STA550

Common Mode Rejection Ratio (Min) :
Operating Supply Voltage :
Packaging : Tube
Maximum Operating Temperature : + 70 C
THD plus Noise : 0.01 %
Output Type : 2-Channel Stereo
Mounting Style : Through Hole
Product : Class-AB
Output Power : 70 W
Package / Case : FLEXIWATT-27 V
Available Set Gain : 100 dB
Supply Current : 110 mA
Maximum Power Dissipation : 31000 mW


Features:

 `  MONOCHIP BRIDGE STEREO AMPLIFIER FOR BASH<sup>®</sup> ARCHITECTURE
 `  55+55W OUTPUT POWER @ R_L = 4/8 , THD = 0.5%
 `  70+70W OUTPUT POWER @ R<sub>L</sub> = 4/8 , THD = 10%
 `  HIGH DYNAMIC PREAMPLIFIER INPUT STAGES
 `  EXTERNAL PROGRAMMABLE FEEDBACK TYPE COMPRESSORS
 `  AC COUPLED INPUT TO CLASS AB BRIDGE OUTPUT AMPLIFIER
 `  PRECISION RECTIFIERS TO DRIVE THE DIGITAL CONVERTER
 `  ON-OFF SEQUENCE/ TIMER WITH MUTE AND STANDBY
 `  PROPORTIONAL OVER POWER OUTPUT CURRENT TO LIMIT THE DIGITAL CONVERTER
 ` ABSOLUTE POWER BRIDGE OUTPUT TRANSISTOR POWER PROTECTION
 `  ABSOLUTE OUTPUT CURRENT LIMIT
 `  INTEGRATED THERMAL PROTECTION
 `  POWER SUPPLY OVER VOLTAGE PROTECTION
 `  FLEXIWATT POWER PACKAGE WITH 27 PIN
 `  BASH® LICENCE REQUIRED


Pinout




Specifications

Symbol	Parameter	Value	Unit
+VS	Positive supply voltage referred to pin 13 (GND)	30	V
-VS	Negative supply voltage referred to pin 13 (GND)	-24	V
VCD+	Positive supply voltage tracking rail referred to pin 13 (GND)	22	V
VCD+	Positive supply voltage operated to Vs+(1)	0.3	V
VCD-	Negative supply voltage referred to -Vs (1)	-0.3	V
VCD-	Negative supply voltage tracking rail referred to pin 13 (GND)	-22	V
VAtt_Rel1 VAtt_Rel2	Pin 3, 25 Negative & Positive maximum voltage referred to GND (pin 13)	-0.5 to +20	V
VPwr_Imp1 VPwr_Imp2 VTrk_1 VTrk_2	Pin 7, 21, 18, 10 Negative & Positive maximum voltage referred to GND (pin 13)	-20 to +20	V
VIn_pre1 VIn_pre2	Pin 8, 20 Negative & Positive maximum voltage referred to GND (pin 13)	-0.5 to +0.5	V
Vthreshold	Pin 17 Negative & Positive maximum voltage referred to GND (pin 13)	-7 to +0.5	V
Istb-max	Pin 11 maximum input current (Internal voltage clamp at 5V)	500	A
Vstbymute	Pin 11 negative maximum voltage referred to GND (pin 13)	-0.5	V
Iout	Output current	7.0	A

Note 1: V_CD- must not be more negative than -Vs and V_CD+ must not be more positive than +V_S
Note 2: All pins withstand ±2KV ESD but not pin 11


Description

The STA550 is a fully integrated power module designed to implement a BASH® amplifier when used in conjunction with STABP01 digital processor.

Notice that normally only one Digital Converter is needed to supply a stereo or multi-channel amplifier system, therefore most of the functions implemented in the STA550 have summing outputs.

The STA550 signal circuits are biased by fixed negative and positive voltages referred to Ground. Instead the final stages of the output amplifiers are supplied by two external voltages that are following the audio signal . In this way the headroom for the output transistors is kept at minimum level to obtain a high efficiency power amplifier.

The STA550 Compressor circuits, one for each channel, performs a particular transfer behavior to avoid the dynamic restriction that an adaptive system like this requires. To have a high flexibility the attack / release time and the threshold levels are externally programmable. The tracking signal for the external digital converter is generated from the Absolute Value block that rectifies the audio signal present at the compressor output. The outputs of these STA550s are decoupled by a diode to permit an easy sum of this signal for the multichannel application. The output power bridges have a dedicated input pin to perform an AC decoupling to cancel the compressor output DC offset. The gain of the stage is equal to 4 (+12dB). A sophisticated circuit performs the output transistor power detector that , with the digital converter, reduces the power supply voltage . Moreover, a maximum current output limiting and the over temperature sensor have been added to protect the circuit itself. The external voltage applied to the STBY/MUTE pin forces the two amplifiers in the proper condition to guarantee a silent turnon and turn-off.