M41T94MH6F STMicroelectronics

M41T94 Serial real-time clock with 44 bytes NVRAM and reset Datasheet - production data Choice of power-fail deselect voltages 16 (V = 2.7 to 5.5 V): CC THS = V 2.55 V V 2.70 V SS PFD 1 THS = V 4.20 V V 4.50 V CC PFD SO16 (MQ) Packaging includes a 28-lead SOIC and SNAPHAT top (to be ordered separately) or 16-lead SOIC 28-lead SOIC package provides direct SNAPHAT (SH) connection for a SNAPHAT top which battery & crystal contains the battery and crystal RoHS compliant Lead-free second level interconnect 28 1 SOH28 (MH) Features Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century 32 KHz crystal oscillator integrating load capacitance (12.5 pF) providing exceptional oscillator stability and high crystal series resistance operation Serial peripheral interface (2 MHz SPI) Ultralow battery supply current of 500 nA (max) 2.7 to 5.5 V operating voltage 2.5 to 5.5 V oscillator operating voltage Battery low flag Automatic switchover and deselect circuitry 44 bytes of general purpose RAM Programmable alarm and interrupt function (valid even during battery backup mode) Accurate programmable watchdog timer (from 62.5 ms to 128 s) Microprocessor power-on reset December 2014 DocID007564 Rev 7 1/39 This is information on a product in full production. www.st.comContents M41T94 Contents 1 Description . 6 2 Signal description 11 2.1 Serial data output (SDO) . 11 2.2 Serial data input (SDI) . 11 2.3 Serial clock (SCL) . 11 2.4 Chip enable (E) 11 3 Operation . 12 3.1 SPI bus characteristics . 13 3.2 Read and write cycles . 15 3.3 Data retention mode . 15 4 Clock operations . 17 4.1 Power-down time-stamp 17 4.2 Clock registers . 17 4.3 Setting alarm clock registers 19 4.4 Watchdog timer 21 4.5 Square wave output . 21 4.6 Power-on reset . 22 4.7 Reset inputs (RSTIN1 & RSTIN2) 22 4.8 Calibrating the clock . 23 4.9 Century bit 25 4.10 Output driver pin 25 4.11 Battery low warning . 25 4.12 t bit . 26 REC 4.13 Initial power-on defaults 26 5 Maximum ratings . 27 6 DC and AC parameters 28 7 Package mechanical data 31 2/39 DocID007564 Rev 7