OPA445BM Datasheet, PDF (13/25 Pages) Texas Instruments – High Voltage FET-Input OPERATIONAL AMPLIFIER

OPA445
www.ti.com
9. With these preparatory steps in place, the PowerPAD
IC is simply placed in position and run through the
solder reflow operation as any standard surfacemount
component. This preparation results in a properly
installed part.
For detailed information on the PowerPAD package,
including thermal modeling considerations and repair
procedures, see technical brief SLMA002 PowerPAD
Thermally-Enhanced Package available for download at
www.ti.com.
SBOS156B − MARCH 1987 − REVISED APRIL 2008
Thermal Land
(Copper)
Minimum Size
4.8mm x 3.8mm
(189 mils x 150 mils)
O PT IO NAL:
Additional four vias outside
of thermal pad area but
under the package.
REQUIRED:
Thermal pad area 2.286mm x 2.286mm
(90 mils x 90 mils) with five vias
(via diameter = 13 mils)
Figure 14. 8-Pin PowerPAD PCB Etch and Via
Pattern
TYPICAL APPLICATIONS
R₁
100kΩ
V₁
R₂
10kΩ
+40V
OPA445
−40V
V₂
R₃
100kΩ
R₄
9.9kΩ
I_L = [(V₂ − V₁)/R₅] (R₂/R₁)
I_L
= (V₂ − V₁)/1kΩ
Compliance Voltage Range = ±35V
NOTE: R₁ = R₃ and R₂ = R₄ + R₅
R₅
100Ω
Load
+60V
0.1µF
25kΩ
DAC8811
or
DAC7811
0−2mA
Protects DAC
During Slewing
OPA445
0.1µF
V_O = 0V to +50V
at 10mA
−12V
Figure 15. Voltage-to-Current Converter
Figure 16. Programmable Voltage Source
R₁
R₂
1kΩ
9kΩ
+45V
R₃
10kΩ
R₄
10kΩ
+45V
OPA445
V_IN
±4V
Master
−45V
160V
Piezo⁽¹⁾
Crystal
OPA445
Slave
−45V
NOTE: (1) For transducers with large capacitance the stabilization
technique described in Figure 6 may be necessary. Be certain that the
Master amplifier is stable before stabilizing the Slave amplifier.
Figure 17. Bridge Circuit Doubles Voltage for Piezo Crystals
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