HT1380/HT1381 Serial Timekeeper Chip Features Operating voltage: 2.0V~5.5V Two data transmission modes: single-byte, Maximum input serial clock: 500kHz at or burst mode V =2V, 2MHz at V =5V Serial I/O transmission DD DD Operating current: less than 400nA at 2V, All registers store BCD format HT1380: 8-pin DIP package less than 1.2 Aat5V TTL compatible HT1381: 8-pin SOP package V : 2.0V~V +0.3V at V =5V IH DD DD V : 0.3V~+0.8V at V =5V IL DD Applications Microcomputer serial clock Clock and Calendar General Description The HT1380/HT1381 is a serial timekeeper IC The HT1380/HT1381 has several registers to which provides seconds, minutes, hours, day, store the corresponding information with 8-bit date, month and year information. The number data format. A 32768Hz crystal is required to of days in each month and leap years are auto- provide the correct timing. In order to minimize matically adjusted. The HT1380/HT1381 is de- the pin number, the HT1380/HT1381 use a se- signed for low power consumption and can rial I/O transmission method to interface with a operate in two modes: one is the 12-hour mode microprocessor. Only three wires are required: with an AM/PM indicator, the other is the (1) REST, (2) SCLK and (3) I/O. Data can be de- 24-hour mode. livered 1 byte at a time or in a burst of up to 8 bytes. Block Diagram Pin Assignment % % & & %% ( % & & ) 1 September 18, 2000HT1380/HT1381 Pad Assignment Pad Coordinates Unit: m Pad No. X Y 1 851.40 775.00 2 851.40 494.60 3 844.40 203.90 *+ , + - 4 845.90 618.30 5 848.40 4.30 6 845.90 332.60 7 844.40 572.60 2 Chip size: 2010 1920 ( m) * The IC substrate should be connected to VSS in the PCB layout artwork. Pad Description Internal Pad No. Pad Name I/O Description Connection 1 X1 I CMOS 32768Hz crystal input pad 2 X2 O CMOS Oscillator output pad 3 VSS CMOS Negative power supply, ground 4 REST I CMOS Reset pin with serial transmission 5 I/O I/O CMOS Data input/output pin with serial transmission 6 SCLK I CMOS Serial clock pulse pin with serial transmission 7 VDD CMOS Positive power supply Absolute Maximum Ratings Supply Voltage.............................. 0.3V to 5.5V Storage Temperature................. 50 Cto125 C Input Voltage.................V 0.3V to V +0.3V Operating Temperature ..................0 Cto70 C SS DD Note: These are stress ratings only. Stresses exceeding the range specified under Absolute Maxi- mum Ratings may cause substantial damage to the device. Functional operation of this de- vice at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability. 2 September 18, 2000