PA162 View Datasheet(PDF) - Cirrus Logic
Part Name
Description
Manufacturer
PA162 Datasheet PDF : 6 Pages
| |||
Product Innova tionFrom
PA162
TYPICAL APPLICATION (cont)
The amplifiers are especially well-suited for applications
such as this. The extended common mode range allows
command inputs as low as 0V. The output swing lets
it drive within 2V of the supply at an output of 1A. This
means that a command input that ranges from 0 to 10V
will drive a 24V motor from full scale CCW to full scale
N
CW at ±1A.
-Vs (pins 11, 15, 16 and 20) must be tied to the heatslug
o
S
externally on the PCB. To ease metal routing on the PCB,
run a direct trace from the -Vs pin to the center heat slug.
The PA162 can be used in a three amplifier configuration
for a three phase inverter or motor as shown in Figure 4.
GENERAL
Please read Application Note 1 "General Operating Con-
Using 3 amplifiers from PA162
PA162 as 3 phase motor driver.
Quad
siderations" which covers stability, supplies, heatsinking, FIGURE 4. 3 Phase Inverter
mounting, SOA interpretation, and specification interpre-
tation. Visit www.cirrus.com for design tools that help automate tasks such as calculations for stability, internal
power dissipation, heatsink selection; Apex Precision Power's complete Application Notes library; Technical Semi-
nar Workbook; and Evaluation Kits.
STABILITY CONSIDERATIONS
All monolithic power op amps use output stage topologies that present special sta-
bility problems. This is primarily due to non-complementary (both devices are NPN)
output stages with a mismatch in gain and phase response for different polarities of
output current. It is difficult for the op amp manufacturer to optimize compensation
for all operating conditions. For applications with load current exceeding 300mA,
oscillation may appear. The oscillation may occur only with the output voltage swing
at the negative or positive half cycle. Under most operating and load conditions
acceptable stability can be achieved by providing a series RC snubber network
connected from the output to ground (see Figure 5). The recommended component
values of the of the network are, RSN = 10Ω and CSN = 0.01µF. Please refer to Ap-
plication Note 1 for further details.
+
–
CSN
0.01µF
RSN
10Ω
FIGURE 5. R-C Snubber
SAFE OPERATING AREA (SOA)
The SOA curves combine the effect of all limits for this
power op amp. For a given application, the direction and
magnitude of the output current should be calculated or
measured and checked against the SOA curves. This is
simple for resistive loads but more complex for reactive
and EMF generating loads. The following guidelines may
save extensive analytical efforts.
SOA
10
DC, TC = 25°C
DC, TC = 85°C
1
4 AMPLIFIERS LOADED
3 AMPLIFIERS LOADED
2 AMPLIFIERS LOADED
1 AMPLIFIER LOADED
0.1
1
10
50
SUPPLY TO OUTPUT DIFFERENTIAL VOLTAGE, VS - VO (V)
PA162U
5
Share Link: 