HT1381 – Serial Timekeeper Chip

HT1381 Datasheet PDF learn more.

Part number : HT1381

Functions : This is a kind of semiconductor, Serial Timekeeper Chip.

Pin arrangement :

Package information :

Manufacturer : Holtek Semiconductor Inc

Image :

HT1381 Datasheet PDF

The texts in the PDF file :

HT1380/HT1381 Serial Timekeeper Chip


· · · · Operating voltage: 2.0V~5.5V Maximum input serial clock: 500kHz at VDD=2V, 2MHz at VDD=5V Operating current: less than 400nA at 2V, less than 1.2mA at 5V TTL compatible – V : 2.0V~V IH DD+0.3V at VDD=5V – V : -0.3V~+0.8V at V IL DD=5V · · · · Two data transmission modes: single-byte, or burst mode Serial I/O transmission All registers store BCD format HT1380: 8-pin DIP package HT1381: 8-pin SOP package Applications · Microcomputer serial clock · Clock and Calendar General


The HT1380/HT1381 is a serial timekeeper IC which provides seconds, minutes, hours, day, date, month and year information. The number of days in each month and leap years are automatically adjusted. The HT1380/HT1381 is designed for low power consumption and can operate in two modes: one is the 12-hour mode with an AM/PM indicator, the other is the 24-hour mode. The HT1380/HT1381 has several registers to store the corresponding information with 8-bit data format. A 32768Hz crystal is required to provide the correct timing. In order to minimize the pin number, the HT1380/HT1381 use a serial I/O transmission method to interface with a microprocessor. Only three wires are required: (1) REST, (2) SCLK and (3) I/O. Data can be delivered 1 byte at a time or in a burst of up to 8 bytes. Block Diagram I/O S C L K D a ta S h ift R e g is te r R e a l T im e C lo c k Pin Assignment N C X 1 X 2 V S S 4 5 3 6 2 7 1 8 V D D S C L K I/O R E S T N C X 1 X 2 V S S 4 5 3 6 2 7 1 8 V D D S C L K I/O R E S T R E S T C o m m a n d C o n tr o l L o g ic O s c illa to r a n d D iv id e r C ir c u it X 1 X 2 H T 1 3 8 0 8 D IP H T 1 3 8 1 8 S O P 1 October 2, 1999 HT1380/HT1381 Pad Assignment X 1 1 7 2 V D D 6 Pad Coordinates Pad No. 1 2 3 (0 ,0 ) 5 I/O Unit: mm X Y 775.00 494.60 -203.90 -618.30 -4.30 332.60 572.60 X 2 -851.40 -851.40 -844.40 845.90 848.40 845.90 844.40 S C L K 4 5 V S S 3 6 4 R E S T 7 Chip size: 20 [ … ]

HT1381 PDF File

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