1. the electrical parameters of ．LP1101SB are as follows, with a nominal protection level of 10/700uS 4KV.

Second, the device principle analysis

The distance from the telecommunications bureau to the user's home is several kilometers, and the telephone line will be interfered by high-voltage electricity such as lightning strike, power line collision and power line induction. If these high-voltage electricity rushes to the SLIC chip, it will break down the SLIC. Therefore, it is necessary to add an overvoltage protector before SLIC.

There are two types of overvoltage protection devices, one is fixed voltage, such as LP1101SB series products of LEIDITECH, and the other is programmable voltage, such as TISP61089B of Bourns. Its characteristic curve is as follows:

Third, the device principle analysis

(1) The feed voltage in the SLIC line is -48V, and the voltage will reach about 90V only when ringing. Therefore, the VDRM working voltage value of LP1101SB series products can protect the SLIC line from overvoltage.

The following are the schematic circuit diagrams of LP1101SB series and TISP61089B respectively:

(2) Analysis of device principle

(3) Analysis of device principle

Third, the test results

The LP1101SB circuit scheme was used to test and verify in the customer system, and it passed 10/700μs 40Ω 4KV ±5 tests.

V advantages of LP1101SB series products

1. Performance advantages:

LP1101SB is packaged in L/F+CLIP mode SMB, which can meet the lightning strike level requirements of 10/700US-40ω 4kV or even 6KV.

TISP61089B adopts integrated circuit design, and can only pass the lightning strike level requirement of 10/700US-40ω 2kV.

2. Cost advantage

LP1101SB has great advantages in chip and package cost. Replacing TISP61089B with LP1101SB in SLIC scheme can reduce the cost by 20% on the basis of improving the lightning protection level.

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