Datasheet
OPA564
I
SET
47mF
R
2
1kW
R
1
20kW
R
4
1kW
R
4
20kW
R
5
50mW
V
O
-5V
+1V/+1A
V
DIG
+5V
0.1 Fm
0.1 Fm
47 Fm
R
SET
R
3
OPA564
C
5
+
C
6
R
1
C
1
C
10pF
4
R
F
C
F
C
47 Fm
3
C
0.1 Fm
2
3
4
6
1
T
1
D
1
(3)
SMBJ12CA
or
SMBJ6.0CA
V
S
V
DIG
INPUT
1/2 V
S
E/S
GND
S
2
(1)
R
4
(4)
S
1
(1)
S
3
(1)
S
4
(1)
L
1
(2)
OPA564
www.ti.com
SBOS372E –OCTOBER 2008– REVISED JANUARY 2011
APPLICATIONS CIRCUITS
The high output current and low supply of the
OPA564 make it a good candidate for driving laser
diodes and thermoelectric coolers. Figure 51 shows
an improved Howland current pump circuit.
POWERLINE COMMUNICATION
Powerline communication (PLC) applications require
some form of signal transmission over an existing ac
power line. A common technique used to couple
these modulated signals to the line is through a signal
transformer. A power amplifier is often needed to
provide adequate levels of current and voltage to
drive the varying loads that exist on today’s
powerlines. One such application is shown in
Figure 52. The OPA564 is used to drive signals used
in frequency modulation schemes such as FSK
(Frequency-Shift Keying) or OFDM (Orthogonal
Frequency-Division Multiplexing) to transmit digital
information over the powerline. The power output
capabilities of the OPA564 are needed to drive the
current requirements of the transformer that is shown
in the figure, coupled to the ac power line via a
coupling capacitor. Circuit protection is often needed
or required to prevent excessive line voltages or
(1) See Figure 35 for an example of a basic noninverting amplifier
with V
DIG
not exceeding 5.5V. current surges from damaging the active circuitry in
the power amplifier and application circuitry.
Figure 51. Improved Howland Current Pump
(1) S
1
, S
2
, S
3
, and S
4
are Schottky diodes. S
1
and S
2
are B350 or equivalent. S
3
and S
4
are BAV99T or equivalent.
(2) L
1
should be small enough so that it does not interfere with the bandwidth of interest but large enough to suppress transients that could
damage the OPA564.
(3) D
1
is a transient suppression diode. For 24V supplies, use SMBJ12CA. For 12V supplies, use SMBJ6.0CA. Voltage rating of transient
voltage suppressor should be half the supply rating or less.
(4) The minimum recommended value for R
4
is 7.5kΩ.
Figure 52. Powerline Communication Line Coupling
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