PT7C4302 (Not Recommended for New Design (NRND))

Description

The PT7C4302 serial real-time clock is a lowpower
clock/calendar with a programmable square-wave
output and 31 bytes of nonvolatile RAM.
Address and data are transferred serially via a 3-
wire bus. The clock/calendar provides seconds, minutes,
hours, day, date, month, and year information. The date
at the end of the month is automatically adjusted for
months with fewer than 31 days, including corrections
for leap year. The clock operates in either the 24-hour or
12-hour format with AM/PM indicator.
Table 1 shows the basic functions of PT7C4302.
More details are shown in section: overview of functions.

Features

• Using external 32.768kHz quartz crystal
• Real-time clock (RTC) counts seconds, minutes, hours, date of the month, month, day of the week, and year with leap-year compensation valid up to 2099
• 31-byte, nonvolatile (NV) RAM for data storage
• Time keeping voltage: 1.5V to 5.5V
• Uses less than 300nA at 2.0V
• Simple 3-wire interface
• Serial I/O for minimum pin count
• Burst mode for reading/writing successive addresses in clock/RAM
• TTL-compatible (VCC = 5V)
• Optional industrial temperature range: -40°C to +85°C
• Battery backup
• Trickle charger on chip for rechargeable energy source backup