AmplifierCircuits

LM1875   g eneral description: LM1875 pcb layout The LM1875 is a monolithic power amplifier offering very low distortion and high quality performance for consumer audio applications. The LM1875 delivers 20 watts into a 4Ω or 8Ω load on ±25V supplies. Using an 8Ω load and ±30V supplies, over 30 watts of power may be delivered. The amplifier is designed to operate with a minimum of external components. Device overload protection consists of both internal current limit and thermal shutdown.The LM1875 design takes advantage of advanced circuit techniques and processing to achieve extremely low distortion levels even at high output power levels. Other outstanding features include high gain, fast slew rate and a wide power bandwidth, large output voltage swing, high current capability, and a very wide supply range. The amplifier is internally compensated and stable for gains of 10 or greater. LM1875  amplifier circuit : LM1875 AUDIO AMPLIFIER 20W...

TDA8922   g eneral description: The TDA8922 is a high efficiency class-D audio power amplifier with very low dissipation.  The typical output power is 2 × 25 W. The device is available in the HSOP24 power package with a small internal heatsink and in the DBS23P through-hole power package. Depending on the supply voltage and load conditions, a very small or even no external heatsink is required. The amplifier operates over a wide supply voltage range from ±12.5 to ±30 V and consumes a very low quiescent current. TDA8922  features : High efficiency (∼90%) Operating supply voltage from ±12.5 to ±30 V Very low quiescent current Low distortion Usable as a stereo Single-Ended (SE) amplifier or as amono amplifier in Bridge-Tied Load (BTL) Fixed gain of 30 dB in Single-Ended (SE) and 36 dB in Bridge-Tied Load (BTL) High output power Good ripple rejection Internal switching frequency can be overruled by an external clock No switch-on or swi...

TDA7490   g eneral description: The TDA7490 is a dual audio class D amplifier assembled in Flexiwatt 25 package; it is specially designed for high efficiency application mainly for TV and Home Stereo sets. TDA7490 features:  25W + 25W OUTPUT POWER: RL = 8Ω/4Ω; THD = 10% HIGH EFFICIENCY WIDE SUPPLY VOLTAGE RANGE (FROM ±10 TO ±25V) SPLIT SUPPLY TURN OFF/ON POP FREE ST-BY AND MUTE FEATURES SHORT CIRCUIT PROTECTION ACROSS THE LOAD THERMAL OVERLOAD PROTECTION EXTERNALLY SINCHRONIZABLE BRIDGE CONFIGURATION TDA7490 amplifier diagram, circuits: TDA7490 Audio Amplifier 2x25W TDA7490 layout, pcb: TDA7490 layout, pcb TDA7490 layout, pcb

 TDA1562Q   g eneral description: Philips designers have further improved a number of properties of the IC, among which the power output. According to the Philips datasheet, the improved device, the TDA1562Q, can deliver 70 watts into 4 ohms, but that is at the cost of the distortion, which at 10 per cent is rather too high, even for in a car. The prototype of the design described in this article provides 54 watts into 4 ohms at 1 per cent distortion. Since the number of requisite external components is smaller than in the case of the earlier device, the printed-circuit board is even more compact than that for the February 1995 amplifier.  TDA1562Q  features : Low power dissipation during reproduction of music signals Proof against short-circuits Protection against excessive temperatures Standby switch No power-on or power-off clicks Visible error indication Measurement results (at Ub =14.4 V) Supply voltage 8–18 V Sensitivity 760 mV r.m...

General description:   All resistors are standard metal film 250mW except: R1/3/4/7, these are 2W metal film, and the 0.22ohm beeing 5W. Around R7 is wounded a 0.6mm isolated (enamelled) copper wire forming the output coil. (~12 windings)  For c19 i used 470uf/16v, all other electrolytics 63v. The 10/100/330pF should be mica-caps. The 100nf and 47nf is recommended to be Wima MKS2 (or better), also for C1 i suggest Wima MKS2, 4.7uf is enough. For Trimpot i use a Piher. The MPSA18 can be substituted by BC550C, for all other parts i do not recommend changes, especially the feedback network (r29/30) should be kept unchanged, feedback compensation is very delicate for this circuit ! Be careful when substituting the MPSA18 with BC550C, the pinout is reversed between these 2 transistors !!! The bias is adjusted via the trimpot (R22). Recommended bias is 55ma, resulting in 12mv across a single 0.22ohms or 24mv across both 0.22ohms. Connect a DMM to the upper wires of these resisto...