TurboTrans™ Technology

TurboTrans™ Selection

PTH08T240F

TurboTrans technology is a feature introduced in the T2 generation of the PTH/PTV family of power modules.

TurboTrans optimizes the transient response of the regulator with added external capacitance using a single

external resistor. Benefits of this technology include reduced output capacitance, minimized output voltage

deviation following a load transient, and enhanced stability when using ultra-low ESR output capacitors. The

amount of output capacitance required to meet a target output voltage deviation is reduced with TurboTrans

activated. Likewise, for a given amount of output capacitance, the amplitude of the voltage deviation following a

load transient is reduced. Applications requiring tight transient voltage tolerances and minimized capacitor

footprint area benefits greatly from this technology.

(pin 9). The value of the resistor directly corresponds to the amount of output capacitance required. All T2

products require a minimum value of output capacitance. For the PTH08T240F, the minimum required

capacitance is 1000

µF. Capacitors with a capacitance × ESR product above 1000 µF×mΩ and below 10,000

µF×mΩ are required. (Multiply the capacitance (in µF) by the ESR (in mΩ) to determine the capacitance × ESR

product.) See the Capacitor Selection section of the datasheet for a variety of capacitors that meet this criteria.

Figure 14 thru Figure 21 show the amount of output capacitance required to meet a desired transient voltage

deviation for Type B (e.g. polymer-tantalum) and Type C (e.g. OS-CON) capacitors. To calculate the proper

step. Next, determine what type of output capacitors are used. (If more than one type of output capacitor is used,

select the capacitor type that makes up the majority of your total output capacitance.) Knowing this information,

use the chart (Figure 14 thru Figure 21) that corresponds to the capacitor type selected. To use the chart, begin

by dividing the maximum voltage deviation limit (in mV) by the magnitude of your load step (in Amps). This gives

a mV/A value. Find this value on the Y-axis of the appropriate chart. Read across the graph to the 'TurboTrans'

from the TurboTrans table. The TurboTrans tables include both the required output capacitance and the

75% (7.5 A) output load steps.

The chart can also be used to determine the achievable transient voltage deviation for a given amount of output

capacitance. By selecting the amount of output capacitance along the X-axis, reading up to the desired

'TurboTrans'' curve, and then over to the Y-axis, gives the transient voltage deviation limit for that value of output

TurboTrans table.

As an example, let's look at a 5-V application requiring a 15-mV deviation during a 3-A load transient. A majority

of 680-

µF, 10-mΩ ouput capacitors will be used. (680 (in µF) × 10 (in mΩ) = 6,800; therefore this is Type C

capacitance). Use the 5-V, Type C capacitor chart, Figure 19. Dividing 15 mV by 3 A gives 5 mV/A transient

voltage deviation per amp of transient load step. Select 5 mV/A on the Y-axis and read across to the

'TurboTrans'' plot. Following this point down to the X-axis gives a minimum required output capacitance of

approximately 1800

µF. The required R

Applications operating from an input bus greater than 8 V may encounter reduced transient performance when

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Product Folder Link(s): PTH08T240F