User's Manual

Cinterion
®
ELS31-/ELS51-US Hardware Interface Overview
2 Interface Characteristics
29
 ELS31-US_ELS51-US_HIO_v01.000a 2016-12-28
Confidential / Preliminary
Page 11 of 46
2 Interface Characteristics
ELS31-US/ELS51-US is equipped with an SMT application interface that connects to the ex-
ternal application. The SMT application interface incorporates the various application interfac-
es as well as the RF antenna interfaces.
2.1 Application Interface
2.1.1 USB Interface
ELS31-US/ELS51-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 interface and for downloading firmware.
The V
USB
line is used for cable detection only, this is to be supplied by the external device. The
USB circuitry in the ELS31-US/ELS51-US is designed to meet the USB 2.0 specification for
self-power.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 ELS31-US/ELS51-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)
It is recommended to add EMI suppression filter (see section 2.1.3.1)
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 90Ohm for proper signal integrity.
SMT