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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
I I I I I I I
PINOUT
(Top view)
I
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
LDISET NC MUTE PCK DUTYADJ FLOCK NC GND
1
16
RG1 NC RG2 VCC LDIOUT LDOFF NC
APPLICATIONS
I
Portable CD player
8
9
PDVIN
ORDERING INFORMATION
Device SM8610CV Package 16-pin VSOP
PACKAGE DIMENSIONS
(Unit: mm) Weight: 0.07g
4.4 0.2 6.4 0.2
0.10 0.05
5.1 0.2
1.15 0.1
0.275typ
0.15 -
+ 0.1 5 0.0
0 to 10
0.65
0.10 0.22 - 0.05
+ 0.1
0.12 M
0.5 0.2
NIPPON PRECISION CIRCUITS INC.--1
SM8610CV
BLOCK DIAGRAM
VCC LDISET LDOFF FLOCK DMUTE Processor LDIOUT RLD Pick-up
PCK
2 multiplier
Pulse control logic
Laser diode driver
DUTYADJ RDUTY
Duty rate adjustor
Feedback V-I amplifier
PDVIN
GND RG1 RG CG RG2
NIPPON PRECISION CIRCUITS INC.--2
SM8610CV
PIN DESCRIPTION
Number 1 2 Name LDISET NC i/o o - Description Laser drive maximum current setting resistor connection No connection (must be open) Muting signal DMUTE 3 MUTE ip L H 4 5 PCK DUTYADJ i o Laser switching drive Laser constant-current drive Laser drive state
Data extract clock input Laser switching pulse duty adjust Focus servo lead-in signal FLOCK Laser drive state Laser constant-current drive Laser switching drive
6
FLOCK
ip
L H
7 8 9 10
NC GND PDVIN NC
- - i -
No connection (must be open) Ground connection Laser current monitor voltage input No connection (must be open) Laser drive current stop signal input LDOFF Laser drive state Laser drive OFF In this state, the SM8610CV is in power-save mode. Laser drive ON
11
LDOFF
ip
L H
12 13 14 15 16
LDIOUT VCC RG2 NC RG1
o - o - o
Laser drive current output 2.4V supply voltage Laser control loop gain setting resistor connection No connection (must be open) Laser control loop gain setting resistor connection
ip: Built-in pull-down resistor
NIPPON PRECISION CIRCUITS INC.--3
SM8610CV
SPECIFICATIONS
Absolute Maximum Ratings
Parameter Supply voltage Input voltage Input current Operating temperature Storage temperature Power dissipation Symbol VCC VIN IIN TOPR TSTG PW Rating - 0.5 to 7.0 - 0.5 to VCC + 0.5 - 3.0 to + 3.0 - 20 to 70 - 40 to 125 96 Unit V V mA C C mW
DC Electrical Characteristics
VCC = 2.3V, Ta = + 25 C unless otherwise noted
Rating Parameter Guaranteed operating supply voltage Symbol Condition min VCC VCC = 2.5V, PDVIN = 0V, RLDISET = 47k, RG = 33k, LDOFF = HIGH, Excluding LDIOUT current LDOFF = LOW 2.3 typ 2.5 max - V Unit Test level I
Current consumption
ICC1
-
4.9
6.2
mA
I
ICC2
-
-
30
A
I
Input Specifications
VCC = 2.3V, Ta = + 25 C unless otherwise noted
Rating Parameter PCK HIGH-level voltage PCK LOW-level voltage PCK HIGH-level sink current LDOFF HIGH-level voltage LDOFF LOW-level voltage LDOFF HIGH-level sink current FLOCK HIGH-level voltage FLOCK LOW-level voltage FLOCK HIGH-level sink current MUTE HIGH-level voltage MUTE LOW-level voltage MUTE HIGH-level sink current Symbol VIHPCK VILPCK IHPCK VIHLDOFF VILLDOFF IHLDOFF VIHFLOCK VILFLOCK IHFLOCK VIHDMUTE VILDMUTE IHDMUTE Condition min VCC x 0.7 - - VCC x 0.7 - - VCC x 0.7 - - VCC x 0.7 - - typ - - - - - - - - - - - - max - VCC x 0.3 20 - VCC x 0.3 20 - VCC x 0.3 20 - VCC x 0.3 20 V V A V V A V V A V V A Unit
NIPPON PRECISION CIRCUITS INC.--4
SM8610CV
Electrical Characteristics
VCC = 2.3V, Ta = + 25 C unless otherwise noted
Rating Parameter PCK minimum input frequency PCK maximum input frequency Laser switching frequency range LDOFF response time 1 LDOFF response time 2 FLOCK response time 1 FLOCK response time 2 DMUTE response time 1 DMUTE response time 2 LDIOUT maximum output current LDIOUT rise time LDIOUT fall time LDISET voltage PDVIN convergence voltage PDVIN input impedance APC loop cutoff frequency Minimum duty ratio Maximum duty ratio Minimum LD pulsewidth Symbol fPCKMIN fPCKMAX fLD tLDOFF1 tLDOFF2 tFLOCK1 tFLOCK2 tDMUTE1 tDMUTE2 ILDMAX trLDIOUT tfLDIOUT VLDISET VPDVIN ZPDVIN fAPC Dutymin Dutymax TLDON RG = 3k, CG = 1000pF PCK = 13MHz, RDUTY = 15k PCK = 4.3MHz, RDUTY = 3k RG = 33k, VCC = 2.5V LDOFF HIGH LOW LDOFF LOW HIGH FLOCK HIGH LOW DMUTE = LOW FLOCK LOW HIGH DMUTE = LOW DMUTE HIGH LOW FLOCK = HIGH DMUTE LOW HIGH FLOCK = HIGH RLD = 27k, RG = 33k, V(PDVIN) = DC, 0V fixed Condition min - 13 8.6 - - - - - - 40 - - - 150 1 - - - - typ - - - 12 - - - - - - - - 1/3VCC - - 53 26 69 15 180 - - - - - max 4.3 - 26 15 15 15 15 15 15 - 15 15 MHz MHz MHz s s ns ns ns ns mA ns ns V mV M kHz % % ns Unit Test level I I I III III III III III III I III III I I I I I III III
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 Test level II Test level III Test level IV 100% of devices tested at 25C Samples tested only Specifications guaranteed according to design and evaluation tests. 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 H H H H L Note) x : Don't care. FLOCK L L H H x MUTE L H L H x Laser drive state LDIOUT constant-current output LDIOUT constant-current output LDIOUT chopper current output LDIOUT constant-current output LDIOUT = 0mA (power-save mode)
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) a b duty ratio (a/b) control
large current
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[k] - 2 x RDUTY x 100 [%] x 100 = dutyratio = 1- 2 1 VCC(Vth) RDUTY + 22[k] 2 V(DUTYADJ) = RDUTY x VCC [V] RDUTY + 22[k]
RDUTY : DUTYADJ connected resistance [k]
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 x 1000 =
800[V] [A] RLD
RLD : LDISET connected resistance []
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 x 10 -5 RG [S]
LDIOUT current /PDVIN voltage ratio [S] RG : Resistance connected between RG1 and RG2 []
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 2RGCG
[Hz]
If CG is connected between RG2 and VCC, the cutoff frequency is given as follows.
fC2 =
1 [Hz] 2 2RGCG
NIPPON PRECISION CIRCUITS INC.--7
SM8610CV
TYPICAL PERFORMANCE CHARACTERISTICS
Conditions: VCC = 2.4V, RLD = 12k, RDUTY = 2.5k, RG = 2.5k
APC loop cut-off frequency (CG = 0.01F)
-10 -15 -20
Output duty ratio
100 90 80 70 duty ratio [%] RDUTY = 3k RDUTY = 5.6k RDUTY = 15k
-25 Gain [dB] -30 -35 -40
60 50 40 30 20
-45 -50 100
10 1000 10000 frequency [Hz] 100000 1000000 0 1.00E+06
1.00E+07
1.00E+08
1.00E+09
frequency [Hz]
Open loop gain and LDIOUT maximum output current (RLDIOUT = 20)
0.08
0.07
0.06
SM8610
0.05 LDIOUT [A]
0.04
LDIOUT
0.03 0.02
RLDIOUT
0.01
0.00 0 0.05 0.1 0.15 0.2 PDVIN [V] 0.25 0.3 0.35 0.4
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: sales@npc.co.jp
NC0102AE 2001.07
NIPPON PRECISION CIRCUITS INC.--9

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