参数资料
型号: FT245BL-REEL
厂商: FTDI, Future Technology Devices International Ltd
文件页数: 10/24页
文件大小: 0K
描述: IC USB FS PARALLEL FIFO 32-LQFP
标准包装: 1,000
系列: *
类型: *
应用: *
安装类型: 表面贴装
封装/外壳: 32-LQFP
供应商设备封装: 32-LQFP(7x7)
包装: 带卷 (TR)
DS245BL Version 1.7
Future Technology Devices Intl. Ltd. 2005
Page 18 of 24
FT245BL USB FIFO ( USB - Parallel ) I.C.
Figure 8
USB Self Powered Conguration
Figure 8 illustrates a typical USB self powered conguration. A USB Self Powered device gets its power from its own
POWER SUPPLY and does not draw current from the USB bus. The basic rules for USB Self power devices are as
follows –
a) A Self-Powered device should not force current down the USB bus when the USB Host or Hub Controller is
powered down.
b) A Self Powered Device can take as much current as it likes during normal operation and USB suspend as it has its
own POWER SUPPLY.
c) A Self Powered Device can be used with any USB Host and both Bus and Self Powered USB Hubs
The USB power descriptor option in the EEPROM should be programmed to a value of zero (self powered).
To meet requirement a) the 1.5K pull-up resistor on USBDP is connected to RSTOUT# as per the bus-power circuit.
However, the USB Bus Power is used to control the RESET# Pin of the FT245BL device. When the USB Host or Hub
is powered up RSTOUT# will pull the 1.5K resistor on USB DP to 3.3V, thus identifying the device as a full speed
device to USB. When the USB Host or Hub power is off, RESET# will go low and the device will be held in reset. As
RESET# is low, RSTOUT# will also be low, so no current will be forced down USBDP via the 1.5K pull-up resistor
when the host or hub is powered down. Failure to do this may cause some USB host or hub controllers to power up
erratically.
Note : When the FT245BL is in reset, the FIFO interface pins all go tri-state. These pins have internal 200K pull-up
resistors to VCCIO so they will gently pull high unless driven by some external logic.
VCC
27R
USB "B"
Connector
27R
USB DM
RSTOUT#
8
FT245BM
USB DP
7
5
V
C
V
C
V
C
I
O
3
26
13
1
2
3
4
1k5
33nF
3v3OUT
6
470R
A
V
C
30
0.1uF
G
N
D
G
N
D
A
G
N
D
9
17
29
RESET#
4
10k
4k7
Decoupling Capacitors
10uF
VCC
0.1uF
+
FT245BL
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相关代理商/技术参数
参数描述
FT245BL-TRAY 制造商:Future Technology Devices International (FTDI Chip) 功能描述:USB FIFO ( USB - PARALLEL ) I.C.
FT245BM 功能描述:先进先出 Obsolete See FT245RL RoHS:否 制造商:IDT 电路数量: 数据总线宽度:18 bit 总线定向:Unidirectional 存储容量:4 Mbit 定时类型:Synchronous 组织:256 K x 18 最大时钟频率:100 MHz 访问时间:10 ns 电源电压-最大:3.6 V 电源电压-最小:6 V 最大工作电流:35 mA 最大工作温度:+ 85 C 封装 / 箱体:TQFP-80 封装:
FT245BM-TRAY 功能描述:USB 接口集成电路 Obsolete See FT245RL 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
FT245BQ 制造商:未知厂家 制造商全称:未知厂家 功能描述:FT245BQ USB FIFO ( USB - Parallel ) I.C.
FT245BQ-REEL 功能描述:USB 接口集成电路 USB to Parallel FIFO IC QFN-32 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