DS1346 Datasheet, PDF (1/17 Pages) Maxim Integrated Products – Low-Current, SPI-Compatible Real-Time Clocks

19-6007; Rev 0; 8/11
Low-Current, SPI-Compatible Real-Time Clocks
General Description
The DS1346/DS1347 SPI™-compatible real-time clocks
(RTCs) contain a real-time clock/calendar and 31 x 8
bits of static random-access memory (SRAM). The real-
time clock/calendar provides seconds, minutes, hours,
day, date, month, year, and century information. A
time/date programmable polled ALARM is included in
the devices. The end-of-the-month date is automatically
adjusted for months with fewer than 31 days, including
corrections for leap year. The clock operates in either
the 24hr or 12hr format with an AM/PM indicator. The
devices operate with a supply voltage of +2V to +5.5V,
are available in the ultra-small 8-pin TDFN package,
and work over the -40°C to +85°C industrial tempera-
ture range.
Point-of-Sale Equipment
Intelligent Instruments
Fax Machines
Battery-Powered Products
Portable Instruments
Applications
Ordering Information
PART
TEMP RANGE
OSC C_L
(pF)
PIN-PACKAGE
DS1346T+* -40°C to +85°C
6
8 TDFN-EP**
DS1347T+ -40°C to +85°C 12.5 8 TDFN-EP**
+Denotes a lead(Pb)-free/RoHS-compliant package.
*Future product—contact factory for availability.
**EP = Exposed pad.
Features
♦ RTC Counts Seconds, Minutes, Hours, Day of Week,
Date of Month, Month, Year, and Century
♦ Leap-Year Compensation
♦ +2V to +5.5V Wide Operating Voltage Range
♦ SPI (Mode 1 or 3) Interface: 4MHz at 5V, 1MHz at 2V
♦ 31 x 8-Bit SRAM for Scratchpad Data Storage
♦ Uses Standard 32.768kHz Watch Crystal
♦ Low Timekeeping Current (400nA at 2V)
♦ Single-Byte or Multiple-Byte (Burst Mode) Data
Transfer for Read or Write of Clock Registers or
SRAM
♦ Ultra-Small, 3mm x 3mm x 0.8mm, 8-Pin TDFN
Package
♦ Programmable Time/Date Polled ALARM Function
♦ No External Crystal Bias Resistors or Capacitors
Required
Typical Operating Circuit
+3.3V
μc
+3.3V _0.1μF
6
V_CC
DS1346 ^{X1 8}
1
DS1347
SCLK
5 _CS
X2 ⁷
2 _DOUT
3 _DIN
GND
4
32.768kHz
CRYSTAL
SPI is a trademark of Motorola, Inc.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.