User's Manual

PART 2 – Embedded Wireless Modems Chapter 5 – SocketModem HSDPA

Multi-Tech Systems, Inc. Universal Socket Hardware Guide for Developers (S000342K) 91

Interface Signal Descriptions

USB Interface

The SocketModem supports a USB 2.0 Full Speed (12Mbit/s) device interface. A USB host has to support at

least 6 ‘Message Pipes” to work with the HSPDA USB interface.

The USB I/O-pins are capable of driving the signal at min 3.0V. They are 5V I/O compliant.

The USB interface is powered by VUSB. VUSB must be supplied by USB host in the range 4.5 to 5.25V. The

maximum load in VUSB is 10mA.

While the USB connection is active, the SocketModem will not change into SLEEP Mode. To enable switching

into SLEEP mode the USB host must bring its USB interface into Suspend state. On incoming calls, the

SocketModem will then generate a remote wake up request to resume the USB connection.

Note: The MTSMC-H will not transition to sleep mode.

USB Interface Signal Descriptions

Signal Name I/O Signal Form and Level Commend

VUSB I VINmin = 4.5V

VINmax = 5.25V

Active current:

IItyp = 2.5mA

IImax = 10mA

Suspend current:

IItyp = 900μA

If lines are unused,

keep pins open.

USB_DP

USB_DN

I/O

Input sensitivity (Diff),

|D+ - D-|, VIN = 0.8V to 2.5V:

0.2V min

Common mode range (Diff),

VIN = 0.8V to 2.5V

Receiver threshold (single-end),

Vthresholdmin = 0.8V

Vthresholdmax = 2.0V

Receiver hysteresis,

Vhystyp = 200mV

If lines are unused,

keep pins open.

Note: For more information about the USB interface, see the separate USB Reference Guide available on the

Universal Guide CD.