Document No.: FT_000060
FT4232H QUAD HIGH SPEED USB TO MULTIPURPOSE UART/MPSSE IC
Datasheet Version 2.07
Clearance No.: FTDI#78
+1.8V LDO Regulator. The +1.8V LDO regulator generates the +1.8 volts for the core and the USB
transceiver cell. Its input (VREGIN) must be connected to a +3.3V external power source. It is also
recommended to add an external filtering capacitor to the VREGIN. There is no direct connection from the
+1.8V output (VREGOUT) and the internal functions of the FT4232H. The PCB must be routed to connect
VREGOUT to the pins that require the +1.8V including VREGIN.
UTMI PHY. The Universal Transceiver Macrocell Interface (UTMI) physical interface cell. This block handles
the Full speed / High Speed SERDES (serialise - deserialise) function for the USB TX/RX data. It also
provides the clocks for the rest of the chip. A 12 MHz crystal should be connected to the OSCI and OSCO
pins. A 12K Ohm resistor should be connected between REF and GND on the PCB.
The UTMI PHY functions include:
Supports 480 Mbit/s "High Speed" (HS)/ 12 Mbit/s “Full Speed” (FS), FS Only and "Low Speed"
SYNC/EOP generation and checking.
Data and clock recovery from serial stream on the USB.
Bit-stuffing/unstuffing; bit stuff error detection.
Manages USB Resume, Wake Up and Suspend functions.
Single parallel data clock output with on-chip PLL to generate higher speed serial data clocks.
EEPROM Interface. When used without an external EEPROM the FT4232H defaults to a quad USB to an
asynchronous serial port device. Adding an external 93C46 (93C56 or 93C66) EEPROM allows
customization of USB VID, PID, Serial Number, Product Description Strings and Power Descriptor value of
the FT4232H for OEM applications. Other parameters controlled by the EEPROM include Remote Wake Up,
Soft Pull Down on Power-Off and I/O pin drive strength.
The EEPROM must be a 16 bit wide configuration such as a Microchip 93LC46B or equivalent capable of a
1Mbit/s clock rate at VCC = +3.00V to 3.6V. The EEPROM is programmable in-circuit over USB using a
utility program called MPROG available from FTDI’s web site (www.ftdichip.com). This allows a blank part
to be soldered onto the PCB and programmed as part of the manufacturing and test process.
If no EEPROM is connected (or the EEPROM is blank), the FT4232H will default to serial ports. The device
uses its built-in default VID (0403), PID (6011) Product Description and Power Descriptor Value. In this case,
the device will not have a serial number as part of the USB descriptor.
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