LinkSwitch-TN2BYPASSDRAIN(BP/M)(D)REGULATOR5.0 VFAULT IFBSD IFB PRESENTBYPASS PIN 5.2 V CAPACITORDETECTAUTO-RESTARTBYPASS PINCOUNTERUNDERVOLTAGE OVL + CLOCKCURRENT LIMIT 5.0 V COMPARATORRESET 4.5 V - + - VILIMIT JITTERCLOCKTHERMALSHUTDOWNDCMAXOSCILLATORSQFEEDBACK(FB)RQ 2.0 V -VT LEADINGEDGEBLANKINGOVPDETECTSOURCE(S) PI-7879-020819 Figure 3. Functional Block Diagram. Pin Functional DescriptionSOURCE (S) Pin: This pin is the power MOSFET source connection. It is also the DRAIN (D) Pin: ground reference for the BYPASS and FEEDBACK pins. Power MOSFET drain connection. Provides internal operating current for both start-up and steady-state operation. BYPASS (BP/M) Pin: This pin has multiple functions: • It is the connection point for an external bypass capacitor for the P Package (DIP-8C) internally generated 5.0 V supply. G Package (SMD-8C)D Package (SO-8C) • It is a mode selector for the current limit value, depending on the value of the capacitance added. Use of a 0.1 μF capacitor results in the standard current limit value. Use of a 1 μF capacitor results BP/M1818 SBP/MS in the current limit being reduced, al owing design with lowest cost 27 surface mount buck chokes. FB27 SFBS • It provides a shutdown function. When the current into the BYPASS 6 S pin exceeds I for a time equal to 2 to 3 cycles of the internal 6 S BPSD 4 oscilator (f ), the device enters auto-restart. This can be used to 5DS OSC D45 S provide an output overvoltage protection function with external circuitry. FEEDBACK (FB) Pin: During normal operation, switching of the power MOSFET is con- PI-7842-022416 trol ed by the FEEDBACK pin. MOSFET switching is terminated when a current greater than I (49 μA) is delivered into this pin. Line Figure 4. Pin Configuration. FB overvoltage protection is detected when a current greater than IFBSD (670 μA) is delivered into this pin for 2 consecutive switching cycles. 2 Rev. M 10/20 www.power.com Document Outline Product Highlights Description Output Current Table Pin Functional Description LinkSwitch-TN2 Functional Description Applications Example Key Application Considerations Quick Design Checklist Absolute Maximum Ratings Thermal Resistance Key Electrical Characteristics Typical Performance Characteristics PDIP-8C (P Package) SMD-8C (G Package) SO-8C (D Package) PDIP-8C (P) and SMD-8C Package Marking SO-8C (D) Package Marking MSL Table ESD and Latch-Up Part Ordering Information