参数资料
型号: FT232BQ-REEL
厂商: FTDI, Future Technology Devices International Ltd
文件页数: 14/34页
文件大小: 0K
描述: IC NEW DESIGNS REFER TO FT232RQ
标准包装: 1
系列: USBmadeEZ-UART
通道数: 1,UART
FIFO's: 256 字节
规程: RS232,RS422,RS485
电源电压: 4.35 V ~ 5.25 V
带自动流量控制功能:
带调制解调器控制功能:
带CMOS:
安装类型: 表面贴装
封装/外壳: 32-WFQFN 裸露焊盘
供应商设备封装: 32-QFN 裸露焊盘(5x5)
包装: 标准包装
其它名称: 768-1067-6
Copyright 2011 Future Technology Devices International Limited
21
Document No.: FT_000329
FT232BL
/BQ USB UART IC Datasheet Version 2.2
Clearance No.: FTDI#
171
6.4 Bus Powered Circuit (<=100mA) with Power Control
Figure 6.5 Bus Powered with Power Switching Configuration
USB Bus powered circuits need to be able to power down in USB suspend mode in order to meet the <=
500uA total suspend current requirement (including external logic). This limit is 2.5mA for devices that
support remote wake-up. Some external logic can power itself down into a low current state by
monitoring the PWREN# pin. For external logic that cannot power itself down in that way, the FT232B
provides a simple but effective way of turning off power to external circuitry during USB suspend.
Figure 8.3 shows how to use a discrete P-Channel Logic Level MOSFET to control the power to external
logic circuits. A suitable device could be a Fairchild NDT456P, or International Rectifier IRLML6402, or
equivalent. It is recommended that a “soft start” circuit consisting of a 1K series resistor and a 0.1 uF
capacitor are used to limit the current surge when the MOSFET turns on. Without the soft start circuit
there is a danger that the transient power surge of the MOSFET turning on will reset the FT232B, or the
USB host / hub controller. The values used here allow attached circuitry to power up with a slew rate of
~12.5 V per millisecond, in other words the output voltage will transition from GND to 5V in
approximately 400 microseconds.
Alternatively, a dedicated power switch i.c. with inbuilt “soft-start” can be used instead of a MOSFET. A
suitable power switch I.C. for such an application would be a Micrel (www.micrel.com) MIC2025-2BM or
equivalent.
Please note the following points in connection with power controlled designs –
a) The logic to be controlled must have its own reset circuitry so that it will automatically reset itself
when power is re-applied on coming out of suspend.
b) Set the Pull-down on Suspend option in the FT232B’s EEPROM.
c) For USB high-power bus powered device (one that consumes greater than 100 mA, and up to 500
mA of current from the USB bus), the power consumption of the device should be set in the max
power field in the EEPROM. A high-power bus powered device must use this descriptor in the
EEPROM to inform the system of its power requirements.
d) For 3.3V power controlled circuits VCCIO must not be powered down with the external circuitry
(PWREN# gets its VCC supply from VCCIO). Either connect the power switch between the output
of the 3.3V regulator and the external 3.3V logic OR if appropriate power VCCIO from the
3V3OUT pin of the FT232B.
相关PDF资料
PDF描述
ATMEGA168P-20MUR MCU AVR 16K FLASH 20MHZ 32-QFN
SC16IS740IPW,112 IC UART SINGLE W/FIFO 16-TSSOP
ATMEGA88-15AT MCU AVR 8K FLASH 15MHZ 32-TQFP
ATMEGA88V-15AT MCU AVR 8K FLASH 15MHZ 32-TQFP
ATMEGA88-15AT1 MCU AVR 8K FLASH 15MHZ 32-TQFP
相关代理商/技术参数
参数描述
FT232HL 制造商:FTDI 制造商全称:FTDI 功能描述:FT232H Single Channel Hi-Speed USB to Multipurpose UART/FIFO IC
FT232HL-REEL 功能描述:USB 接口集成电路 USB HS to UART/FIFO SPI/JTAG/I2C LQFP-48 RoHS:否 制造商:Cypress Semiconductor 产品:USB 2.0 数据速率: 接口类型:SPI 工作电源电压:3.15 V to 3.45 V 工作电源电流: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:WLCSP-20
FT232HL-TRAY 功能描述:USB 接口集成电路 USB HS to UART/FIFO SPI/JTAG/I2C LQFP-48 RoHS:否 制造商:Cypress Semiconductor 产品:USB 2.0 数据速率: 接口类型:SPI 工作电源电压:3.15 V to 3.45 V 工作电源电流: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:WLCSP-20
FT232HQ-REEL 功能描述:USB 接口集成电路 USB HS to UART/FIFO SPI/JTAG/I2C QFN-48 RoHS:否 制造商:Cypress Semiconductor 产品:USB 2.0 数据速率: 接口类型:SPI 工作电源电压:3.15 V to 3.45 V 工作电源电流: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:WLCSP-20
FT232HQ-TRAY 功能描述:USB 接口集成电路 USB HS to UART/FIFO SPI/JTAG/I2C QFN-48 RoHS:否 制造商:Cypress Semiconductor 产品:USB 2.0 数据速率: 接口类型:SPI 工作电源电压:3.15 V to 3.45 V 工作电源电流: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:WLCSP-20