DS1390–DS1394
Low-Voltage SPI/3-Wire RTCs with
Trickle Charger
12
Maxim Integrated
Detailed Description
The DS1390–DS1394 RTCs are low-power clocks/calen-
dars with alarms. Address and data are transferred seri-
ally through a 4-wire SPI interface for the DS1390 and
DS1391 and through a 3-wire interface for the DS1392,
DS1393, and DS1394. The DS1390/DS1391 operate as a
slave device on the SPI serial bus. The DS1392/DS1393
operate using a 3-wire synchronous serial bus. Access is
obtained by selecting the part by the CS pin (CE on
DS1392/DS1393) and clocking data into/out of the part
using the SCLK and DIN/DOUT pins (I/O on
DS1392/DS1393). Multiple-byte transfers are supported
within one CS low period (see the
SPI Serial-Data Bus
section). The clocks/calendars provide hundredths of
seconds, seconds, minutes, hours, day, date, month,
and year information. The alarm functions are performed
off all timekeeping registers, allowing the user to set high
resolution alarms. The date at the end of the month is
automatically adjusted for months with fewer than 31
days, including corrections for leap year. The clocks
operate in either the 24-hour or 12-hour format with an
AM/PM indicator. All five devices have a built-in tempera-
ture-compensated voltage reference that detects power
failures and automatically switches to the battery supply.
Additionally, the devices can provide trickle charging of
the backup voltage source, with selectable charging
resistance and diode voltage drops.
Functional Diagram
BUS
INTERFACE
VCC LEVEL DETECT,
POWER SWITCH,
WRITE PROTECT,
TRICKLE CHARGER
(DS1390/91/94) DIN
(DS1390/91/94) DOUT
(DS1392/93) I/O
X2
SCLK
VCC
GND
VBACKUP
X1
(DS1390/91/94) CS
(DS1392/93) (CE)
SQUARE-WAVE RATE
SELECTOR, INT, MUX,
RST OUTPUT
HUNDREDTHS-OF-
SECONDS
GENERATOR
REAL-TIME CLOCK
WITH HUNDREDTHS
OF SECONDS
TRICKLE REGISTER
SQW/INT (DS1390/93/94)
CONTROL/STATUS
REGISTERS
ALARM REGISTERS
RST (DS1391)
SQW (DS1392)
DS1390/DS1391/
DS1392/DS1393/DS1394
CL
N
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相关代理商/技术参数
DS1395 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:RAMified Real Time Clock
DS1395N 制造商:未知厂家 制造商全称:未知厂家 功能描述:Peripheral IC
DS1395S 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:RAMified Real Time Clock
DS1395SN 制造商:未知厂家 制造商全称:未知厂家 功能描述:Peripheral IC
DS1397 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:RAMified Real Time Clock
DS-14 功能描述:非热缩管和套管 FLEX BRAIDED SHIELD 14MM X 100M ROLL RoHS:否 制造商:Panduit 产品:Cable Wraps 类型:Spiral 颜色:Black 材料:PP 内径:0.03 in 长度:100 ft
DS14-00 制造商:FLOWLINE 功能描述:Sensor, Liquid Level, Ultrasonic Switch/Control 4 Relays; Range 49.2 in, 1NPT
DS1-40-0001 制造商:SCHURTER 制造商全称:Schurter Inc. 功能描述:Storage Choke, fully potted resign