- 您现在的位置：买卖IC网 > PDF目录16433 > KIT33972AEWEVBE (Freescale Semiconductor)KIT EVALUATION FOR MC33972 PDF资料下载
参数资料
| 型号： | KIT33972AEWEVBE |
| 厂商： | Freescale Semiconductor |
| 文件页数： | 14/32页 |
| 文件大小： | 0K |
| 描述： | KIT EVALUATION FOR MC33972 |
| 标准包装： | 1 |
| 主要目的： | 接口，开关探测 |
| 嵌入式： | 否 |
| 已用 IC / 零件： | MC33972 |
| 主要属性： | 8 可编程输入（电池开关或接地开关） |
| 次要属性： | 14 开关至接地输入 |
| 已供物品： | 板，CD |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页当前第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页
Analog Integrated Circuit Device Data
Freescale Semiconductor
21
33972
TYPICAL APPLICATIONS
INTRODUCTION
TYPICAL APPLICATIONS
INTRODUCTION
The 33972’s primary function is the detection of open or
closed switch contacts. However, there are many features
that allow the device to be used in a variety of applications.
The following is a list of applications to consider for the IC:
Sensor Power Supply
Switch Monitor for Metallic or Elastomeric Switches
Analog Sensor Inputs (Ratiometric)
Power MOSFET/LED Driver and Monitor
Multiple 33972 Devices in a Module System
The following paragraphs describe the applications in
detail.
SENSOR POWER SUPPLY
Each input may be used to supply current to sensors
external to a module. Many sensors such as Hall effect,
pressure sensors, and temperature sensors require a supply
voltage to power the sensor and provide an open collector or
analog output. Figure 13 shows how the 33972 may be used
to supply power and interface to these types of sensors. In an
application where the input makes continuous transitions,
consider using the wake-up/interrupt command to disable
the interrupt for the particular input.
Figure 13. Sensor Power Supply
METALLIC/ELASTOMERIC SWITCH
Metallic switch contacts often develop higher contact
resistance over time owing to contact corrosion. The
corrosion is induced by humidity, salt, and other elements
that exist in the environment. For this reason the 33972
provides two settings for contacts. When programmed for
metallic switches, the device provides higher wetting current
to keep switch contacts free of oxides. The higher current
occurs for the first 20 ms of switch closure. Where longer
duration of wetting current is desired, the user may send the
wetting current timer command and disable the timer. Wetting
current will be continuous to the closed switch. After the time
period set by the MCU, the wetting current timer command
may be sent again to enable the timer. The user must
consider power dissipation on the device when disabling the
timer. (Refer to the paragraph entitled Temperature Monitor,
page 20.)
To increase the amount of wetting current for a switch
contact, the user has two options. Higher wetting current to a
switch may be achieved by paralleling SGn or SPn inputs.
This will increase wetting current by 16 mA for each input
added to the switch contact. The second option is to simply
add an external resistor pull-up to the VPWR supply for switch-
to-ground inputs or a resistor to ground for a switch-to-battery
input. Adding an external resistor has no effect on the
operation of the device.
Elastomeric switch contacts are made of carbon and have
a high contact resistance. Resistance of 1.0 k
Ω is common.
In applications with elastomeric switches, the pull-up and
pulldown currents must be reduced to prevent excessive
power dissipation at the contact. Programming for a lower
current settings is provided in the Functional Device
Metallic Command.
ANALOG SENSOR INPUTS (RATIOMETRIC)
The 33972 features a 22-to-1 analog multiplexer. Setting
the binary code for a specific input in the analog command
allows the microcontroller to perform analog to digital
conversion on any of the 22 inputs. On rising edge of CS the
multiplexer connects a requested input to the AMUX pin. The
AMUX pin is clamped to max of VDD volts regardless of the
higher voltages present on the input pin. After an input has
been selected as the analog, the corresponding bit in the next
SO data stream will be logic [0].
The input pin, when selected as analog, may be
configured as analog with high-impedance, analog with
2.0 mA pull-up, or analog with 16 mA pull-up. Figure 14,
page 22, shows how the 33972 may be used to provide a
ratiometric reading of variable resistive input.
VDD
VPWR
VDD
SI
SO
SCLK
INT
CS
MOSI
MISO
VBAT
SP0
SP1
SP7
SG1
SG0
SG12
SG13
WAKE
33972
SCLK
CS
INT
MCU
16
2.0
VPWR VPWR
16 mA
IOC[7:0]
X
Reg
Input Capture
Timer Port
Hall-Effect
Sensor
2.5 k
Ω
mA
16
2.0
VPWR VPWR
mA
2.5 k
Ω
VBAT
mA
相关PDF资料 |
PDF描述 |
|---|---|
| EBM31DCMS | CONN EDGECARD 62POS .156 WW |
| VI-J1L-EX | CONVERTER MOD DC/DC 28V 75W |
| XR16V598IQ-0B-EVB | EVAL BOARD FOR XR16V598-A 100QFP |
| CM322522-820KL | INDUCTOR 82UH 60MA SMD |
| VI-2V2-EX | CONVERTER MOD DC/DC 15V 75W |
相关代理商/技术参数 |
参数描述 |
|---|---|
| KIT33975AEWEVBE | 功能描述:交换机 IC 开发工具 MULTIPLE SWITCH DETECT I RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:USB Power Switches 工具用于评估:MAX4984E 工作电源电压:2.8 V to 5.5 V |
| KIT33982CEVBE | 功能描述:电源管理IC开发工具 2.0 M HIGH-SIDE SW RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| KIT33982PNAEVB | 功能描述:电源管理IC开发工具 SPSS HIGH-SIDE SWTCH RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| KIT33984CEVBE | 功能描述:电源管理IC开发工具 4.0 M HIGH-SIDE SW RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| KIT33984PNAEVB | 功能描述:电源管理IC开发工具 33984 - SPD4 EVAL KIT RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
发布紧急采购，3分钟左右您将得到回复。