Wafer scale packaging for 4A FET

New Products | March 8, 2017

By Nick Flaherty

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Employing its own FET IP, the company has released three low-RDS_ON switches. These are the first products that Silego has issued in chip-scale packaging; the company hints that other devices from its range, such as the configurable-function PAC devices, may appear in similar outlines in the future. In the GFET3 Integrated Power Switch (IPS) portfolio, the three new switches are aimed at extremely PCB-space-constrained, high-performance applications in tablet PC, smartphones and fitness band markets, and offer high-side power control.

For smartphone and fitness band applications, the 0.64 mm² (0.8 x 0.8 mm) SLG59M1730C (33 mΩ/1A) and the SLG59M1736C (33 mΩ/2.2A) are low-leakage, self-powered p-FET IPSs that can operate from 2.5 V to 5.5 V supply voltages and draw very little supply current. Both products offer low-threshold ON/OFF control, fast output voltage discharge, and a controlled input current profile on startup. This can, Silego says, avoid battery-voltage ‘sag’ when powering from small, high-internal-resistance cells, which may cause an associated MCU to re-boot. The SLG59M1730C/SLG59M1736C offer a controlled 16.5 mA inrush current profile on startup. Other 4-ball WLCSPs in the market typically offer fast, fixed output voltage rise times allowing large inrush currents.

For higher-power tablet pc applications, the SLG59M1735C is a 10.5 mΩ/4A n-FET IPS with a full suite of protection features. Powered from 2.5V to 5.5V supplies, the input voltage range extends down to 0.9V to accommodate 1.0V high-current rails found in FPGA, ASIC, and processor power sequencing applications. The SLG59M1735C feature set includes: ON/OFF control, soft-start control, undervoltage detection, and two-level current-limit protection. When compared to other packaged products in Silego’s GFET3 portfolio with similar features, the 1.5 mm² SLG59M1735C is a 50% smaller footprint. When compared to other 4A WLCSP/DFN products in the market with similar protection features, the SLG59M1735C is a 14% to 32% smaller footprint.

Product	Switch Type	RDS_ON	Continuous Operating Current	Supply Voltage Range, VDD	Input Voltage Range, VIN	Operating TA (°C)	WLCSP
SLG59M1735C	nFET	10.5 mΩ	4 A	2.5 V – 5.5 V	0.9 V – VDD	-40 to 85	8L 1.5 mm2
SLG59M1730C*	pFET	33 mΩ	1 A	—	2.5 V – 5.5 V	-40 to 85	4L 0.64 mm2
SLG59M1736V*	pFET	33 mΩ	2.2 A	—	2.5 V – 5.5 V	-40 to 85	4L 0.64 mm2

Using its own MOSFET design IP and its CuFET technology to efficiently eliminate a conventional lead-frame maximizes system-level performance while minimizing thermal gradients in space-constrained, medium-current applications.

As p-FET devices, the ‘30 and ‘36 parts need no separate VDD supply and are powered from the VIN line; the ‘35 uses an n-FET and therefore requires a charge pump (which is integrated), slightly raising the quiescent current consumption. Detail features include; internally-controlled inrush current profile (SLG59M1730C and SLG59M1736C); fast VOUT discharge (SLG59M1730C and SLG59M1736C); external capacitor-adjustable output voltage slew rate (SLG59M1735C); and two-level current-limit protection (SLG59M1735C).

Silego; www.silego.com