SUMMIT SMS2902/SMS2904/SMS2916 MICROELECTRONICS, Inc. Voltage Supervisory Circuit With Watchdog Timer OVERVIEW FEATURES * Precision Voltage Monitor - VCC Supply Monitor - Complementary reset outputs for complex microcontroller systems - Integrated memory write lockout function - No external components required *Watchdog Timer - 1600 ms, internal * Two Wire Serial Interface (I2CTM) The SMS29xx is a power supervisory circuit that monitors VCC and will generate complementary reset outputs. The reset pins also act as I/Os and may be used for signal conditioning. The SMS29xx also has an on-board watchdog timer. The SMS29xx integrates a nonvolatile serial memory. It features the industry standard I 2 C serial interface allowing quick implementation in an end-users' system. * Extended Programmable Functions available on SMS24 * High Reliability - Endurance: 100,000 erase/write cycles - Data retention: 100 years * 8-Pin PDIP or SOIC Packages BLOCK DIAGRAM VCC 8 SCL 6 SDA 5 NONVOLATILE MEMORY ARRAY WRITE CONTROL PROGRAMMABLE RESET PULSE GENERATOR + VTRIP 1.26V 1 RESET# 7 RESET RESET CONTROL - WDI# 2 WATCHDOG TIMER 4 2028 T BD 2.0 GND SUMMIT MICROELECTRONICS, Inc. * 300 Orchard City Drive, Suite 131 (c) SUMMIT MICROELECTRONICS, Inc. 2000 2028 5.0 4/18/00 * Campbell, CA 95008 * Telephone 408-378-6461 * Fax 408-378-6586 * www.summitmicro.com Characteristics subject to change without notice 1 SMS2902/SMS2904/SMS2916 PIN NAMES PIN CONFIGURATIONS 8-Pin PDIP or 8-Pin SOIC WDI# RESET# NC GND 1 2 3 4 8 7 6 5 VCC RESET SCL SDA 2028 T PCon 2.0 Symbol Pin Description WDI# 1 Watchdog Input /a high to low transition will clear the watchdog timer RESET# 2 Active Low RESET Input/Output NC 3 No Connect, tie to ground or leave open GND 4 Analog and Digital Ground SDA 5 Serial Memory Input/ Output data line SCL 6 Serial Memory clock input RESET 7 Active High RESET Input/ Output VCC 8 Supply Voltage 2028 PGM T1.1 CAPACITANCE TA = 25C, f = 100KHz Symbol CIN LOUT Parameter Max Units Input Capacitance 5 pF Output Capacitance 8 pF 2028 PGM T2..0 tR tH IGH tLOW tSU:STO tF SCL tSU:SDA tHD:SDA tSU:DAT tHD:DAT tBUF SDA In tDH tAA SDA Out 2028 ILL5.0 FIGURE 1. SERIAL BUS TIMING DIAGRAM 2028 5.0 4/18/00 2 SMS2902/SMS2904/SMS2916 ABSOLUTE MAXIMUM RATINGS Temperature Under Bias ............................................................................................................................... -40C to +85C Storage Temperature ..................................................................................................................................... -65C to +125C Soldering Temperature (less than 10 seconds) ................................................................................................................... 300C Supply Voltage ............................................................................................................................................................. 0 to 6.5V Voltage on Any Pin ....................................................................................................................................... -0.3V to VCC+0.3V ESD Voltage (JEDEC method) .......................................................................................................................................... 2,000V NOTE: These are STRESS ratings only. Appropriate conditions for operating these devices are given elsewhere in this specification. Stresses beyond those listed here may permanently damage the part. Prolonged exposure to maximum ratings may affect device reliability. RECOMMENDED OPERATING CONDITIONS Temperature Commercial Min 0C Max +70C Industrial -40C +85C 2028 PGM T3.0 DC ELECTRICAL CHARACTERISTICS (over recommended operating conditions unless otherwise specified) Symbol Parameter Supply Current (CMOS) ICC Conditions Min Max Units 3 mA SCL = CMOS Levels @ 100KHz SDA = Open All other inputs = GND or VCC VCC =5.5V VCC =3.3V 2 mA VCC =5.5V VCC =3.3V 50 25 A A ISB Standby Current (CMOS) SCL = SDA = VCC All other inputs = GND ILI Input Leakage VIN = 0 To VCC 10 A ILO Output Leakage VOUT = 0 To VCC 10 A VIL Input Low Voltage S0, S1, S2, SCL, SDA, RESET# 0.3xVCC V VIH Input High Voltage S0, S1, S2, SCL, SDA, RESET VOL Output Low Voltage IOL = 3mA SDA 0.7xVCC V 0.4 V 2028 PGM T4.0 AC ELECTRICAL CHARACTERISTICS (over recommended operating conditions unless otherwise specified) Symbol Parameter Conditions 2.7V to 4.5V 4.5V to 5.5V Min Max Min 0 100 Max Units 400 KHz fSCL SCL Clock Frequency tLOW Clock Low Period 4.7 1.3 s tHIGH Clock High Period 4.0 0.6 s tBUF Bus Free Time 4.7 1.3 s tSU:STA Start Condition Setup Time 4.7 0.6 s tHD:STA Start Condition Hold Time 4.0 0.6 s tSU:STO Stop Condition Setup Time 4.7 0.6 s tAA Clock to Output SCL Low to SDA Data Out Valid 0.3 tDH Data Out Hold Time SCL Low to SDA Data Out Change 0.3 tR SCL and SDA Rise Time 1000 300 ns tF SCL and SDA Fall Time 300 300 ns tSU:DAT Data In Setup Time 250 100 ns tHD:DAT Data In Hold Time 0 0 ns TI Noise Spike Width @ SCL, SDA Inputs tWR Write Cycle Time Before New Transmission Noise Suppression Time Constant 3.5 0.2 0.9 s 0.2 s 100 100 ns 10 10 ms 2028 PGM T5.0 2028 5.0 4/18/00 3 SMS2902/SMS2904/SMS2916 tGLITCH VTRIP VRVALID tRPD VCC tPURST tPURST RESET# tRPD RESET 2028 T fig02 2.0 FIGURE 2. RESET OUTPUT TIMING RESET CIRCUIT AC and DC ELECTRICAL CHARACTERISTICS TA=-40C to +85C Symbol Parameter Part no. Suffix A (or) Blank B 2.7 Min. Typ. Max. Unit VTRIP Reset Trip Point 4.250 4.50 2.55 4.375 4.625 2.65 200 4.5 4.75 2.75 V V V ms tPURST Reset Timeout tRPD VTRIP to RESET Output Delay 5 s VRVALID RESET Output Valid to VCC min. Guarantee tGLITCH Glitch Reject Pulse Width note 1 VOLRS RESET Output Low Voltage IOL = 1mA VOHRS RESET High Voltage Output IOH = 800A VULH VSENSE Under-voltage threshold low to high 1.20 1.25 1.30 V VUHL VSENSE Under-voltage threshold high to low 1.20 1.25 1.30 V VOLH VSENSE Over-voltage threshold low to high 1.20 1.25 1.30 V VOHL VSENSE Over-voltage threshold high to low 1.20 1.25 1.30 V tVD1 Delay to VLOW Active 5 s tVD2 Delay to VLOW Released 5 s tWDTO Watchdog timeout Period 1 V 30 ns 0.4 VCC-.75 1600 2028 5.0 4/18/00 4 V V ms SMS2902/SMS2904/SMS2916 WDI# < tWDTO tWDTO tPURST RESET# WDI# tWDTO tPURST tWDTO tPURST RESET# 2028 T fig03 2.0 FIGURE 3. WATCHDOG TIMER TIMING DIAGRAM RESET# (in) RESET# (out) tPURST tPURST RESET (out) 2028 T fig04 2.0 FIGURE 4. RESET AS AN INPUT FUNCTION 2028 5.0 4/18/00 5 SMS2902/SMS2904/SMS2916 PIN DESCRIPTIONS ENDURANCE AND DATA RETENTION Serial Clock (SCL) - The SCL input is used to clock data into and out of the device. In the WRITE mode, data must remain stable while SCL is HIGH. In the READ mode, data is clocked out on the falling edge of SCL. The SMS29xx is designed for applications requiring 100,000 erase/write cycles and unlimited read cycles. It provides 100 years of secure data retention, with or without power applied, after the execution of 100,000 erase/write cycles. Serial Data (SDA) - The SDA pin is a bidirectional pin used to transfer data into and out of the device. Data may change only when SCL is LOW, except START and STOP conditions. It is an open-drain output and may be wireORed with any number of open-drain or open-collector outputs. Reset Controller Description The SMS29xx provides a precision RESET controller that ensures correct system operation during brown-out and power-up/-down conditions. It is configured with two open drain RESET outputs; pin 7 is an active high output and pin 2 is an active low output. RESET# - RESET# is an active low output. Whenever VCC is below VTRIP the SMS29xx will drive the RESET# pin to ground. The RESET# pin is an I/O and can be used as a reset input. Refer to Figure 1 as an example use of this pin as a push button switch debounce circuit. It should be noted this is an open drain output and an external pull-up resistor tied to VCC is needed for proper operation. During power-up, the RESET outputs remain active until VCC reaches the VTRIP threshold and will continue driving the outputs for tPURST (200 msec) after reaching VTRIP. The RESET outputs will be valid so long as VCC is > 1.0V. During power-down, the RESET outputs will begin driving active when VCC falls below VTRIP. RESET -- RESET is an active high output. Whenever VCC is below VTRIP the SMS29xx will drive the RESET pin to the VCC rail. The RESET pin is an I/O and can be used as a reset input. It should be noted this is an open drain output and an external pull-down resistor tied to ground is needed for proper operation. The RESET pins are I/Os; therefore, the SMS29xx can act as a signal conditioning circuit for an externally applied reset. The inputs are edge triggered; that is, the RESET input will initiate a reset timeout after detecting a low to high transition and the RESET# input will initiate a reset timeout after detecting a high to low transition. Refer to the applications Information section for more details on device operation as a reset conditioning circuit. WDI# - The WDI# input is used as a hardware method of clearing the watchdog timer. A high to low transition on this pin will clear the watchdog timer. If a transition is not detected within 1.6 seconds the watchdog will time out and force the reset outputs active. WATCHDOG TIMER OPERATION The SMS29xx has a watchdog timer with a programmable timeout period. Whenever the watchdog times out it will generate a reset output on both RESET# and RESET. Any transition on WDI will clear the watchdog timer. If a transition is not detected within tWDTO seconds the watchdog will time out and force the reset outputs active. 2028 5.0 4/18/00 6 SMS2902/SMS2904/SMS2916 SCL from Master Data Output from Transmitter 1 9 8 Start Condition tAA Data Output from Receiver ACKnowledge tAA 2028 ILL7.0 FIGURE 5. ACKNOWLEDGE RESPONSE FROM RECEIVER CHARACTERISTICS OF THE I2C BUS Acknowledge (ACK) Acknowledge is a software convention used to indicate successful data transfers. The transmitting device, either the master or the slave, will release the bus after transmitting eight bits. During the ninth clock cycle, the receiver will pull the SDA line LOW to ACKnowledge that it received the eight bits of data (See Figure 5). General Description The I2C bus was designed for two-way, two-line serial communication between different integrated circuits. The two lines are: a serial data line (SDA), and a serial clock line (SCL). The SDA line must be connected to a positive supply by a pull-up resistor, located somewhere on the bus (See Figure 1). Data transfer between devices may be initiated with a START condition only when SCL and SDA are HIGH (bus is not busy). The SMS29xx will respond with an ACKnowledge after recognition of a START condition and its slave address byte. If both the device and a write operation are selected, the SMS29xx will respond with an ACKnowledge after the receipt of each subsequent 8-bit word. Input Data Protocol One data bit is transferred during each clock pulse. The data on the SDA line must remain stable during clock HIGH time, because changes on the data line while SCL is HIGH will be interpreted as start or stop condition. In the READ mode, the SMS29xx transmits eight bits of data, then releases the SDA line, and monitors the line for an ACKnowledge signal. If an ACKnowledge is detected, and no STOP condition is generated by the master, the SMS29xx will continue to transmit data. If an ACKnowledge is not detected, the SMS29xx will terminate further data transmissions and awaits a STOP condition before returning to the standby power mode. START and STOP Conditions When both the data and clock lines are HIGH, the bus is said to be not busy. A HIGH-to-LOW transition on the data line, while the clock is HIGH, is defined as the "START" condition. A LOW-to-HIGH transition on the data line, while the clock is HIGH, is defined as the "STOP" condition . Device Addressing Following a start condition the master must output the address of the slave it is accessing. The most significant four bits of the slave address are the device type identifier (`1010') (see figure 6). DEVICE OPERATION The SMS29xx is a 2K/4K/16K serial E2PROM. The device supports the I2C bidirectional data transmission protocol. The protocol defines any device that sends data onto the bus as a "transmitter" and any device which receives data as a "receiver." The device controlling data transmission is called the "master" and the controlled device is called the "slave." In all cases, the SMS29xx will be a "slave" device, since it never initiates any data transfers. DEVICE IDENTIFIER 1 0 1 0 A 10 * A 9 * A 8 ** R/W 2028 ILL8.1 * = 2916 only ** = 2904 only FIGURE 6. SLAVE ADDRESS BYTE 2028 5.0 4/18/00 7 SMS2902/SMS2904/SMS2916 The next three bits are the high order address bits on the 2904 and 2916 and are "Don't Care" on the 2902. While the internal write cycle is in progress, the SMS29xx inputs are disabled, and the device will not respond to any requests from the master. Refer to Figure 7 for the address, ACKnowledge and data transfer sequence. Read/Write Bit The last bit of the data stream defines the operation to be performed. When set to "1," a read operation is selected; when set to "0," a write operation is selected. Page WRITE The SMS29xx is capable of a 16-byte page write operation. It is initiated in the same manner as the byte-write operation, but instead of terminating the write cycle after the first data word, the master can transmit up to 15 more bytes of data. After the receipt of each byte, the SMS29xx will respond with an ACKnowledge. WRITE OPERATIONS The SMS29xx allows two types of write operations: byte write and page write. The byte write operation writes a single byte during the nonvolatile write period (tWR). The page write operation allows up to 16 bytes in the same page to be written during tWR. The SMS29xx automatically increments the address for subsequent data words. After the receipt of each word, the low order address bits are internally incremented by one. The high order five bits of the address byte remain constant. Should the master transmit more than 16 bytes, prior to generating the STOP condition, the address counter will "roll over," and the previously written data will be overwritten. As with the byte-write operation, all inputs are disabled during the internal write cycle. Refer to Figure 7 for the address, ACKnowledge and data transfer sequence. Byte WRITE Upon receipt of both the slave address and word address, the SMS29xx responds with an ACKnowledge for each. After receiving the next byte of data, it again responds with an ACKnowledge. The master then terminates the transfer by generating a STOP condition, at which time the SMS29xx begins the internal write cycle. If single byte-write only, Stop bit issued here. Acknowledges Transmitted from SMS29xx to Master Receiver SDA Bus Activity A A X R 10 9 W 1010 A A X 10 9 0 A C Word Address K A A A A A A A A 7 6 5 4 3 2 1 0 A C K Data Byte n D D D D D D D D 7 6 5 4 3 2 1 0 A C K Acknowledges Transmitted from SMS29xx to Master Receiver A A Data Byte n+1 C Data Byte n+15 C K K D D D D D D D D 7 6 5 4 3 2 1 0 D D D D D D D D 7 6 5 4 3 2 1 0 S T O P S T Device Type A R Address Read/Write T 0= Write Slave Address Master Sends Read Request to Slave Master Transmitter to Slave Receiver Master Writes Word Address to Slave Master Transmitter to Slave Receiver Slave Transmitter to Master Receiver Master Writes Data to Slave Master Transmitter to Slave Receiver Slave Transmitter to Master Receiver Master Writes Data to Slave Master Transmitter to Slave Receiver Slave Transmitter to Master Receiver Master Writes Data to Slave Master Transmitter to Slave Receiver Slave Transmitter to Master Receiver Slave Transmitter to Master Receiver 2028 ILL9.1 Shading Denotes SMS29xx SDA Output Active FIGURE 7. PAGE/BYTE WRITE MODE 2028 5.0 4/18/00 8 SMS2902/SMS2904/SMS2916 Acknowledge Polling When the SMS29xx is performing an internal WRITE operation, it will ignore any new START conditions. Since the device will only return an acknowledge after it accepts the START, the part can be continuously queried until an acknowledge is issued, indicating that the internal WRITE cycle is complete. READ OPERATIONS Read operations are initiated with the R/W bit of the identification field set to "1." There are four different read options: 1. 2. 3. 4. To poll the device, give it a START condition, followed by a slave address for a WRITE operation (See Figure 8). Current Address Byte Read The SMS29xx contains an internal address counter which maintains the address of the last word accessed, incremented by one. If the last address accessed (either a read or write) was to address location n, the next read operation would access data from address location n+1 and increment the current address pointer. When the SMS29xx receives the slave address field with the R/W bit set to "1," it issues an acknowledge and transmits the 8bit word stored at address location n+1. Internal WRITE Cycle In Progress; Begin ACK Polling Issue Start Issue Slave Address and R/W = 0 ACK Returned? Issue Stop No The current address byte read operation only accesses a single byte of data. The master does not acknowledge the transfer, but does generate a stop condition. At this point, the SMS29xx discontinues data transmission. See Figure 9 for the address acknowledge and data transfer sequence. Yes (Internal WRITE Cycle is completed) Next operation a WRITE? No Yes Issue Byte Address Issue Stop Proceed with WRITE Await Next Command Current Address Byte Read Random Address Byte Read Current Address Sequential Read Random Address Sequential Read 2028 ILL10.0 FIGURE 8. ACKNOWLEDGE POLLING SDA Bus Activity X X X R W 1 1 0 1 0 S Device T Type A Address R T A C K Data Byte D D D D D D D D 7 6 5 4 3 2 1 0 1 1 Lack of ACK (low) from Master determines last data byte to be read Read/Write 1= Read Slave Address S T O P Slave sends Data to Master Master sends Read request to Slave Slave Transmitter to Master Receiver Master Transmitter to Slave Receiver Shading Denotes SMS29xx SDA Output Active 2028 ILL11.1 FIGURE 9. CURRENT ADDRESS BYTE READ MODE 2028 5.0 4/18/00 9 SMS2902/SMS2904/SMS2916 Random Address Byte Read Random address read operations allow the master to access any memory location in a random fashion. This operation involves a two-step process. First, the master issues a write command which includes the start condition and the slave address field (with the R/W bit set to WRITE) followed by the address of the word it is to read. This procedure sets the internal address counter of the SMS29xx to the desired address. x x A A X R W 10 9 SDA Bus Activity 1 0 1 0 S T Device Type A Address R T A A 10 9 X 0 A C K After the word address acknowledge is received by the master, the master immediately reissues a start condition followed by another slave address field with the R/W bit set to READ. The SMS29xx will respond with an acknowledge and then transmit the 8-data bits stored at the addressed location. At this point, the master does not acknowledge the transmission but does generate the stop condition. The SMS29xx discontinues data transmission and reverts to its standby power mode. See Figure 10 for the address, acknowledge and data transfer sequence. Word Address A A A A 7 6 5 4 A A 3 2 A A 1 0 Slave Address Master Transmitter to Slave Receiver Shading Denotes SMS29xx SDA Output Active X X X R W 1 0 1 0 S T Device Type A Address R T Read/Write 0= Write Master sends Read request to Slave A C K 1 Read/Write 1= Read Slave Address Master Writes Word Address to Slave Master Requests Data from Slave Master Transmitter to Slave Receiver Master Transmitter to Slave Receiver Slave Transmitter to Master Receiver Slave Transmitter to Master Receiver A C K Data Byte D D D D D D D D 7 6 5 4 3 2 1 0 1 Lack of ACK (low) from Master determines last data byte to be read Slave sends Data to Master Slave Transmitter to Master Receiver Slave Transmitter to Master Receiver 2028 ILL12.1 FIGURE 10. RANDOM ADDRESS BYTE READ MODE 2028 5.0 4/18/00 10 S T O P SMS2902/SMS2904/SMS2916 Sequential READ Sequential READs can be initiated as either a current address READ or random access READ. The first word is transmitted as with the other byte read modes (current address byte READ or random address byte READ); however, the master now responds with an ACKnowledge, indicating that it requires additional data from the SMS29xx. The SMS29xx continues to output data for each ACKnowledge received. The master terminates the sequential READ operation by not responding with an ACKnowledge, and issues a STOP conditions. During a sequential read operation, the internal address counter is automatically incremented with each acknowledge signal. For read operations, all address bits are incremented, allowing the entire array to be read using a single read command. After a count of the last memory address, the address counter will `roll-over' and the memory will continue to output data. See Figure 11 for the address, acknowledge and data transfer sequence. Acknowledge from Master Receiver Acknowledges from SMS29xx SDA Bus Activity A A R X 10 9 W A A 9 X 1 0 1 0 10 S T Device A Type R Address T 0 A C Word Address K A A A A A A A A 7 6 5 4 3 2 1 0 Slave Address Master Transmitter to Slave Receiver X X X 1 0 1 0 S T Device A Type R Address T Read/Write 0= Write Master sends Read request to Slave A C K R W 1 A C K A First Data Byte C Master Transmitter to Slave Receiver Slave Transmitter to Master Receiver D D D D D D D D 7 6 5 4 3 2 1 0 D D D D D D D D 7 6 5 4 3 2 1 0 1 S T O P Read/Write 1= Read Master Requests Data from Slave Master Transmitter to Slave Receiver Lack of ACK (low) determines last data byte to be read Slave sends Data to Master Slave Transmitter to Master Receiver Slave Transmitter to Master Receiver Slave Transmitter to Master Receiver Last Data Byte K Slave Address Master Writes Word Address to Slave Lack of Acknowledge from Master Receiver Slave sends Data to Master Slave Transmitter to Master Receiver Master Transmitter to Slave Receiver Shading Denotes SMS29xx SDA Output Active 2028 ILL13.1 FIGURE 11. SEQUENTIAL READ OPERATION (starting with a Random Address READ) 2028 5.0 4/18/00 11 SMS2902/SMS2904/SMS2916 VCC = 3.0V or 5.0V PB_RST# ALE SMS29xx WDI# RESET# NC GND 8051 Type MCU VCC RESET SCL SDA RST SCL (P0.0) SDA (P0.1) I2C Peripheral RESET# SCL SDA 2028 T fig12 2.0 TYPICAL APPLICATION USING DUAL RESET FUNCTION AND WATCHDOG TIMER 5.0VDC PB_RST# SMS29xx Z80 VCC RESET SCL SDA WDI# RESET# NC GND I/O I/O DECODER RST# 2028 T fig13 2.0 TYPICAL APPLICATION CONFIGURATION USING SYSTEM DECODE LOGIC TO RESET WDI 5.0VDC VCC 1232 PBRST# TOL GND VCC ST# RST# RST 24C16 GND ALE ALE I/O I/O 8051 Family Part RST SMS29xx RST 8051 Family Part WDI# RESET# NC GND VCC RESET SCL SDA I/O I/O SCL SDA 2028 T fig14 2.0 From This To This 2028 5.0 4/18/00 12 SMS2902/SMS2904/SMS2916 8 Pin PDIP (Type P) Package .375 (9.525) .250 (6.350) PIN 1 INDICATOR .300 (7.620) .070 (1.778) .0375 (0.952) .015 (.381) Min. 5-7TYP. (4 PLCS) 0-15 SEATING PLANE .130 (3.302) .060 .005 (1.524) .127 TYP. .100 (2.54) TYP. .130 (3.302) .018 (.457) TYP. .350 (8.89) .009 .002 (.229 .051) 8pn PDIP/P ILL.3 8 Pin SOIC (Type S) Package JEDEC (150 mil body width) .050 (1.27) TYP. .050 (1.270) TYP. 8 Places .157 (4.00) .150 (3.80) .275 (6.99) TYP. .030 (.762) TYP. 8 Places 1 .196 (5.00) .189 (4.80) FOOTPRINT .061 (1.75) .053 (1.35) .020 (.50) x45 .010 (.25) .0192 (.49) .0138 (.35) .0098 (.25) .004 (.127) .05 (1.27) TYP. .035 (.90) .016 (.40) .244 (6.20) .228 (5.80) 8pn JEDEC SOIC ILL.2 2028 5.0 4/18/00 13 SMS2902/SMS2904/SMS2916 ORDERING INFORMATION SMS2902 P A Base Part Number VTRIP A = 4.5V B = 4.75V 2.7 = 2.7V Blank = 4.5V Package P = PDIP S = SOIC 2028-02 Tree 2.0 SMS2904 P A Base Part Number VTRIP A = 4.5V B = 4.75V 2.7 = 2.7V Blank = 4.5V Package P = PDIP S = SOIC 2028-04 Tree 2.0 SMS2916 Base Part Number P A VTRIP A = 4.5V B = 4.75V 2.7 = 2.7V Blank = 4.5V Package P = PDIP S = SOIC 2028-16 Tree 2.0 NOTICE SUMMIT Microelectronics, Inc. reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. SUMMIT Microelectronics, Inc. assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. Charts and schedules contained herein reflect representative operating parameters, and may vary depending upon a user's specific application. While the information in this publication has been carefully checked, SUMMIT Microelectronics, Inc. shall not be liable for any damages arising as a result of any error or omission. SUMMIT Microelectronics, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless SUMMIT Microelectronics, Inc. receives written assurances, to its satisfaction, that: (a) the risk of injury or damage has been minimized; (b) the user assumes all such risks; and (c) potential liability of SUMMIT Microelectronics, Inc. is adequately protected under the circumstances. I2C is a trademark of Philips Corporation. (c) Copyright 2000 SUMMIT Microelectronics, Inc. 2028 5.0 4/18/00 14