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CN-121984597-A - TO packaging type light receiving module resistant TO electromagnetic interference and internal routing method thereof

CN121984597ACN 121984597 ACN121984597 ACN 121984597ACN-121984597-A

Abstract

The invention discloses an anti-electromagnetic interference TO packaging type light receiving module and an internal routing method thereof, belongs TO the technical field of optical communication, and aims TO solve the problems of insufficient anti-interference capability, high cost and limited performance caused by adopting a TIA bare chip internal integrated bias and filtering scheme in the traditional ROSA. The invention has the core that the internal bias is abandoned, the power is directly supplied TO the cathode of the photodiode PD by the external power pin VDD_TO of the TO package instead, and the split off-chip capacitor is adopted for filtering. Specifically, two schemes are provided, namely, a scheme one adopts 470pF and 1nF double capacitors to filter the PD cathode and the TIA power supply respectively, and a scheme two omits a special capacitor, so that the PD cathode and the TIA power supply share 1nF capacitor for filtering so as to save cost. The critical wire bonding method requires that gold wires connecting the filter capacitors be bonded at the lowest height and shortest distance to minimize parasitic inductance. The invention obviously improves the electromagnetic compatibility of the module, obviously improves the sensitivity under strong interference and reduces the manufacturing cost.

Inventors

  • LI JINGHU
  • TU HANGHUI
  • HUANG YUNHONG
  • CHENG SIYUAN

Assignees

  • 厦门亿芯源半导体科技有限公司

Dates

Publication Date
20260505
Application Date
20260210

Claims (10)

  1. 1. The utility model provides an anti-electromagnetic interference's TO encapsulation formula light receiving module, includes metal tube shell and draws TO the outer power pin VDD_TO of tube shell, ground pin GND_TO, first signal output pin OUTP_TO and second signal output pin OUTN_TO, be equipped with in the metal tube shell and put thing platform, its characterized in that still includes: TIA die and PD die disposed on the deposit stand; A first filter capacitor C1 and a second filter capacitor C2; Wherein, the The TIA bare chip is provided with a power supply pad VDD_TIA, an input pad PINA_TIA, a ground pad GND_TIA, a first output pad OUTP_TIA and a second output pad OUTN_TIA; An anode bonding pad and a cathode bonding pad are arranged on the PD bare chip; The first end of the first filter capacitor C1 is electrically connected with the cathode bonding pad of the PD bare chip and the power supply pin VDD_TO through a first conductive connecting piece; The second end of the first filter capacitor C1 is electrically connected with the metal tube shell; the first end of the second filter capacitor C2 is electrically connected with the power supply pin VDD_TO through a second conductive connecting piece and is electrically connected with a power supply pad VDD_TIA of the TIA bare chip through a third conductive connecting piece; The second end of the second filter capacitor C2 is electrically connected with the metal tube shell; The anode pad of the PD die is electrically connected with the input pad PINA_TIA of the TIA die through a fourth conductive connection.
  2. 2. The TO package type light receiving module of claim 1, wherein the first filter capacitor C1 and the second filter capacitor C2 are discrete patch capacitors, the capacitance value of the first filter capacitor C1 is 470pF, and the capacitance value of the second filter capacitor C2 is 1nF.
  3. 3. The anti-electromagnetic interference TO package type light receiving module according TO claim 1, wherein the first, second, third and fourth conductive connecting members are gold wires.
  4. 4. The internal routing method of TO-package type light receiving module according TO any one of claims 1 TO 3, comprising the steps of: S1, fixing a TIA bare chip and a PD bare chip on a placement table in a TO packaging metal tube shell; s2, fixing a first filter capacitor C1 and a second filter capacitor C2 in the metal tube shell or on the object placing table, and enabling the second end of the first filter capacitor C1 and the second end of the second filter capacitor C2 to be electrically connected with the metal tube shell; s3, performing wire bonding connection, including: s31, using gold wires TO interconnect a cathode bonding pad of the PD bare chip, a first end of the first filter capacitor C1 and the power supply pin VDD_TO TO form the first conductive connection piece; S32, connecting the first end of the second filter capacitor C2 with the power pin VDD_TO by using a gold wire TO form the second conductive connecting piece; S33, connecting the first end of the second filter capacitor C2 with a power supply pad VDD_TIA of the TIA bare chip by using a gold wire to form the third conductive connecting piece; And S34, connecting an anode pad of the PD bare chip with an input pad PINA_TIA of the TIA bare chip by using a gold wire to form the fourth conductive connecting piece.
  5. 5. The wire bonding method according to claim 4, wherein in step S32 and step S33, connection is performed at the lowest crossing height and the shortest distance by two gold wires at the time of wire bonding.
  6. 6. The utility model provides an anti-electromagnetic interference's TO encapsulation formula light receiving module, includes metal tube shell and draws TO the outer power pin VDD_TO of tube shell, ground pin GND_TO, first signal output pin OUTP_TO and second signal output pin OUTN_TO, be equipped with in the metal tube shell and put thing platform, its characterized in that still includes: A TIA die and a photodiode PD die disposed on the mount; A second filter capacitor C2; Wherein, the The TIA bare chip is provided with a power supply pad VDD_TIA, an input pad PINA_TIA, a ground pad GND_TIA, a first output pad OUTP_TIA and a second output pad OUTN_TIA; An anode bonding pad and a cathode bonding pad are arranged on the PD bare chip; The cathode bonding pad of the PD bare chip is electrically connected with the power supply pin VDD_TO through a fifth conductive connecting piece; the first end of the second filter capacitor C2 is electrically connected with the power supply pin VDD_TO through a second conductive connecting piece and is electrically connected with a power supply pad VDD_TIA of the TIA bare chip through a third conductive connecting piece; The second end of the second filter capacitor C2 is electrically connected with the metal tube shell; The anode pad of the PD die is electrically connected with the input pad PINA_TIA of the TIA die through a fourth conductive connection.
  7. 7. The anti-electromagnetic interference TO package type optical receiving module as claimed in claim 6, wherein the second filter capacitor C2 is a discrete patch capacitor, and the capacitance value of the second filter capacitor C2 is 1nF.
  8. 8. The TO package type light receiving module of claim 6, wherein the fifth conductive connecting member, the second conductive connecting member, the third conductive connecting member and the fourth conductive connecting member are gold wires.
  9. 9. An internal routing method of the TO package type light receiving module according TO any one of claims 6 TO 8, comprising the steps of: p1, fixing a TIA bare chip and a PD bare chip on a placement table in a TO packaging metal tube shell; p2, fixing a second filter capacitor C2 in the metal tube shell or on the object placing table, and enabling a second end of the second filter capacitor C2 to be electrically connected with the metal tube shell; p3, carry out wire bonding and connect, include: p31, connecting a cathode bonding pad of the PD bare chip with the power supply pin VDD_TO by using a gold wire TO form the fifth conductive connecting piece; p32, connecting the first end of the second filter capacitor C2 with the power pin VDD_TO by using a gold wire TO form the second conductive connecting piece; P33, connecting the first end of the second filter capacitor C2 with a power supply pad VDD_TIA of the TIA bare chip by using a gold wire to form the third conductive connecting piece; and P34, connecting an anode pad of the PD die with an input pad PINA_TIA of the TIA die by using gold wires to form the fourth conductive connecting piece.
  10. 10. The wire bonding method according to claim 9, wherein in step P32 and step P33, connection is performed at the lowest crossing height and the shortest distance by two gold wires at the time of wire bonding.

Description

TO packaging type light receiving module resistant TO electromagnetic interference and internal routing method thereof Technical Field The invention relates TO the technical field of optical communication, in particular TO a TO packaging type optical receiving module with strong electromagnetic interference resistance and an internal routing method thereof, which are suitable for FTTR or FTTH scenes. Background FTTR (Fiber to the Room, fiber-to-room) technology is to extend fiber from a communication base station all the way to each room in a home, thereby providing very high speed internet access services for home users. As shown in figure 1 for FTTR application scenario, the operator network transmits data to the user's home via fiber, a segment commonly referred to as FTTH (Fiber to the Home ). In this scenario, the operator side device is similar to a local OLT (optical line terminal), while the main device in the user's home is equivalent to a user side ONU (optical network unit). The FTTR technology is characterized in that an optical fiber is used for replacing a traditional network cable, an optical networking terminal is deployed to be interconnected with a home gateway, and the seamless coverage of the kilomega bandwidth of a whole house is realized by combining wireless technologies such as dual-frequency Wi-Fi, wi-Fi6 and the like. This is an important direction for future gigabit home network upgrades. In the FTTR-networking optical fiber communication module, a ROSA (Receiver Optical Sub-Assembly) is a key component responsible for converting a received optical signal into an electrical signal. The photoelectric conversion circuit has the core functions of being cooperatively completed by two key components, namely a Photodiode (PD) is used for realizing photoelectric conversion and converting an optical signal into a weak current signal, and a transimpedance amplifier (TIA) is responsible for amplifying and converting the current signal into a voltage signal which can be processed by a subsequent circuit. In addition, a typical ROSA includes capacitors for signal filtering, lenses for focusing, and TO (Transistor Outline) metal-encapsulated packages that provide electromagnetic shielding and mechanical protection, among others. In an actual TO package structure, the functional components are integrated in a specific physical form. The PD and TIA are fixed on a placing table inside the package through conductive adhesive in the form of PD bare chip and TIA bare chip respectively, and then are electrically interconnected by gold wires, so that a complete signal link is formed. However, in a complex home electromagnetic environment, the performance of ROSA presents a significant challenge. High-frequency heating household appliances such as microwave ovens and electromagnetic ovens used daily, wireless communication equipment such as mobile phones and routers, and motor appliances such as refrigerators and washing machines can generate strong electromagnetic radiation or instant pulses when being started and operated. These electromagnetic interference (EMI) signals can intrude into the ROSA interior through a variety of pathways. As shown in fig. 2, the TO package, while grounded with a metal tube housing TO achieve electromagnetic shielding, has a lens opening at its top and exposed metal pins (like an antenna) that still act as an intrusion path for EMI. Once the interfering signal enters the package interior and couples onto the sensitive signal path, particularly the cathode of the PD, it can have a severe impact on the system. Since the transimpedance amplifier (TIA) amplifies extremely weak current signals (typically at the microampere level), even small disturbances are significantly amplified, thereby severely reducing the ROSA's receive sensitivity and shortening its effective communication distance. To suppress such interference, conventional ROSA designs (as shown in fig. 3, 4) typically employ schemes that integrate a bias circuit and on-chip filter capacitors inside the TIA die. The scheme provides an operating bias voltage for the PD cathode by the TIA die and utilizes internal capacitance for filtering. However, the scheme has the inherent defects that the integration of the capacitor with a large capacitance value on the semiconductor silicon chip consumes huge chip area, so that the manufacturing cost is increased sharply, the process and economy are limited, the integrable capacitance value is limited, the filter effect of the integrable capacitance value cannot meet the strict EMC (electromagnetic compatibility) requirement, and the performance of the ROSA in a strong interference environment is unstable. Therefore, how to design a new ROSA internal interconnection and filtering structure on the premise of not significantly increasing the cost so as to greatly improve the suppression capability of the ROSA internal interconnection and filtering structure on the high-frequency