ver: 0.4 oct 31, 2013 tel: 886-3-5788833 http://www.gmt.com.tw 1 G2120 global mixed-mode technology 3 channels, high efficiency, synchronous step down with ldo features ? continuous loading: 3a (buck 1), 1a (buck 2 and 3) ? 1mhz switching frequency ? 1.0v 2% voltage reference over temperature ? external enable/sequencing and soft start pins ? adjustable soft start ? power good output ? cycle by cycle current limit, thermal and overload protection. ? built in 500ma ldo ? thermally enhanced 4mm 4mm 28-pin qfn applications ? set top boxes ? blue-ray dvd general description the G2120 device features three synchronous 5.5v input range high efficiency buck converters. the con- verters are designed to simplify its application while giving the designer the option to optimize their usage according to the target application. the converters can operate in 5v systems and have integrated power transistors. the output voltage can be set externally using a resistor divider to any value between 1.0v and close to the input supply. each converter features enable pin that allows a delayed start-up for sequencing purposes, soft start pin that allows adjustable soft-start time by choosing the soft-start capacitor. the current mode control allows a simple rc compensation. the switching frequency of the converters can operate 1 mhz. the G2120 features a supervisor circuit that monitors each converter output. the pgood pin is asserted once sequencing is done, all pg signals are reported and a selectable end of reset time lapses. the polarity of the pgood signal is active high. the G2120 buck1 also features a light load pulse skipping mode, psm mode allows for a reduction on the input power supplied to the system when the host processor is in stand-by (low activity) mode. ordering information order number marking temp. range package (green) G2120rv1u 2120 -40 c to +85 c tqfn4x4-28 note: rv: tqfn4x4-28 1: bonding code u: tape & reel pin configuration typical application circuit G2120 vin en pgood gnd ep v33p c i33 5v v33 c o33 3.3v mode ss1 comp1 fb1 lx1 bs1 c o1 c bs1 l 1 1.2v c ss1 r c1 c c1 pvcc1 c i1 5v en1 c z1 ss2 comp2 fb2 lx2 c o2 l 2 1.5v c ss2 r c2 c c2 pvcc2 en2 c z2 c d1 c i2 5v r 2 r 1 r 4 r 3 c d2 ss3 comp3 fb3 lx3 c o3 l 3 3.3v c ss3 r c3 c c3 pvcc3 en3 c z3 c i3 5v r 6 r 5 c d3 c en1 c i 5v r pg c i0 r i c in c o331 c i11 c i21 c i31 G2120 tqfn4x4-28 en3 pvcc3 lx3 mode lx2 pvcc2 v33 pgood bs1 pvcc1 pvcc1 lx1 1 2 3 4 5 6 16 17 18 19 20 21 gnd fb3 v33p vin comp3 ss3 27 22 23 24 26 25 fb1 en1 fb2 8 9 10 11 12 comp1 ss1 thermal pad (pgnd) 7 ss2 13 14 comp2 en2 15 en 28 lx1 note: recommend connecting the thermal pad to the round for excellent power dissipation. G2120 tqfn4x4-28 en3 pvcc3 lx3 mode lx2 pvcc2 v33 pgood bs1 pvcc1 pvcc1 lx1 1 2 3 4 5 6 16 17 18 19 20 21 gnd fb3 v33p vin comp3 ss3 27 22 23 24 26 25 fb1 en1 fb2 8 9 10 11 12 comp1 ss1 thermal pad (pgnd) 7 ss2 13 14 comp2 en2 15 en 28 lx1 note: recommend connecting the thermal pad to the round for excellent power dissipation.
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