MB3889
Key Features
- Built-in timer-latch overcurrent protection circuit (requiring no current sense resistor) Built-in timer-latch overvoltage protection circuit Synchronous rectification system providing high efficiency Power supply voltage range: 5.5 V to 18 V PWRGOOD terminals (open-drain) to output the protection status Symmetrical-phase system reducing the input capacitor loss Built-in channel control function Reference voltage: 3.5 V ± 1 % (Continued) s PACKAGE 30-pin plastic TSSOP (FPT-30P-M04) MB3889 (Continued)
- Error amplifier threshold voltage: 1.23 V ± 1 % (0 °C to + 85 °C)
- Support for frequency setting using an external resistor (Frequency setting capacitor integrated)
- Oscillation frequency range: 100 kHz to 500 kHz
- Built-in circuit for load-independent soft-start and discharge control
- Built-in totem-pole output for Nch MOS FET 2 MB3889 s PIN ASSIGNMENT (TOP VIEW) -INE1 : 1 FB1 : 2 CS1 : 3 N.C. : 4 RT : 5 CTL : 6 SGND : 7 VREF : 8 CTL1 : 9 CTL2 : 10 CSCP : 11 PWRGOOD : 12 CS2 : 13 FB2 : 14 -INE2 : 15 30 : CB1 29 : OUT1-1 28 : VS1 27 : OUT2-1 26 : PGND1 25 : ILIM1 24 : VCC 23 : ILIM2 22 : VB 21 : N.C. 20 : PGND2 19 : OUT2-2 18 : VS2 17 : OUT1-2 16 : CB2 (FPT-30P-M04) 3 MB3889 s PIN DESCRIPTION Pin No. 1 2 3 4 5 6 7 8 9 Symbol -INE1 FB1 CS1 N.C. RT CTL SGND VREF CTL1 I/O I O I O I CH1 error amp output terminal CH1 soft-start capacitor connection terminal No connection Triangular waveform oscillation frequency setting resistor connection terminal Power supply control terminal. “H” level : IC operating mode “L” level : IC Standby mode Ground terminal Reference voltage output terminal CH1 control terminal “H” level : CH1 ON state “L” level : CH1 OFF state and protection status reset CH2 control terminal “H” level : CH2 ON state “L” level : CH2 OFF state and protection status reset Timer-latch short-circuit protection capacitor connection terminal CH1, CH2 protection status output terminal CH2 soft-start capacitor connection terminal CH2 error amp output terminal CH2 error amp inverted input terminal CH2 boot capacitor connection terminal Connect a capacitor between the CB2 and VS2 terminals. CH2 totem-pole output terminal (External main-side FET gate drive) CH2 external main-side FET source connection terminal CH2 totem-pole output terminal (External synchronous-rectification-side FET gate drive) Ground terminal No connection Output circuit bias output terminal CH2 overcurrent detection resistor connection terminal Reference voltage, control circuit power supply terminal CH1 overcurrent detection resistor connection terminal Ground terminal CH1 totem-pole output terminal (External synchronous-rectification-side FET gate drive) CH1 external main-side FET source connection terminal CH1 totem-pole output terminal (External main-side FET gate drive) CH1 boot capacitor connection terminal Connect a capacitor between the CB1 and VS1 terminals. Descriptions CH1 error amp inverted input terminal
