FT201XQ-R FTDI, FT201XQ-R Datasheet - Page 23

• Manufacturer Part Number: FT201XQ-R
• Description: USB Interface IC USB to I2C IC QFN-16
• Manufacturer: FTDI

Specifications of FT201XQ-R

• Rohs: yes
• Product: USB 2.0
• Data Rate: 12 Mbps, 480 Mbps
• Interface Type: I2C, USB
• Operating Supply Voltage: 2.97 V to 5.5 V
• Operating Supply Current: 6.4 mA to 8.65 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-16
• Tradename: X-Chip

7.2 Self Powered Configuration
Figure 7.2 Self Powered Configuration
Figure 7.2 illustrates the FT201X in a typical USB self powered configuration. A USB self powered device
gets its power from its own power supply, VCC, and does not draw current from the USB bus. The basic
rules for USB self powered devices are as follows –
The power descriptor in the internal MTP memory of the FT201X should be programmed to a value of
zero (self powered).
In order to comply with the first requirement above, the USB bus power (pin 1) is used to control the
VBUS_Sense pin of the FT201X device. When the USB host or hub is powered up an internal 1.5kΩ
resistor on USBDP is pulled up to +3.3V, thus identifying the device as a full speed device to the USB
host or hub. When the USB host or hub is powered off, VBUS_Sense pin will be low and the FT201X is
held in a suspend state. In this state the internal 1.5kΩ resistor is not pulled up to any power supply
(hub or host is powered down), so no current flows down USBDP via the 1.5kΩ pull-up resistor. Failure to
do this may cause some USB host or hub controllers to power up erratically.
Figure 7.2 illustrates a self powered design which has a +3.3V to +5.25V supply.
Note:
i)
ii)
iii)
1. When the FT201X is in reset, the interface I/O pins are tri-stated. Input pins have internal 75kΩ
pull-up resistors to VCCIO, so they will gently pull high unless driven by some external logic.
100nF
SHIELD
A self powered device should not force current down the USB bus when the USB host or hub
controller is powered down.
A self powered device can use as much current as it needs during normal operation and USB
suspend as it has its own power supply.
A self powered device can be used with any USB host, a bus powered USB hub or a self
powered USB hub.
5
100nF
Copyright © 2013 Future Technology Devices International Limited
GND
1
2
3
4
VCC
+
GND
4.7uF
GND
4k7
10k
47pF
FT201X USB I2C SLAVE IC Datasheet
VCC(3.3-5.25V)
GND
Document No.: FT_000627 Clearance No.: FTDI# 264
47pF
GND
27R
27R
100nF
USBDM
VBUS_SENSE
USBDP
VCC
3V3OUT
VCCIO
RESET#
FT201X
Version 1.3
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