Uim Card Interface; Figure 2-20 Reference Design Of Sim Card Interface - Neoway N20 Hardware User's Manual

N20 Hardware User Guide

2.5 UIM Card Interface

Name Pin
VUIM 29
UIM_DATA 30
UIM_CLK 31
UIM_RESET 32
UIM_PRESENT 33
N20 supports 1.8 V/2.85 VUIM cards. VUIM is the power supply pin of the UIM card and its maximum
load is 30 mA. The UIM_DATA pin is not pulled up internally, so reserve a pull-up resistor externally in
design. UIM_CLK is the clock signal pin, supporting 3.25 GHz of clock frequency. Figure 2-20 shows the
reference design of the UIM card interface.
UIM_DATA
UIM_CLK
UIM_RESET
VUIM
UIM_PRESENT
N20
UIM
ESD protectors, such as ESD diodes or TVS diodes (with a junction capacitance of less than 33 pF), are
recommended to be added on the SIM signals, in most applications with a high requirement of ESD
protection. Add a 20 Ω resistor respectively to UIM_DATA, UIM_RESET, UIM_CLK, and
UIM_PRESENT to enhance the ESD performance.
N20 supports UIM card detection. UIM_PRESENT is a 1.8 V interrupt pin. The UIM detection circuit
works by checking the level across the UIM_PRESENT pin before and after a UIM card is inserted. In the
reference circuit, SIM-DET is not connected before a UIM card is inserted and is grounded after a UIM
card is inserted. Low level means UIM card detected while high level mean no UIM card detected.
Copyright © Neoway Technology Co., Ltd
I/O Function
PO UIM power supply
IO UIM data
DO UIM clock
DO UIM reset
DI UIM detect

Figure 2-20 Reference design of SIM card interface

20Ω
20Ω
20Ω
20Ω
Remarks
Compatible with 1.8 V/3 V UIM card
A 10 kΩ resistor is required between
VIM_VCC and UIM_DATA.
A pull-up resistor is recommended
10KΩ
UIM card
DATA
CLK
RST
VCC
SIM-DET
47KΩ
VDD_1P8
1 uF
VPP
GND
GND
21