SBOS394E November 2007 – July 2019 VCA824
PRODUCTION DATA.
The VCA824 provides output voltage and current capabilities that are unsurpassed in a low-cost monolithic VCA. Under no-load conditions at 25°C, the output voltage typically swings closer than 1 V to either supply rails; the 25°C swing limit is within 1.2 V of either rails. Into a 15-Ω load (the minimum tested load), the VCA824 device is tested to deliver more than ±160 mA.
The specifications described above, though familiar in the industry, consider voltage and current limits separately. In many applications, it is the voltage × current, or V-I product, that is more relevant to circuit operation (See Figure 38). The X- and Y-axes of this graph show the zero-voltage output current limit and the zero-current output voltage limit, respectively. The four quadrants give a more detailed view of the VCA824 output drive capabilities, noting that the graph is bounded by a Safe Operating Area of 1-W maximum internal power dissipation. Superimposing resistor load lines onto the plot shows that the VCA824 can drive ±2.5 V into 25-Ω or ±3.5 V into 50-Ω without exceeding the output capabilities or the 1-W dissipation limit. A 100-Ω load line (the standard test circuit load) shows the full ±3.9-V output swing capability, as shown in Typical Characteristics.
The minimum specified output voltage and current overtemperature are set by worst-case simulations at the cold temperature extreme. Only at cold startup do the output current and voltage decrease to the numbers shown in Electrical Characteristic. As the output transistors deliver power, the respective junction temperatures increase, thereby increasing the available output voltage swing and output current.
In steady-state operation, the available output voltage and current are always greater than the temperature shown in the overtemperature specifications because the output stage junction temperatures are higher than the specified operating ambient.