Usim Card Interface; Overview; Circuit Recommended For The Usim Card Interface - Huawei ME909u-523 Hardware Manual

HUAWEI ME909u-523 LTE LGA Module
Hardware Guide

3.7 USIM Card Interface

3.7.1 Overview

The ME909u-523 module provides a USIM card interface complying with the ISO
7816-3 standard and supports both Class B and Class C USIM cards.
Table 3-9 USIM card interface signals
PIN No. Pin Name
88 SIM_RESET
90 SIM_CLK
89 SIM_DATA
34 SIM_VCC

3.7.2 Circuit Recommended for the USIM Card Interface

As the ME909u-523 module is not equipped with an USIM socket, you need to place
an USIM socket on the user interface board.
Figure 3-16 shows the circuit of the USIM card interface.
Issue 01 (2014-05-24)
USB_DM and USB_DP are required to control the differential impedance – 90 ohm (±10%).

 The length of the gap between USB_DM and USB_DP should not exceed 5 mil.
The USB differential signal trace must be as short as possible, and laid out away from

high-speed clock signals and other periodic signals as far as possible.
 Minimize through-holes and turning angles on the USB signal trace to reduce signal
reflection and impedance change.
 Do not route the USB signal trace under the following components: crystal, oscillator, clock
circuit, electromagnetic component, and IC that uses or generates clocks.
 Avoid stubs on the USB signal trace because stubs generate reflection and affect the signal
quality.
 Route the USB signal trace on a complete reference plane (GND) and avoid crossing
inter-board gaps because inter-board gaps cause a large reflow channel area and increase
inductance and radiation. In addition, avoid signal traces on different layers.
 The USB signal trace must be far away from core logical components because the high
current pulse generated during the state transitions process of core components may
impose interference on signals.
 The USB signal trace must be far away from board edges with a minimum distance of 20 × h
(h indicates the vertical distance between the trace and the reference layer) to avoid signal
radiation.
 C1 and C2 are ready for dealing with filter differential mode interference and C3 is ready for
dealing with filter common mode interference. You can choose the value of the C1, C2 and
C3 according to the actual PCB which is integrated 30 mm × 30 mm LGA module.
Pad Type
O
O
I/O
PO
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Copyright © Huawei Technologies Co., Ltd.
Description of the Application Interfaces
Description
USIM card reset
USIM card clock
USIM card data
Power supply for
USIM card
Min. (V) Typ. (V)
- 1.8/2.85
- 1.8/2.85
- 1.8/2.85
- 1.8/2.85
Max. (V)
-
-
-
-
36