PA09 View Datasheet(PDF) - Cirrus Logic
Part Name
Description
MFG CO.
'PA09' PDF : 6 Pages View PDF
Product Innova tionFrom
PA09 • PA09A
current. Output voltage is given as peak. Currents are aver-
age responding supply readings, but AC monitoring will reveal
current pulses corresponding to periods of high slew rate. For
QUIESCENT vs. SINE DRIVE
1.5
1.4
1.3
1.2
1.1
1.0
100
300
FREQUENCY, F (KHz)
1000
QUIESCENT vs. SQUARE DRIVE
7.0
32VO /40VS
5.5
15VO /23VS
4.0
15VO /40VS
2.5
1.0
10K
100K
1M
FREQUENCY, F (KHz)
example, driving ±30V outputs at 500KHz on ±40V supplies
produces a .8A pulse during negative slew and a 1.2A pulse
during positive slew. If the input signal is over driven by several
times the output swing capability, pulses up to 4A may be seen.
THERMAL SHUTDOWN PROTECTION
The thermal protection circuit shuts off the amplifier when
the substrate temperature exceeds approximately 150°C. This
allows heatsink selection to be based on normal operating
conditions while protecting the amplifier against excessive
junction temperature during temporary fault conditions.
Thermal protection is a fairly slow-acting circuit and therefore
does not protect the amplifier against transient SOA violations
(areas outside of the TC = 25°C boundary). It is designed to
protect against short-term fault conditions that result in high
power dissipation within the amplifier, If the conditions that
cause thermal shutdown are not removed, the amplifier will
oscillate in and out of shutdown. This will result in high peak
power stresses, destroy signal integrity, and reduce the reli-
ability of the device.
STABILITY
Due to its large bandwidth the PA09 is more likely to oscillate
than lower bandwidth Power Operational Amplifiers.To prevent
oscillations a reasonable phase margin must be maintained by:
1. Pay very careful attention to supply bypassing and circuit
grounding. This is very important when step functions are
driven and the PA09 shares supplies with more active
devices.
2. Keeping the external sumpoint stray capacitance to ground
at a minimum and the sumpoint load resistance (input and
feedback resistors in parallel) below 500Ω. Larger sumpoint
load resistances can be used with increased phase com-
pensation and/or bypassing of the feedback resistor.
3. Connect the case to a local AC ground potential.
CURRENT LIMIT
Internal current limiting is provided in the PA09. Note the
current limit curve given under typical performance graphs is
based on junction temperature. If the amplifier is operated at
cold junction temperatures, current limit could be as high as 8
amps. This is above the maximum allowed current on the SOA
curve of 5 amps. Systems using this part must be designed to
keep the maximum output current to less than 5 amps under all
conditions. The internal current limit only provides this protec-
tion for junction temperatures of 80°C and above.
PA09U
5
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