M41T56C64 Serial Real Time Clock with 56 bytes of NVRAM + 64 Kbit (8192 bit x 8) EEPROM Feature summary ■ 5V ±10% supply voltage ■ I2C bus compatible ■ Operating temperature of –40 to 85°C ■ Packaging includes: – 18-lead SOIC (with embedded crystal) ■ RoHS compliant Embedded crystal 18 1 Serial RTC features ■ Counters for seconds, minutes, hours, day, date, month, years, and century ■ Embedded crystal package ■ Software clock calibration ■ Automatic power-fail detect and switch circuitry ■ 56 bytes of general purpose SRAM ■ Ultra-low battery supply current of 450nA ■ Automatic leap year compensation ■ Special software programmable output ■ Two-wire I2C serial interface supports 100kHz protocol SOX18(MY) 18-pin (300mil) SOIC Serial EEPROM features ■ 8192 bytes of general purpose EEPROM (more than 1e6 erase/write cycles) ■ Two-wire I2C serial interface supports 400kHz protocol ■ Byte and page write (up to 32 bytes) ■ More than 40 year data retention ■ Self-timed programming cycle September 2006 Rev 4 1/19 www.st.com 1 Contents M41T56C64 Contents 1 Summary description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1 2 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2 Pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.1 Serial RTC device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.2 EEPROM device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5 Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6 DC and AC parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 8 Order codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2/19 M41T56C64 List of tables List of tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Table 10. Table 11. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Device select code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Operating and AC measurement conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Capacitance and input parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 DC characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 AC characteristics, (serial RTC, M41T56) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 AC characteristics (Serial EEPROM, M24C64) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 SOX18 – 18-lead plastic small outline, 300mils, embedded crystal, package mech. . . . . . 16 Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3/19 List of figures M41T56C64 List of figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. 4/19 Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 18-pin SOIC connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Crystal accuracy across temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 AC measurement I/O waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 AC Bus timing requirements sequence (serial RTC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 SOX18 – 18-lead plastic small outline, 300mils, embedded crystal . . . . . . . . . . . . . . . . . . 16 M41T56C64 1 Summary description Summary description The M41T56C64 is a low power, Serial Real Time Clock with 56 bytes of NVRAM plus a 64Kb EEPROM (see Figure 3). A built-in 32,768Hz oscillator (crystal controlled) and the first 8 bytes of the RAM are used for the clock/calendar function and are configured in binary coded decimal (BCD) format. Addresses and data are transferred serially via a two-line, bidirectional bus. The built-in address register is incremented automatically after each WRITE or READ data byte. The M41T56C64 clock has a built-in power sense circuit which detects power failures and automatically switches to the battery supply during power failures. The energy needed to sustain the RAM and clock operations can be supplied from a small lithium coin cell. Typical data retention time for the Serial RTC is in excess of 10 years with a 50mAh, 3V lithium cell. The M41T56C64 is supplied in an 18-lead Plastic SOIC package. 1.1 Calibration As the crystal is molded together with the silicon in this package, ST can program the appropriate calibration value necessary to achieve ±5 ppm accuracy at 25°C after two SMT reflows (see Figure 4). This calibration value will be written into address 1550h of the EEPROM. This clock accuracy can then be guaranteed to drift no more than ±3 ppm the first year, and ±1 ppm for each following year due to crystal aging. Figure 1. Logic diagram VCC VBAT SCL E0 E1 E2 M41T56 + M24C64 (EEPROM) SDA FT/OUT(1) WC VSS AI09123 1. Open drain output 5/19 Pin settings M41T56C64 2 Pin settings 2.1 Pin description Table 1. Signal names FT/OUT (1) Frequency test / output driver (open drain) SDA Serial data address input / output SCL Serial clock WC Write control E0, E1, E2 Chip enables VBAT Battery supply voltage VCC Supply voltage VSS Ground NC (2) No connect NF (3) No function 1. Open drain output 2. No connect (NC) pins should be tied to VSS. 3. No function (NF) pins should be tied to VSS. Pins 2 and 3, and pins 16 and 17 are internally shorted together. 2.2 Pin connections Figure 2. 18-pin SOIC connection NC(1) NF(2) NF(2) (1) NC E0 E1 E2 VBAT VSS 18 1 2 17 3 16 M41T56 4 15 + 5 14 M24C64 6 13 (EEPROM) 7 12 8 11 9 10 NC(1) NF(2) (2) NF VCC NC(1) FT/OUT(3) WC SCL SDA AI09124 1. No connect (NC) pins should be tied to VSS 2. No function (NF) pins should be tied to VSS. Pins 2 and 3, and pins 16 and 17 are internally shorted together. 3. Open drain output 6/19 M41T56C64 Application 3 Application Figure 3. Block diagram 1 Hz OSCILLATOR 32.768 kHz SECONDS MINUTES DIVIDER CENTURY/HOURS DAY FT/OUT DATE MONTH VOLTAGE SENSE and SWITCH CIRCUITRY VCC VSS VBAT YEAR CONTROL LOGIC CONTROL E0 E1 E2 56 x8 (SRAM) SCL SERIAL BUS INTERFACE M24C64 8192 x8 (EEPROM) ADDRESS REGISTER SDA AI09125 Figure 4. Crystal accuracy across temperature Frequency (ppm) 20 0 –20 –40 –60 ∆F = offset + K x (T – 25)2 F –80 K = –0.034 ppm/°C2 ± 0.004 ppm/°C2 –100 offset = 6 ppm ± 6 ppm –120 –140 –160 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 Temperature °C AI09159 7/19 Application M41T56C64 Table 2. Device select code Device type identifier(1) Chip enable address(2) b7 b6 b5 b4 b3 b2 b1 b0 M24C64 1 0 1 0 E2 E1 E0 RW M41T56 1 1 0 1 0 0 0 RW 1. The most significant bit, b7, is sent first. 2. E0, E1, and E2 are compared against the respective external pins on the memory device. 8/19 RW M41T56C64 Operation 4 Operation 4.1 Serial RTC device The M41T56C64 contains one Serial RTC (M41T56). For detailed information on how to use the devices, see the M41T56 datasheet, which is available from your local STMicroelectronics distributor or from the STMicroelectronics website, http://www.st.com/rtc/. 4.2 EEPROM device The M41T56C64 contains a 64 Kbit Serial EEPROM (M24C64). For detailed information on how to use the devices, see the M24C64 datasheet, which is available from your local STMicroelectronics distributor or from the STMicroelectronics website, http://www.st.com/eeprom/. 9/19 Maximum rating 5 M41T56C64 Maximum rating Stressing the device above the rating listed in the “absolute maximum ratings” table may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other conditions above those indicated in the Operating sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Refer also to the STMicroelectronics SURE program and other relevant quality documents. Table 3. Absolute maximum ratings Symbol TA TSTG TSLD(1) Parameter Value Unit Ambient operating temperature –40 to 85 °C Storage temperature (VCC off, oscillator off) –55 to 125 °C 240 °C Lead solder temperature for 10 seconds VIO Input or output voltages –0.3 to 6.5 V VCC Supply voltage –0.3 to 6.5 V IO Output current 20 mA PD Power dissipation 0.25 W 1. For SOX18 package, Lead-free (Pb-free) lead finish: Reflow at peak temperature of 240°C (total thermal budget not to exceed 180°C for between 90 to 150 seconds). No direct exposure to infrared (IR) reflow, or IR preheat allowed, to avoid damaging the embedded 32KHz crystal. Caution: 10/19 Negative undershoots below –0.3V are not allowed on any pin while in the battery back-up mode. M41T56C64 6 DC and AC parameters DC and AC parameters This section summarizes the operating and measurement conditions, as well as the DC and AC characteristics of the device. The parameters in the following DC and AC characteristic tables are derived from tests performed under the measurement conditions listed in the relevant tables. Designers should check that the operating conditions in their projects match the measurement conditions when using the quoted parameters. Table 4. Operating and AC measurement conditions(1) Parameter Value Unit Supply voltage (VCC) 4.5 to 5.5 V Ambient operating temperature (TA) –40 to 85 °C Load capacitance (CL) 100 pF Input rise and fall times 50 (max) ns Input pulse voltages 0.2VCC to 0.8VCC V Input and output timing ref. voltages 0.3VCC to 0.7VCC V 1. Output Hi-Z is defined as the point where data is no longer driven. Figure 5. AC measurement I/O waveform 0.8VCC 0.2VCC 0.7VCC 0.3VCC AI02568 11/19 DC and AC parameters M41T56C64 Table 5. Capacitance and input parameters CIN Test condition Parameter (1) (2) Symbol Min Max Unit Input capacitance (SCL) 13 pF Input capacitance (SDA) 18 pF Input Capacitance (Other pins) 6 pF 20 kΩ ZWCL WC input impedance VIN < 0.5V 5 ZWCH WC input impedance VIN < 0.7VCC 500 COUT(3) kΩ Output capacitance (SDA) 18 pF Output capacitance (FT/OUT) 10 pF Max Unit 0V ≤VIN ≤VCC ±3 µA 0V ≤VOUT ≤VCC ±3 µA Switch frequency = 100kHz 310 µA Supply current (Serial EEPROM active) VCC = 5V, fc=400kHz (rise/fall time < 30ns) 2.2 mA Supply current (standby) SCL, SDA = VCC – 0.3V 1. Effective capacitance measured with power supply at 5V; sampled, not 100% tested. 2. At 25°C, f = 400kHz.. 3. Outputs deselected. Table 6. DC characteristics Symbol Parameter ILI Input leakage current ILO Output leakage current Supply current (Serial RTC active) ICC1 ICC2 VIL Test Condition(1) VOL 100 µA –0.3 1.5 V Input low voltage (E2, E1, E0) –0.45 0.3VCC V Input low voltage (WC) –0.45 0.5 V 3 VCC + 0.8 V 0.7VCC VCC + 1 V 0.4 V 3 3.5 V 450 550 nA Input high voltage (E2, E1, E1, WC) Output low voltage IOL = 3mA, VCC = 5V VBAT(2) Battery supply voltage IBAT Typ Input low voltage (SCL, SDA) Input high voltage (SCL, SDA) VIH Min Battery supply current 2.5 TA = 25°C, VCC = 0V, Oscillator ON, VBAT = 3V 1. Valid for ambient operating temperature: TA = –40 to 85°C; VCC = 4.5 to 5.5V (except where noted). 2. STMicroelectronics recommends the RAYOVAC BR1225 or BR1632 (or equivalent) as the battery supply. 12/19 M41T56C64 DC and AC parameters Figure 6. AC Bus timing requirements sequence (serial RTC) SDA tBUF tHD:STA tR tHD:STA tF SCL tHIGH P S tLOW tSU:DAT tHD:DAT tSU:STA tSU:STO SR P AI00589 Table 7. AC characteristics, (serial RTC, M41T56) Parameter (1) Symbol Min Max Unit 0 100 kHz fSCL SCL clock frequency tLOW Clock low period 4.7 µs tHIGH Clock high period 4 µs tR SDA and SCL rise time 1 µs tF SDA and SCL fall time 300 ns tHD:STA START condition hold time (after this period the first clock pulse is generated) tSU:STA tSU:DAT 4 µs START condition setup time (only relevant for a repeated start condition) 4.7 µs Data setup time 250 ns 0 µs STOP condition setup time 4.7 µs tBUF Time the bus must be free before a new transmission can start 4.7 µs tLP Low-pass filter input time constant (SDA and SCL) for Serial RTC 0.25 tHD:DAT(2) Data hold time tSU:STO 1 µs 1. Valid for ambient operating temperature: TA = –40 to 85°C; VCC = 4.5 to 5.5V (except where noted). 2. Transmitter must internally provide a hold time to bridge the undefined region (300ns max.) of the falling edge of SCL. 13/19 DC and AC parameters M41T56C64 Table 8. AC characteristics (Serial EEPROM, M24C64) Parameter Test condition Symbol Alt. Min. Max. Unit fC fSCL Clock frequency 400 kHz tCHCL tHIGH Clock pulse width high 600 ns tCLCH tLOW Clock pulse width low 1300 ns tDL1DL2(1) tF tDXCX SDA fall time 20 tSU:DAT Data in set up time 100 ns tCLDX tHD:DAT Data in hold time 0 ns tCLQX tDH Data out hold time 200 ns tCLQV(2) tAA Clock low to next data valid (access time) 200 tCHDX(3) tSU:STA Start condition set up time 600 ns tDLCL tHD:STA Start condition hold time 600 ns tCHDH tSU:STO Stop condition set up time 600 ns 1300 ns tDHDL tBUF Time between stop condition and next start condition tW tWR Write time tNS Pulse width ignored (input filter on SCL and SDA for serial EEPROM) Single glitch 300 900 ms 100 ns 2. To avoid spurious START and STOP conditions, a minimum delay is placed between SCL=1 and the falling or rising edge of SDA. 14/19 ns 5 1. Sampled only, not 100% tested. 3. For a reSTART condition, or following a Write cycle. ns M41T56C64 7 Package mechanical data Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a Lead-free second level interconnect . The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com 15/19 Package mechanical data Figure 7. M41T56C64 SOX18 – 18-lead plastic small outline, 300mils, embedded crystal D 9 h x 45° 1 C E 10 H 18 A2 A B ddd A1 e A1 α L SO-J 1. Drawing is not to scale. Table 9. SOX18 – 18-lead plastic small outline, 300mils, embedded crystal, package mech. millimetres inches Symbol Typ Min Max A 2.44 A1 Min Max 2.69 0.096 0.106 0.15 0.31 0.096 0.012 A2 2.29 2.39 0.090 0.094 B 0.41 0.51 0.016 0.020 C 0.20 0.31 0.008 0.012 11.56 11.66 0.455 0.459 D 11.61 ddd 0.457 0.10 E 7.57 7.67 – – H 10.16 L 0.004 0.298 0.302 – – 10.52 0.400 0.414 0.51 0.81 0.020 0.032 a 0° 8° 0° 8° N 18 e 16/19 Typ 1.27 0.050 18 M41T56C64 8 Order codes Order codes Table 10. Ordering information scheme Example: M41T 56 C64 MY 6 E Device type M41T = Serial RTC Supply voltage and write protect voltage 56 = VCC = 4.5 to 5.5V EEPROM density C64 = 64 Kbit (8192 bit x 8) Package MY(1)= SOX18 Temperature range 6 = –40°C to 85°C Shipping method E = ECOPACK® package, tubes F = ECOPACK® package, tape & reel 1. The SOX18 package includes an embedded 32,768Hz crystal. For other options, or for more information on any aspect of this device, please contact the ST Sales Office nearest you. 17/19 Revision history 9 M41T56C64 Revision history Table 11. Revision history 18/19 Date Version Description 14-Sep-2004 1 First Edition 25-Mar-2005 2 Clarify pin connections, maximum rating 4-Sep-2006 3 Datasheet status updated to full datasheet; changed title on page 1; small text changes to Section 1: Summary description; reformatted figure in the Feature summary, reformatted Figure 1, Figure 2, Table 2 and Table 9; ecopack compliant; updated disclaimer 22-Sep-2006 4 Added information on EEPROM density Table 10: Ordering information scheme M41T56C64 Please Read Carefully: Information in this document is provided solely in connection with ST products. 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