus interface circuits are disabled, SDA is allowed to remain high, and the device does not respond to its slave address. 3 Doc. No. 25079-00 1/98 M-1 CAT24CXX1/XX2 Advanced RESET CIRCUIT CHARACTERISTICS Symbol Parameter tGLITCH Glitch Reject Pulse Width VRT Reset Threshold Hystersis VOLRS Reset Output Low Voltage (IOLRS=1mA) VOHRS Reset Output High Voltage Vcc-0.75 Reset Threshold (Vcc=5V) (24CXXX-45) 4.50 4.75 Reset Threshold (Vcc=5V) (24CXXX-42) 4.25 4.50 Reset Threshold (Vcc=3.3V) (24CXXX-30) 3.00 3.15 Reset Threshold (Vcc=3.3V) (24CXXX-28) 2.85 3.00 Reset Threshold (Vcc=3V) (24CXXX-25) 2.55 2.70 tPURST Power-Up Reset Timeout 130 270 ms tRPD VTH to RESET Output Delay 5 µs VRVALID RESET Output Valid VTH Doc. No. 25079-00 1/98 M-1 Min. Max. Units 100 ns 15 mV 0.4 V V V 1 4 V CAT24CXX1/XX2 Advanced PIN DESCRIPTIONS WP: WRITE PROTECT If the pin is tied to VCC the entire memory array becomes Write Protected (READ only). When the pin is tied to VSS or left floating normal read/write operations are allowed to the device. VTH threshold and will continue driving the outputs for approximately 200ms (tPURST) after reaching VTH. After the tPURST timeout interval, the device will cease to drive reset outputs. At this point the reset outputs will be pulled up or down by their respective pull up/pull down devices. During power-down, the RESET outputs will begin driving active when VCC falls below VTH. The RESET outputs will be valid so long as VCC is >1.0V (VRVALID). SCL: SERIAL CLOCK The serial clock input clocks all data transferred into or out of the device. RESET/RESET RESET: RESET I/O RESET These are open drain pins and can be used as reset trigger inputs. By forcing a reset condition on the pins the device will initiate and maintain a reset condition for approximately 200ms. RESET pin must be connected through a pull-down and RESET pin must be connected through a pull-up device. The RESET pins are I/Os; therefore, the CAT24CXXX can act as a signal conditioning circuit for an externally applied reset. The inputs are level triggered; that is, the RESET input in the 24CXXX will initiate a reset timeout after detecting a high and the RESET input in the 24CXXX will initiate a reset timeout after detecting a low. Watchdog Timer SDA: SERIAL DATA/ADDRESS The bidirectional serial data/address pin is used to transfer all data into and out of the device. The SDA pin is an open drain output and can be wire-ORed with other open drain or open collector outputs. In the 24CXX1, the SDA line is also used as the Watchdog Timer Monitor. The Watchdog Timer provides an independent protection for microcontrollers. During a system failure, the CAT24CXX1 will respond with a reset signal after a timeout interval of 1.6 seconds for lack of activity. 24CXX1 is designed with the Watchdog Timer feature on the SDA input. For the 24CXX1, if the microcontroller does not toggle the SDA input pin within 1.6 seconds the Watchdog Timer times out. This will generate a reset condition on reset outputs. The Watchdog Timer is cleared by any transition on SDA. DEVICE OPERATION Reset Controller Description The CAT24CXXX provides a precision RESET controller that ensures correct system operation during brownout and power-up/down conditions. It is configured with open drain RESET outputs. During power-up, the RESET outputs remain active until VCC reaches the Figure 1. RESET Output Timing As long as the reset signal is asserted, the Watchdog Timer will not count and will stay cleared. 24CXX2 does not feature the Watchdog Timer function. t GLITCH VTH VRVALID VCC t PURST t RPD t PURST RESET t RPD RESET 5 Doc. No. 25079-00 1/98 M-1 CAT24CXX1/XX2 Advanced Hardware Data Protection Reset Threshold Voltage The 24CXXX is designed with the following hardware data protection features to provide a high degree of data integrity. From the factory the 24CXXX is offered in five different variations of reset threshold voltages. They are 4.504.75V, 4.25-4.50V, 3.00-3.15V, 2.85-3.00V and 2.552.70V. To provide added flexibility to design engineers using this product, the 24CXXX is designed with an additional feature of programming the reset threshold voltage. This allows the user to change the existing reset threshold voltage to one of the other four reset threshold voltages. Once the reset threshold voltage is selected it will not change even after cycling the power, unless the user uses the programmer to change the reset threshold voltage. However, the programming function is available only through third party programmer manufacturers. Please call Catalyst for a list of programmer manufacturers who support this function. (1) The 24CXXX features a WP pin. When WP pin is tied high the entire memory array becomes write protected (read only). (2) The VCC sense provides write protection when VCC falls below the reset threshold value (VTH). The VCC lock out inhibits writes to the serial EEPROM whenever VCC falls below (power down) VTH or until VCC reaches the reset threshold (power up) VTH. Figure 2. Bus Timing tF tHIGH tLOW tR tLOW SCL tSU:STA tHD:STA tHD:DAT tSU:DAT tSU:STO SDA IN tAA tBUF tDH SDA OUT Figure 3. Write Cycle Timing SCL SDA 8TH BIT BYTE n ACK tWR STOP CONDITION START CONDITION Figure 4. Start/Stop Timing SDA SCL START BIT Doc. No. 25079-00 1/98 M-1 STOP BIT 6 ADDRESS CAT24CXX1/XX2 Advanced FUNCTIONAL DESCRIPTION STOP Condition The CAT24CXXX supports the I2C Bus data transmission protocol. This Inter-Integrated Circuit Bus protocol defines any device that sends data to the bus to be a transmitter and any device receiving data to be a receiver. The transfer is controlled by the Master device which generates the serial clock and all START and STOP conditions for bus access. The CAT24CXXX operates as a Slave device. Both the Master device and Slave device can operate as either transmitter or receiver, but the Master device controls which mode is activated. A LOW to HIGH transition of SDA when SCL is HIGH determines the STOP condition. All operations must end with a STOP condition. I2 C DEVICE ADDRESSING The Master begins a transmission by sending a START condition. The Master sends the address of the particular slave device it is requesting. The four most significant bits of the 8-bit slave address are fixed as 1010. The next three bits (Fig. 6) define memory addressing. For the 24C021/022, the three bits are don't care. For the 24C041/042, the next two bits are don't care and the third bit is the high order address bit. For the 24C081/ 082, the next bit is don't care and the successive bits define the higher order address bits. For the 24C161/ 162 the three bits define higher order bits. BUS PROTOCOL The features of the I2C bus protocol are defined as follows: (1) Data transfer may be initiated only when the bus is not busy. The last bit of the slave address specifies whether a Read or Write operation is to be performed. When this bit is set to 1, a Read operation is selected, and when set to 0, a Write operation is selected. (2) During a data transfer, the data line must remain stable whenever the clock line is high. Any changes in the data line while the clock line is high will be interpreted as a START or STOP condition. After the Master sends a START condition and the slave address byte, the CAT24CXXX monitors the bus and responds with an acknowledge (on the SDA line) when its address matches the transmitted slave address. The CAT24CXXX then performs a Read or Write operation depending on the state of the R/W bit. START Condition The START Condition precedes all commands to the device, and is defined as a HIGH to LOW transition of SDA when SCL is HIGH. The CAT24CXXX monitors the SDA and SCL lines and will not respond until this condition is met. Figure 5. Acknowledge Timing SCL FROM MASTER 1 8 9 DATA OUTPUT FROM TRANSMITTER DATA OUTPUT FROM RECEIVER ACKNOWLEDGE START Figure 6. Slave Address Bits 24C021/022 1 0 1 0 X X X R/W 24C081/082 1 0 1 0 X a9 a8 R/W 24C041/042 1 0 1 0 X X a8 R/W 24C161/162 1 0 1 0 a10 a9 a8 R/W * 'X' Corresponds to Don't Care Bits (can be a zero or a one) ** a8, a9 and a10 correspond to the address of the memory array address word. 7 Doc. No. 25079-00 1/98 M-1 CAT24CXX1/XX2 Advanced ACKNOWLEDGE location. The CAT24CXXX acknowledges once more and the Master generates the STOP condition. At this time, the device begins an internal programming cycle to nonvolatile memory. While the cycle is in progress, the device will not respond to any request from the Master device. After a successful data transfer, each receiving device is required to generate an acknowledge. The Acknowledging device pulls down the SDA line during the ninth clock cycle, signaling that it received the 8 bits of data. The CAT24CXXX responds with an acknowledge after receiving a START condition and its slave address. If the device has been selected along with a write operation, it responds with an acknowledge after receiving each 8bit byte. Page Write The 24CXXX writes up to 16 bytes of data in a single write cycle, using the Page Write operation. The page write operation is initiated in the same manner as the byte write operation, however instead of terminating after the initial byte is transmitted, the Master is allowed to send up to 15 additional bytes. After each byte has been transmitted, CAT24CXXX will respond with an acknowledge, and internally increment the lower order address bits by one. The high order bits remain unchanged. When the CAT24CXXX begins a READ mode it transmits 8 bits of data, releases the SDA line, and monitors the line for an acknowledge. Once it receives this acknowledge, the CAT24CXXX will continue to transmit data. If no acknowledge is sent by the Master, the device terminates data transmission and waits for a STOP condition. WRITE OPERATIONS If the Master transmits more than 16 bytes before sending the STOP condition, the address counter ‘wraps around’, and previously transmitted data will be overwritten. Byte Write In the Byte Write mode, the Master device sends the START condition and the slave address information (with the R/W bit set to zero) to the Slave device. After t he Slave generates an acknowledge, the Master sends a 8-bit address that is to be written into the address pointers of the CAT24CXXX. After receiving another acknowledge from the Slave, the Master device transmits the data to be written into the addressed memory When all 16 bytes are received, and the STOP condi tion has been sent by the Master, the internal programming cycle begins. At this point, all received data is written to the CAT24CXXX in a single write cycle. Figure 7. Byte Write Timing BUS ACTIVITY: MASTER SDA LINE S T A R T SLAVE ADDRESS BYTE ADDRESS S T O P DATA S P A C K A C K A C K Figure 8. Page Write Timing BUS ACTIVITY: MASTER SDA LINE S T A R T SLAVE ADDRESS BYTE ADDRESS (n) DATA n+1 S P A C K Doc. No. 25079-00 1/98 M-1 DATA n S T DATA n+15 O P A C K A C K 8 A C K A C K CAT24CXX1/XX2 Advanced Acknowledge Polling protected and becomes read only. The CAT24CXXX will accept both slave and byte addresses, but the memory location accessed is protected from programming by the device's failure to send an acknowledge after the first byte of data is received. Disabling of the inputs can be used to take advantage of the typical write cycle time. Once the stop condition is issued to indicate the end of the host’s write operation, CAT24CXXX initiates the internal write cycle. ACK polling can be initiated immediately. This involves issuing the start condition followed by the slave address for a write operation. If CAT24CXXX is still busy with the write operation, no ACK will be returned. If CAT24CXXX has completed the write operation, an ACK will be returned and the host can then proceed with the next read or write operation. READ OPERATIONS The READ operation for the CAT24CXXX is initiated in the same manner as the write operation with one exception, that R/W bit is set to one. Three different READ operations are possible: Immediate/Current Address READ, Selective/Random READ and Sequential READ. WRITE PROTECTION The Write Protection feature allows the user to protect against inadvertent programming of the memory array. If the WP pin is tied to VCC, the entire memory array is Figure 9. Immediate Address Read Timing BUS ACTIVITY: MASTER SDA LINE S T A R T S T O P SLAVE ADDRESS S P A C K DATA N O A C K SCL SDA 8 9 8TH BIT DATA OUT NO ACK STOP 24C1601Fig.8 9 Doc. No. 25079-00 1/98 M-1 CAT24CXX1/XX2 Advanced Immediate/Current Address Read The CAT24CXXX’s address counter contains the address of the last byte accessed, incremented by one. In other words, if the last READ or WRITE access was to address N, the READ immediately following would access data from address N+1. If N=E (where E= 255 for 24C021/022, E=511 for 24C041/042, E=1023 for 24C081/082 and E=2047 for 24C161/162) then the counter will ‘wrap around’ to address 0 and continue to clock out data. After the CAT24CXXX receives its slave address information (with the R/W bit set to one), it issues an acknowledge, then transmits the 8-bit byte requested. The master device does not send an acknowledge, but will generate a STOP condition. does not send an acknowledge but will generate a STOP condition. Selective/Random Read The data being transmitted from CAT24CXXX is outputted sequentially with data from address N followed by data from address N+1. The READ operation address counter increments all of the CAT24CXXX address bits so that the entire memory array can be read during one operation. If more than E (where E= 255 for 24C021/ 022, E=511 for 24C041/042, E=1023 for 24C081/082 and E=2047 for 24C161/162) bytes are read out, the counter will ‘wrap around’ and continue to clock out data bytes. Sequential Read The Sequential READ operation can be initiated by either the Immediate Address READ or Selective READ operations. After the CAT24CXXX sends the initial 8-bit byte requested, the Master will respond with an acknowledge which tells the device it requires more data. The CAT24CXXX will continue to output an 8-bit byte for each acknowledge sent by the Master. The operation will terminate when the Master fails to respond with an acknowledge, thus sending the STOP condition. Selective/Random READ operations allow the Master device to select at random any memory location for a READ operation. The Master device first performs a ‘dummy’ write operation by sending the START condition, slave address and byte addresses of the location it wishes to read. After CAT24CXXX acknowledges, the Master device sends the START condition and the slave address again, this time with the R/W bit set to one. The CAT24CXXX then responds with its acknowledge and sends the 8-bit byte requested. The master device Figure 10. Selective Read Timing BUS ACTIVITY: MASTER SDA LINE S T A R T SLAVE ADDRESS S T A R T BYTE ADDRESS (n) S T O P SLAVE ADDRESS S S A C K P A C K A C K DATA n N O A C K 24C1601Fig.9 Figure 11. Sequential Read Timing BUS ACTIVITY: MASTER SLAVE ADDRESS DATA n DATA n+1 DATA n+2 S T O P DATA n+x SDA LINE P A C K A C K A C K A C K N O A C K 24C1601Fig.10 Doc. No. 25079-00 1/98 M-1 10 CAT24CXX1/XX2 Advanced Ordering Information Prefix CAT Optional Company ID Device # 24C162 Product Number 24C161: 16K 24C162: 16K 24C081: 8K 24C082: 8K 24C041: 4K 24C042: 4K 24C021: 2K 24C022: 2K Suffix J -30 I Temperature Range Blank = Commercial (0˚ to 70˚C) I = Industrial (-40˚ to 85˚C) A = Automotive (-40˚to +105˚C)* Package P: PDIP J: SOIC (JEDEC) * -40˚ to +125˚C is available upon request TE13 Tape & Reel TE13: 2000/Reel Reset Threshold Voltage 45: 4.5-4.75V 42: 4.25-4.5V 30: 3.0-3.15V 28: 2.85-3.0V 25: 2.55-2.7V Note: (1) The device used in the above example is a CAT24C162JI-30TE13 (16K I2C Memory, SOIC, Industrial Temperature, 3.0-3.15V Reset Threshold Voltage, Tape and Reel) 11 Doc. No. 25079-00 1/98 M-1 CAT24CXX1/XX2 Doc. No. 25079-00 1/98 M-1 Advanced 12