User's Manual

Cinterion
®
ELS61-US Hardware Interface Overview
2 Interface Characteristics
21
 ELS61-US_HIO_v00.281 2016-02-11
Confidential / Preliminary
Page 10 of 40
2 Interface Characteristics
ELS61-US is equipped with an SMT application interface that connects to the external applica-
tion. The SMT application interface incorporates the various application interfaces as well as
the RF antenna interface.
2.1 Application Interface
2.1.1 USB Interface
ELS61-US supports a USB 2.0 High Speed (480Mbit/s) device interface that is Full Speed
(12Mbit/s) compliant. The USB interface is primarily intended for use as command and data in-
terface and for downloading firmware.
The external application is responsible for supplying the VUSB_IN line. This line is used for ca-
ble detection only. The USB part (driver and transceiver) is supplied by means of BATT+. This
is because ELS61-US is designed as a self-powered device compliant with the “Universal Se-
rial Bus Specification Revision 2.0”
1
.
Figure 2: USB circuit
To properly connect the module's USB interface to the external application, a USB 2.0 compat-
ible connector and cable or hardware design is required. Furthermore, the USB modem driver
distributed with ELS61-US needs to be installed.
1. The specification is ready for download on http://www.usb.org/developers/docs/
VBUS
DP
DN
VREG (3V075)
BATT+
USB_DP
2)
lin. reg.
GND
Module
Detection only
VUSB_IN
USB part
1)
RING0
Host wakeup
1)
All serial (including R
S
) and pull-up resistors for data lines are implemented.
USB_DN
2)
2)
If the USB interface is operated in High Speed mode (480MHz), it is recommended to take
special care routing the data lines USB_DP and USB_DN. Application layout should in this
case implement a differential impedance of 90 ohms for proper signal integrity.
R
S
R
S
SMT