Design example
60-V Class 3-A Power Operational Amplifier
A power operational amplifier design targeting 3 A continuous output, with adjustable current limiting and combined output-enable and thermal-status interface.
Design targets
- Supply range target
- 8–60 V total; ±4 to ±30 V with symmetric supplies, subject to operating margin
- Continuous output-current target
- 3 A; package, cooling and safe-operating-area dependent
- Peak output-current target
- 5 A class; transient operation within the safe operating area
- Small-signal gain-bandwidth target
- 1 MHz, based on reference typical values with an 8 Ω load
- Slew-rate target
- 10 V/µs at unity gain, 50 V peak-to-peak output and an 8 Ω load, based on the reference typical value
- Control and protection
- Adjustable current limit, output enable/disable and thermal-shutdown status
Practical operating notes
- These specifications are reference-based design targets. Small-signal bandwidth and slew rate describe different operating conditions and do not establish full-swing performance at every load.
- 60 V is the total supply span, not output amplitude. It is also the absolute maximum in the reference. Allow margin for supply tolerance and transients; output swing requires load-dependent headroom.
- The 3 A continuous and 5 A peak targets depend on voltage across the output stage, cooling, temperature and pulse duration. A current-limit setting up to 5 A does not turn the peak-current target into a continuous rating.
- The current limit is set through a low-power control interface rather than a load-current sensing resistor in series with the output. The enable/status interface is referenced to the negative supply; its logic and monitoring circuit must be checked for the selected supply arrangement.
- Thermal shutdown is a protection objective, not a normal operating mode. Check heatsinking, capacitive-load stability, inductive-energy return paths and transient protection. Package, pinout and thermal connections require verification for the intended board.
Possible applications
- Semiconductor test equipment
- Laboratory and field instrumentation
- Programmable voltage and current source circuits
Discuss your power-amplifier requirements and operating conditions.
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