Four-channel high-speed signal line ESD protection and domestic alternative solutions

High-speed differential signal interfaces such as USB, HDMI, MIPI, Ethernet ports, as well as various storage card interfaces like SIM cards, SD cards, and TF cards, are prone to electrostatic and surge interference due to frequent insertion and removal operations. Therefore, it is essential to implement effective electrostatic and surge protection measures for these interfaces.

Depending on the requirements of different user circuit environments and equipment application scenarios, the parameter selection of ESD protection diodes also varies. To this end, Shanghai Leiditech  EMC team provides solutions with multiple model parameters for different customers' requirements. Among them, the SOT23-6 package is highly representative due to its wide application, and its package appearance and internal circuit structure are as follows:

The representative application circuit is as follows

For the SOT23-6 package, we offer five different parameter models for customers to choose from. We have also listed the foreign brands that can be used as alternatives for each part number for reference.

1、 The working voltage of Part No. USRV05-4 is 5V, and according to IEC61000-4-5, it is 5A/17A (8/20μs):

5A is for the IO ports (PIN 1, 3, 4, 6) to ground (PIN 2),

17A is for VCC (PIN 5) to ground (PIN 2). The parameters and alternative models are as follows:

Leiditech USRV05-4 could replace:

a)         MCC( SRV05-4L ，SRV05-4C )

b)         ST (USBLC6-4， HDMIULC6-4SC6)

c)          Semtech (SRV05-4.TCT)

d)         Panjit (PJSRV05-4)

e)         ONSEMI (SRV05-4)

f)          Protek Devices (SRV05-4M)

g)         Diotech (SRV05-4M)

2、 The Part No. SRV05W4 operates at a voltage of 5V, and the IEC61000-4-5 standard specifies a current of 12A (8/20μs):

12A is an IO port (PINS 1, 3, 4, 6) connected to ground (PIN 2). The parameters and alternative Part No. are as follows:

Leiditech PN: SRV05W4 could replace Littelfuse and Willas PN: SRV05-4.

3、 The Part No. SRV05-4W operates at a voltage of 5V, and the IEC61000-4-5 standard specifies a current of 25A (8/20μs).

25A is an IO port (PINS 1, 3, 4, 6) connected to ground (PIN 2). The parameters and alternative Part No. are as follows:

Leiditech PN: SRV05-4W could replace MCC PN: PSRV05-4  

4、 The Part No. SRV05-4LV operates at a 5V backscanning voltage. According to IEC61000-4-5, the current rating is 25A/38A (8/20μs):

25A is for the IO ports (PIN 1, 3, 4, 6) to ground (PIN 2),

38A is for VCC (PIN 5) to ground (PIN 2). The parameters and alternative Part No. are as follows:

Leiditech PN: SRV05-4LV pin-pin replace Bourns PN: CDSOT23-SRV05-4, Protek Devices PN: SRV05-4.

5、The working voltages for Part No. SR33-04A and SR33-04AW are both 3.3V. According to IEC61000-4-5, the values for 5A (8/20μs) and 25A (8/20μs) are 5A and 25A respectively. These 5A and 25A are connected to the IO ports (PIN 1, 3, 4, 6) and are grounded (PIN 2). The parameters are as follows.

6、How to select Part Number

The principles are as follows:

l  First, select based on the operating voltage of the signal. If the signal voltage is 3.3V, 3.3V ESD can be selected or 5V ESD can be selected. The voltage of the ESD device must be equal to or higher than the operating voltage.

l  If the device interface is frequently plugged and unplugged, or is in an environment with high risks of static electricity and surges, it is recommended to choose ESD devices with high anti-static grade and large peak pulse current (IPP), such as Part Number SRV05W4, SRV05-4W, etc.

l  To further enhance the protection effect, one can also preferentially select devices that have high protection grade, high surge tolerance and low clamping voltage characteristics, such as SRV05-4LV, SR33-04AW, etc., to provide more reliable protection for the downstream circuit.

7、Application Circuit

l  SIM card interface

l  HDMI interface

l  Network port

For any inquiries regarding the above plans and Part numbers, please contact Leiditech salesperson.