Multimedia ICs Headphone / speaker amplifier BA7785FS The internal linear audio circuits of the BA7785FS include a stereo headphone amplifier, BTL monaural speaker amplifier, and an electronic volume circuit, making this IC ideal for LCD TVs and notebook computers. •LCDApplications TVs, notebook computers, and wordprocessors, etc. •1)Features Internal stereo headphone amplifier that allows for 4) Low-voltage operation (3.3V). 5) Internal input switch that also allows for the input of computer beeps. mixed input, along with a BTL monaural speaker amplifier. 2) Internal anti-pop circuit, which prevents popping sounds when the power is turned on. 3) Internal electronic volume and mute circuit. •Absolute maximum ratings (Ta = 25°C) Parameter Symbol Limits Unit VCC 18 V Pd 750∗ mW Power supply voltage Power dissipation Operating temperature Topr – 10 ~ + 70 °C Storage temperature Tstg – 55 ~ + 125 °C ∗ Reduced by 7.5mW for each increase in Ta of 1°C over 25°C. When mounted on a 90 × 50 × 1.6mm glass epoxy board. •Recommended operating conditions (Ta = 25°C) Parameter Power supply voltage Symbol Min. Typ. Max. Unit SP / HP VCC 3.0 — 6.0 V 1 Multimedia ICs BA7785FS •Block diagram EVR CTRL 1 LINE IN (L) 2 20 HP VCC 19 HP OUT (L) 18 HP OUT (R) 17 HP GND 16 SP VCC 15 FILTER OUT (1) 14 SP OUT (1) 13 SP OUT (2) 6dB VR HP Amp R MUTE CTRL 3 LINE IN (R) 4 VR HP Amp R 6dB BIAS IN 5 MIX OUT 6 R R MIX Amp 6dB SP IN 1 SP 7 Amp INV SP SP IN 2 8 Amp 6dB 2 SP IN CTRL 9 12 FILTER OUT (2) SP ON / OFF 10 11 SP GND Multimedia ICs BA7785FS •Pin descriptions Pin No. Pin name 1 EVR CTRL 2, 4 LINE IN L, R Function EVR control input. Maximum gain at Vcc. Headphone input L, R ZIN = 30kΩ Voltage Type — B (NPN) 1 / 2VCC B (PNP) 3 MUTE CTRL — B (NPN) 5 BIAS IN Bias buffer input 1 / 2VCC B (NPN) 6 MIX OUT Output of the headphone output mixing amplifier 1 / 2VCC PP 7, 8 SP IN 1, 2 Speaker inputs 1 and 2 Switched with SP IN CTRL (9pin) ZIN = 50kΩ 1 / 2VCC B (NPN) 9 SP IN CTRL SP IN1 / SP IN2 input selection control — B (PNP) 10 SP ON / OFF Speaker on / off (power saving mode) control — B (NPN) 11 SP GND 12, 15 FILTER OUT 1, 2 13, 14 SP OUT 1, 2 16 SP VCC 17 HP GND 19, 18 HP OUT L, R 20 HP VCC Input for controlling the muting of headphone output GND — Connecting the oscillation prevention capacitor Speaker output ground 1 / 2VCC B (NPN) BTL speaker outputs 1 and 2 1 / 2VCC PP VCC — GND — 1 / 2VCC PP VCC — Speaker output VCC Ground for the headphone, mixing amplifier, inputs and controls Headphone amplifier output VCC for the headphone, amplifier, mixing amplifier, inputs and controls Note: Pin types: P-P = push-pull, B = base, C = collector. All figures are standard values. 3 Multimedia ICs BA7785FS •Input / output circuits EVR CTRL MUTE CTRL VCC 56k 50k 1 3 47k 1 / 2VCC 32k GND GND SP IN CTRL SP ON / OFF VCC VCC 50k 45k 45k 50µA 9 50k 10 45k 2k GND 4 45k GND Multimedia ICs BA7785FS characteristics •· Electrical Unless otherwise noted, measurement conditions are as follows. HP VCC = SP VCC = 5V Ta = 25°C EVR control Mute control Speaker input control Speaker on / off control (EVR CTRL pin 1) (MUTE CTRL pin 3) (SP IN CTRL pin 9) (SP ON / OFF CTRL pin 10) : Max. (HP VCC) : LOW (MUTE OFF) : LOW (SP IN1) : HIGH (SP ON) Signal frequency = 1kHz HP amp: RL = 100Ω SP amp: RL = 8Ω, BTL = operating ∗1: DIN AUDIO ∗2: IHF A Parameter Supply current Supply current power save Symbol Min. Typ. Max. Unit I 7.8 12.0 18.5 mA No input Ips 3.5 5.4 8.3 mA No input, SP ON / OFF: L – 3.5 – 2.0 dBV VIN = – 10.0dBV, Conditions [HP Amp] INPUT: LINE IN L / R, OUTPUT: HP OUT L / R Output voltage level VOHP – 5.0 Channel balance CBHP – 1.0 0.0 1.0 dB VIN = – 10.0dBV, EVR range GEVR 70.0 88.0 — dB VIN = – 10.0dBV, EVR Max-Min difference THDHP — 0.3 1.0 % VIN = – 10.0dBV, ∗1 Distortion HHP 8.0 10.0 mW VCC = 3.0V, THD = 10% Output residual noise VONHP — – 81.0 – 73.0 dBV Rg = 1kΩ, ∗2 Interchannel crosstalk CTHP — – 78.0 – 70.0 dBV VIN = – 6.5dBV, ∗1 Muting level MTHP — – 95.0 – 84.0 dBV VIN = – 6.5dBV, ∗1 – 13.5 – 11.5 dBV VIN = – 20.0dBV Maximum rated output voltage — [MIX Amp] INPUT: LINE IN L / R, OUTPUT: MIX OUT Output level VOMIX – 15.5 [SP Amp (BTL) ] INPUT: SP IN 1 / 2, OUTPUT: SP OUT 1 / 2, BTL measurement Speaker output level Distortion Maximum rated output power Residual output noise Speaker-off level VOSP – 0.25 1.25 2.75 dBV VIN = – 10.0dBV 0.6 1.5 % VIN = – 10.0dBV, THDSP — PSP 250 300 mW VCC = 3.0V, THD = 10% VONSP — – 98.0 – 90.0 dBV Rg = 1kΩ, ∗2 VOSPOFF — – 108.0 – 85.0 dBV VIN = – 7.0dBV, ∗1, when SP is off — 5 Multimedia ICs Parameter BA7785FS Symbol Min. Typ. Max. Unit Mute-off holding voltage VTH3L 0.0 — 0.5 V Mute-on holding voltage VTH3H 2.0 — VCC V SP IN1 holding voltage VTH9L 0.0 — 0.5 V SP IN2 holding voltage VTH9H 2.2 — VCC V Speaker-off holding voltage VTH10L 0 — 0.2VCC V Speaker-on holding voltage VTH10H 0.8VCC — VCC V [Control mode holding voltage] 〈MUTE CTRL〉 〈SP IN CTRL〉 〈Speaker on / off control〉 6 Conditions SP IN 2 SP IN 1 MIX OUT LINE IN(R) LINE IN (L) 1k 1k 10k 1k 1k SP VCC SP GND 0.22µ 13 1500p 8 1500p HP GND 0.047µ 47µ 0.047µ 47µ HP VCC 0.22µ 14 15 16 11 SP Amp SP Amp R 17 10 6dB INV 6dB R 6dB HP Amp 18 19 SP ON/OFF MIX Amp BIAS VR 6dB HP Amp 12 8 7 6 5 R R VR 20 9 4.7µ 4 3 2 1 SP IN CTRL 0.47µ 0.47µ 0.47µ 0.47µ MUTE CTRL 0.47µ EVR CTRL SP OUT (2) 10µ 10µ HP OUT (R) SP OUT (1) 100 100 HP OUT (L) A A Multimedia ICs BA7785FS •Measurement circuit Fig.1 7 Multimedia ICs BA7785FS Circuit operation •Control pins • There are three control pins, described below. (1) Mute control (MUTE CTRL: pin 3) • Stops headphone output and mixing output. Mode Control signal MUTE OFF L MUTE ON H Note — Mutes the line. Note: This pin should always be at the high level (muted) when the power is turned on or off. (2) Speaker input control (SP IN CTRL: pin 9) • Switches speaker input between SP IN1 and SP IN2. Mode Control signal Note SP IN1 L — SP IN2 H — (3) Power saving control (SP ON / SP OFF CTRL: pin 10) • Turns the speaker on and off. Mode Control signal Note SP OFF L Power saving mode SP ON H Normal speaker operation ∗ Power saving mode: The speaker amplifier is stopped. To begin output, pull up to bias at 50kΩ. components •UseAttached capacitors with low temperature coefficient and low variation for oscillation prevention for pins 13, 14, 18 and 19 (0.47µF and 0.1µF), and for phase correction for pins 12 and 15 (1800pF). If capacitors with high variation or temperature coefficient are used (B characteristics, etc.), be sure to compensate with an according capacitance. Also use electrolytic capacitors for pins 5, 16 and 20 (among others) according to the characteristic changes caused by temperature change. 8 notes •(1)Operation Use the same supply voltage for HP V CC (pin 20) and SP VCC (pin 16). Using different supply voltages could result in output voltage drops or circuit malfunctioning. (2) The common impedance of the two power lines for HP VCC (pin 20) and SP VCC (pin 16) should be as low as possible. A large common impedance could cause oscillation. Multimedia ICs BA7785FS •External dimensions (Units: mm) 1 10 5.4 ± 0.2 11 0.8 0.36 ± 0.1 0.15 ± 0.1 1.8 ± 0.1 0.11 7.8 ± 0.3 8.7 ± 0.2 20 0.3Min. 0.15 SSOP-A20 9