OPA452FASLASH500G3 datasheet(11/21 Pages) TI1

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OPA452, 453

SBOS127C

www.ti.com

typical output current of 125mA. With

±40V power supplies,

this creates an internal dissipation of 10W. This far exceeds

practical heat sinking and is not recommended. If operation

in this region is unavoidable, use the part with a heat sink.

HEAT SINKING

Power dissipated in the OPA452 or OPA453 will cause the

junction temperature to rise. For reliable operation, the junc-

tion temperature should be limited to +125

°C. Many applica-

tions will require a heat sink to assure that the maximum

operating junction temperature is not exceeded. The heat

sink required depends on the power dissipated and on

ambient conditions.

For heat sinking purposes, the tab of the DDPAK is typically

soldered directly to a circuit board copper area. Increasing

the copper area improves heat dissipation. Figure 4 shows

typical thermal resistance from junction-to-ambient as a

function of copper area.

Depending on conditions, additional heat sinking may be

required. Aavid Thermal Products Inc. manufactures sur-

face-mountable heat sinks designed specifically for use with

these packages. Further information is available on Aavid’s

web site, www.aavid.com.

FIGURE 4. DDPAK Thermal Resistance versus Circuit Board

Copper Area.

CAPACITIVE LOADS

The dynamic characteristics of the OPA452 and OPA453

have been optimized for commonly encountered gains, loads,

and operating conditions. The combination of low closed-

loop gain and capacitive load will decrease the phase margin

and may lead to gain peaking or oscillations. Figure 5 shows

a circuit that preserves phase margin with capacitive load.

Figure 6 shows the small-signal step response for the circuit

in Figure 5. Consult Application Bulletin SBOA015, at

www.ti.com, for more information.

FIGURE 5. Driving Large Capacitive Loads.

Ω

1.8nF

10nF

OPA452

+40V

–40V

270pF

Ω

THERMAL RESISTANCE vs

CIRCUIT BOARD COPPER AREA

012345

Copper Area (inches2)

OPA452FA, OPA453FA

Surface-Mount Package

1oz. copper

Circuit Board Copper Area

OPA452FA, OPA453FA

Surface-Mount Package

FIGURE 6. Small-Signal Step Response for Figure 5.

SMALL-SIGNAL STEP RESPONSE

(G = –1, C

L = 10nF)

2.5

µs/div

OPA452

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