SD7401 six-channel audio amplifier hangzhou silan microelectronics co.,ltd rev:1.0 2008.07.07 http://www.silan.com.cn page 1 of 7 block diagram ssop-20-225-0.65 description SD7401 is a 6-channel audio amplifier with built-in microphone input amplifier. high quality audio output is available through simple peripheral circuit and the amplifier gain can be adjusted flexibly by external resistor. it is widely used as pre-amplification in various multi-channel audio systems. features * bicmos technology * dual power supply (+5v/-12v) * built-in voltage regulation module * low distortion * standby function applications * audio amplification system, such as vcd/dvd * mute function * on/off pop noise suppression ordering information part no. package marking SD7401 ssop-20-225-0.65 SD7401
SD7401 absolute maximum ratings (unless otherwise specified, t amb = 25 c) characteristics symbol rating unit supply voltage (v cc -vss) v cc /v ss +6/-- 1 v operating temperature t opr -20~85 c storage temperature t stg -40~125 c note 1: tolerable voltage is decided by external resistor because of built-in voltag e regulator at negative power supply. electrical characteristic (unless otherwise specified, v cc = 5v, v ss = -12v, r l = 10k , t amb = 25 c, f = 1khz) characteristics symbol test condition min. typ. max. unit v cc -- 5 -- v operating voltage v ss -- -12 -- v i cc 2.0 2.2 2.5 ma operating current i ss external resistor 470 ? at negative power supply 14.7 14.8 14.9 ma standby current i stby stby_n connect tovss 550 600 640 a max. output voltage v omax fin=1khz; r l =10k ?; thd=0.1% 2.50 2.51 2.53 vrms audio amplitude response 20hz~20k hz, vo=2vrms 7.7 8.3 8.5 db voltage gain g no input resistor, thd=0.1% -- 11.5 -- db total harmonic distortion thd fin=1khz; r l =10k ?; vo=2vrms -- 0.05 0.06 db signal-noise ratio snr fin=1khz; r l =10k ?; vo=2vrms 75 76 78 db dynamic range dr fin=1khz, vin=-60db 78 79 80 db mute restrain mr fin=1khz; r l =10k ?; vo=2vrms 75 77 80 db channel separation ct fin=1khz; r l =10k ?; vo=2vrms 62 65 70 db channel balance cb fin=1khz; r l =10k ?; vo=2vrms -- -- 0.2 db input impedance r i fin=1khz, r l =10k ? -- 27.6 -- hangzhou silan microelectronics co.,ltd rev:1.0 2008.07.07 http://www.silan.com.cn page 2 of 7
SD7401 pin configuration pin description pin no. pin name i/o pin description 1 v cc -- positive power supply 2 pmute i/o pop restrain control 3 mic in i microphone input 4 mute i mute control 5 cent in i center input 6 ls in i left surround input 7 l in i left channel input 8 r in i right channel input 9 sub in i subwoofer input 10 rs in i right surround input 11 rs out o right surround output 12 sub out o subwoofer output 13 r out o right channel output 14 l out o left channel output 15 ls out o left surround output 16 cent out o center output 17 mic out o microphone output 18 stby_n i standby control 19 v ss -- negative power supply 20 gnd -- ground hangzhou silan microelectronics co.,ltd rev:1.0 2008.07.07 http://www.silan.com.cn page 3 of 7
SD7401 function description 1. channel amplifier the second-order filter structure shown as above is adopted for 6-channel audio amplifier, with in-band gain of about 12db and -3db bandwidth of 40khz above which is well meet audio requ irements. as principle structure, in-band gain is decided by: hangzhou silan microelectronics co.,ltd rev:1.0 2008.07.07 http://www.silan.com.cn page 4 of 7 1 2 r r g ?= , thus, gain can be adjusted by changing r1. 2. microphone amplifier + - r1 r2 c v cc v ss micin micout agnd the proportional amplifier shown as above is adopted fo r microphone amplifier with setting gain of about 29db, and capacitor c is used for high frequency signal filteri ng. as described above, the gain can be also adjusted by changing r1. 3. mute & on/off pop noise control mute control pin (pin 4) controls 6-channel as mute by internal switches. it comes to mute mode when pin 4 is
SD7401 connected to vcc (high level) and comes to normal mode when connected to ground. pin 2 is used for pop noise restrain by connecting an external capacitor which can be increased appropriately for better pop noises restrain effect. in general, pop noise restrain is re alized by mute control. mute pulse is generated when turned on for zero output and ended afte r powered on for normal output; mute pulse is also generated when power supply is threshold value below during turned off for zero output. thus, pop noise is restrained during power on/down. 4. power supply the built-in voltage regulator for negative power supply is shown as below. an external resistor r guarantees voltage stability near -5 v on pin 19 and the chip po wer supply is 5v for normal operation. because the negative power to provide current is decided by this re sistance, if the system output is light load, this resistance can be properly increased to reduce operate current, but the voltage of pin 19 must be maintained and can not drop significantly. 5. system standby the pin stby_n controls system entering standby mode by turning off internal amplifier bias circuit. when this pin is connected to vss, system enters standby mode, and when floated, system works normally. note: internal voltage regulating circuit still wor ks in standby mode and supplies working current. hangzhou silan microelectronics co.,ltd rev:1.0 2008.07.07 http://www.silan.com.cn page 5 of 7
SD7401 typical application circuit hangzhou silan microelectronics co.,ltd rev:1.0 2008.07.07 http://www.silan.com.cn page 6 of 7
SD7401 package outline ssop-20-225-0.65 unit: mm 6.50 0.20 6.40 0.20 hangzhou silan microelectronics co.,ltd rev:1.0 2008.07.07 http://www.silan.com.cn page 7 of 7 1.45max 0.10 + 0.10 - 0.05 1.20 0.05 0.25 0.65 11 0 11 20 0.127 0 ? 8 - 0.04 + 0.08 0.60 0.15 4.40 0.10 mos devices operate notes: electrostatic charges may exist in many things. please take following preventive measures to prevent effectively the mos electric circuit as a result of the damage which is caused by discharge: z the operator must put on wrist strap which should be earthed to against electrostatic. z equipment cases should be earthed. ? z all tools used during assembly, including soldering tools and solder baths, must be earthed. z mos devices should be packed in antistatic/conductive containers for transportation. note silan reserves the right to make changes without notice in this specification for the improvement of the design and performance . silan will supply the best possible product for customers.
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