参数资料
型号: DS1388Z-3+
厂商: Maxim Integrated Products
文件页数: 19/19页
文件大小: 0K
描述: IC RTC I2C W/CHARGER 8-SOIC
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 48
类型: 时钟/日历
特点: EEPROM,闰年,监控器,涓流充电器,监视计时器
存储容量: 512B
时间格式: HH:MM:SS:hh(12/24 小时)
数据格式: YY-MM-DD-dd
接口: I²C,2 线串口
电源电压: 2.7 V ~ 3.3 V
电压 - 电源,电池: 1.3 V ~ 5.5 V
工作温度: -40°C ~ 85°C
安装类型: 表面贴装
封装/外壳: 8-SOIC(0.154",3.90mm 宽)
供应商设备封装: 8-SOIC
包装: 管件
产品目录页面: 1434 (CN2011-ZH PDF)
I2C RTC/Supervisor with Trickle Charger
and 512 Bytes EEPROM
Maxim Integrated
9
DS1388
Detailed Description
The DS1388 I2C RTC, supervisor, and EEPROM is a
multifunction device that provides a clock/calendar,
programmable watchdog timer, power-supply monitor
with reset, and 512 bytes of EEPROM. The clock pro-
vides hundredths of seconds, seconds, minutes, and
hours, and operates in 24-hour or 12-hour format with
an AM/PM indicator. The calendar provides 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. A
watchdog timer provides a reset for an unresponsive
microprocessor. It is programmable in 10ms intervals
from 0.01 to 99.99 seconds. A temperature-compensat-
ed voltage reference and comparator circuit monitors
the status of VCC. If a primary power failure is detected,
the device automatically switches to the backup supply
and drives the reset output to the active state. When
VCC returns to nominal levels, the reset is held low for a
period to allow the power supply and processor to sta-
bilize. The device also has a pushbutton reset con-
troller, which debounces a reset input signal. The
device is accessed through an I2C serial interface.
Operation
The DS1388 operates as a slave device on the I2C bus.
Access is obtained by implementing a START condition
and providing a device identification code followed by
data. Subsequent registers can be accessed sequen-
tially until a STOP condition is executed. See the
Block
Diagram, which shows the main elements of the serial
real-time clock.
Power Control
The power-control function is provided by a precise,
temperature-compensated voltage reference and a
comparator circuit that monitors the VCC level. The
device is fully accessible and data can be written and
read when VCC is greater than VPF. However, when
VCC falls below VPF, the internal clock registers are
blocked from any access. If VPF is less than VBACKUP,
the device power is switched from VCC to VBACKUP
when VCC drops below VPF. If VPF is greater than
VBACKUP, the device power is switched from VCC to
VBACKUP when VCC drops below VBACKUP. The regis-
ters are maintained from the VBACKUP source until VCC
is returned to nominal levels (Table 1). After VCC
returns above VPF, read and write access is allowed
after RST goes high (Figure 1).
On first application of power to the device, the time and
date registers are set to 00/00/00 00 00:00:00
(DD/MM/YY DOW HH:MM:SS). The user should initial-
ize all RTC registers to valid date and time settings.
Oscillator Circuit
The DS1388 uses an external 32.768kHz crystal. The
oscillator circuit does not require any external resistors
or capacitors to operate. Table 2 specifies several
crystal parameters for the external crystal. Using a
crystal with the specified characteristics, the startup
time is usually less than one second.
SUPPLY CONDITION
READ/WRITE
ACCESS
POWERED
BY
VCC < VPF, VCC < VBACKPUP
No
VBACKUP
VCC < VPF, VCC > VBACKUP
No
VCC
VCC > VPF, VCC < VBACKUP
Yes
VCC
VCC > VPF, VCC > VBACKUP
Yes
VCC
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
Nominal
Frequency
fO
32.768
kHz
Series
Resistance
ESR
50
k
Ω
Load
Capacitance
CL
6pF
*
The crystal, traces, and crystal input pins should be isolated
from RF generating signals. Refer to Application Note 58:
Crystal Considerations for Dallas Real-Time Clocks for addi-
tional specifications.
Table 1. Power Control
Table 2. Crystal Specifications*
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DS1388Z-33 功能描述:实时时钟 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube
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