MIC2537 Micrel MIC2537 Quad Power Distribution Switch Final Information General Description Features The MIC2537 is a cost-effective high-side power switch with Compliant to USB specifications four independently controlled channels, optimized for bus- 3V to 5.5V input powered Universal Serial Bus (USB) applications. Few exter- 100mA minimum continuous load current per port nal components are necessary to satisfy USB requirements. 425m typical on-resistance < 400mA current limit The MIC2537 satisfies the following USB requirements: each Individual open-drain fault flag leads switch channel supplies up to 100mA as required by USB 3V/5V-compatible enable inputs bus-powered downstream devices fault current is limited to Active-high (-1) and active-low (-2) versions typically 250mA, well below the UL 25VA safety require- 100 A max. on-state supply current ments and a flag output is available to indicate fault condi- <1 A typical off-state supply current tions to the local USB controller. Soft start eliminates the 16-lead SOP package momentary voltage drop on the upstream port that may occur 40C to 85C operation when the switch is enabled in bus-powered applications. Additional features include thermal shutdown to prevent Applications catastrophic switch failure from high-current loads and 3.3V and 5V logic compatible enable inputs. USB keyboards The MIC2537 is available in active-high and active-low ver- USB bus-powered docking stations sions in a 16-lead SOP package. Notebook docking stations Notebook PCs PDA General power distribution Typical Application Upstream V BUS 4.75V to 5.25V 500mA max. Ferrite Bead V 10k BUS 10k 10k 10k Downstream MIC5207-3.3 D+ 33F* USB LDO Regulator 3.3V USB Controller MIC2537 0.01F D Port 1 IN IN OUT V+ EN ENA 100mA max. GND 1F OC FLGA NC 4.7 GND 0.1 F EN ENB OUTA F V BUS OC FLGB OUTB Downstream D+ 33F* EN ENC OUTC USB D+ 0.01F D Port 2 FLGC OUTD OC D GND 100mA max. EN END NC FLGD OC GND Bold lines indicate GND 0.1 wide, 1-oz. copper V BUS high-current traces. Downstream D+ 33F* USB 0.01F D Port 3 * 33F, 16V tantalum or 100F, 10V electrolytic per port GND 100mA max. V BUS Downstream D+ 33F* USB 0.01F D Port 4 100mA max. GND Typical Bus-Powered Hub UL Recognized Component Micrel, Inc. 1849 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 944-0970 MIC2537 Micrel Ordering Information Part Number Enable Temperature Range Package MIC2537-1BM Active High 40C to +85C 16-Lead SOP MIC2537-2BM Active Low 40C to +85C 16-Lead SOP Pin Configuration MIC2537-x FLGA FLGD 1 16 ENA 2 15 END OUTA 3 14 OUTD GND 4 13 IN NC 5 12 NC OUTB 6 11 OUTC ENB 7 10 ENC FLGB 8 9 FLGC 16-Lead SOP (M) Pin Description Pin Number Pin Name Pin Function 1 FLGA Flag A: (Output): Channel A open-drain fault flag output. 2 ENA Enable A (Input): Channel A control input. 3 OUTA Output A: Channel A switch output. 4 GND Ground: Supply return. Connect both leads to ground. 5, 12 NC Not internally connected 6 OUTB Output B: Channel B switch output. 7 ENB Enable B (Input): Channel B control input. 8 FLGB Flag B (Output): Channel B open-drain fault flag output. 9 FLGC Flag C (Output): Channel C open-drain fault flag output. 10 ENC Enable C (Input): Channel C control input. 11 OUTC Output C: Channel C switch output. 13 IN Positive Supply Input 14 OUTD Output D: Channel D switch output. 15 END Enable D (Input): Channel D control input. 16 FLGD Flag D (Output): Channel D open-drain fault flag output. December 1999 2 MIC2537