Copyright © 2010 Future Technology Devices International Limited

12

Document Reference No.: FT_000132

USB-COM485-PLUS1 Datasheet

Version 1.21

Clearance No.: FTDI# 95

4 Electrical details

4.1 USB

Parameter

Description

Minimum

Typical

Maximum

Units

Conditions

USB_VCC

Input Power Voltage*

4.25

5.0*

5.25

V

*Present when USB

cable is attached and

USB Host or Hub

powered.

Icc

USB current***

30

50

mA

***Does not include

power supplied to

external device

connected to pin 9

Table 4.1 USB Electrical Details

4.2 RS485

Parameter

Description

Minimum

Typical

Maximum

Units

Conditions

Receiver Input

VCM

Common-mode input

voltage range

-7

+12

V

IN

Input Current

1.0

mA

VIN = +12V

-0.8

VIN = -7V

VTH

Differential Threshold

Voltage

-0.2

+0.2

V

VIHYST

Input Hysteresis

20

mV

RIN

Input Resistance, RIN

12

15

k

Ω

Transmitter Output

VOD

Differential Output

Voltage

1.5

5

V

With RL = 54

Ω.

CL = 50pF *

ESD Tolerance

ESD HBM

RS485 Inputs and

Outputs

±15

kV

EN61000-4-2

Contact Discharge

RS-485 Inputs and

Outputs

±8

kV

EN61000-4-2 Air

Gap Discharge

RS-485 Inputs and

Outputs

±15

kV

Table 4.2 RS485 Electrical Details

* - The 54 ohms is the equivalent of two 120 ohm termination resistors placed on each side of the