Better - Lae801p Rev 20 Schematic

Rev 20 adds Schottky diodes from each input/output to ground and supply rails (BAT54S configuration). This clamping network increases ESD robustness from 2kV to 8kV (HBM), per IEC 61000-4-2.

Perhaps the most elegant fix in Rev 20 involves the feedback network. Earlier revisions tied the feedback pin directly to the output rail with a simple resistor divider. This worked, but it made the loop sensitive to output capacitor ESR.

Rev 20 introduces a Type-III compensation network with a dedicated high-frequency feedforward capacitor (C22, value 47pF, NPO dielectric). This does two things: lae801p rev 20 schematic better

In practical terms, this means the LAE801P Rev 20 can power sensitive analog circuits (op-amps, ADCs) that would have been impossible with Rev 18 due to ripple-induced noise.

Original:
AC_L ---[Fuse]---[Varistor]---[Bridge]---[Bulk Cap]---(no CM choke)
Improved:
AC_L ---[Fuse]---[Varistor]---[CM Choke (20mH)]---[Bridge]---[Bulk Cap]---[X-cap 0.47uF]
 Rev 20 adds Schottky diodes from each input/output

Reasoning: The common-mode choke reduces conducted EMI by 18dB (measured). In practical terms, this means the LAE801P Rev

| Component | Original Rev 20 | Improved Value | Effect | |-----------|----------------|----------------|--------| | R_gate | 100Ω | 22Ω + 1N4148 parallel (fast turn-off) | Reduces overshoot | | R_pulldown | 10kΩ | 4.7kΩ | Prevents false turn-on | | Zener clamp | None | 15V Zener (gate to source) | Protects MOSFET |

New gate drive snippet:

PWM_out ---[22Ω]---+---[1N4148 cathode]---MOSFET gate
                     |
                    [15V Zener]
                     |
                    GND

Rev 20 shifts from passive protection to active clamping.