1/9 www.rohm.com 2010.06 - rev.a ? 2010 rohm co., ltd. all rights reserved. class-ab speaker amplifiers 2w + 2w stereo speaker / headphone amplifier bh7881efv description the bh7881efv is a low voltage, low noise, high output speaker /headphone amplifier ic, in which a bi-cmos process is used. an on-chip speaker amplifier circuit that is capabl e of 2w+2w output can be used as a headphone amplifier by switching the operating mode. this makes it possible to co nfigure an audio system using few external devices. with a built-in, low saturation regulator with programmable output voltage and outpu t current, clear tone quality is obtained even when directly connected to a digital power supply. a peri pheral analog circuit can also be regulator driven. furthermore , the bh7881efv provides speaker output and vreg output short-circuit detection functi ons, a thermal shutdown function with hysteresis, and a speaker protection function. features 1) built-in low saturation type regulator (digital power supp ly driver, voltage and current variable, short circuit detection) 2) bass boost mode, gain switching functions 3) speaker mute function (headphone mode) 4) built-in line amplifier output (gain adjustment, lpf setting) active/suspend function (ttl input control pin) 5) hysteretic thermal shutdown function (set for approximately 150 /90 ) 6) ic protection function (sp pin vcc/gnd short circuit detection) 7) speaker protection function (o utput voltage amplitude control) applications notebook computers, lcd tvs, etc. absolute maximum ratings (ta=25 ) parameter ratings unit supply voltage +6.0 v power dissipation 1100 *1 mw storage temperature -55 +125 operating temperature -10 +70 *1 reduced by 11 mw/ at 25 or higher, when mounting on a 70mmx70mmx1.6mm pcb board). operating conditions (ta=25 ) parameter ratings unit supply voltage +3.3 +5.5 v * this ic is not designed to be radiation-resistant. no.10077eat05
technical note 2/9 www.rohm.com 2010.06 - rev.a ? 2010 rohm co., ltd. all rights reserved. bh7881efv electrical characteristics (unless otherwise noted, vcc=3.3v,ta=25 ,f=1khz,r=4 ? ,400hz 30khzbpf) parameter limits unit conditions min. typ. max. 1chip circuit current (active) - 18 30 ma no signal circuit current(suspend) - 0 10 a no signal sp amp voltage gain1 8.5 11.0 13.5 db se,vin=-18dbv voltage gain 2 14.5 17.0 19.5 db btl,vin=-18dbv distortion - 0.04 1.0 % btl,vin=-18dbv maximum output level 1.5 4.5 - dbv btl,dstn=1% output noise level - -90 -80 dbv se,din-audio cross talk - -85 -75 dbv se,din-audio output level on mute - -110 -80 dbv btl,vin=-18dbv hp amp voltage gain 3.0 5.5 8.0 db se,vin=-18dbv,r l =32 ? distortion - 0.02 1.0 % se,vin=-18dbv,r l =32 ? maximum output level -1.6 1.4 - dbv se,dstn=1% ,r l =10k ? output noise level - -95 -80 dbv se,din-audio ,r l =32 ? cross talk - -90 -80 dbv se,din-audio ,r l =32 ? output level on mute - -105 -80 dbv se,vin=-18dbv,r l =32 ? bias output voltage 1.40 1.65 1.90 v no signal regulator output voltage 2.7 3.0 - v no signal psrr - -80 - dbv v in =0.28vpp,1khz control pin actv/spnd ctrl 2pin control pin suspend mode vcc/3+0.8 - vcc v sp/hp® suspend active mode 0 - 0.8 v sp/hp® active sp/hp ctrl 12pin control pin sp&hp mode vcc/3+0.8 - vcc v sp/hp on hp(sp mute) mode 0 - 0.8 v sp off(sp mute),hp on bassboost ctrl 11pin control pin bass-boost mode vcc/3+0.8 - vcc v sp/hp gain up non-boost mode 0 - 0.8 v sp/hp gain normal
technical note 3/9 www.rohm.com 2010.06 - rev.a ? 2010 rohm co., ltd. all rights reserved. bh7881efv block diagram fig.1 control pin descriptions 1. active/suspend:2pin control input mode function h suspend suspended state (except reg) l active active state when suspended, the regulator (reg) is in an active state and the sp/hp/line amplifier is in a suspended state. originally, signals from input resistance and feedback resistance leaked into the speaker output even when suspended, because of the series connection of an inverting amplifier. however, sinc e the signals are cut off on their way in this ic, signal leaks d o not occur in speaker output. (signals due to feedb ack resistance are output in line amplifier output.) 2. power level:8pin control input mode function h limiter h 3vf peak limiter on (output approx. 1.25 w) open limiter l 2vf peak limiter on(output approx .0.70w) l limiter off limiter off *vcc=5v,rl=4ohm,vin=-8dbv since a limiter uses diode characteristics, it has temperature characteristics. on the high temperature side, amplitude tends to decrease, which is a characte ristic that protects the ic. since setting in speaker mode is a ssumed, it is ineffective (limi ter off) in headphone mode. moreover, precautions must be ta ken when input is so great, that output becomes a square wave, since this could cause local oscillation. 3. bassboost on/off:11pin control input mode function h on bassboost:on l off bassboost:off the capacitor that constitutes bassboost is elim inated, and also functi ons as a gain switch. 4. sp/hp:12pin control input mode function h sp+hp sp:on, hp:on l hp sp:off,hp:on by using the headphone mode in a speaker mute mode, it is possible to completely cut off the pop noise when switching when vcc on or off, or to actv or spnd. for cont rol sequence and other information, see the following pages. *not all control pins have pull up or pull internal resistors. therefore add pull up or pull down resistors, accordingly (pin8 is an exception.)
technical note 4/9 www.rohm.com 2010.06 - rev.a ? 2010 rohm co., ltd. all rights reserved. bh7881efv description of operations 1. line amplifier 1) the voltage gain of the line amplifier is calculated by the following equations: gain = 20 log(68k/r4 +1k)) [db] gain = 20 log(68k/r9 +1k)) [db] r4 and r9 are resistances connected to pin4 and pin9 2) in order to make it operable with mixing input, the line amplifier can be realized by connecting multiple resistors to pin4 and pin9. since the input pin is al so the feedback of an inverti ng differential amplifier, each individual signal is simply added. 3) to configure lpf and remove unnecessary frequency com ponents, the line amplifier can be realized by connecting capacitors between pin3 and pin4, and between pin9 and pin10. the lpf cut-off frequency at that time is calculated by the following equation: fc = 1/(2 c 68k) [hz] 2. sp amplifier (hp amplifier) 1) the voltage gain of the sp amplifier for non-boost is about 12 [db] (se: single end). 2) the voltage gain of the sp amplifier for bass- boost is calculated by the following equations: gain = 20 log((40k+r22-23)/10k) [db] where r22-23 is the resistance connected between pin22 and pin23. gain = 20 log((40k+r14-15)/10k) [db] where r14-15 is the resistance connected between pin14 and pin15. 3) the cut-off frequency for bass-boost is calculated by the following equations: fc = 1/(2 c22-23 r22-23) [hz] where rc22-23 is connected between pin22 and pin23. fc = 1/(2 c14-15 r14-15) [hz] where rc14-15 is connected between pin14 and pin15. 4) apply power to rchvcc (pin13), for mono only. 3. regulator 1) the reg output voltage is calculated by the follo wing equation, and numeric values are shown below: v = 1.15 [v] (1+r(vlev)/r(vref)) [v] reg setting voltage 3.0 3.3 3.6 4.0 4.6 v supply voltage(vcc) 3.3 3.6 4.0 5.0 5.0 v r(vlev) 30k 30k 30k 30k 30k ? r(vref) 18k 16k 14k 12k 10k ? use 1% resistors to eliminate errors in actual output voltages. 2) the reg maximum output current is determined by the exte rnal tr capability (hfe) of the ic. if more current is necessary, select one icmax with large hfe. dr ive output current to the base is about 5 ma. 3) when using the regulator, connect reg out put to pin6. the line amplifier, bias , and other sections essential to tone quality, are driven by the reg voltage. clear sound output is obtained even if a digital power supply is the vcc. 4) when using the regulator for an applic ation, other than this ic, and driving t he ic by vcc only, apply vcc at pin6. 5) when not using the regulator , it is set to off mode by connecting pin 19 to open and pin18 to open. apply vcc at pin6. 6) do not set a vcc applied voltage that is smaller than the set voltage of the regulator. since the reg output transistor operates in a saturation region, an abnormal circuit current occurs. 7) for the reg output transistor, rohm trans istors 2sa1900 and 2sa933 are recommended.
technical note 5/9 www.rohm.com 2010.06 - rev.a ? 2010 rohm co., ltd. all rights reserved. bh7881efv 4. short circuit detection 1) overview of sp amplifier vcc/gnd short circuit detection. if the output pin of the sp amplifier is short circuited to vc c or gnd, the detection function operates to suspend the output stage of the sp amplifier. if the sp output pin is short circuited to reg output, the detection function does not oper ate. it is conf igured so that it resets automatically if the short circui t is canceled. moreover, although a short circuit is detected from the dc voltage of the output pin, and there is a short delay distinguishing it from maximum out put amplitude, malfunction may occur due to factors such as power supply voltage and load. in this case, connect ?pin7? to gnd. the short circuit function is set to the off mode. 2) sp amplifier vcc/gnd short circuit detection cautions when the output pin of the sp amplifier is short circuited with vcc or gnd, exce ssive current flows in the ic and stress is applied to the chip. accordingly, if it is shorted a number of times, the ic gradually deteriorates and is finally destroyed. the short circuit detection function does not guarantee operation after numerous shorts. 3) regulator short circuit detection if the output pin of the r egulator is short circuited to gnd, the detection function operat es to suspend the output stage of the regulator. if t he output pin of the regulator is short circuited to vcc, an abnormal current does not occur in any circuit. after the short circuit, the regulator resets autom atically, due to the pull-up re sistance (for example, 2.2 k ? ) connected to pin1, as shown in the full option example of the sample application circuit. (example: 3.9 k is the resistance load for lowering the output im pedance of the regulator when it is no load.) 5. pop noise 1) the following table shows the sequence for eliminating the pop noise that occurs from turning the power supply on or off, or turning control pins on or off. order vcc act/spnd sp/hp conditions 1 off suspend hp power supply on 2 on suspend hp turning on in the suspend 3 on active hp sp mute countermeasure 4 on active sp+hp mute cancellation operation 5 on active sp+hp operation 6 on active hp sp mute counter measure 7 on suspend hp turning off in the suspend 8 off suspend hp power supply off 2) in speaker mute state, pop noise does not occur even when starting or changing modes. it is recommended to use speaker mute (headphone) mode during conditions where pop noise can occur. 3 ) any changes of the components values in the sample appli cation circuit can the effect the pop noise cut-off function. 6. bypass and bias capacitor 1) although this ic is designed so that bypass capacitors are not needed, when bypass capacitors are in fact necessary, place them close to the vcc~gnd pins. 2) similarly, place a bias capacitor close to the gnd pin. 7. capacitive load drive 1) do not connect a capacitive load to the sp amplifier, hp am plifier, or ic pin. there is a possibility of oscillation. 2) adding rc to the hp amplifier output, as in the sample application circuit, makes the output noise, voltage, and distortion sensitive to oscillation.
technical note 6/9 www.rohm.com 2010.06 - rev.a ? 2010 rohm co., ltd. all rights reserved. bh7881efv 8. pop noise at start/end when switching actv/spnd pop noise can be suppressed by mode transition due to software as in ?pop noise? above, or by hardware as shown below. this is realized (in sp mode) by forcibly setting hp mode temporarily, using the cr differential circuit. fig.2 9. power package 1) in order to expand the power dissipation of the package, make the gnd pattern, directly below the ic, as wide as possible and solder the gnd pattern to the back of the ic. 2) power dissipation of the package varies greatly depending on fa ctors such as the number of layers, area, film thickness, and material quality of the board used. 10. other beween voltages of vcc=1.4 1.6 v, momentary oscillation sometimes is obser ved at the spout pin. nevertheless, this occurrence is not reproduced on a momentar y rise or fall of vcc. when slowly raising vcc pay attention to transient voltage. in order to avoid such occurrenc es, a sample circuit is illustrated below: fig.3
technical note 7/9 www.rohm.com 2010.06 - rev.a ? 2010 rohm co., ltd. all rights reserved. bh7881efv application circuit fig.4 minimum external components example fig.5 maximum external components example
technical note 8/9 www.rohm.com 2010.06 - rev.a ? 2010 rohm co., ltd. all rights reserved. bh7881efv operation notes 1. numbers and data in entries are representative desi gn values and are not guaranteed values of the items. 2. although rohm is confident that the example application circuit reflects the best possible recommendations, be sure to verify circuit characteristics for your particular application. modification of constants for other externally connected circui ts may cause variations in both static and transient characteristi cs for external components as well as this rohm ic. allow for sufficient margins when determining circuit constants. 3. absolute maximum ratings use of the ic in excess of absolute maximum ratings, such as the applied voltage or operating temperature range (topr), may result in ic damage. assumptions should not be made r egarding the state of the ic (short mode or open mode) when such damage is suffered. a physical safety measure, such as a fuse, should be implemented when using the ic at times where the absolute maximum ratings may be exceeded. 4. gnd potential ensure a minimum gnd pin potential in all operating conditions. ma ke sure that no pins are at a voltage below the gnd at any time, regardless of whether it is a transient signal or not. 5. thermal design perform thermal design, in which there are adequate margins, by taking into account the permissible dissipation (pd) in actual states of use. 6. short circuit between terminals and erroneous mounting pay attention to the assembly direction of the ics. wrong m ounting direction or shorts between terminals, gnd, or other components on the circuits, can damage the ic. 7. operation in strong electromagnetic field using the ics in a strong electromagnetic field can cause oper ation malfunction.
technical note 9/9 www.rohm.com 2010.06 - rev.a ? 2010 rohm co., ltd. all rights reserved. bh7881efv ordering part number b h 7 8 8 1 e f v - e 2 part no. part no. package efv: htssop-b24 packaging and forming specification e2: embossed tape and reel (unit : mm) htssop-b24 0.65 1.0max 0.850.05 0.080.05 0.24 +0.05 - 0.04 0.08 m s 0.08 1.00.2 0.530.15 0.17 +0.05 - 0.03 4 + 6 ? 4 s 24 13 112 0.325 (3.4) (5.0) 7.80.1 7.60.2 5.60.1 (max 8.15 include burr) 1pin mark ? order quantity needs to be multiple of the minimum quantity. embossed carrier tape (with dry pack) tape quantity direction of feed the direction is the 1pin of product is at the upper left when you hold reel on the left hand and you pull out the tape on the right hand 2000pcs e2 () direction of feed reel 1pin
r1010 a www.rohm.com ? 2010 rohm co., ltd. all rights reserved. notice rohm customer support system http://www.rohm.com/contact/ thank you for your accessing to rohm product informations. more detail product informations and catalogs are available, please contact us. notes no copying or reproduction of this document, in part or in whole, is permitted without the consent of rohm co.,ltd. the content specied herein is subject to change for improvement without notice. the content specied herein is for the purpose of introducing rohm's products (hereinafter "products"). if you wish to use any such product, please be sure to refer to the specications, which can be obtained from rohm upon request. examples of application circuits, circuit constants and any other information contained herein illustrate the standard usage and operations of the products. the peripheral conditions must be taken into account when designing circuits for mass production. great care was taken in ensuring the accuracy of the information specied in this document. however, should you incur any damage arising from any inaccuracy or misprint of such information, rohm shall bear no responsibility for such damage. the technical information specied herein is intended only to show the typical functions of and examples of application circuits for the products. rohm does not grant you, explicitly or implicitly, any license to use or exercise intellectual property or other rights held by rohm and other parties. rohm shall bear no responsibility whatsoever for any dispute arising from the use of such technical information. the products specied in this document are intended to be used with general-use electronic equipment or devices (such as audio visual equipment, ofce-automation equipment, commu- nication devices, electronic appliances and amusement devices). the products specied in this document are not designed to be radiation tolerant. while rohm always makes efforts to enhance the quality and reliability of its products, a product may fail or malfunction for a variety of reasons. please be sure to implement in your equipment using the products safety measures to guard against the possibility of physical injury, re or any other damage caused in the event of the failure of any product, such as derating, redunda ncy, re control and fail-safe designs. rohm shall bear no responsibility whatsoever for your use of any product outside of the prescribed scope or not in accordance with the instruction manual. the products are not designed or manufactured to be used with any equipment, device or system which requires an extremely high level of reliability the failure or malfunction of which may result in a direct threat to human life or create a risk of human injury (such as a medical instrument, transportation equipment, aerospac e machinery, nuclear-reactor controller, fuel- controller or other safety device). rohm shall bear no responsibility in any way for use of any of the products for the above special purposes. if a product is intended to be used for any such special purpose, please contact a rohm sales representative before purchasing. if you intend to export or ship overseas any product or technology specied herein that may be controlled under the foreign exchange and the foreign trade law, you will be required to obtain a license or permit under the law.
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