Datasheet > X1286A8

X1286A8

更新时间： 2024-02-17 11:28:49

品牌	Logo	应用领域
英特矽尔 - INTERSIL		监控可编程只读存储器电动程控只读存储器电可擦编程只读存储器时钟
页数	文件大小	规格书
25页	362K
描述
Intersil Real Time Clock/Calendar/CPU Supervisor with EEPROM X1286

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X1286A8 技术参数

是否Rohs认证：	符合	生命周期：	Obsolete
零件包装代码：	SOIC	包装说明：	SOP, SOP8,.3
针数：	8	Reach Compliance Code：	unknown
ECCN代码：	EAR99	HTS代码：	8542.39.00.01
风险等级：	5.69	最大时钟频率：	0.032 MHz
信息访问方法：	I2C	中断能力：	Y
JESD-30 代码：	R-PDSO-G8	长度：	5.255 mm
端子数量：	8	计时器数量：	1
最高工作温度：	70 °C	最低工作温度：
封装主体材料：	PLASTIC/EPOXY	封装代码：	SOP
封装等效代码：	SOP8,.3	封装形状：	RECTANGULAR
封装形式：	SMALL OUTLINE	峰值回流温度（摄氏度）：	NOT SPECIFIED
电源：	3/5 V	认证状态：	Not Qualified
座面最大高度：	2.03 mm	子类别：	Timer or RTC
最大供电电压：	5.5 V	最小供电电压：	2.7 V
标称供电电压：	5 V	表面贴装：	YES
技术：	CMOS	温度等级：	COMMERCIAL
端子形式：	GULL WING	端子节距：	1.27 mm
端子位置：	DUAL	最短时间：	1/100 SECOND
处于峰值回流温度下的最长时间：	NOT SPECIFIED	易失性：	NO
宽度：	5.23 mm	uPs/uCs/外围集成电路类型：	TIMER, REAL TIME CLOCK
Base Number Matches：	1

X1286A8 数据手册

X1286

A final application for the ATR control is in-circuit cali-

bration for high accuracy applications, along with a

temperature sensor chip. Once the RTC circuit is pow-

ered up with battery backup, the PHZ output is set at

32.768kHz and frequency drift is measured. The ATR

control is then adjusted to a setting which minimizes

drift. Once adjusted at a particular temperature, it is

possible to adjust at other discrete temperatures for

minimal overall drift, and store the resulting settings in

the EEPROM. Extremely low overall temperature drift

is possible with this method. The Intersil evaluation

board contains the circuitry necessary to implement

this control.

frequency, noise can couple to the X1 or X2 pins and

cause double-clocking. The layout in figure 15 can

help minimize this by running the PHZ output away

from the X1 and X2 pins. Also, minimizing the switch-

ing current at this pin by careful selection of the pullup

resistor value will reduce noise. Intersil suggests a

minimum value of 5.1k for 32.768kHz, and higher val-

ues (i.e. 20kΩ) for lower frequency PHZ outputs.

For other RTC products, the same rules stated above

should be observed, but adjusted slightly since the

packages and pinouts are slightly different.

Assembly

For more detailed operation see Intersil’s application

note AN154 on Intersil’s website at www.Intersil.com.

Most electronic circuits do not have to deal with

assembly issues, but with the RTC devices assembly

includes insertion or soldering of a live battery into an

unpowered circuit. If a socket is soldered to the board,

and a battery is inserted in final assembly, then there

are no issues with operation of the RTC. If the battery

is soldered to the board directly, then the RTC device

Vback pin will see some transient upset from either

soldering tools or intermittent battery connections

which can stop the circuit from oscillating. Once the

battery is soldered to the board, the only way to assure

the circuit will start up is to momentarily (very short

period of time!) short the Vback pin to ground and the

circuit will begin to oscillate.

Layout Considerations

The crystal input at X1 has a very high impedance and

will pick up high frequency signals from other circuits on

the board. Since the X2 pin is tied to the other side of

the crystal, it is also a sensitive node. These signals can

couple into the oscillator circuit and produce double

clocking or mis-clocking, seriously affecting the accu-

racy of the RTC. Care needs to be taken in layout of the

RTC circuit to avoid noise pickup. Below in Figure 15 is

a suggested layout for the X1286 or X1288 devices.

Figure 15. Suggested Layout for Intersil RTC in SO-8

Oscillator Measurements

When a proper crystal is selected and the layout guide-

lines above are observed, the oscillator should start up

in most circuits in less than one second. Some circuits

may take slightly longer, but startup should definitely

occur in less than 5 seconds. When testing RTC cir-

cuits, the most common impulse is to apply a scope

probe to the circuit at the X2 pin (oscillator output) and

observe the waveform. DO NOT DO THIS! Although in

some cases you may see a useable waveform, due to

the parasitics (usually 10pF to ground) applied with the

scope probe, there will be no useful information in that

waveform other than the fact that the circuit is oscillat-

ing. The X2 output is sensitive to capacitive impedance

so the voltage levels and the frequency will be affected

by the parasitic elements in the scope probe. Applying a

scope probe can possibly cause a faulty oscillator to

start up, hiding other issues (although in the Intersil

RTC’s, the internal circuitry assures startup when using

the proper crystal and layout).

0.1µF

R1 10k

XTAL1

X1286/X1288

32.768kGz

The X1 and X2 connections to the crystal are to be

kept as short as possible. A thick ground trace around

the crystal is advised to minimize noise intrusion, but

ground near the X1 and X2 pins should be avoided as

it will add to the load capacitance at those pins. Keep

in mind these guidelines for other PCB layers in the

vicinity of the RTC device. A small decoupling capaci-

tor at the Vcc pin of the chip is mandatory, with a solid

connection to ground.

The best way to analyze the RTC circuit is to power it

up and read the real time clock as time advances, or if

the chip has the PHZ output, look at the output of that

pin on an oscilloscope (after enabling it with the con-

trol register, and using a pullup resistor for an open-

drain output). Alternatively, the X1226/X1286/1288

The X1286 product has a special consideration. The

PHZ/IRQ- pin on the 8-lead SOIC package is located

next to the X2 pin. When this pin is used as a fre-

quency output (PHZ) and is set to 32.768kHz output

FN8101.0

March 29, 2005

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与X1286A8相关器件

型号	品牌	描述	获取价格	数据表
X1286A8I	INTERSIL	Intersil Real Time Clock/Calendar/CPU Supervisor with EEPROM X1286	获取价格
X1286A8IT1	RENESAS	1 TIMER(S), REAL TIME CLOCK, PDSO8, EIAJ, PLASTIC, SOIC-8	获取价格
X1286A8I-T1	RENESAS	Real Time Clock, Non-Volatile, 1 Timer(s), CMOS, PDSO8	获取价格
X1286A8-T1	RENESAS	Real Time Clock, Non-Volatile, 1 Timer(s), CMOS, PDSO8	获取价格
X1286A8Z	RENESAS	1 TIMER(S), REAL TIME CLOCK, PDSO8, EIAJ, PLASTIC, SOIC-8	获取价格
X1286A8ZT1	RENESAS	1 TIMER(S), REAL TIME CLOCK, PDSO8, EIAJ, PLASTIC, SOIC-8	获取价格
X1286V14	INTERSIL	Intersil Real Time Clock/Calendar/CPU Supervisor with EEPROM X1286	获取价格
X1286V14I	INTERSIL	Intersil Real Time Clock/Calendar/CPU Supervisor with EEPROM X1286	获取价格
X1286V14I-T1	RENESAS	1 TIMER(S), REAL TIME CLOCK, PDSO14, 4.40 MM, PLASTIC, TSSOP-14	获取价格
X1286V14IZ	RENESAS	1 TIMER(S), REAL TIME CLOCK, PDSO14, 4.40 MM, ROHS COMPLIANT, PLASTIC, TSSOP-14	获取价格

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