TA2123AF Schematic ( PDF Datasheet ) - Toshiba Semiconductor

Teilenummer	TA2123AF
Beschreibung	1.5V Stereo Headphone Amplifier
Hersteller	Toshiba Semiconductor
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Gesamt 20 Seiten TOSHIBA Bipolar Integrated Circuit Silicon Monolithic TA2123AF 1.5V Stereo Headphone Amplifier TA2123AF The TA2123AF is the system amplifier IC which is developed for playback stereo headphone equipments. It is built in dual auto−reverse preamplifiers, dual power amplifiers with bass / treble boost function, AMS (automatic music sensor) function, beep function, AGC for power amplifier etc. Features · Power amplifier stage · In case of output coupling type, the supply current decreases. (built−in center amplifier switch) Weight: 0.17g (typ.) · Built−in bass boost function · Built−in treble boost function · Built−in power amplifier muting function · Built−in input terminal for beep signal · Built−in input capacitor for reducing buzz noise · GV = 24dB (typ.) · Built−in AGC circuit (in case of boost mode, this circuit operates.) · Low supply current (VCC = 1.3V, f = 1kHz, RL = 32Ω, Ta = 25°C, typ.) No Signal 0.1mW × 2 0.5mW × 2 Output coupling type OCL type 1.5mA 2.2mA 3.0mA 4.9mA 5.0mA 8.6mA · Preamplifier stage · Auto-reverse compatible · Built-in input capacitor for reducing buzz noise · Input coupling condensor-less · Built-in metal mode drivers · Preamplifier muting function · Built-in ripple filter circuit · Built-in AMS (automatic music sensor) function (mixer amplifier and level comparator) · Built-in power switch · Operating supply voltage range (Ta = 25°C) VCC (opr) = 0.95~2.2V 1 2002-10-30 Terminal No. Name 39 BEEP 41 MT SW 44 F / R SW 45 PRE SW Function Input of beep signal ・This terminal receives beep signal of a microcomputer etc. ・This terminal should be set as high impedance or “H” when not using this function Muting switch of power amplifier Power amp. on: “H” level Power amp. off: “L” level Refer to application note 3 (2) Forward / reverse switch Forward: “L” level Reverse: “H” level Refer to application note 3 (2) Muting switch of preamplifier Preamp. on: “L” level Preamp. off: “H” level Refer to application note 3 (2) 42 PW SW Power on / off switch IC on: “H” level IC off: “L” level Refer to application note 3 (2) 43 BST SW Boost on / off switch BST on: OPEN / “H” level BST off: “L” level Refer to application note 3 (2) 46 M / N SW 47 PRE GND Metal / normal mode switch Metal mode: OPEN / “H” level Normal mode: “L” level Refer to application note 3 (2) Power GND for power drive stage TA2123AF Internal Circuit 20kΩ 39 Power amplifier Terminal Voltage (V) 0.7 47kΩ 41 — — — 42 — 20kΩ 43 10kΩ 46 — — — 0 6 2002-10-30 6 Page TA2123AF (4) Treble boost The EQ terminal is synchronizes with the BST SW, and the input impedance is changed. BST OFF: 100kΩ (typ.) BST ON: 1.9kΩ (typ.) The voltage gain increase 6 dB (typ.) at high frequency range in case that the capacitor CX is connected between the EQ terminal and the PW NF terminal. PW IN 28 PW NF 29 + PWA / B − EQ30 Fig.6 Treble boost (5) Cross talk of output coupling type In case of output coupling mode, the cross talk is determined by resistor RL and capacitor C which are connected with power amplifier output as shown in Fig.7. The formula is shown below. G (ω) = 1 / 2 [1 + jωC (RL / 2)] CT = 20ℓog|Gv| = 20ℓog [1 / 2 [ 1+ (w / w0 )2 ]], ω0 = 1 / C (RL / 2) At f = 1kHz, C1 = 220µF, RL = 32Ω, The cross talk becomes about 33 dB. PWA R2 PWC PWB RL + RL VREF ~ + Fig.7 Cross talk of output coupling type 12 2002-10-30 12 Page
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Besondere Datenblatt

Teilenummer	Beschreibung	Hersteller
TA2123AF	1.5V Stereo Headphone Amplifier	Toshiba Semiconductor

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