M48T201V-85MH1E STMicroelectronics

M48T201Y M48T201V 5.0 or 3.3 V TIMEKEEPER supervisor Features Converts low power SRAM into NVRAMs Year 2000 compliant SNAPHAT (SH) crystal/battery Battery low flag Integrated real time clock, power-fail control circuit, battery and crystal Watchdog timer Choice of write protect voltages (V = power-fail deselect voltage): PFD M48T201Y: V = 4.5 to 5.5 V CC 4.1V V 4.5 V PFD M48T201V: V = 3.0 to 3.6 V CC 2.7 V V 3.0 V PFD Microprocessor power-on reset (valid even 44 during battery backup mode) 1 Programmable alarm output active in the battery backed-up mode Packaging includes a 44-lead SOIC and SOH44 (MH) SNAPHAT top (to be ordered separately) 44-pin SOIC SOIC package provides direct connection for a SNAPHAT top which contains the battery and crystal RoHS compliant Lead-free second level interconnect March 2009 Rev 7 1/37 www.st.com 1Contents M48T201Y, M48T201V Contents 1 Description . 6 2 Operation . 10 2.1 Address decoding . 10 2.2 Read mode 11 2.3 Write mode 13 2.4 Data retention mode . 15 3 Clock operation 17 3.1 TIMEKEEPER registers . 17 3.2 Reading the clock . 17 3.3 Setting the clock 17 3.4 Stopping and starting the oscillator . 17 3.5 Setting the alarm clock . 19 3.6 Watchdog timer 20 3.7 Square wave output . 21 3.8 Power-on reset . 22 3.9 Reset inputs (RSTIN1 & RSTIN2) 22 3.10 Calibrating the clock . 22 3.11 Battery low warning . 24 3.12 Initial power-on defaults 25 3.13 V noise and negative going transients . 26 CC 4 Maximum ratings . 27 5 DC and AC parameters 28 6 Package mechanical data 31 7 Part numbering 34 8 Environmental information . 35 2/37