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? 2015 semtech corporation power management 1 SC21152 tiny 1.2a synchronous buck regulator with power good typical application circuit rev 1.0 features input voltage range 2.3v to 5.5v 1.2a continuous output current 4mhz switching frequency adjustable output voltage 1% output voltage accuracy adaptive on-time architecture up to 100% duty cycle up to 96% peak efciency power save mode for efcient light load operation >90% efciency 30ma to 75ma 0.1a shutdown current 21a quiescent current power good indicator pre-bias startup protection internal soft start 1.5mm x 2mm, 6-lead mlpd package weee and rohs compliant and halogen-free applications tablet pcs gps devices battery powered equipment portable devices smart phones wearable electronics ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? description the SC21152 is an ultra high efciency 1.2a dc/dc buck regulator available in a small mlpd package. these fea - tures make the SC21152 perfect for small form factor con - sumer applications where high efficiency is essential. SC21152 is an adaptive on-time 4mhz switching regula - tor at full load conditions. under light load conditions it transitions into pfm power save mode and reduces switch - ing frequency thus saving energy. high switching fre - quency operation allows the use of a very small 0.47h inductor along with small input and output capacitors to minimize overall circuit size. the SC21152 is highly confgurable with a wide range of factory options including internal soft start time, fxed or adjustable output voltage, automatic output discharge, and switching frequency. the SC21152 is ofered in a small 6-lead 1.5mm x 2mm mlpd package. adjustable output voltage 2 . 3 v - 5 . 5 v supply sc 21152 0 . 47 h 1 . 2 a output en vin lx en gnd fb 10 f 4 . 7 f pg power good fixed output voltage 2 . 3 v - 5 . 5 v supply sc 21152 0 . 47 h 1 . 2 a output en vin lx en gnd fb 10 f 4 . 7 f pg power good
SC21152 2 ordering information device (1)(2) options (3) package output (3) soft start (3) output discharge (3) SC21152aultrc adjustable 100s automatic 1.5mm x 2mm 6-lead mlpd SC21152evb evaluation board 1.5mm x 2.0mm 6-lead mlpd notes: (1) available in tape and reel only. a reel contains 3,000 devices. (2) lead-free packaging only. device is weee and rohs compliant and halogen-free. (3) for other device options not shown contact semtech marketing. the following options can be made available: vout options : adustable and fxed output voltage from 0.8v to 3.6v in 50mv increments. soft start options: internal 100s, 200s, 400s, or 800s. output discharge options: automatic discharge and no discharge. frequency: the default operating frequency is 4mhz with options of 2.2mhz, 3mhz, or 6mhz. pin confguration marking information 6 5 4 2 1 3 t o p v ie w 6 - l e a d m l p d 1 . 5 x 2 . 0 ( m m ) 1 . 5 x 2 . 0 ( m m ) 6 - l e a d m l p d t o p v ie w r c a oyw pin assignments 6-lead mlpd pin # name 1 vin 2 pg 3 en 4 fb 5 gnd 6 lx pad pad 1.5x2.0 (mm) 6-lead mlpd marking diagram rca = device marking code oyw = pin 1 indicator and date code SC21152 3 absolute maximum ratings vin (v) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.0 en, fb (v). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +(vin+0.3) pg (v) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (vin+0.3) lx (v). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +(vin+0.3) esd protection level (kv) (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 recommended operating conditions input voltage range (v) . . . . . . . . . . . . . . . . . . . . . . . . 2.3 to 5.5 output voltage range, adjustable vout (v) . . . 0.8 to vin output voltage range, fixed vout (v) . . . . . . . . . . 0.8 to 3.6 maximum continuous current (a). . . . . . . . . . . . . . . . . . . . . 1.2 junction temperature range (c) . . . . . . . . . -40 < t j < +125 thermal information thermal resistance junction to ambient (2) (c/w ) mlpd package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120 maximum junction temperature (c) . . . . . . . . . . . . . . +150 operating junction temperature (c ) . . . . . . . -40 to +125 storage temperature range (c) . . . . . . . . . . . . -65 to +150 peak ir refow temperature (10s to 30s) (c) . . . . . . . +260 exceeding the above specifcations may result in permanent damage to the device or device malfunction. operation outside of the parameters specifed in the electrical characteristics section is not recommended. notes: (1) tested according to jedec standard jesd22-a114-b. (2) calculated from package in still air, mounted to 3 x 4.5 (in), 4 layer fr4 pcb with thermal vias under the exposed pad per jesd51 standards. electrical characteristics unless otherwise noted vin = 5.0v, cin = 4.7f, cout = 10f, l = 0.47h, en = vin, t j = -40 to +125c. typical values are at t a = 25c. parameter symbol conditions min typ max units input supply input supply voltage range vin 2.3 5.5 v shutdown current isd en = 0v 0.1 a quiescent current iq operating, no load, power save option 21 a under voltage lock out threshold uvlorise vin rising edge 2.05 2.16 2.27 v under voltage lock out hysteresis uvlohyst 85 mv output voltage feedback voltage vfb adjustable vout option only 0.80 v feedback voltage tolerance vfbtol pwm operation, 500ma load -2 +/- 1 +2 % feedback input leakage current ifb adjustable vout option 1 25 na output voltage range vout adjustable output voltage 0.8 vin v SC21152 4 parameter symbol conditions min typ max units output voltage (continued) output voltage line regulation dvline 5.5v > vin > (vout +1), pwm operation 0.17 %/v output voltage load regulation dvload 500ma < iload < 1.2a -0.13 %/a maximum output current iout continuous current 1.2 a soft start (1) soft start time (1) tss fb: from rising edge to 95% of fnal value 100 s lx switching node on resistance high-side rdson_hs fb = 0v; ilx = 500ma 180 m? on resistance low-side rdson_ls fb = vin; ilx = 500ma 140 m? lx leakage current high side ilx_hs vin = 5.5v; fb = vin; vlx = 0v -1.5 -0.1 a lx leakage current low side ilx_ls fb = 0v; vlx = vin; vout automatic discharge disabled 0.1 1 a lx pulldown current (1) ilx_pd en = 0v; vlx = 1v; vout automatic discharge enabled 20 ma switching frequency (1) fsw 4mhz pwm operation, 500ma load, adjustable output, vout = 2.5v 3.6 4.0 4.4 mhz current sense high side current limit ilimhs current from vin to lx 1.5 2.2 3.0 a low side current limit ilimls current from lx to gnd -0.8 a zero cross detector threshold ithzcpfm power save mode and dc test condition 0 ma thermal protection over-temperature shutdown tts_rise rising temperature 160 c over-temperature hysteresis tts_hyst 10 c en input en input high threshold vihen 1.2 v en input low threshold vilen 0.4 v en input high current iihen ven = vin -1 a en input low current iilen ven = 0v 1 a electrical characteristics (continued) SC21152 5 electrical characteristics (continued) parameter symbol conditions min typ max units power good output (1) pg low voltage vlopg ipg = 5ma 0.4 v pg open leakage current iohpg vpg = vin 1 a power good threshold pgth fb rising edge, percentage of fb fnal value 95 % power good threshold hysteresis pgthhy percentage of fb fnal value (rising to falling edge) 3 % power good assert time pgtdr from fb = power good threshold to pg open drain 75 s power good deassert time pgtdf from falling edge of fb to pg pulled to gnd 13 s notes: (1) the SC21152 can be confgured with a range of options as shown. contact semtech marketing for more information. vout options: adjustable or fxed output voltage. for fxed vout, the voltage can be specifed from 0.8v to 3.6v in 50mv increments. soft start options: fixed 100s with options of 200s, 400s, and 800s. frequency options: operating frequency is 4mhz with options of 2.2mhz, 3mhz, or 6mhz. output discharge options: vout automatic discharge or no discharge. SC21152 6 typical characteristics efciency vs. load - 5vin 50 55 60 65 70 75 80 85 90 95 100 0.01 0.10 1.00 efficiency (%) load (a) 0.8v 1.0v 1.2v 1.5v 1.8v 2.2v 2.5v 3.3v efciency vs. load - 4.2vin 50 55 60 65 70 75 80 85 90 95 100 0.01 0.10 1.00 efficiency (%) load (a) 0.8v 1.0v 1.2v 1.5v 1.8v 2.2v 2.5v 3.3v efciency vs. load - 3.3vin 50 55 60 65 70 75 80 85 90 95 100 0.01 0.10 1.00 efficiency (%) load (a) 0.8v 1.0v 1.2v 1.5v 1.8v 2.2v 2.5v efciency vs. load - 2.3vin 50 55 60 65 70 75 80 85 90 95 100 0.01 0.10 1.00 efficiency (%) load (a) 0.8v 1.0v 1.2v 1.5v efciency vs. load - vout 1.0v 50 55 60 65 70 75 80 85 90 95 100 0.01 0.10 1.00 efficiency (%) load (a) 2.3vin 3.3vin 4.2vin 5.0vin vin = 5.0v, vout as shown, load = 0 to 1.2a vin = 4.2v, vout as shown, load = 0 to 1.2a vin = 3.3v, vout as shown, load = 0 to 1.2a vin = 2.3v, vout as shown, load = 0 to 1.2a efciency vs. load - vout 1.8v 50 55 60 65 70 75 80 85 90 95 100 0.01 0.10 1.00 efficiency (%) load (a) 2.3vin 3.3vin 4.2vin 5.0vin vin as shown, vout = 1.0v, load = 0 to 1.2a vin as shown, vout = 1.8v, load = 0 to 1.2a SC21152 7 typical characteristics frequency vs load - 5vin, pwm operation 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 frequency (mhz) load (a) 0.8v 1.0v 1.2v 1.5v 1.8v 2.2v 2.5v 3.3v frequency vs load - 3.3vin, pwm operation 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 frequency (mhz) load (a) 0.8v 1.0v 1.2v 1.5v 1.8v frequency vs load - 2.3vin, pwm operation 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 frequency (mhz) load (a) 0.8v 1.0v quiescent current vs output voltage 16 18 20 22 24 26 28 30 0.8 1.2 1.6 2.0 2.4 2.8 3.2 quiescent current (ua) vout (v) 2.3v 3.3v 4.2v 5.0v rds on vs. input voltage 80 120 160 200 240 280 320 360 2.3 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 rds on (m ? ) vin (v) high-side low-side vin = 5.0v, vout as shown, load = 0.5a to 1.2a vin = 3.3v, vout as shown, load = 0.5a to 1.2a vin = 2.3v, vout as shown, load = 0.5a to 1.2a vin as shown, vout as shown, no load, rbot = 100k rds on vs. temperature 80 100 120 140 160 180 200 220 240 260 280 -40 -25 -10 5 20 35 50 65 80 95 110 125 rds on (m ? ) junction temperature (c) high-side low-side vin = 2.3v, vout as shown, load = 0.5a to 1.2a vin = 2.3v, 3.3v,. 4.2v, 5.0v. vout as shown., no load, rbot = 100k SC21152 8 typical characteristics (continued) power save operation no load time (4ms/div) vin = 5v, vout = 1.5v, 0ma load vout (20mv/div) lx (5v/div) startup - vin ramp time (100s/div) vin = en = ramp to 2.3v , vout = 1.5v, 0ma load vout (0.5v/div) lx (5v/div) power save operation 50ma load time (2s/div) vin = 5v, vout = 1.5v, 50ma load vout (20mv/div) lx (5v/div) startup - en control time (100s/div) vout (0.5v/div) lx (5v/div) vin = 5v, vout = 1.5v, 0ma load pwm operation 1.2a time (200ns/div) vout (20mv/div) lx (5v/div) vin = 5v, vout = 1.5v, 1.2a load startup - 1.2a load time (100s/div) vout (2v/div) lx (5v/div) vin = 5v, vout = 3.3v, 1.2a load pg (2v/div) vin, en (2v/div) en (5v/div) pg (5v/div) en (5v/div) pg (5v/div) SC21152 9 typical characteristics (continued) load transient - power save pfm to pwm time (100s/div) vin = 5v, vout = 1.0v, load 0a to 1.2a to 0a vout (50mv/div) lx (5v/div) load transient - power save pfm to pwm time (100s/div) vin = 5v, vout = 3.3v, load 0a to 1.2a to 0a vout (0.1v/div) lx (5v/div) load transient - pwm to pwm time (100s/div) vin = 5v, vout = 1.0v, load 0.5a to 1.2a to 0.5a vout (50mv/div) lx (5v/div) load transient - pwm to pwm time (100s/div) load (1a/div) lx (5v/div) vin = 5v, vout = 3.3v, load 0.5a to 1.2a to 0.5a pwm minimum of operation time (2s/div) vout (50mv/div) lx (5v/div) vin = 3.6v, vout = 3.3v, 500ma load overcurrent shutdown and recovery time (2ms/div) vout (1v/div) lx (5v/div) vin = 5v, vout = 1.0v, load 0a to 2.0a to 0a load (1a/div) vout (0.1v/div) load (1a/div) load (1a/div) load (1a/div) SC21152 10 detailed application circuits adjustable output voltage 2 . 3 v - 5 . 5 v supply sc 21152 0 . 47 h 1 . 2 a output en vin lx en gnd fb 10 f 4 . 7 f pg power good fixed output voltage 2 . 3 v - 5 . 5 v supply sc 21152 0 . 47 h 1 . 2 a output en vin lx en gnd fb 10 f 4 . 7 f pg power good rbot rtop ctop vout l cin cout rtop ctop rbot 0.8v 0.47uh current rating 1.2a minimum murata lqm21pnr47mgh 2x1mm, 40m wurth 74479876147 2x1mm, 40m 4.7uf 0402 x5r 10uf 0402 x5r zero n/a n/a 1.0v 24.9k 22pf 100k 1.2v 49.9k 100k 1.5v 88.7k 100k 1.8v 124k 100k 2.2v 24.9k 100k 2.5v 174 100k 2.8v 249k 100k 3.3v 316k 100k SC21152 11 pin descriptions - 1.5x2mm 6-lead mlpd pin # pin name pin description 1 vin input supply voltage for the device and sense point for the input under voltage lock out. 2 pg power good output. open-drain power good indicator. an open indicates that the output voltage is in regulation. the power good pin requires an external pullup. 3 en enable input. connect to logic high or vin to enable the device. connect to logic low or gnd to dis - able the device. 4 fb feedback input (output voltage sense). for adjustable vout options, connect to the midpoint of a resistor divider between the output capacitor and gnd. for fxed vout options connect to the output capacitor. 5 gnd ground connection. 6 lx switching node connection to inductor. pad pad thernal ground for heatsinking. connect to gnd with multiple vias. block diagram p w m / p o w e r s a ve c o n tro lle r g n d v in g a in a m p l x e n p m o s n m o s r a m p g e n ic o m p p w m c o m p g a te d rive ic o m p r e f f ixe d / a d ju sta b le v o u t s e le ct d e vice e n a b le a n d u v l o p g p o w e r g o o d 1 6 5 4 3 2 f b p a d p a d f b SC21152 12 synchronous buck converter the SC21152 is a synchronous buck regulator that employs an adaptive on-time architecture to provide fast transient response and very small circuit area. the SC21152 oper - ates over an input voltage range of 2.3 to 5.5v. operating modes the SC21152 operates in one of four diferent modes depending on the status of vin, vout, and load. pwm adaptive on-time operation (aot) pwm minimum of-time operation (min of ) pfm (pulse frequency modulation for power saving) drop-out operation (ldo mode) pwm aot mode operation during pwm aot operation the controller uses adaptive on-time control. the fb ripple signal is routed to a gain stage and then to the internal comparator and reference which trigger the high-side pulses. the reference includes a compensation ramp which emulates the inductor current to provide stable switching. aot operation is used when the low-side pulse-width (of- time) is greater than the minimum 60nsec. a switching cycle in aot mode is as follows: on-time: the cycle starts with the high-side mosfet turn-on. the pulse width is set by the following formula where f sw is 4mhz: 6 : , 1 0 $ ; 2 8 7 2 1 i 9 9 7 u off-time: after the high-side on-time is com - pleted, the low-side mosfet turns on to begin the of-time. the of-time pulse width is set by the internal compensation ramp and under static conditions results in typically 4mhz switch - ing frequency. note that the SC21152 enters aot operation if vin is less than vout/0.88. pwm min of operation the device will enter minimum of-time operation (min of ) when vin, vout, and load conditions force the of- time (time between high-side pulses) to the minimum ? ? value, typically 60nsec. this indicates that the controller has reached maximum duty cycle for aot operation and longer duty cycles are needed. in min of operation the SC21152 uses constant of-time control. as in aot operation, the fb ripple signal is routed to a gain stage and then to the internal aot comparator and reference. in min of mode, the fb ripple triggers the low-side turn-on. min of switching cycle operation is as follows: of-time: the low-side mosfet is on for a fxed minimum of time of 60nsec. this draws current from the output capacitor through the inductor via the lx pin and causes the output to fall. on-time: after the min of time of 60nsec has elapsed, the high-side mosfet turns on. this helps recharge the output capacitor and bring the output voltage up. the on-time pulse width is determined by the internal compensation ramp. drop-out operation when operating in min of mode, the of-time is constant and the high-side on-time varies in order to regulate the output. for cases where vin is near vout, the high-side will remain on continually with 100% duty cycle. the output voltage will then be limited by the input voltage, high-side rds on and inductor dcr as shown in the fol - lowing equation: ' & |