80V input ceiling — the 48V bus decision
The LM5069MMX-1/NOPB is a single-channel hot swap controller from TI, built for inrush limiting and fault protection on supply rails from 9V up to 80V. That 80V ceiling covers 48V telecom buses with margin for transients, 24V industrial rails, and 12V backplane supplies without needing a pre-regulator. It does not integrate the pass FET — the external N-channel MOSFET is sized to the load current and thermal budget, which keeps the controller small in a 10-MSOP package but adds a BOM component the designer must select for Rds(on) and gate charge.
Latched fault vs auto-retry — the -1 / -2 fork
The -1 suffix means the controller latches off after a fault (overcurrent or overvoltage) and stays off until the input is cycled or the UVLO pin is toggled. The sibling LM5069MMX-2/NOPB auto-retries after a fault timeout. Pick the -1 when a fault must be investigated before restart — telecom line cards, base stations, safety-critical industrial nodes. Pick the -2 when the load can tolerate automatic recovery, like a fan tray or a redundant PSU.
Programmable protection setpoints
Four programmable features are available: current limit (set by an external sense resistor), fault timeout (capacitor on the TIMER pin), overvoltage protection (OVP resistor divider), and undervoltage lockout (UVLO resistor divider). The 1.3 mA supply current is the controller's own draw — the pass FET gate drive adds a transient load during startup.
Package and rework note
10-MSOP with 0.118-inch (3.00 mm) body width — the 0.50 mm lead pitch is reworkable with a fine-tip iron and flux, but the small thermal pad under the package (if present on the layout) needs a preheat to avoid tombstoning.