Features

If the device has a user-accessible slot for a Universal Integrated Circuit Card (UICC) card, Electrostatic Discharge (ESD) sensitivity should be considered. The nRF9160-internal ESD protection is intended for a 1.5 kV Human Body Model (HBM) level. External ESD/EMI filtering is recommended between the UICC card slot and nRF9160.

Several ESD/EMI filtering options are available. A commonly used option is a dedicated integrated component, such as STM EMIF03-SIM02M8, TI TPD3F303, or OnSemi CM1402. Typically, an integrated ESD filter consists of lowpass filters and ESD diodes in a small SMD package. Another option is discrete ESD protection which takes more space on the Printed Circuit Board (PCB), but can be more flexible for certain applications and a lower-cost solution.

Discrete ESD protection can consist of the following components:

• Bypass capacitors in the range of ≤ 22 pF to SIM_RST, SIM_DET, SIM_CLK, SIM_IO, and SIM_1V8.
  • A separate supply capacitor ranging from 100 nF to 220 nF connected to SIM_1V8 can be considered.
• Low capacitance type ESD diodes to SIM_RST, SIM_DET, SIM_CLK, SIM_IO, and SIM_1V8.
  • Multichannel ESD diodes are commonly used and recommended.
  • Some multichannel diode components incorporate EMI filtering. This type is recommended if the product integrates an LTE antenna, or an external antenna is located close to the Subscriber Identity Module (SIM) holder.

The electrical specifications for all UICC signals that should be verified in product design and in the prototyping phase are defined in ETSI TS 102 221, chapter Electrical specifications of the UICC. For more information, see nRF9160 Hardware Verification Guidelines.