SM8610CV Laser Switching Driver IC OVERVIEW The SM8610CV is a portable CD player laser driver IC. It uses a laser switching drive that reduces the laser power dissipation, thereby reducing data read current consumption and extending battery life significantly, when compared with existing devices which use a constant-current laser control method with corresponding high dissipation which places limits on battery life. FEATURES ■ ■ ■ ■ ■ ■ ■ ■ PINOUT 2.4V supply voltage Laser switching driver built-in Laser switching frequency range: 8.6 to 26MHz Switching pulsewidth duty adjustable Laser drive maximum current adjustable Laser control loop gain adjustable Power-save mode (Laser driver current stop function) Package: 16-pin VSOP (Top view) LDISET 1 16 NC NC MUTE RG2 PCK VCC LDIOUT DUTYADJ APPLICATIONS ■ RG1 FLOCK LDOFF NC Portable CD player GND NC 8 9 PDVIN ORDERING INFORMATION 16-pin VSOP PACKAGE DIMENSIONS (Unit: mm) Weight: 0.07g + 0.1 0.05 0.275typ 5.1 0.2 0.15 - 0.10 0.05 SM8610CV 4.4 0.2 6.4 0.2 Package 1.15 0.1 Device 0 to 10 0.65 0.10 + 0.1 0.22 - 0.05 0.12 M 0.5 0.2 NIPPON PRECISION CIRCUITS INC.—1 SM8610CV BLOCK DIAGRAM VCC LDISET LDOFF RLD FLOCK Pick-up DMUTE Processor PCK DUTYADJ RDUTY 2 multiplier Duty rate adjustor Pulse control logic Laser diode driver Feedback V-I amplifier LDIOUT PDVIN GND RG1 RG2 RG CG NIPPON PRECISION CIRCUITS INC.—2 SM8610CV PIN DESCRIPTION Number Name i/o Description 1 LDISET o Laser drive maximum current setting resistor connection 2 NC – No connection (must be open) Muting signal DMUTE 3 MUTE ip Laser drive state L Laser switching drive H Laser constant-current drive 4 PCK i Data extract clock input 5 DUTYADJ o Laser switching pulse duty adjust Focus servo lead-in signal FLOCK 6 FLOCK ip Laser drive state L Laser constant-current drive H Laser switching drive 7 NC – No connection (must be open) 8 GND – Ground connection 9 PDVIN i Laser current monitor voltage input 10 NC – No connection (must be open) Laser drive current stop signal input LDOFF 11 LDOFF ip Laser drive state L Laser drive OFF In this state, the SM8610CV is in power-save mode. H Laser drive ON 12 LDIOUT o Laser drive current output 13 VCC – 2.4V supply voltage 14 RG2 o Laser control loop gain setting resistor connection 15 NC – No connection (must be open) 16 RG1 o Laser control loop gain setting resistor connection ip: Built-in pull-down resistor NIPPON PRECISION CIRCUITS INC.—3 SM8610CV SPECIFICATIONS Absolute Maximum Ratings Parameter Symbol Rating Unit Supply voltage VCC − 0.5 to 7.0 V Input voltage VIN − 0.5 to VCC + 0.5 V Input current IIN − 3.0 to + 3.0 mA Operating temperature TOPR − 20 to 70 °C Storage temperature TSTG − 40 to 125 °C PW 96 mW Power dissipation DC Electrical Characteristics VCC = 2.3V, Ta = + 25 °C unless otherwise noted Rating Parameter Guaranteed operating supply voltage Current consumption Symbol Unit Test level – V I 4.9 6.2 mA I – 30 µA I Condition min typ max 2.3 2.5 ICC1 VCC = 2.5V, PDVIN = 0V, RLDISET = 47kΩ, RG = 33kΩ, LDOFF = HIGH, Excluding LDIOUT current – ICC2 LDOFF = LOW – VCC Input Specifications VCC = 2.3V, Ta = + 25 °C unless otherwise noted Rating Parameter Symbol Condition Unit min typ max PCK HIGH-level voltage VIHPCK VCC × 0.7 – – V PCK LOW-level voltage VILPCK – – VCC × 0.3 V PCK HIGH-level sink current IHPCK – – 20 µA LDOFF HIGH-level voltage VIHLDOFF VCC × 0.7 – – V LDOFF LOW-level voltage VILLDOFF – – VCC × 0.3 V LDOFF HIGH-level sink current IHLDOFF – – 20 µA FLOCK HIGH-level voltage VIHFLOCK VCC × 0.7 – – V FLOCK LOW-level voltage VILFLOCK – – VCC × 0.3 V FLOCK HIGH-level sink current IHFLOCK – – 20 µA MUTE HIGH-level voltage VIHDMUTE VCC × 0.7 – – V MUTE LOW-level voltage VILDMUTE – – VCC × 0.3 V MUTE HIGH-level sink current IHDMUTE – – 20 µA NIPPON PRECISION CIRCUITS INC.—4 SM8610CV Electrical Characteristics VCC = 2.3V, Ta = + 25 °C unless otherwise noted Rating Parameter Symbol Condition min typ max Unit Test level PCK minimum input frequency fPCKMIN – – 4.3 MHz I PCK maximum input frequency fPCKMAX 13 – – MHz I Laser switching frequency range fLD 8.6 – 26 MHz I LDOFF response time 1 tLDOFF1 LDOFF HIGH → LOW – 12 15 µs III LDOFF response time 2 tLDOFF2 LDOFF LOW → HIGH – – 15 µs III FLOCK response time 1 tFLOCK1 FLOCK HIGH → LOW DMUTE = LOW – – 15 ns III FLOCK response time 2 tFLOCK2 FLOCK LOW → HIGH DMUTE = LOW – – 15 ns III DMUTE response time 1 tDMUTE1 DMUTE HIGH → LOW FLOCK = HIGH – – 15 ns III DMUTE response time 2 tDMUTE2 DMUTE LOW → HIGH FLOCK = HIGH – – 15 ns III LDIOUT maximum output current ILDMAX RLD = 27kΩ, RG = 33kΩ, V(PDVIN) = DC, 0V fixed 40 – – mA I LDIOUT rise time trLDIOUT – – 15 ns III LDIOUT fall time tfLDIOUT – – 15 ns III LDISET voltage VLDISET – 1/3VCC V I PDVIN convergence voltage VPDVIN 150 – 180 mV I PDVIN input impedance ZPDVIN 1 – – MΩ I RG = 3kΩ, CG = 1000pF – 53 – kHz I APC loop cutoff frequency fAPC RG = 33kΩ, VCC = 2.5V Minimum duty ratio Dutymin PCK = 13MHz, RDUTY = 15kΩ – 26 – % I Maximum duty ratio Dutymax PCK = 4.3MHz, RDUTY = 3kΩ – 69 – % III – 15 – ns III Minimum LD pulsewidth TLDON Note 1) LDOFF has internal pull-down resistor. Note 2) FLOCK has internal pull-down resistor. Note 3) DMUTE has internal pull-down resistor. Note 4) LDISET is in high-impedance state when LDOFF is HIGH. Note 5) DUTYADJ is in high-impedance state when LDOFF is HIGH. Test level description Test level I 100% of devices tested at 25°C Test level II Samples tested only Test level III Specifications guaranteed according to design and evaluation tests. Test level IV Parameter typical values only guaranteed. NIPPON PRECISION CIRCUITS INC.—5 SM8610CV FUNCTIONAL DESCRIPTION LD Driver Control The laser diode is controlled by 3 logic-level input signals: LDOFF, FLOCK, and MUTE. When LDOFF is HIGH, the laser diode driver is ON, and the mode is controlled by FLCOK and MUTE. When LDOFF is LOW, the laser diode drive is OFF and the IC is in power-save mode (LDIOUT output current = 0mA). The LD has a chopper drive input when FLOCK is HIGH and MUTE is LOW. Table 1. Laser diode control signals LDOFF FLOCK MUTE Laser drive state H L L LDIOUT constant-current output H L H LDIOUT constant-current output H H L LDIOUT chopper current output H H H LDIOUT constant-current output L × × LDIOUT = 0mA (power-save mode) Note) × : Don’t care. Pulsewidth Adjust and Frequency Multiplication Function The SM8610CV internal waveform processor multiplies the PCK input signal frequency by 2, and the pulsewidth of this signal can be adjusted to control the duty ratio. PCK I(LDIOUT) large current a b duty ratio (a/b) control The output pulse current (LD chopper signal) on LDIOUT is automatically adjusted to maintain roughly constant duty ratio, even for changes in frequency. The LD chopper signal duty ratio can be adjusted by changing the resistance RDUTY connected between the DUTYADJ and GND pins, as given by the following equation. 3 V(DUTYADJ) 22[kΩ] − 2 × RDUTY × 100 [%] × 100 = dutyratio = 1− 2 1 VCC(≈Vth) RDUTY + 22[kΩ] 2 V(DUTYADJ) = RDUTY × VCC [V] RDUTY + 22[kΩ] RDUTY : DUTYADJ connected resistance [kΩ] NIPPON PRECISION CIRCUITS INC.—6 SM8610CV Laser Diode Drive Current Mid-value Set Function The laser diode drive current mid-value can be adjusted by changing the resistance RLD connected between the LDISET and GND pins. The laser diode drive current mid-value base value ILDSET, given by the following equation, is set to the LDIOUT output current when the PDVIN voltage is in balance state (147 to 193mV). Note that the actual LDIOUT current may change due to feedback gain, and laser diode/photo diode variations. ILDSET = ILDSET × 1000 = 800[V] [A] RLD RLD : LDISET connected resistance [Ω] APC Loop Gain Setting The APC (Auto Power Control) loop gain can be adjusted by changing the external gain set resistance (RG) connected between the RG1 and RG2 pins. The PDVIN voltage-to-laser drive current open-loop gain is given approximately by the following equation. GmPDVIN = 9.1 × 10 −5 RG [S] ∆LDIOUT current /∆PDVIN voltage ratio [S] RG : Resistance connected between RG1 and RG2 [Ω] APC Loop Cutoff Frequency Setting The APC loop cutoff frequency fc is determined by the external resistance RG and the capacitance CG, connected between RG1 and RG2. fC1 = 1 2πRGCG [Hz] If CG is connected between RG2 and VCC, the cutoff frequency is given as follows. fC2 = 1 [Hz] 2√ 2πRGCG NIPPON PRECISION CIRCUITS INC.—7 SM8610CV TYPICAL PERFORMANCE CHARACTERISTICS Conditions: VCC = 2.4V, RLD = 12kΩ, RDUTY = 2.5kΩ, RG = 2.5kΩ APC loop cut-off frequency (CG = 0.01µF) Output duty ratio -10 100 90 -15 RDUTY = 3kΩ 80 RDUTY = 5.6kΩ -20 RDUTY = 15kΩ 70 duty ratio [%] Gain [dB] -25 -30 -35 60 50 40 30 -40 20 -45 10 -50 100 1000 10000 100000 0 1.00E+06 1000000 frequency [Hz] 1.00E+07 1.00E+08 1.00E+09 frequency [Hz] Open loop gain and LDIOUT maximum output current (RLDIOUT = 20Ω) 0.08 0.07 SM8610 0.06 LDIOUT [A] 0.05 0.04 LDIOUT 0.03 RLDIOUT 0.02 0.01 0.00 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 PDVIN [V] NIPPON PRECISION CIRCUITS INC.—8 SM8610CV NIPPON PRECISION CIRCUITS INC. reserves the right to make changes to the products described in this data sheet in order to improve the design or performance and to supply the best possible products. Nippon Precision Circuits Inc. assumes no responsibility for the use of any circuits shown in this data sheet, conveys no license under any patent or other rights, and makes no claim that the circuits are free from patent infringement. Applications for any devices shown in this data sheet are for illustration only and Nippon Precision Circuits Inc. makes no claim or warranty that such applications will be suitable for the use specified without further testing or modification. The products described in this data sheet are not intended to use for the apparatus which influence human lives due to the failure or malfunction of the products. Customers are requested to comply with applicable laws and regulations in effect now and hereinafter, including compliance with export controls on the distribution or dissemination of the products. Customers shall not export, directly or indirectly, any products without first obtaining required licenses and approvals from appropriate government agencies. NIPPON PRECISION CIRCUITS INC. 4-3, Fukuzumi 2-chome, Koto-ku, Tokyo 135-8430, Japan Telephone: +81-3-3642-6661 Facsimile: +81-3-3642-6698 http://www.npc.co.jp/ Email: [email protected] NC0102AE 2001.07 NIPPON PRECISION CIRCUITS INC.—9