SA9618A RF AMPLIFIER FOR CD DIGITAL SERVO SYSTEM DESCRIPTION SA9618A can be used for ALPC and signal conversion between CD optical pickup and decoding chip. This IC incorporates an interconnection to general CD optical pickup photodiode, bias voltage VREF generation circuit, RF amplifier and ALPC circuit.(This IC is adaptive for CD-A/V,CD-R,CD-R/W,CD-ROM). FEATURES SOP-16-225-1.27 * RF amplitude automatic adjustment circuit .(It is adaptive for CDA/V,CD-R,CD-R/W,CD-ROM) * Low power consumption.(35mW ~ 3.5V) * ALPC circuit * Operating voltage range:2.8V – 7.0V ORDERING INFORMATION APPLICATIONS * CD Players Device Package SA9618A SOP-16-225-1.27 * VCD Players BLOCK DIAGRAM HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.1 2006.07.14 Page 1 of 6 SA9618A ABSOLUTE MAXIMUM RATINGS (Tamb=25°C) Symbol Rating Unit Supply Voltage Characteristics VDD -0.5 ~ +12 V Operating Temperature Topr -20 ~ +75 °C PD 370 mW Power Dissipation DC ELECTRICAL CHARACTERISTICS Characteristics Supply voltage Bias Output Of Photoelectric Signal Current Consumption Symbol Min. Typ. Max. Unit VDD 2.8 5.0 7.0 V VREF -- 2.5 -- V -- 12 -- mA Min. Typ. Max. Unit -- 0.17 -- V DA11 0 -- 0.60 V KSS213 0 -- 0.15 V DA11 0 -- 0.60 V KSS213 0 -- 0.15 V 1MHZ, 300mVpp -- 15 -- dB IDD Test Condition VDD=5V AC ELECTRICAL CHARACTERISTICS Characteristics Symbol Diode Control Input MON Photoelectric Input 1(A+C) PD1 Photoelectric Input 2(B+D) PD2 Gain Of RF Signal GAIN Test Conditions Note 1: The resistance between Pin RFM and Pin RFO is 5.5K. PIN CONFIGURATION HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.1 2006.07.14 Page 2 of 6 SA9618A PIN DESCRIPTION Pin No. Symbol Description 1 VTH 2 LD APC circuit output pin. 3 MON Diode control input pin. 4 PD1 Photoelectric input1 (A+C) pin. Reference level variable pin for RF level control. 5 PD2 Photoelectric input2 (B+D) pin. 6 GND GND 7 VREF Bias output pin of OEIC. 8 NC RF level control ON/OFF switching pin 9 NC Gain select pin for RF signal. 10 RFM RF level control output pin 11 RFO 12 RFI RF amplifier input pin. 13 RFRC External time-constant pin for RF level control. 14 AGC The automatic switching pin for optical power. 15 LDON 16 VDD RF amplifier inverted side output pin. RF amplifier gain is determined by the resistor connected between RFO pin and RFM pin. ALPC circuit ON/OFF switching pin. VDD pin. NOTE: LDON pin is low active in SA9618A, but it must be connected to an external resistor of 150kΩ. FUNCTION DESCRIPTIONS SA9618A can be divided into three parts: Reference voltage generation circuit; RF signal processing circuit incorporating two RF Amplifiers and an RF adder; Automatic switching APC circuit incorporating optical power switching circuit, RF demodulation circuit and automatic optical power control circuit. Reference voltage is half of VDD. It is not only the common level for amplifier in circuit, but also the bias voltage of OEIC. The feedback resistor of each RF Amplifier is 58kΩ. And the gain of RF amplifier is the ratio of the 58kΩ equivalent resistance and external resistor connected between PD1 pin and PD2 pin. When the resistance value is 33k, the gain of RF Amplifier is 1.76. The output of each RF Amplifier is added by RF adder. The gain of RF adder can be adjusted by varying the resistor connected between RFM pin and RFO pin. When the resistance value is 5.5k, the gain of RF summing amplifier is 2.75. The output of Peak value of RF demodulation circuit comes from the output of RF adder. The DC voltage formed by external RC filter of RFRC pin, and it is related to the level of input of PD1 pin and PD2 pin. The DC voltage will increase as the level of the input becomes higher. Optical Power switching circuit is controlled by AGC pin. It has three modes: connected to GND, open, connected to supply voltage. The optical power can be adjusted by varying the voltage of VL. There are five VL values, and it is as follows. HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.1 2006.07.14 Page 3 of 6 SA9618A AGC The level of input Value of VL Strength of optical power VCC * 1.25V middle OPEN large RFRC>VTH 0.9V weaker OPEN small RFRC>VTH 1.6V stronger GND large RFRC>VTH 0.7 weakest GND small 1.8 strongest RFRC>VTH Pin LDON controls APC circuit. In SA9618A, APC is set to ON by connecting the LDON pin to GND; and set to OFF by connecting it to VDD, and SA9618A should be connected to an external resistance of 150kΩ between LDON pin and external MCU. TEST CIRCUITS SA9618A HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn REV:1.1 2006.07.14 Page 4 of 6 SA9618A TYPICAL APPLICATION CIRCUIT PACKAGE OUTLINE SOP-16-225-1.27 HANGZHOU SILAN MICROELECTRONICS CO.,LTD Http: www.silan.com.cn UNIT: mm REV:1.1 2006.07.14 Page 5 of 6