Quectel RM520N-GL - Normally Closed (U)SIM Card Connector

5G Module Series

RM520N-GL_Hardware_Design 41 / 84

Parameter

1. Hot-plug function is invalid if the configured value of <insert_level> is inconsistent with hardware

design.

2. Hot-plug function takes effect after the module is restarted.

3. The underlined value is the default parameter value.

4. USIM1_DET hot-plug is enabled by default, while USIM2_DET hot-plug is disabled by default.

4.1.3. Normally Closed (U)SIM Card Connector

With a normally closed (U)SIM card connector, USIM_DET pin is shorted to ground when there is no

(U)SIM card inserted. (U)SIM card detection by high level is applicable to this type of connector. Once

(U)SIM hot-plug is enabled by executing AT+QSIMDET=1,1, a (U)SIM card insertion will drive

USIM_DET from low to high level, and the removal of it will drive USIM_DET from high to low level.

⚫ When the (U)SIM is absent, CD is shorted to ground and USIM_DET is at low level.

⚫ When the (U)SIM is present, CD is open from ground and USIM_DET is at high level.

The following figure shows a reference design for (U)SIM interface with a normally closed (U)SIM card

connector.

Module (U)SIM Card

Connector

USIM_DET

USIM_DATA

USIM_CLK

RST

CLK

CD

IO

USIM_VDD

USIM_RST

VCC

GND

VPP

GND

TVS array

22 Ω

10k-20k

100 nF

10pF 10 pF 10 pF

NOTE: All these resistors, capacitors and TVS should be close to (U)SIM card connector in PCB layout.

Figure 15: Reference Circuit for Normally Closed (U)SIM Card Connector

<enable> Integer type. Enable or disable (U)SIM card detection.

0 Disable

1 Enable

<insert_level> Integer type. The level of (U)SIM detection pin when a (U)SIM card is inserted.

0 Low level

1 High level

NOTE