NE58633 Noise reduction class-D headphone driver amplifier Rev. 01 — 22 January 2009 Product data sheet 1. General description The NE58633 is a stereo, noise reduction, class-D, Bridge-Tied Load (BTL) headphone driver amplifier. Each channel comprises a class-D BTL headphone driver amplifier, an electret microphone low noise preamplifier, feedback noise reduction circuit and a music amplifier input. The NE58633 operates with a battery voltage of 0.9 V to 1.7 V. The chip employs an on-chip DC-to-DC boost converter and internal Vref voltage reference which is filtered and output to ground for noise decoupling. It features mute control and plop and click reduction circuitry. The gain of the microphone amplifier and filter amplifier is set using external resistors. Differential architecture provides increased immunity to noise. The NE58633 is capable of driving 800 mVrms across a 16 Ω or 32 Ω load and provides ElectroStatic Discharge (ESD) and short-circuit protection. It is available in the 32-pin HVQFN32 (5 mm × 5 mm × 0.85 mm) package suitable for high density small-scale layouts and is an ideal choice for noise reduction headphones and educational audio aids. 2. Features n n n n n n n n n n n n n Low current consumption of 4.4 mA 0.9 V to 1.7 V battery operating voltage range 1 % THD+N at VO = 1 VM driving 16 Ω with a battery voltage of 1.5 V 10 % THD+N at 800 mVrms output voltage driving 16 Ω and 32 Ω loads with a battery voltage of 1.5 V Output noise voltage with noise reduction circuit typically 31 mVrms for Gv(cl) = 25 dB On-chip mute function Plop and click reduction circuitry Class-D BTL differential output configuration Electret microphone noise reduction polarization amplifier with external gain adjustment using resistors Music and filter amplifier with external gain adjustment using resistors DC-to-DC converter circuitry (3 V output) with 2.5 mA (typical) load current Internal voltage reference pinned out for noise decoupling Available in HVQFN32 package NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 3. Ordering information Table 1. Ordering information Type number Package Name NE58633BS Description Version HVQFN32 plastic thermal enhanced very thin quad flat package; SOT617-1 no leads; 32 terminals; body 5 × 5 × 0.85 mm 4. Block diagram MA_OUTR 21 internal oscillator 14, 19 PGNDR AVDD MA_INRN MA_INRP NMIC_OUTR 18 22 PWM 23 24 1 kΩ NMIC_INRP OUTRN MUTE 10 kΩ Vref NMIC_INRN 15 H-BRIDGE OUTRP 17 Vref 16 PVDDR PVDDR AVDD 25 NE58633 26 20 5 kΩ VREF MUTE AGND B_IN BS VBAT 27 Vref 28 DC-to-DC BOOST CONVERTER 29 AVDD 9 31 MA_INLP MA_INLN MA_OUTL AGND internal oscillator Vref AVDD 10 kΩ MUTE 8 10 7 H-BRIDGE 32 AGND 1 PVDDL PVDDL AVDD PWM 1 kΩ NMIC_OUTL 12 Vref Vref Vref NMIC_INLN MUTE CONTROL 30 5 kΩ NMIC_INLP Vref BUFFER OUTLN OUTLP MUTE 6, 11 PGNDL 2 3 4 5 001aaj506 Fig 1. Block diagram NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 2 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 5. Pinning information 25 NMIC_INRN 26 NMIC_INRP 27 AGND 28 B_IN 29 BS 30 VBAT terminal 1 index area 31 NMIC_INLP 32 NMIC_INLN 5.1 Pinning NMIC_OUTL 1 24 NMIC_OUTR MA_INLP 2 23 MA_INRP MA_INLN 3 22 MA_INRN MA_OUTL 4 AGND 5 PGNDL 6 19 PGNDR OUTLP 7 18 OUTRP PVDDL 8 17 PVDDR 21 MA_OUTR PVDDR 16 20 VREF OUTRN 15 PGNDR 14 n.c. 13 MUTE 12 PGNDL 11 9 PVDDL OUTLN 10 NE58633BS 002aad751 Transparent top view Fig 2. Pin configuration for HVQFN32 5.2 Pin description Table 2. Pin description Symbol Pin Description NMIC_OUTL 1 noise reduction microphone preamplifier output, left channel MA_INLP 2 music amplifier positive input, left channel MA_INLN 3 music amplifier negative input, left channel MA_OUTL 4 music amplifier output, left channel AGND 5 analog ground PGNDL 6 power ground, headphone driver, left channel OUTLP 7 headphone positive output, left channel PVDDL 8, 9 battery supply voltage, headphone driver output, left channel OUTLN 10 headphone negative output, left channel PGNDL 11 power ground, headphone driver, left channel MUTE 12 mute, headphone outputs (active LOW) n.c. 13 not connected internally; connect pin to ground PGNDR 14 power ground, headphone driver, right channel OUTRN 15 headphone negative output, right channel PVDDR 16, 17 battery supply voltage, headphone driver output, right channel OUTRP 18 headphone positive output, right channel PGNDR 19 power ground, headphone driver, right channel VREF 20 internal voltage reference output NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 3 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier Table 2. Pin description …continued Symbol Pin Description MA_OUTR 21 music amplifier output, right channel MA_INRN 22 music amplifier negative input, right channel MA_INRP 23 music amplifier positive input, right channel NMIC_OUTR 24 noise reduction microphone preamplifier output, right channel NMIC_INRN 25 noise reduction microphone preamplifier negative input, right channel NMIC_INRP 26 noise reduction microphone preamplifier positive input, right channel AGND 27 ground, analog B_IN 28 boost converter input BS 29 boost converter switching transistor collector VBAT 30 battery supply voltage NMIC_INLP 31 Noise reduction microphone preamplifier positive input, left channel NMIC_INLN 32 Noise reduction microphone preamplifier negative input, left channel 6. Limiting values Table 3. Limiting values In accordance with the Absolute Maximum Rating System (IEC 60134). Tamb = 25 °C, unless otherwise specified. Symbol Parameter Conditions VBAT battery supply voltage pins VBAT, PVDDL, PVDDR VI input voltage Min Max Unit in active mode −0.3 +1.7 V in mute mode −0.3 +1.7 V −0.3 +2.0 V Tamb ambient temperature operating 0 70 °C Tj junction temperature operating 0 150 °C Tstg storage temperature 0 150 °C 7. Recommended operating conditions Table 4. Operating conditions Symbol Parameter VBAT battery supply voltage AVDD, PVDD 0.9 1.7 V Vi(cm) common-mode input voltage music and noise reduction amplifier inputs 0.2 Vbst − 1 V VIH HIGH-level input voltage unmuted; MUTE 1 VBAT V VIL LOW-level input voltage muted; MUTE 0 0.8 V Tamb ambient temperature operating 0 70 °C Conditions NE58633_1 Product data sheet Min Max Unit © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 4 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 8. Characteristics Table 5. Electrical characteristics Tamb = 25 °C; unless otherwise specified. Symbol Parameter Conditions Min Typ Max Unit |VO(offset)| output offset voltage measured differentially; inputs AC grounded; Gv(cl) = 25 dB; VBAT = 0.9 V to 1.7 V - 5 25 mV |VI(offset)| input offset voltage music amplifier and noise reduction microphone amplifier; measured differentially - 1 - mV Zi input impedance music amplifier, non-inverting terminal; VBAT = 0.9 V to 1.7 V - 10 - kΩ inverting terminal noise reduction - 1 - kΩ non-inverting terminal noise reduction - 5 - kΩ microphone preamplifier; VBAT = 0.9 V to 1.7 V ILI input leakage current music amplifier; inverting terminal VBAT = 0.9 V to 1.7 V - - 500 nA VOH HIGH-level output voltage music amplifier and noise reduction microphone preamplifier; IOH = 1 mA; VBAT = 0.9 V to 1.7 V 2.6 - - V VOL LOW-level output voltage music amplifier and noise reduction microphone preamplifier; IOH = 1 mA; VBAT = 0.9 V to 1.7 V - - 0.35 V Vref reference voltage VBAT = 0.9 V to 1.7 V - 0.5Vbst - V VBAT = 1.7 V - 5.0 6.0 mA VBAT = 1.5 V - 6.0 - mA VBAT = 1.3 V - 7.0 - mA VBAT = 1.05 V - 8.0 - mA VBAT = 0.9 V - 9.0 11 mA - 2.8 - Ω supply current IDD AC grounded; no load RDSon drain-source on-state resistance fsw switching frequency VBAT = 0.9 V to 1.7 V 250 300 350 kHz Gv(cl) closed-loop voltage gain with noise reduction microphone circuit; VBAT = 0.9 V to 1.7 V; RF = 18 kΩ - 25 - dB Vth(mute) mute threshold voltage VBAT = 0.9 V to 1.7 V LOW-level; active LOW (muted) 0 - 0.8 V HIGH-level; inactive HIGH (unmuted) 1.0 - - V [1] VBAT = 0.9 V to 1.7 V; no load [1] Music amplifier at unity gain; noise preamplifier at 25 dB gain; noise preamplifier output connected to corresponding inverting input of music amplifier; non-inverting inputs. NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 5 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier Table 6. Operating characteristics Symbol Parameter Conditions ∆Vo output voltage variation per channel; RL = 16 Ω; f = 1 kHz; THD+N = 10 % Po THD+N output power total harmonic distortion-plus-noise Min Typ Max Unit VBAT = 1.7 V - 800 - Vrms VBAT = 1.5 V - 800 - Vrms VBAT = 1.05 V - 550 - Vrms per channel; f = 1 kHz; THD+N = 10 % RL = 16 Ω; VBAT = 1.5 V - 40 - mW RL = 32 Ω; VBAT = 1.5 V - 20 - mW RL = 16 Ω; VBAT = 1.05 V - 19 - mW Vo = 1 Vpeak; f = 1 kHz; VBAT = 1.5 V to 1.7 V - 1.0 - % Vo = 620 mVpeak; f = 1 kHz; VBAT = 1.05 - 1.0 - % Gv(ol) open-loop voltage gain music amplifier and noise reduction microphone preamplifier; VBAT = 1.5 V - 100 - dB αct crosstalk attenuation f = 1 kHz; VBAT = 1.5 V; Rg = 1 kΩ; RL = 16 Ω; Vo = 800 mVrms 40 50 - dB SVRR supply voltage ripple rejection Vbst(ripple) = 100 mVrms; Gv(cl) = 25 dB; f = 1 kHz VBAT = 0.9 V 30 40 - dB VBAT = 1.5 V - 60 - dB Zi input impedance microphone preamplifier; Gv(cl) = 25 dB (from noise reduction microphone to class-D output) - 1 - kΩ Vn(i) input noise voltage spectral noise; VBAT = 1.5 V; f = 20 to 20 kHz; Gv(cl) = 25 dB; Rg = 1 kΩ - 12 - nV/√Hz Vn(o) output noise voltage VBAT = 1.5 V; f = 20 to 20 kHz; inputs AC grounded; Gv(cl) = 25 dB no weighting - 26 - µV A weighting - 20 - µV DC-to-DC boost converter VI input voltage 1.05 - 1.7 V VI(startup)min minimum start-up input voltage - 0.9 1.05 V Vbst boost voltage VBAT = 1.05 V to 1.7 V; 2.65 mA external load 2.75 3.1 3.45 V Ibst(load)O output load boost current VBAT = 1.05 V to 1.7 V; Vbst > 2.8 V - 2.65 - mA ηbst boost efficiency VBAT = 1.05 V to 1.7 V; RL(tot) = 600 Ω - 80 - % NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 6 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 9. Typical performance curves 002aad921 12 002aad920 3.5 Vbst (V) 3.3 IBAT (mA) 8 3.1 2.9 4 2.7 0 0.8 1.1 1.4 2.5 0.8 1.7 1.1 VBAT (V) 1.4 1.7 VBAT (V) Vbst = 3.14 V Fig 3. Battery supply current as a function of battery supply voltage Fig 4. Boost voltage as a function of battery supply voltage 3.20 Vbst (V) 3.15 3.10 3.05 3.00 2.95 2.90 2.85 2.80 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 lbst (mA) Fig 5. 1.70 1.50 VBAT (V) 1.30 1.25 1.20 1.15 1.10 1.05 1.00 002aad917 Boost voltage, battery supply voltage and boost current 3D profile NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 7 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 80 η (2) (%) 70 002aad922 80 η (2) (%) 70 (3) (1) 60 60 50 50 40 40 30 002aad926 (3) (1) 30 0 1 2 3 4 5 RL(ext) (kΩ) 0 1 (1) VBAT = 0.9 V (1) VBAT = 1.0 V (2) VBAT = 1.2 V (2) VBAT = 1.3 V (3) VBAT = 1.5 V (3) VBAT = 1.6 V a. Battery supply voltage = 0.9 V, 1.2 V and 1.5 V 2 3 4 5 RL(ext) (kΩ) b. Battery supply voltage = 1.0 V, 1.3 V and 1.6 V 002aad925 80 η (%) 70 (3) (1) (2) 60 50 40 30 0 1 2 3 4 5 RL(ext) (kΩ) (1) VBAT = 1.1 V (2) VBAT = 1.4 V (3) VBAT = 1.7 V c. Battery supply voltage = 1.1 V, 1.4 V and 1.7 V Fig 6. Efficiency as a function of external load resistance; boost voltage = 3.14 V NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 8 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 002aad923 102 THD+N ratio (%) 002aad924 102 THD+N ratio (%) (2) (3) (2) (1) 10 10 (3) (4) (1) 1 1 (4) 10−1 10−5 10−4 10−3 10−2 10−1 10−5 10−4 10−3 10−2 Po (W) RL = 16 Ω speaker load + 2 × ferrite bead + 2 × 18 Ω resistor; measured across 16 Ω speaker; fi = 1 kHz; A-weighting filter for THD+N. RL = 16 Ω speaker load + 2 × ferrite bead + 2 × 18 Ω resistor; measured across 32 Ω speaker; fi = 1 kHz; A-weighting filter for THD+N (1) VBAT = 1.05 V (1) VBAT = 1.05 V (2) VBAT = 1.3 V (2) VBAT = 1.3 V (3) VBAT = 1.5 V (3) VBAT = 1.5 V (4) VBAT = 1.7 V (4) VBAT = 1.7 V Fig 7. Total harmonic distortion-plus-noise as a function of output power; 16 Ω load 002aad958 40 G (dB) Fig 8. Total harmonic distortion-plus-noise as a function of output power; 32 Ω load 002aae323 40 G (dB) 20 20 0 0 −20 1 10 102 103 104 105 −20 10 f (Hz) Gain as a function of frequency response of feedforward noise reduction circuit; NMIC_INx to MA_OUTx for feedforward application circuit 103 104 105 VNMIC_IN = 10 mV to 50 mV; VBAT = 1.5 V; Vbst = 3.1 V Fig 10. Gain as a function of frequency; NMIC_INx to MA_OUTx for feedback application circuit NE58633_1 Product data sheet 102 f (Hz) VNMIC_IN = 6.3 mVRMS; Vbst = 3 V; VBAT = 1.5 V Fig 9. 10−1 Po (W) © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 9 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier (1) (2) (3) (4) 002aad930 At start-up, no signal on music input. No pop or click. The small glitches on trace (2) are just noise from the noise reduction amplifier feed-through. Start-up delay approximately 135 ms. (1) VBAT switch ON to 1.5 V (50 ms; 1.0 V) (2) Difference between trace (3) and (4), which equates to the pop or click (0.5 ms; 0.54 V) (3) OUTLP (50 ms; 1.0 V) (4) OUTLN (50 ms; 1.0 V) Fig 11. Power-on delay and pop-on noise performance (1) (2) (3) (4) 002aad929 (1) 50 ms; 1.0 V (2) 1 ms; 0.5 V (3) 50 ms; 1.0 V (4) 50 ms; 1.0 V Fig 12. Pop-off click performance NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 10 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 10. Application information 10.1 General application description The NE58633 is a stereo noise reduction IC with a boost converter output at 3.2 V with 2.5 mA load current. Using the on-chip boost converter, it operates from a single cell alkaline battery (0.9 V to 1.7 V). The NE58633 is optimized for low current consumption at 6 mA quiescent current for VBAT = 1.5 V. Each channel is comprised of a low noise preamplifier which is driven by an electret microphone, a music amplifier and class-D, BTL headphone driver amplifier (see Figure 1 “Block diagram”). The NE58633 output drivers are capable of driving 800 mVrms across 16 Ω and 32 Ω loads. THD+N performance is 1 % at VO = 1 VM and 10 % THD+N at 800 mVrms output voltage driving 16 Ω at a battery voltage of 1.5 V. The internal reference voltage is set for 1⁄2 Vbst and is pinned out so it can be externally decoupled to enhance noise performance. The NE58633 differential architecture provides immunity to noise. The output noise is typically 26 µVrms for Gv(cl) = 25 dB. The NE58633 provides ESD and short-circuit protection. It features mute control and plop and click reduction circuitry. As shown in the application circuit schematics (Figure 13 and Figure 14), the NE58633 may be used for Active Noise Reduction (ANR) in either feedforward or feedback noise-cancelling headphones and earphones in consumer and industrial applications. The gain and filter characteristics of the ANR circuit are set using external resistors and capacitors. NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 11 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 10 nF 10 kΩ 22 kΩ 21 MA_OUTR PGNDR 14 2.2 kΩ internal oscillator PGNDR 19 AVDD 10 nF OUTRN 15 23 MA_INRP PWM 22 MA_INRN H-BRIDGE 18 Ω 18 Ω MUTE 47 kΩ 100 nF FB OUTRP 18 FB 24 NMIC_OUTR right speaker 10 nF PVDDR 17 10 kΩ AVDD 22 kΩ 10 nF PVDDR 16 25 NMIC_INRN 1 µF 10 kΩ 26 NMIC_INRP VBAT 1 µF 4.7 kΩ switch shown in OFF position NE58633 27 AGND 28 B_IN 100 µF 1 kΩ 29 BS OFF DC-to-DC BOOST CONVERTER 10 µF 4.7 kΩ 20 1 µF MUTE CONTROL 30 VBAT VBAT VREF AVDD MUTE 12 right audio input 1 µF 1 µF 270 Ω AVDD 560 Ω PVDDL 9 31 NMIC_INLP 1 µF 10 kΩ 10 nF PVDDL 8 32 NMIC_INLN 22 kΩ 1 NMIC_OUTL AGND AVDD OUTLN 10 10 kΩ 100 nF 1 µF internal oscillator PWM 47 kΩ 2 MA_INLP H-BRIDGE OUTLP 7 3 MA_INLN 10 nF 270 Ω 560 Ω 1 µF 10 nF FB FB 18 Ω 18 Ω left audio input left speaker MUTE 10 nF PGNDL 6 10 kΩ 2.2 kΩ 22 kΩ power switch ON 4 MA_OUTL PGNDL 11 5 AGND 001aaj507 Fig 13. NE58633 feedback application schematic NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 12 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 47 nF 1.8 kΩ 21 MA_OUTR PGNDR 14 3.3 kΩ internal oscillator PGNDR 19 AVDD 27 nF OUTRN 15 23 MA_INRP PWM 22 MA_INRN H-BRIDGE 3.3 kΩ 330 nF FB 18 Ω OUTRP 18 FB 18 Ω MUTE 3.3 kΩ 24 NMIC_OUTR right speaker 27 nF PVDDR 17 10 nF AVDD 22 kΩ PVDDR 16 25 NMIC_INRN 8.2 kΩ 1 µF 26 NMIC_INRP VBAT 1 µF 6.8 kΩ switch shown in OFF position NE58633 27 AGND 28 B_IN 1 kΩ 100 µF 29 BS OFF DC-to-DC BOOST CONVERTER 10 µF 6.8 kΩ 1 µF 10 nF 330 nF 3.3 kΩ 3.3 kΩ 12 AVDD PVDDL 9 32 NMIC_INLN PVDDL 8 22 kΩ 1 NMIC_OUTL right audio input 1 µF 31 NMIC_INLP 1 µF 390 Ω 1 µF internal oscillator AGND power switch ON AVDD OUTLN 10 PWM 2 MA_INLP H-BRIDGE OUTLP 7 560 Ω 390 Ω 1 µF 27 nF FB FB 18 Ω 18 Ω left audio input left speaker MUTE 27 nF PGNDL 6 3 MA_INLN 47 nF 1.8 kΩ MUTE 560 Ω 1 µF 8.2 kΩ 20 AVDD MUTE CONTROL 30 VBAT VBAT VREF 4 MA_OUTL PGNDL 11 3.3 kΩ 5 AGND 001aaj508 Fig 14. NE58633 feedforward application schematic NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 13 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 10.2 Power supply decoupling The power supply pins B_IN, PVDDL and PVDDR are decoupled with 1 µF capacitors directly from the pins to ground. 10.3 Speaker output filtering considerations The ferrite beads form a low-pass filter with a shunt capacitor to reduce radio frequency > 1 MHz. Choose a ferrite bead with high-impedance at high frequencies and low-impedance at low frequencies. A typical ferrite bead is 600 Ω at 100 MHz. The low frequency impedance is not as important as in power amplifiers because headphone speakers are stabilized with a series impedance of about 18 Ω on each output. A shunt capacitor is added to complete the low-pass filter. 10.4 Boost converter and layout considerations 10.4.1 Boost converter operation The boost converter operates in asynchronous mode as shown in Figure 15. As VBAT drops, the boost converter efficiency decreases (see Figure 3 and Figure 6). The boost converter is capable of driving 2.65 mA external load (see Figure 5). If the NE58633 is operated without the boost converter, pins B_IN, PVDDL and PVDDR may be powered directly from a 3 V power supply source such as 2 AAA alkaline batteries. The VBAT pin is not used. (1) (2) (3) 2 Gs/s 002aad957 (1) Positive or negative output of the class-D driver with VBAT at 1.5 V. (2) Pin BS (VBS = Vbst). Remark: This is a normal pulse. It does not change with VBAT but remains at the level of the boosted voltage. (3) Current at pin B_IN (Ibst(load)O) measures approximately 40 mA peak, but averaged DC current is a few milliamperes per the specification. Fig 15. Switching waveform at the BS pin NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 14 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 10.4.2 Critical layout consideration and component selection The trace between pin BS and the switching inductor must be kept as short as possible. The VBAT side of the boost switching inductor is decoupled by use of a low Equivalent Series Resistance (ESR) 10 µF, 6 V capacitor. A power inductor with low ESR (typically 50 mΩ) should be used. The boost inductor must be 22 µH minimum and 47 µH maximum to ensure proper operation. Pin B_IN is decoupled by use of a 1 µF capacitor directly at the pin with 33 µF to 47 µF at the Vbst output at the Schottky diode. 10.5 Mute Mute may be invoked by directly grounding the pin with a momentary switch. The MUTE pin is active LOW. The outputs are muted automatically when VBAT is less than or equal to 0.9 V. The MUTE pin is decoupled to ground with a 1 µF capacitor. 10.6 Internal reference, VREF pin The internal reference is pinned out so it can be filtered with a capacitor to ground. The recommended value is 1 µF to 10 µF. Ensure that the biasing time constant at pin VREF does not exceed the power-on delay time or a pop-on click will heard. 10.7 Power-on delay time and pop and click performance Power-on delay time of typically 135 ms is imposed to allow the input biasing to power-up and stabilize. This eliminates pop-on noise. 10.8 Active Noise Reduction (ANR) concepts 10.8.1 Basic concept Noise reduction headphones utilize Passive Noise Reduction (PNR) provided by the passive noise reduction of the headphone acoustical plant alone. The amount of PNR is greatest at the high frequencies and least at the low frequencies. The addition of Active Noise Reduction (ANR) greatly increases the amount of noise reduction at low frequencies. The combined effect of PNR and ANR provides noise reduction over an appreciable hearing range. Figure 16 shows the combined effect of both PNR and ANR in an over-the-ear noise-cancelling FB headphone. NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 15 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 002aad911 10 α (dB) α (dB) 0 0 −10 −10 −20 −20 −30 −30 −40 102 002aad912 10 103 104 −40 102 103 f (Hz) a. Passive attenuation left b. Passive attenuation right 002aad913 10 α (dB) 002aad914 10 α (dB) 0 0 −10 −10 −20 −20 −30 −30 −40 102 103 104 −40 102 103 f (Hz) 104 f (Hz) c. Total attenuation left d. Total attenuation right 002aad915 10 α (dB) 002aad916 10 α (dB) 0 0 −10 −10 −20 −20 −30 −30 −40 102 104 f (Hz) 103 104 −40 102 103 f (Hz) e. Active attenuation left 104 f (Hz) f. Active attenuation right Fig 16. Combined noise reduction (PNR + ANR) of typical over-the-ear FB application NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 16 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 10.8.2 Feedforward circuit 10.8.2.1 Conceptual diagram of feedforward application Figure 17 shows the typical feedforward application diagram in which the noise cancelling microphone samples the noise outside the acoustic plant of the headphone or earphone. external noise human head E electronic compartment ear −2 noise detection microphone FILTER AMP H.P. driver NE58633 transducer (speaker) acoustic compartment or plant headphone shell or body 002aad927 Fig 17. Feedforward conceptual diagram This method produces a noise-cancelling signal that tries to replicate the noise in the acoustical plant at the loudspeaker and entrance to the ear. The replication is never exact because the microphone is located outside the headphones; the noise sampled is not a perfect replica of the noise inside the ear cup, which is altered by passing through the ear cup as well as by the internal reflections. In fact, in some cases the anti-noise may actually introduce noise inside the headphones. The headphone loudspeaker or transducer is used to send the normal audio signal as well as the feedforward signal providing noise cancellation. The microphone detects the external noise and its output is amplified and filtered, and phase is inverted by the low noise preamplifier and music amplifier in the NE58633. 10.8.2.2 Feedforward demo board schematic The evaluation demo board uses a typical filter design and may not yield the optimal noise cancelling performance for a given headphone mechanical-acoustical plant. NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 17 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 10.8.3 Feedback circuit 10.8.3.1 Conceptual diagram of feedback application Figure 18 shows the typical feedback application diagram in the which the noise cancelling microphone samples the noise and music inside the acoustical plant. acoustic compartment or plant noise detection microphone human head ear −2 electronic compartment FILTER AMP H.P. driver NE58633 transducer (speaker) E headphone shell or body external noise 002aad928 Fig 18. Feedback conceptual diagram The feedback solution employs a low cost, battery operated analog Active Noise Reduction (ANR) technique. The topology uses negative feedback circuitry in which the noise reduction microphone is placed close to the ear and headphone loudspeaker. By detecting the noise with the microphone in the position closer to the ear, a noise cancelling effect with high accuracy is realized. This technique produces a noise cancelling signal that always minimizes the noise in the ear canal or entrance to the ear canal. The audio signal is analyzed with exact timing with the noise cancelling signal. The noise cancelling signal increases with increasing noise level. The headphone loudspeaker or transducer is used to send the normal audio signal as well as the feedback signal providing noise cancellation. The microphone is placed near the loudspeaker and its output is amplified, filtered, and phase inverted by the feedback network and sent back to the loudspeaker. The design of the feedback filter for a given headphone plant involves a trade-off between performance on one hand and stability and robustness with respect to variations of the headphone plant on the other. Traditional feedback design methods use filter elements such as, lead, lag and notch filters which are appropriately tuned to shape the audio response of the system to obtain good performance with sufficient stability margins. NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 18 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier Since the attenuation performance of an analog ANR headphone is defined in the design stage, it has limited applicability to work in different environments. Overall noise cancelling performance is achieved by first characterizing the passive attenuation of headphone plant and then designing the ANR circuitry to obtain the optimal overall noise reduction performance and stability. Figure 16 shows combined noise reduction results of typical over-the-ear feedback headphone. The combined noise reduction is the sum of the PNR of the plant and the active noise reduction of the feedback filter circuit. 10.8.3.2 Feedback demo board schematic The evaluation demo board embodies a typical filter design and may not yield the optimal noise cancelling performance for a given headphone mechanical-acoustical plant. 11. Test information 15 µH AP585 AUDIO ANALYZER INxP OUTxP RL DUT INxN OUTxN + 15 µH AUX0025 30 kHz LOW-PASS FILTER − POWER SUPPLY AP585 MEASUREMENT INPUTS 002aad417 Fig 19. NE58633 test circuit NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 19 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 12. Package outline HVQFN32: plastic thermal enhanced very thin quad flat package; no leads; 32 terminals; body 5 x 5 x 0.85 mm A B D SOT617-1 terminal 1 index area A A1 E c detail X C e1 e 1/2 e 16 y y1 C v M C A B w M C b 9 L 17 8 e e2 Eh 1/2 e 1 terminal 1 index area 24 32 25 X Dh 0 2.5 5 mm scale DIMENSIONS (mm are the original dimensions) UNIT A(1) max. A1 b c D (1) Dh E (1) Eh e e1 e2 L v w y y1 mm 1 0.05 0.00 0.30 0.18 0.2 5.1 4.9 3.25 2.95 5.1 4.9 3.25 2.95 0.5 3.5 3.5 0.5 0.3 0.1 0.05 0.05 0.1 Note 1. Plastic or metal protrusions of 0.075 mm maximum per side are not included. REFERENCES OUTLINE VERSION IEC JEDEC JEITA SOT617-1 --- MO-220 --- EUROPEAN PROJECTION ISSUE DATE 01-08-08 02-10-18 Fig 20. Package outline SOT617-1 (HVQFN32) NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 20 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 13. Soldering of SMD packages This text provides a very brief insight into a complex technology. A more in-depth account of soldering ICs can be found in Application Note AN10365 “Surface mount reflow soldering description”. 13.1 Introduction to soldering Soldering is one of the most common methods through which packages are attached to Printed Circuit Boards (PCBs), to form electrical circuits. The soldered joint provides both the mechanical and the electrical connection. There is no single soldering method that is ideal for all IC packages. Wave soldering is often preferred when through-hole and Surface Mount Devices (SMDs) are mixed on one printed wiring board; however, it is not suitable for fine pitch SMDs. Reflow soldering is ideal for the small pitches and high densities that come with increased miniaturization. 13.2 Wave and reflow soldering Wave soldering is a joining technology in which the joints are made by solder coming from a standing wave of liquid solder. The wave soldering process is suitable for the following: • Through-hole components • Leaded or leadless SMDs, which are glued to the surface of the printed circuit board Not all SMDs can be wave soldered. Packages with solder balls, and some leadless packages which have solder lands underneath the body, cannot be wave soldered. Also, leaded SMDs with leads having a pitch smaller than ~0.6 mm cannot be wave soldered, due to an increased probability of bridging. The reflow soldering process involves applying solder paste to a board, followed by component placement and exposure to a temperature profile. Leaded packages, packages with solder balls, and leadless packages are all reflow solderable. Key characteristics in both wave and reflow soldering are: • • • • • • Board specifications, including the board finish, solder masks and vias Package footprints, including solder thieves and orientation The moisture sensitivity level of the packages Package placement Inspection and repair Lead-free soldering versus SnPb soldering 13.3 Wave soldering Key characteristics in wave soldering are: • Process issues, such as application of adhesive and flux, clinching of leads, board transport, the solder wave parameters, and the time during which components are exposed to the wave • Solder bath specifications, including temperature and impurities NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 21 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 13.4 Reflow soldering Key characteristics in reflow soldering are: • Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to higher minimum peak temperatures (see Figure 21) than a SnPb process, thus reducing the process window • Solder paste printing issues including smearing, release, and adjusting the process window for a mix of large and small components on one board • Reflow temperature profile; this profile includes preheat, reflow (in which the board is heated to the peak temperature) and cooling down. It is imperative that the peak temperature is high enough for the solder to make reliable solder joints (a solder paste characteristic). In addition, the peak temperature must be low enough that the packages and/or boards are not damaged. The peak temperature of the package depends on package thickness and volume and is classified in accordance with Table 7 and 8 Table 7. SnPb eutectic process (from J-STD-020C) Package thickness (mm) Package reflow temperature (°C) Volume (mm3) < 350 ≥ 350 < 2.5 235 220 ≥ 2.5 220 220 Table 8. Lead-free process (from J-STD-020C) Package thickness (mm) Package reflow temperature (°C) Volume (mm3) < 350 350 to 2000 > 2000 < 1.6 260 260 260 1.6 to 2.5 260 250 245 > 2.5 250 245 245 Moisture sensitivity precautions, as indicated on the packing, must be respected at all times. Studies have shown that small packages reach higher temperatures during reflow soldering, see Figure 21. NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 22 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier maximum peak temperature = MSL limit, damage level temperature minimum peak temperature = minimum soldering temperature peak temperature time 001aac844 MSL: Moisture Sensitivity Level Fig 21. Temperature profiles for large and small components For further information on temperature profiles, refer to Application Note AN10365 “Surface mount reflow soldering description”. 14. Abbreviations Table 9. Abbreviations Acronym Description ANR Active Noise Reduction BTL Bridge Tied Load DUT Device Under Test ESD ElectroStatic Discharge ESR Equivalent Series Resistance FB FeedBack RMS Root Mean Squared PNR Passive Noise Reduction PWM Pulse Width Modulation 15. Revision history Table 10. Revision history Document ID Release date Data sheet status Change notice Supersedes NE58633_1 20090122 Product data sheet - - NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 23 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 16. Legal information 16.1 Data sheet status Document status[1][2] Product status[3] Definition Objective [short] data sheet Development This document contains data from the objective specification for product development. Preliminary [short] data sheet Qualification This document contains data from the preliminary specification. Product [short] data sheet Production This document contains the product specification. [1] Please consult the most recently issued document before initiating or completing a design. [2] The term ‘short data sheet’ is explained in section “Definitions”. [3] The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status information is available on the Internet at URL http://www.nxp.com. 16.2 Definitions Draft — The document is a draft version only. The content is still under internal review and subject to formal approval, which may result in modifications or additions. NXP Semiconductors does not give any representations or warranties as to the accuracy or completeness of information included herein and shall have no liability for the consequences of use of such information. Short data sheet — A short data sheet is an extract from a full data sheet with the same product type number(s) and title. A short data sheet is intended for quick reference only and should not be relied upon to contain detailed and full information. For detailed and full information see the relevant full data sheet, which is available on request via the local NXP Semiconductors sales office. In case of any inconsistency or conflict with the short data sheet, the full data sheet shall prevail. 16.3 Disclaimers General — Information in this document is believed to be accurate and reliable. However, NXP Semiconductors does not give any representations or warranties, expressed or implied, as to the accuracy or completeness of such information and shall have no liability for the consequences of use of such information. Right to make changes — NXP Semiconductors reserves the right to make changes to information published in this document, including without limitation specifications and product descriptions, at any time and without notice. This document supersedes and replaces all information supplied prior to the publication hereof. Suitability for use — NXP Semiconductors products are not designed, authorized or warranted to be suitable for use in medical, military, aircraft, space or life support equipment, nor in applications where failure or malfunction of an NXP Semiconductors product can reasonably be expected to result in personal injury, death or severe property or environmental damage. NXP Semiconductors accepts no liability for inclusion and/or use of NXP Semiconductors products in such equipment or applications and therefore such inclusion and/or use is at the customer’s own risk. Applications — Applications that are described herein for any of these products are for illustrative purposes only. NXP Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing or modification. Limiting values — Stress above one or more limiting values (as defined in the Absolute Maximum Ratings System of IEC 60134) may cause permanent damage to the device. Limiting values are stress ratings only and operation of the device at these or any other conditions above those given in the Characteristics sections of this document is not implied. Exposure to limiting values for extended periods may affect device reliability. Terms and conditions of sale — NXP Semiconductors products are sold subject to the general terms and conditions of commercial sale, as published at http://www.nxp.com/profile/terms, including those pertaining to warranty, intellectual property rights infringement and limitation of liability, unless explicitly otherwise agreed to in writing by NXP Semiconductors. In case of any inconsistency or conflict between information in this document and such terms and conditions, the latter will prevail. No offer to sell or license — Nothing in this document may be interpreted or construed as an offer to sell products that is open for acceptance or the grant, conveyance or implication of any license under any copyrights, patents or other industrial or intellectual property rights. 16.4 Trademarks Notice: All referenced brands, product names, service names and trademarks are the property of their respective owners. 17. Contact information For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: [email protected] NE58633_1 Product data sheet © NXP B.V. 2009. All rights reserved. Rev. 01 — 22 January 2009 24 of 25 NE58633 NXP Semiconductors Noise reduction class-D headphone driver amplifier 18. Contents 1 2 3 4 5 5.1 5.2 6 7 8 9 10 10.1 10.2 10.3 10.4 10.4.1 10.4.2 General description . . . . . . . . . . . . . . . . . . . . . . 1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Ordering information . . . . . . . . . . . . . . . . . . . . . 2 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Pinning information . . . . . . . . . . . . . . . . . . . . . . 3 Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 3 Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . . 4 Recommended operating conditions. . . . . . . . 4 Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Typical performance curves . . . . . . . . . . . . . . . 7 Application information. . . . . . . . . . . . . . . . . . 11 General application description . . . . . . . . . . . 11 Power supply decoupling . . . . . . . . . . . . . . . . 14 Speaker output filtering considerations. . . . . . 14 Boost converter and layout considerations . . . 14 Boost converter operation. . . . . . . . . . . . . . . . 14 Critical layout consideration and component selection. . . . . . . . . . . . . . . . . . . . 15 10.5 Mute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 10.6 Internal reference, VREF pin . . . . . . . . . . . . . 15 10.7 Power-on delay time and pop and click performance . . . . . . . . . . . . . . . . . . . . . . . . . . 15 10.8 Active Noise Reduction (ANR) concepts . . . . 15 10.8.1 Basic concept . . . . . . . . . . . . . . . . . . . . . . . . . 15 10.8.2 Feedforward circuit . . . . . . . . . . . . . . . . . . . . . 17 10.8.2.1 Conceptual diagram of feedforward application. . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 10.8.2.2 Feedforward demo board schematic . . . . . . . 17 10.8.3 Feedback circuit . . . . . . . . . . . . . . . . . . . . . . . 18 10.8.3.1 Conceptual diagram of feedback application. . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 10.8.3.2 Feedback demo board schematic. . . . . . . . . . 19 11 Test information . . . . . . . . . . . . . . . . . . . . . . . . 19 12 Package outline . . . . . . . . . . . . . . . . . . . . . . . . 20 13 Soldering of SMD packages . . . . . . . . . . . . . . 21 13.1 Introduction to soldering . . . . . . . . . . . . . . . . . 21 13.2 Wave and reflow soldering . . . . . . . . . . . . . . . 21 13.3 Wave soldering . . . . . . . . . . . . . . . . . . . . . . . . 21 13.4 Reflow soldering . . . . . . . . . . . . . . . . . . . . . . . 22 14 Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . 23 15 Revision history . . . . . . . . . . . . . . . . . . . . . . . . 23 16 Legal information. . . . . . . . . . . . . . . . . . . . . . . 24 16.1 Data sheet status . . . . . . . . . . . . . . . . . . . . . . 24 16.2 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 16.3 16.4 17 18 Disclaimers. . . . . . . . . . . . . . . . . . . . . . . . . . . Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . Contact information . . . . . . . . . . . . . . . . . . . . Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 24 24 25 Please be aware that important notices concerning this document and the product(s) described herein, have been included in section ‘Legal information’. © NXP B.V. 2009. All rights reserved. For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: [email protected] Date of release: 22 January 2009 Document identifier: NE58633_1