CXA2702GA

Optical Pickup Chipset with Photodetector ICs Supports High-Speed Writing to CD and DVD CXA2702GA/CXA2716GA/CXA2701GA Although it has only been a year since Sony released the CXA2676GA and CXA2677GA* for DVD ×8-speed recording, DVD recording speed has already reached ×16. Sony’s newly-developed CXA2701GA and CXA2702GA/ CXA2716GA optical pickup photodetector ICs (PDICs) support this ×16 record speed. *: See CX-News, Volume 32, for details on the CXA2676GA and CXA2677GA. CXA2702GA/CXA2716GA RF/Servo PDICs I Supports high-speed CD/DVD write operations (CD-R: ×52-speed, DVD-R: ×16-speed) I WPP1 (B+C) and WPP2 (A+D) outputs, which are optimal for DVD address pit detection I Variable limiter function I CXA2702GA: Eight-division photodiode CXA2716GA: Twelve-division photodiode I 18-pin LGA COB small package CXA2701GA Laser Front Monitor PDIC I Differential output I Two-channel structure (Vin1, Vin2) I 12-pin LGA COB small package CXA2702GA/CXA2716GA The CXA2702GA is a photodetector IC (PDIC) that was developed as the photodetector for optical pickups used in DVD± R/RW recording drives. Like the earlier ×8-speed CXA2677GA, it provides the WPP1 and WPP2 signals that are optimal for address pit signal detection. In increasing the recording speed to ×16, Sony added a 3× gain switching function to WPP1 and WPP2. The new IC thus has an additional 2 bits of control compared to the earlier gain switching system. The CXA2702GA also now provides an input pin that can control the output limiter volt- age externally so that applications can set the limiter voltage to provide optimal pickup performance. Note that although the CXA2702GA includes a built-in 8-division photodiode that supports the same differential push-pull method as the earlier product (CXA2677GA), Sony has also added to the product lineup the CXA2716GA, which includes a built-in 12-division photodiode that supports the differential astigmatism method. Both the CXA2702GA and CXA2716GA feature the extremely fast main output settling time (for a 1 V amplitude) of 6 ns. Support for Lead-Free Mounting Since the chip on board (COB) package adopted for these ICs has excellent resistance to heat, these ICs support mounting with lead-free solder. They allow two-pass reflow mounting with a peak temperature of 250°C. Note: Since the thermal resistance is strongly influenced by the usage environment, verify the details of the specifications in advance, or contact your Sony representative for consultation. CXA2701GA Like the earlier ×8-speed CXA2676GA, the CXA2701GA adopts a two-channel structure to allow the CD laser and the DVD laser power levels to be set individually. However, the output was changed to the differential type in this new product. This was because the output at the read power became even smaller due to lowering the gain of the first stage I-V amplifier (transimpedance amplifier) to 1/√2 to support ×16-speed laser diodes. Switching to a differential amplifier improves the signal-to-noise ratio by √2 and also allows the common mode noise in the transmission system to be cancelled. V O I C E Our achievement of × 16-speed DVD recording required pushing our circuit technologies to the limit to get the utmost performance from Sony ’ s process technologies. The two of us on this development team had to come up with a lot of mutual support and encouragement during this design effort. We are probably not the only ones who are hoping that this achievement marks the end of the competition for ever higher speeds. 1 kΩ – A' High ×1.8 A – + A 6 ×3 Vcc 4 50 kΩ + 8 Vout+ Low High B' ×1 1 kΩ – Vc 1 Vcc Vc 11 50 kΩ Vc_MONI 12 + 7 Vout– Low B B – + 8 ×3 10 Vc Vc 5 SW 200 Ω 10 200 Ω C' Vin1 C 13 C – + 6 ×3 5 Vc GND GND GND 2 1 Photodiode 740 Ω – + Vin2 VR2 VR1 D' 4 D – + VLIMIT 9 Vc A B C D A B C D Vcc Vc Vc – + IVout D 11 ×3 Vc 14 RF+ I Figure 1 CXA2701GA Block Diagram E9 (EF2) ×3 – + (E2+F2) E Vc F IVout Vin1 9 10 Vc 11 8 Vc_MONI 12 Vout+ F 18 (EF1) ×3 – + – + 17 RF– (E1+F1) Vout– 7 SW 5 1 2 Vc G 6 Vin2 3 NC 4 Vcc G 16 (EF3) ×3 – + (E3+F3) B' C' Vc A' D' – + 12 WPP1 – + 7 WPP2 Vc H GND GND I Figure 3 CXA2701GA Pin Configuration H 15 (EF4) ×3 (E4+F4) – + 3 2 SWA SWB Vc H G F RF+ (EF4) (EF3) RF– (EF1) 14 Vc 10 15 16 D WPP1 11 12 A WPP2 6 7 2 3 17 C 13 B 8 4 18 I Figure 2 CXA2702GA Block Diagram (Items in parentheses apply to the CXA2716GA.) E (EF2) 9 5 1 Vcc SWB SWA VLIMIT GND I Figure 4 CXA2702GA Pin Configuration (Items in parentheses apply to the CXA2716GA.) φ 0.7 mm 120 35 120 35 120 Photosensitive area position: At the package center 150 D H G A C 120 I Figure 5 CXA2701GA Acceptance Pattern Dimensions F E B Unit: µm I Figure 6 CXA2702GA Acceptance Pattern Dimensions Temperature [°C] 250 200 180°C 150 150°C 2 to 4°C/s 100 Peak: 250°C Max. 230°C or more 2 to 6°C/s Pre Heating Zone (3 to 6°C/s) 120 35 120 35 120 90 ± 30 s 30 ± 10 s Soldering Zone F4 F3 120 D A C B E4 E3 150 50 Heating time F1 F2 E1 E2 Unit: µm Note: The temperatures shown are package surface temperatures. I Figure 7 CXA2716GA Acceptance Pattern Dimensions I Figure 8 Recommended Reflow Soldering Temperature Profile (Lead-free soldering)