参数资料
| 型号： | DS32C35-33IND# |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 2/22页 |
| 文件大小： | 0K |
| 描述： | IC RTC W/TCXO 20-SOIC |
| 产品变化通告： | Product Discontinuation 28/Nov/2011 |
| 标准包装： | 37 |
| 类型： | 时钟/日历 |
| 特点： | 警报器，FRAM，闰年，方波输出，TCXO/晶体 |
| 存储容量： | 8KB |
| 时间格式： | HH:MM:SS（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 ~ 3.63 V |
| 电压 - 电源，电池： | 2.3 V ~ 3.6 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-SOIC（0.295"，7.50mm 宽） |
| 供应商设备封装： | 20-SOIC W |
| 包装： | 管件 |
| 产品目录页面： | 1433 (CN2011-ZH PDF) |
DS32B35/DS32C35
Accurate I2C RTC with Integrated
TCXO/Crystal/FRAM
10
____________________________________________________________________
Operation
The
Block Diagram shows the main elements of the
DS32B35/DS32C35. The nine blocks can be grouped
into six functional groups: TCXO, power control, pushbut-
ton function, RTC, I2C interface, and FRAM. Their opera-
tions are described separately in the following sections.
32kHz TCXO
The temperature sensor, oscillator, and control logic
form the TCXO. The controller reads the output of the
on-chip temperature sensor and uses a lookup table to
determine the capacitance required, adds the aging
correction in the AGE register, and then sets the
capacitance selection registers. New values, including
changes to the AGE register, are loaded only when a
change in the temperature value occurs, or when a
user-initiated temperature conversion is completed.
The temperature is read on initial application of VCC
and once every 64 seconds afterwards while the
device is powered by either VCC or VBAT.
Power Control
This function is provided by a temperature-compensat-
ed voltage reference and a comparator circuit that
monitors the VCC level. When VCC is greater than VPF,
the part is powered by VCC. When VCC is less than VPF
but greater than VBAT, the RTC is powered by VCC. If
VCC is less than VPF and is less than VBAT, the device
is powered by VBAT. See Table 1.
The RTC can be accessed when the device is powered
by either VCC or VBAT. The FRAM is only accessible
when the device is powered by VCC. The FRAM must
not be accessed when VCC < VCC(MIN).
To preserve the battery, the first time VBAT is applied to
the device, the oscillator will not start up until VCC
exceeds VPF, or until a valid I2C address is written to
the part. Typical oscillator startup time is less than one
second. Approximately 2 seconds after VCC is applied,
or a valid I2C address is written, the device makes a
temperature measurement and applies the calculated
correction to the oscillator. Once the oscillator is run-
ning, it continues to run as long as a valid power
source is available (VCC or VBAT), and the device con-
tinues to measure the temperature and correct the
oscillator frequency every 64 seconds.
On the first application of power (VCC) or when a valid
I2C address is written to the part (VBAT), the time and
date registers are reset to 01/01/00 01 00:00:00
(MM/DD/YY DOW HH:MM:SS).
Pushbutton Reset Function
The device provides for a pushbutton switch to be con-
nected to the RST output pin. When the device is not in
a reset cycle, it continuously monitors the RST signal
for a low going edge. If an edge transition is detected,
the device debounces the switch by pulling RST low.
After the internal timer has expired (PBDB), the device
continues to monitor the RST line. If the line is still low,
the device continuously monitors the line looking for a
rising edge. Upon detecting release, the device forces
the RST pin low and holds it low for tRST.
RST is also used to indicate a power-fail condition. When
VCC is lower than VPF, an internal power-fail signal is
generated, which forces the RST pin low. When VCC
returns to a level above VPF, the RST pin is held low for
tREC to allow the power supply to stabilize. If the oscilla-
tor is not running (see the
Power Control section) when
VCC is applied, tREC is bypassed and RST immediately
goes high. The state of RST does not affect the operation
of the TCXO, I2C interface, FRAM, or RTC functions.
Real-Time Clock
With the clock source from the TCXO, the RTC provides
seconds, minutes, hours, day, date, month, and year
information. The date at the end of the month is automati-
cally adjusted for months with fewer than 31 days, includ-
ing corrections for leap year. The clock operates in either
the 24-hour or 12-hour format with an AM/PM indicator.
The clock provides two programmable time-of-day
alarms and a programmable square-wave output. The
INT/SQW pin either generates an interrupt due to alarm
condition or outputs a square-wave signal and the
selection is controlled by the bit INTCN.
I2C Interface
The FRAM I2C interface is accessible whenever VCC is
at a valid level. The RTC I2C interface is accessible
whenever either VCC or VBAT is at a valid level. If a
microcontroller connected to the device resets because
of a loss of VCC or other event, it is possible that the
microcontroller and the RTC I2C communications could
become unsynchronized, e.g., the microcontroller resets
while reading data from the RTC. When the microcon-
SUPPLY CONDITION
POWERED
BY
FRAM
ACCESS*
RTC
ACCESS
VCC < VPF, VCC < VBAT
VBAT
No
Yes
VCC < VPF, VCC > VBAT
VCC
No
Yes
VCC > VPF, VCC < VBAT
VCC
Yes
VCC > VPF, VCC > VBAT
VCC
Yes
Table 1. Device Operation
*
Read/write access is not inhibited by the device, but must not
be done to avoid FRAM data errors.
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| DS32C35-33IND# | 功能描述:实时时钟 w/Integrated TCXO/Crystal/FRAM 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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| DS32EL0124_0807 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:125 MHz . 312.5 MHz Deserializer with DDR LVDS Parallel Interface |
| DS32EL0124_09 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:125 MHz- 312.5 MHz FPGA-Link Deserializer with DDR LVDS Parallel Interface |
| DS32EL0124SQ | 制造商:NSC 制造商全称:National Semiconductor 功能描述:125 MHz- 312.5 MHz FPGA-Link Deserializer with DDR LVDS Parallel Interface |
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