Ordering number: EN3534 No. 3534 | Monolithic Linear IC LA4571MB Low-voltage Headphone Amplifier for Stereo Audio OVERVIEW The LA457!1MB is a low-voltage, stereo headphone amplifier incorporating both tape head preamplifiers and headphone power amplifiers in a single chip, making it ideal for portable battery-powered equipment. It features logic-level controlled output signal muting, excellent noise characteristics and easy interconnection with sig- nal sources, such as an AM/FM tuner IC. The LA4571MB requires no input or output coupling capacitors. A buffer amplifier with 10 Q output imped- ance reduces the size of the virtual-earth decoupling capacitor. The preamplifier and power amplifier inputs only require the addition of an external capacitor to provide high-frequency noise filtering. The LA4571MB operates from a 3 V supply and is available in 20-pin MFPs. FEATURES * Stereo tape head preamplifiers and headphone power amplifiers on chip * Output signal muting * Low noise * 8 Q speaker driver * 3 supply * 20-pin MFP PINOUT prea@no [1 | ~ [20] VREF it [2 [19] we nei [3 | [35] NF2 preourt [4 | 17] PRE oUT2 swourt [| LA4571MB [18] swourz POWER INI [6 15] POWER IN2 PRE MuTE [7 14] POWER MUTE RFREF [8 | [13] oure veo [2 | fiz] ours Power Gnd [70 11] COMMON PACKAGE DIMENSIONS Unit: mm 3036B-MFP20 SANYO Electric Co.,Ltd. Semiconductor Business Headquarters TOKYO OFFICE Tokyo Bidg.,1-10,1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN . 3271TS (US) No.3534-1/10BLOCK DIAGRAM VAEF IN2 Reference LA4571MB PRE SW POWER POWER NF2 OUT2 8 6oUuT2 IN2 MUTE OUT2 OUT1 COMMON 1 1 1 it power ampifler power | amplifier preampitiod Channel 1 | exo TMT SU curt PNT Mure omer POND PIN DESCRIPTION Number Name Description i PRE GND Preamplifier ground 2 IN4 Channel 1 preamplifier input 3 NFt Channel preamplifier negative feedback input 4 PRE OUT1 Channel 1 preamplifier output 5 SW OUTI Channel 1 preamplifier mute-control switched output. Rin 2 500 ktz 6 POWER IN1 Channel 1 power amplifier input. Rin = 30kQ2 7 PRE MUTE Preamplifier mute controt 8 RF REF Ripple-filler capacitor connection 9 Voc Supply voltage 10 POWER GND Power amplifier ground 11 COMMON Common amplifier output 12 OUTI Channel 1 power amplifier output 13 OUT2 Channel 2 power amplifier output _A4 POWER MUTE Power amplifier mute control 15 POWER IN? Channel 2 power amplifier input. Riy = 30 ko 16 SW OUT2 Channel 2 preamplifier mute-control switched oulput. Rin 2 500 kQ 7 PRE OUT2 Channel 2 preamplifier output 18 NF2 Channel 2 preamplifier negative feedback input 19 IN2 Channel 2 preamplifier input 20 VREF Reference-voltage amplifier output. Imax = +500 pA No, 35342/10SPECIFICATIONS Absolute Maximum Ratings LA4571MB Parameter Symbol Rating Unit Supply voltage Veco max 45 V Power dissipation Pg max 400 mW Operating temperature range Topr -20 to 75 deg. C Storage temperature range Tatg -40 to 125 - deg. C Recommended Operating Conditions T, = 25 deg. C Parameter Symbal Rating Unit Supply voltage . Vee 3.0 Vv Supply voltage range Veo op 1.8 to 3.6 Vv Electrical Characteristics Preamplifler and power amplifier Vcc = 3.0 V, T, = 25 deg. C, f = 1 kHz, Ry (pre) 10 kQ, Ri (power) = 16 2, 0 dBm at 0.775 V unless otherwise noted Rating Parameter Symbol Condition Unit rin typ max Quiescent supply current * Neco Ry = 2.2 kO, Vi = OV - 7 a7 mA Total voltage gain VGr Vo = ~5 dBm 65 68 71 dB Preamplifier Vcc = 3.0 V, T, = 25 deg. C, f = 1 kHz, Ri (pre) = 10 kM, Ry (power) = 16 Q, 0 dBm at 0.775 V unless otherwise noted Rating - Parameler Symbol Condition Unit ; tain typ max Open-loop voltage gain VGg Vo = -5 dBm 70 80 - dB Closed-toop voltage gain VGy Vo = -5 dBm - 40 - a8 Maximum output voltage Vo max THD = 1%, Voc = 1.8 04 0.2 - V : A . Vo = 02 V, VG = 40 dB _ 4 Total harmonic distortion THD; (NAB standard) 0.05 05 Ms Ry = 2.2 kN, Input conversion noise vollage Vet bandwidth = 20 Hz to - 1.3 20 py 20 kHz Channel crosstalk ct; Ry = 2.2 kQ, 1 kHz tone 60 80 - dB a Ry = 2.2 KO, Voc = 1.8 Y, _ Ripple rejection Bra Vr = 20 dBm, f= 100 Hz 40 50 dB No, 3534--3/10Power amplifier LA4571MB Voc = 3.0 V, Ts = 25 deg. C, f = 1 kHz, Ru (pre) = 10 kQ, Ry (power) = 16 Q, 0 dBm at 0.775 V unless otherwise noted Rating Parameter Symbol Condition Unit min typ max Output power Py 23 32 - mW Closed-loop voltage gain VGz Vo = -5 dBm 25 28 31 dB Total harmonic distortion THD Pp = 1 mW - 0.4 10 % Channel crosstalk ctr Vo = 5 dBm, Ry= 02 30 40 - dB Ry = 0 0, Output noise voltage Vao bandwidth = 20 Hz lo - 24 40 By 20 kHz . _ Ry = 0 G, V; = -20 dBm, _ Ripple rejection Ria f= 100 Hz, Voc = 18 V 45 60 dB Input resistance Ri 22 30 38 kQ Output DC offset voltage Vos -90 - 90 mv Measurement clrcult 22ka A 22yF 27k 4700 pF 18 680kQ 1? 4 13 or power amplifier amplifier 2 Ppreampilfier Channel 1 Preamplifier 1 amplifier . No. 35944/10-Typlcal Performance Characteristics Preamplifier and power amplifier Maximum power dissipation vs. temperature boo 8 3 Maximum power Siealipatin (mi) 8 o 0-000 16 2 % 4 8 Ow 7H OO Ambient temperature (deg. C) Preamplifier Frequency response 100 8 1 Ba . (Opan loop: 51 In dosed, 62 le open 20 D a2 10 28 6 100 25 5 tk 29 8 10k 28 6 100k Frequency (Hx) Open-loop voltage galn vs. supply voltage 100 Ry -10 = RHE & + Opartoop voltage gain (8) Supply voltage (v) LA457iMB Quiescent supply current vs. supply voltage Ags 22k0__ vA-o0 Supply voltage [) Total harmonic distortion vs. output voltage 0 0.1 oz 663 OB Oo? Output voltage () Maximum cutput voltage vs. supply voltage fed kee =10 THO = 1% Bupply voltage () No, 35394-5/10LA4571MB Channel crosstalk vs. frequency . Output nolse voltage vs. supply voltage Voge SOV ipo 10m Bm ~22ko ya 22 = 10kh DIN AULEO (t= T kHz, O = 40 dB NAB} Ouiput noise yoltage Qi} oe B 100 28 BS tk 2 B 1th 2 6 100k Frequency (Ht) Bupply voltage (} Reference-voitage amplifier Output level vs. frequency Supply voltage rejection ratio vs. supply voltage . 11 Vege 90 so | Yn = 40 dan 10) & = Supply voltage rejection ria (63} 4s } 70 90) in (40) : Vo! Yn od x 100 po 20 ile Nin Yo todue _ BSE 100 Ea 775-058 -100 oTen ~(80} e 102 6 10 2 B th 2 & 1% 2 & 100k Frequency (Hz) Bupply voltage (V} Reference voltage vs. output current -2 -1 6 1 2 Qutput cus ont (InA} No. 35346/10Power ampllfier DC voltage vs. supply voltage 2 3 Supply vottage (V) Maximum output voltage vs. supply voltage Supply vonage () Frequency rasponse 10 2 a 100 2 6 tk 2 68 10k 2 5 100k Frequency (Hay Voltage gain vs. supply voltage AL = f6kA f= THz za} Yg= 720. dam Votage gain (dB) | LA4571MB Channel crosstalk vs. frequency Voge 20 VAeon Vg ==5 dam a m2 5 100 2 6 tk 2 B 1hk-2 6 100k Frequency (4x) Total harmonic distortion vs. supply voltage Po=tmw be thkHa LPF: @0 KHz Total remorse dlatortion {%) oO 2 4 5 6 5 Bupply vonage (V) Total harmonic distortlon vs. output power (1) & 7 10 2 4 & 7 100 aoa Outpt pownr (in) Total harmonle distortlon vs. output power (2) s Ff 10 2 8s B68 7 00 @ 3S 6B Output power (mi] No. 3534-7/10LA4571MB Output noise voltage vs. supply current 1 2 3 4 5 a Supply voltage rejection ratlo vs. supply voltage ao Supply volizge refecton rita (8) & FUNCTIONAL DESCRIPTION (channel 1 only) Tape Head Preamplifier Tape head signal sources are connected to the non-in- verting input of the op-amp, negative feedback pream- plifier. When PRE MUTE is open, the preamplifier output is connected to SW OUTI, and when PRE MUTE is HIGH (Vee +0.2 V at 60 WA input current), SW OUTI is open. This can be used to switch, or mute, the preamplifier output. The following figure shows a circuit with preamplifier muting which amplifies an audio signa! from an RF tuner, The internal circuit of the PRE MUTE pin is shown in the following figure. Preampitfier muting Vp a Mog - 0.2) 1, w6O pA when 6* 5.0 V The output pins, PRE OUT! and SW OUT], can both drive a 10 k& load resistance. The preamplifier input pin, IN1, the negative feedback input pin, NFI, and ihe output pin, PRE OUT1, are biased at 1.8 V. Power Amplifler The power amplifier stage comprises an amplifier for each channel and a common amplifier. The power amplifier outputs are connected internally by 60 resistors to prevent oscillation, as shown in the follow- ing figure. A fF A ATA Cheon 2 = Channel 1 Common or power amplifier opie: amplifier a When POWER MUTE is LOW (less than 0.3 V at 2.5 A input current), the power amplifier output signal is muted, The power amplifier mute release time is set by an external capacitor. No. 35348/10LA4571MB The internal circuit of the POWER MUTE pin is shown in the following figure. Power amplifier muting Vg 0.3 hg 326 pA The power amplifier input pin, POWER IN1, is biased at 1.8 V, and the output pins at 1.2 V. DESIGN NOTES The preamplifier inputs should be conriected to Veer through a 2.2 kQ resistor if there is no tape head input signal source. The mute release time capacitor of the power amplifier should be between 1.0 and 4.7 UF. For Ver = 3.0 V and C = 2.2 WF, the mute release time is 0.7 s. The ripple rejection ratio setting capacitor should be between 2.2 and 33 uF. For 2.2 yF, the ripple rejection raio is 35 dB, and for 22 pF, it is 55 dB. When the output amplifier turns OFF, the protection circuit shown in the following figure detects the falling Reference Voltage The input to the voltage reference amplifier is a voltage divided level from the supply voltage rippie filter. The reference voltage is given by 0.6 X Vcc. The supply voltage ripple filter requires the connection of an external filter capacitor to RF REF. A large capacitance results in a high ripple rejection ratio. Noise filtering is achieved by the addition of a single capacitor to VREF. Since the reference vollage amplifier has a buffered output, this capacitor can be as low as 1 HP. supply voltage and then mutes the power amplifier to protect the device. tet @ (Voo Vag }/ 800 mA Igy 4.0 pA when Voc = 30 No. 35349/10LA4571MB TYPICAL APPLICATION 168 22 pF 4700 pF a 27kn Rig ci 650 kt Ro C13 1000 pF I preanpitied Channel 1 l Ri Q 4700 pF 27 kn apr 03 RG HE No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss. @ Anyone purchasing any products described or contained herein for an above-mentioned use shall: @ Accept full responsibility and indemnify and defend SANYO ELECTRIC CO, LTD, its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use: @ Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally. Mi Information (including circuit diagrams and circuit parameters} herein is tor example only; it is not guarant- eed for volume production, SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties. No. 353410/10