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? semiconductor components industries, llc, 2002 march, 2002 rev. 2 1 publication order number: ncp1450a/d ncp1450a pwm step-up dc-dc controller the ncp1450a series are pwm stepup dcdc switching controller that are specially designed for powering portable equipment from one or two cells battery packs. the ncp1450a series have a driver pin, ext pin, for connecting to an external transistor. large output currents can be obtained by connecting a low onresistance external power transistor to the ext pin. the device will automatically skip switching cycles under light load condition to maintain high efficiency at light loads. with only six external components, this series allows a simple means to implement highly efficient converter for large output current applications. each device consists of an onchip pwm (pulse width modulation) oscillator, pwm controller, phasecompensated error amplifier, softstart, voltage reference, and driver for driving external power transistor. additionally, a chip enable feature is provided to power down the converter for extended battery life. the ncp1450a device series are available in the tsop5 package with five standard regulated output voltages. additional voltages that range from 1.8 v to 5.0 v in 100 mv steps can be manufactured. features ? high efficiency 86% at i o = 200 ma, v in = 2.0 v, v out = 3.0 v 88% at i o = 400 ma, v in = 3.0 v, v out = 5.0 v ? low startup voltage of 0.9 v typical at i o = 1.0 ma ? operation down to 0.6 v ? five standard voltages: 1.9 v, 2.7 v, 3.0 v, 3.3 v, 5.0 v with high accuracy 2.5% ? low conversion ripple ? high output current up to 1000 ma (3.0 v version at v in = 2.0 v, l = 10 h, c out = 220 f) ? fixed frequency pulse width modulation (pwm) at 180 khz ? chip enable pin with onchip pullup resistor ? low profile and micro miniature tsop5 package typical applications ? personal digital assistant (pda) ? electronic games ? portable audio (mp3) ? digital still cameras ? handheld instruments http://onsemi.com tsop5 sn suffix case 483 see detailed ordering and shipping information in the ordering information section on page 3 of this data sheet. ordering information pin connections and marking diagram 1 3 gnd ce 2 out nc 4 ext 5 xxxyw (top view) xxx = marking y = year w = work week 1 5
ncp1450a http://onsemi.com 2 1 3 gnd ce 2 out nc 4 ext 5 ncp1450a v in v out figure 1. typical stepup converter application figure 2. representative block diagram out 2 + voltage reference softstart pwm controller 180 khz oscillator driver error amplifier nc 3 gnd 4 1 ce ext 5 phase compensation pin function description pin # symbol pin description 1 ce chip enable pin (1) the chip is enabled if a voltage equal to or greater than 0.9 v is applied. (2) the chip is disabled if a voltage less than 0.3 v is applied. (3) the chip is enabled if this pin is left floating. 2 out output voltage monitor pin and also the power supply pin for the device. 3 nc no internal connection to this pin. 4 gnd ground pin. 5 ext external transistor drive pin.
ncp1450a http://onsemi.com 3 ordering information (note 1) device output voltage switching frequency marking package shipping ncp1450asn19t1 1.9 v day ncp1450asn27t1 2.7 v daz 3000 u it ncp1450asn30t1 3.0 v 180 khz dba tsop5 3000 units on 7 inch reel ncp1450asn33t1 3.3 v dbc on 7 inch reel ncp1450asn50t1 5.0 v dbd 1. the ordering information lists five standard output voltage device options. additional devices with output voltage ranging fr om 1.8 v to 5.0 v in 100 mv increments can be manufactured. contact your on semiconductor representative for availability. maximum ratings rating symbol value unit power supply voltage (pin 2) v out 6.0 v input/output pins ext (pin 5) ext sink/source current v ext i ext 0.3 to 6.0 150 to 150 v ma ce (pin 1) input voltage range input current range v ce i ce 0.3 to 6.0 150 to 150 v ma power dissipation and thermal characteristics maximum power dissipation @ t a = 25 c thermal resistance junction to air p d r q ja 500 250 mw c/w operating ambient temperature range t a 40 to +85 c operating junction temperature range t j 40 to +150 c storage temperature range t stg 55 to +150 c 2. this device series contains esd protection and exceeds the following tests: human body model (hbm) 2.0 kv per jedec standard: jesd22a114. machine model (mm) 200 v per jedec standard: jesd22a115. 3. latchup current maximum rating: 150 ma per jedec standard: jesd78. 4. moisture sensitivity level (msl): 1 per ipc/jedec standard: jstd020a.
ncp1450a http://onsemi.com 4 electrical characteristics (for all values t a = 25 c, unless otherwise noted.) characteristic symbol min typ max unit oscillator frequency (v out = v set 0.96, note 5) f osc 144 180 216 khz frequency temperature coefficient (t a = 40 c to 85 c) f 0.11 %/ c maximum pwm duty cycle (v out = v set 0.96) d max 70 80 90 % minimum startup voltage (i o = 0 ma) v start 0.8 0.9 v minimum startup voltage temperature coefficient (t a = 40 c to 85 c) v start 1.6 mv/ c minimum operation hold voltage (i o = 0 ma) v hold 0.6 0.7 v softstart time (v out = v set ) t ss 55 100 ms ce (pin 1) ce input voltage (v out = v set 0.96) high state, device enabled low state, device disabled v ce(high) v ce(low) 0.9 0.3 v ce input current (note 6) high state, device enabled (v out = v ce = 5.0 v) low state, device disabled (v out = 5.0 v, v ce = 0 v) i ce(high) i ce(low) 0.5 0 0 0.15 0.5 0.5 a ext (pin 5) ext aho output current (v ext = v out 0.4 v) device suffix: 19t1 27t1 30t1 33t1 50t1 i exth 25.0 35.0 37.7 40.0 53.7 20.0 30.0 30.0 30.0 35.0 ma ext alo output current(v ext = 0.4 v) device suffix: 19t1 27t1 30t1 33t1 50t1 i extl 20.0 30.0 30.0 30.0 35.0 38.3 48.0 50.8 52.0 58.2 ma total device output voltage device suffix: 19t1 27t1 30t1 33t1 50t1 v out 1.853 2.633 2.925 3.218 4.875 1.9 2.7 3.0 3.3 5.0 1.948 2.768 3.075 3.383 5.125 v output voltage temperature coefficient (t a = 40 to +85 c) v out 150 ppm/ c operating current (v out = v ce = v set 0.96, note 5) device suffix: 19t1 27t1 30t1 33t1 50t1 i dd 55 93 98 103 136 90 140 150 160 220 a standby current (v out = v ce = v set +0.5 v) i stb 15 20 a offstate current (v out = 5.0 v, v ce = 0 v, t a = 40 to +85 c, note 6) i off 0.6 1.5 a 5. v set means setting of output voltage. 6. ce pin is integrated with an internal 10 m pullup resistor.
ncp1450a http://onsemi.com 5 80 40 0 100 20 60 0 2.0 600 1.8 400 200 v out , output voltage (v) 1.6 i o , output current (ma) figure 3. ncp1450asn19t1 output voltage vs. output current figure 4. ncp1450asn30t1 output voltage vs. output current v out , output voltage (v) figure 5. ncp1450asn50t1 output voltage vs. output current i o , output current (ma) figure 6. ncp1450asn19t1 efficiency vs. output current i o , output current (ma) efficiency (%) v out , output voltage (v) figure 7. ncp1450asn30t1 efficiency vs. output current i o , output current (ma) figure 8. ncp1450asn50t1 efficiency vs. output current i o , output current (ma) efficiency (%) efficiency (%) 2.1 0.01 100 10 1 0.1 1000 i o , output current (ma) 1.7 1.9 800 1000 3.1 2.9 2.7 3.2 2.8 3.0 0 600 400 200 800 1000 0 600 400 200 800 1000 5.1 4.9 4.7 5.2 4.8 5.0 80 40 0 100 20 60 80 40 0 100 20 60 0.01 100 10 1 0.1 1000 0.01 100 10 1 0.1 1000 v in = 0.9 v v in = 1.2 v v in = 1.5 v v in = 2.0 v v in = 2.5 v v in = 4.0 v v in = 3.0 v v in = 2.5 v v in = 2.0 v v in = 4.5 v v in = 0.9 v v in = 1.2 v v in = 1.5 v v in = 0.9 v v in = 1.2 v v in = 1.5 v v in = 0.9 v v in = 1.2 v v in = 1.5 v v in = 2.0 v v in = 2.5 v v in = 4.0 v v in = 3.0 v v in = 4.5 v v in = 0.9 v v in = 1.2 v v in = 1.5 v v in = 2.0 v v in = 2.5 v v in = 0.9 v v in = 1.2 v v in = 1.5 v ncp1450asn19t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c ncp1450asn30t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c ncp1450asn50t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c ncp1450asn19t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c ncp1450asn30t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c ncp1450asn50t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c
ncp1450a http://onsemi.com 6 80 40 0 100 20 60 2.0 1.8 1.6 2.1 1.7 1.9 3.1 2.9 2.7 3.2 2.8 3.0 5.1 4.9 4.7 5.2 4.8 5.0 180 140 100 200 120 160 120 80 40 140 60 100 v out , output voltage (v) temperature ( c) figure 9. ncp1450asn19t1 output voltage vs. temperature figure 10. ncp1450asn30t1 output voltage vs. temperature v out , output voltage (v) figure 11. ncp1450asn50t1 output voltage vs. temperature temperature ( c) figure 12. ncp1450asn19t1 operating current vs. temperature temperature ( c) i dd , operating current ( a) v out , output voltage (v) figure 13. ncp1450asn30t1 operating current vs. temperature temperature ( c) figure 14. ncp1450asn50t1 operating current vs. temperature temperature ( c) i dd , operating current ( a) i dd , operating current ( a) temperature ( c) 50 50 25 0 25 75 100 50 50 25 0 25 75 100 50 50 25 0 25 75 100 50 50 25 0 25 75 100 50 50 25 0 25 75 100 50 50 25 0 25 75 100 ncp1450asn19t1 l = 22 h i o = 0 ma v in = 1.2 v ncp1450asn19t1 v out = 1.9 v x 0.96 openloop test ncp1450asn30t1 l = 22 h i o = 0 ma v in = 1.2 v ncp1450asn50t1 l = 22 h i o = 0 ma v in = 1.2 v ncp1450asn30t1 v out = 3.0 v x 0.96 openloop test ncp1450asn50t1 v out = 5.0 v x 0.96 openloop test
ncp1450a http://onsemi.com 7 i std , standby current ( a) temperature ( c) figure 15. ncp1450asn19t1 standby current vs. temperature figure 16. ncp1450asn30t1 standby current vs. temperature i std , standby current ( a) figure 17. ncp1450asn50t1 standby current vs. temperature temperature ( c) figure 18. ncp1450asn19t1 offstate current vs. temperature temperature ( c) i off , offstate current ( a) i std , standby current ( a) figure 19. ncp1450asn30t1 offstate current vs. temperature temperature ( c) figure 20. ncp1450asn50t1 offstate current vs. temperature temperature ( c) i off , offstate current ( a) i off , offstate current ( a) temperature ( c) 20 10 0 25 5 15 50 50 25 0 25 75 100 20 10 0 25 5 15 50 50 25 0 25 75 100 20 10 0 25 5 15 50 50 25 0 25 75 100 50 50 25 0 25 75 100 0.8 0.4 0.0 1.0 0.2 0.6 1.0 0.6 0.2 1.2 0.4 0.8 0.8 0.4 0.0 1.0 0.2 0.6 50 50 25 0 25 75 100 50 50 25 0 25 75 100 ncp1450asn19t1 v out = 1.9 v + 0.5 v openloop test ncp1450asn30t1 v out = 3.0 v + 0.5 v openloop test ncp1450asn50t1 v out = 5.0 v + 0.5 v openloop test ncp1450asn19t1 v out = 5.0 v v ce = 0 v openloop test ncp1450asn50t1 v out = 5.0 v v ce = 0 v openloop test ncp1450asn30t1 v out = 5.0 v v ce = 0 v openloop test
ncp1450a http://onsemi.com 8 50 50 25 0 25 75 100 50 50 25 0 25 75 100 70 f osc , oscillator frequency (khz) temperature ( c) figure 21. ncp1450asn19t1 oscillator frequency vs. temperature figure 22. ncp1450asn30t1 oscillator frequency vs. temperature figure 23. ncp1450asn50t1 oscillator frequency vs. temperature temperature ( c) figure 24. ncp1450asn19t1 maximum duty cycle vs. temperature temperature ( c) d max, maximum duty cycle (%) figure 25. ncp1450asn30t1 maximum duty cycle vs. temperature temperature ( c) figure 26. ncp1450asn50t1 maximum duty cycle vs. temperature temperature ( c) d max , maximum duty cycle (%) d max , maximum duty cycle (%) 80 50 60 40 90 100 temperature ( c) f osc , oscillator frequency (khz) f osc , oscillator frequency (khz) 250 150 0 300 100 200 50 50 25 0 25 75 100 50 250 150 0 300 100 200 50 250 150 0 300 100 200 50 50 50 25 0 25 75 100 50 50 25 0 25 75 100 50 50 25 0 25 75 100 70 80 50 60 40 90 100 70 80 50 60 40 90 100 ncp1450asn19t1 v out = 1.9 v x 0.96 openloop test ncp1450asn30t1 v out = 3.0 v x 0.96 openloop test ncp1450asn50t1 v out = 5.0 v x 0.96 openloop test ncp1450asn19t1 v out = 1.9 v x 0.96 openloop test ncp1450asn30t1 v out = 3.0 v x 0.96 openloop test ncp1450asn50t1 v out = 5.0 v x 0.96 openloop test
ncp1450a http://onsemi.com 9 50 50 25 0 25 75 100 80 70 60 50 40 30 60 50 40 70 80 90 40 60 30 50 70 20 20 20 i exth , ext aho output current (ma) 50 temperature ( c) figure 27. ncp1450asn19t1 ext aho output current vs. temperature figure 28. ncp1450asn30t1 ext aho output current vs. temperature i exth , ext aho output current (ma) 40 50 60 70 80 90 figure 29. ncp1450asn50t1 ext aho output current vs. temperature temperature ( c) figure 30. ncp1450asn19t1 ext alo output current vs. temperature temperature ( c) i exth , ext aho output current (ma) figure 31. ncp1450asn30t1 ext alo output current vs. temperature temperature ( c) figure 32. ncp1450asn50t1 ext alo output current vs. temperature temperature ( c) 0 30 10 0 40 50 temperature ( c) 40 30 10 50 50 25 0 25 75 10 0 i extl , ext alo output current (ma) i extl , ext alo output current (ma) i extl , ext alo output current (ma) 50 50 25 0 25 75 100 50 50 25 0 25 75 100 50 50 25 0 25 75 10 0 50 50 25 0 25 75 10 0 ncp1450asn19t1 v out = 1.9 v x 0.96 v ext = v out 0.4 v openloop test ncp1450asn30t1 v out = 3.0 v x 0.96 v ext = v out 0.4 v openloop test ncp1450asn50t1 v out = 5.0 v x 0.96 v ext = v out 0.4 v openloop test ncp1450asn19t1 v out = 1.9 v x 0.96 v ext = 0.4 v openloop test ncp1450asn50t1 v out = 5.0 v x 0.96 v ext = 0.4 v openloop test ncp1450asn30t1 v out = 3.0 v x 0.96 v ext = 0.4 v openloop test
ncp1450a http://onsemi.com 10 r exth , ext aho onresistance ( ) 20 10 r exth , ext aho onresistance ( ) 0 temperature ( c) figure 33. ncp1450asn19t1 ext aho onresistance vs. temperature figure 34. ncp1450asn30t1 ext aho onresistance vs. temperature r exth , ext aho onresistance ( ) figure 35. ncp1450asn50t1 ext aho onresistance vs. temperature temperature ( c) figure 36. ncp1450asn19t1 ext alo onresistance vs. temperature temperature ( c) r extl , ext alo onresistance ( ) figure 37. ncp1450asn30t1 ext alo onresistance vs. temperature temperature ( c) figure 38. ncp1450asn50t1 ext alo onresistance vs. temperature temperature ( c) r extl , ext alo onresistance ( ) 25 temperature ( c) 5 15 r extl , ext alo onresistance ( ) 50 50 25 0 25 75 100 50 50 25 0 25 75 10 0 20 10 0 25 5 15 20 10 0 25 5 15 20 10 0 25 5 15 20 10 0 25 5 15 20 10 0 25 5 15 50 50 25 0 25 75 10 0 50 50 25 0 25 75 100 50 50 25 0 25 75 100 50 50 25 0 25 75 10 0 ncp1450asn19t1 v out = 1.9 v x 0.96 v ext = v out 0.4 v openloop test ncp1450asn30t1 v out = 3.0 v x 0.96 v ext = v out 0.4 v openloop test ncp1450asn50t1 v out = 5.0 v x 0.96 v ext = v out 0.4 v openloop test ncp1450asn19t1 v out = 1.9 v x 0.96 v ext = 0.4 v openloop test ncp1450asn50t1 v out = 5.0 v x 0.96 v ext = 0.4 v openloop test ncp1450asn30t1 v out = 3.0 v x 0.96 v ext = 0.4 v openloop test
ncp1450a http://onsemi.com 11 0.6 0.2 0.8 0.4 0.0 1.0 160 0.8 0.4 v start /v hold, startup/hold voltage (v) 0.0 temperature ( c) figure 39. ncp1450asn19t1 startup/hold voltage vs. temperature figure 40. ncp1450asn30t1 startup/hold voltage vs. temperature figure 41. ncp1450asn50t1 startup/hold voltage vs. temperature temperature ( c) figure 42. ncp1450asn19t1 ripple voltage vs. output current i o , output current (ma) v ripple , ripple voltage (mv) figure 43. ncp1450asn30t1 ripple voltage vs. output current i o , output current (ma) figure 44. ncp1450asn50t1 ripple voltage vs. output current i o , output current (ma) v ripple , ripple voltage (mv) v ripple , ripple voltage (mv) 1.0 0 800 600 400 200 1000 120 180 100 140 80 60 200 temperature ( c) 0.2 0.6 50 50 25 0 25 75 100 50 50 25 0 25 75 10 0 v start /v hold, startup/hold voltage (v) v start /v hold, startup/hold voltage (v) 0.8 0.4 0.0 1.0 0.2 0.6 50 50 25 0 25 75 100 40 20 0 0 800 600 400 200 1000 0 800 600 400 200 1000 160 120 180 100 140 80 60 200 40 20 0 160 120 180 100 140 80 60 200 40 20 0 ncp1450asn19t1 l = 22 h c out = 0.1 f i o = 0 ma v hold v start v hold v start v hold v start ncp1450asn30t1 l = 22 h c out = 0.1 f i o = 0 ma ncp1450asn50t1 l = 22 h c out = 0.1 f i o = 0 ma ncp1450asn19t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c ncp1450asn50t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c ncp1450asn30t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c v in = 0.9 v v in = 0.9 v v in = 1.2 v v in = 1.5 v v in = 1.2 v v in = 1.5 v v in = 2.0 v v in = 2.5 v v in = 4.0 v v in = 4.5 v v in = 3.0 v v in = 2.0 v v in = 2.5 v v in = 0.9 v v in = 1.2 v v in = 1.5 v
ncp1450a http://onsemi.com 12 0 1.2 60 40 20 0.0 i o , output current (ma) figure 45. ncp1450asn19t1 startup/hold voltage vs. output current (using mosfet) figure 46. ncp1450asn19t1 startup/hold voltage vs. output current (using bjt) figure 47. ncp1450asn30t1 startup/hold voltage vs. output current (using mosfet) i o , output current (ma) figure 48. ncp1450asn30t1 startup/hold voltage vs. output current (using bjt) i o , output current (ma) figure 49. ncp1450asn50t1 startup/hold voltage vs. output current (using mosfet) i o , output current (ma) figure 50. ncp1450asn50t1 startup/hold voltage vs. output current (using bjt) i o , output current (ma) 2.0 i o , output current (ma) 0.4 0.8 1.6 80 100 v start /v hold, startup/hold voltage (v) v start /v hold, startup/hold voltage (v) v start /v hold, startup/hold voltage (v) v start /v hold, startup/hold voltage (v) v start /v hold, startup/hold voltage (v) v start /v hold, startup/hold voltage (v) 060 40 20 80 100 1.2 0.0 2.0 0.4 0.8 1.6 1.2 0.0 2.0 0.4 0.8 1.6 1.2 0.0 2.0 0.4 0.8 1.6 1.2 0.0 2.0 0.4 0.8 1.6 1.2 0.0 2.0 0.4 0.8 1.6 060 40 20 80 100 0 60 40 20 80 100 060 40 20 80 100 0 60 40 20 80 100 v hold v start ncp1450asn30t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c v hold v start ncp1450asn19t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c ncp1450asn19t1 l = 10 h q = mmjt9410 c out = 220 f t a = 25 c v hold v start v hold v start ncp1450asn30t1 l = 10 h q = mmjt9410 c out = 220 f t a = 25 c v hold v start ncp1450asn50t1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c ncp1450asn50t1 l = 10 h q = mmjt9410 c out = 220 f t a = 25 c v hold v start
ncp1450a http://onsemi.com 13 figure 51. ncp1450asn19t1 operating waveforms (medium load) figure 52. ncp1450asn19t1 operating waveforms (heavy load) figure 53. ncp1450asn30t1 operating waveforms (medium load) figure 54. ncp1450asn30t1 operating waveforms (heavy load) figure 55. ncp1450asn50t1 operating waveforms (medium load) figure 56. ncp1450asn50t1 operating waveforms (heavy load) 2 s/div v out = 1.9 v, v in = 1.2 v, i o = 500 ma, l = 10 h, c out = 220 f 1. v l , 1.0 v/div 2. i l , 500 ma/div 3. v out , 50 mv/div, ac coupled 2 s/div v out = 1.9 v, v in = 1.2 v, i o = 20 ma, l = 10 h, c out = 220 f 1. v l , 1.0 v/div 2. i l , 500 ma/div 3. v out , 50 mv/div, ac coupled 2 s/div v out = 3.0 v, v in = 1.8 v, i o = 500 ma, l = 10 h, c out = 220 f 1. v l , 2.0 v/div 2. i l , 500 ma/div 3. v out , 50 mv/div, ac coupled 2 s/div v out = 3.0 v, v in = 1.8 v, i o = 20 ma, l = 10 h, c out = 220 f 1. v l , 2.0 v/div 2. i l , 500 ma/div 3. v out , 50 mv/div, ac coupled 2 s/div v out = 5.0 v, v in = 3.0 v, i o = 500 ma, l = 10 h, c out = 220 f 1. v l , 2.0 v/div 2. i l , 500 ma/div 3. v out , 50 mv/div, ac coupled 2 s/div v out = 5.0 v, v in = 3.0 v, i o = 20 ma, l = 10 h, c out = 220 f 1. v l , 2.0 v/div 2. i l , 500 ma/div 3. v out , 50 mv/div, ac coupled
ncp1450a http://onsemi.com 14 figure 57. ncp1450asn19t1 load transient response figure 58. ncp1450asn19t1 load transient response figure 59. ncp1450asn30t1 load transient response figure 60. ncp1450asn30t1 load transient response figure 61. ncp1450asn50t1 load transient response figure 62. ncp1450asn50t1 load transient response v in = 1.5 v, l = 4.7 h, c out = 220 f 1. v out , 1.9 v (ac coupled), 200 mv/div 2. i o , 100 ma to 1.0 ma v in = 1.5 v, l = 4.7 h, c out = 220 f 1. v out , 1.9 v (ac coupled), 200 mv/div 2. i o , 1.0 ma to 100 ma v in = 2.0 v, l = 4.7 h, c out = 220 f 1. v out , 3.0 v (ac coupled), 200 mv/div 2. i o , 100 ma to 1.0 ma v in = 2.0 v, l = 4.7 h, c out = 220 f 1. v out , 3.0 v (ac coupled), 200 mv/div 2. i o , 1.0 ma to 100 ma v in = 3.0 v, l = 4.7 h, c out = 220 f 1. v out , 5.0 v (ac coupled), 200 mv/div 2. i o , 100 ma to 1.0 ma v in = 3.0 v, l = 4.7 h, c out = 220 f 1. v out , 5.0 v (ac coupled), 200 mv/div 2. i o , 1.0 ma to 100 ma
ncp1450a http://onsemi.com 15 2.9 3.1 3.0 2.7 3.2 60 0 2.0 600 1.8 400 200 v out , output voltage (v) 1.6 i o , output current (ma) figure 63. ncp1450asn19t1 output voltage vs. output current (ext. bjt) figure 64. ncp1450asn30t1 output voltage vs. output current (ext. bjt) v out , output voltage (v) 5.2 5.1 5.0 4.9 4.8 4.7 figure 65. ncp1450asn50t1 output voltage vs. output current (ext. bjt) i o , output current (ma) figure 66. ncp1450asn19t1 efficiency vs. output current (ext. bjt) i o , output current (ma) efficiency (%) v out , output voltage (v) figure 67. ncp1450asn30t1 efficiency vs. output current (ext. bjt) i o , output current (ma) figure 68. ncp1450asn50t1 efficiency vs. output current (ext. bjt) i o , output current (ma) efficiency (%) efficiency (%) 2.1 20 40 0 80 100 i o , output current (ma) 1.7 1.9 800 1000 2.8 60 20 40 0 80 100 60 20 40 0 80 100 0 600 400 200 800 1000 0.01 10 1 0.1 100 1000 0.01 10 1 0.1 100 1000 0.01 10 1 0.1 100 1000 0 600 400 200 800 1000 ncp1450asn19t1 l = 10 h q = mmjt9410 r b = 560 c b = 0.003 f c out = 220 f t a = 25 c v in = 2.5 v v in = 2.0 v v in = 1.5 v v in = 1.2 v v in = 0.9 v v in = 4.5 v v in = 0.9 v v in = 1.2 v v in = 2.0 v v in = 4.0 v v in = 3.0 v v in = 0.9 v v in = 1.2 v v in = 1.5 v v in = 0.9 v v in = 1.2 v ncp1450asn30t1 l = 10 h q = mmjt9410 r b = 560 c b = 0.003 f c out = 220 f t a = 25 c v in = 2.5 v v in = 2.0 v v in = 1.5 v v in = 1.5 v v in = 1.2 v v in = 0.9 v ncp1450asn19t1 l = 10 h q = mmjt9410 r b = 560 c b = 0.003 f c out = 220 f t a = 25 c v in = 2.5 v v in = 1.5 v ncp1450asn50t1 l = 10 h q = mmjt9410 r b = 560 c b = 0.003 f c out = 220 f t a = 25 c v in = 4.5 v v in = 1.5 v v in = 1.2 v ncp1450asn30t1 l = 10 h q = mmjt9410 r b = 560 c b = 0.003 f c out = 220 f t a = 25 c v in = 4.0 v v in = 3.0 v v in = 2.5 v v in = 2.0 v v in = 0.9 v ncp1450asn50t1 l = 10 h q = mmjt9410 r b = 560 c b = 0.003 f c out = 220 f t a = 25 c
ncp1450a http://onsemi.com 16 14 0.1 3 2 i in , no load input current (ma) 0.01 v in , input voltage (v) figure 69. ncp1450asnxxt1 no load input current vs. input voltage (using mosfet) figure 70. ncp1450asnxxt1 no load input current vs. input voltage (using bjt) i in , no load input current (ma) 10 v in , input voltage (v) 1 51 4 3 25 0 0.1 0.01 100 1 10 a. v out = 1.9 v, r b = 1 k b. v out = 3.0 v, r b = 1 k c. v out = 5.0 v, r b = 1 k d. v out = 1.9 v, r b = 560 e. v out = 3.0 v, r b = 560 f. v out = 5.0 v, r b = 560 ncp1450asnxxt1 l = 10 h q = mmjt9410 c out = 220 f t a = 25 c a d b e c f ncp1450asnxxt1 l = 10 h q = ntgs3446t1 c out = 220 f t a = 25 c v out = 5.0 v v out = 3.0 v v out = 1.9 v
ncp1450a http://onsemi.com 17 detailed operating description operation the ncp1450a series are monolithic power switching controllers optimized for battery powered portable products where large output current is required. the ncp1450a series are low noise fixed frequency voltagemode pwm dcdc controllers, and consist of startup circuit, feedback resistor divider, reference voltage, oscillator, loop compensation network, pwm control circuit, and low on resistance driver. due to the onchip feedback resistor and loop compensation network, the system designer can get the regulated output voltage from 1.8 v to 5.0 v with 0.1 v stepwise with a small number of external components. the quiescent current is typically 93 a (v out = 2.7 v, f osc = 180 khz), and can be further reduced to about 1.5 a when the chip is disabled (v ce 0.3 v). the ncp1450a operation can be best understood by referring to the block diagram in figure 2. the error amplifier monitors the output voltage via the feedback resistor divider by comparing the feedback voltage with the reference voltage. when the feedback voltage is lower than the reference voltage, the error amplifier output will decrease. the error amplifier output is then compared with the oscillator ramp voltage at the pwm controller. when the ramp voltage is higher than the error amplifier output, the highside driver is turned on and the lowside driver is turned off which will then switch on the external transistor; and vice versa. as the error amplifier output decreases, the highside driver turnon time increases and duty cycle increases. when the feedback voltage is higher than the reference voltage, the error amplifier output increases and the duty cycle decreases. when the external power switch is on, the current ramps up in the inductor, storing energy in the magnetic field. when the external power switch is off, the energy stored in the magnetic field is transferred to the output filter capacitor and the load. the output filter capacitor stores the charge while the inductor current is higher than the output current, then sustains the output voltage until the next switching cycle. as the load current is decreased, the switch transistor turns on for a shorter duty cycle. under the light load condition, the controller will skip switching cycles to reduce power consumption, so that high efficiency is maintained at light loads. soft start there is a soft start circuit in ncp1450a. when power is applied to the device, the soft start circuit first pumps up the output voltage to approximately 1.5 v at a fixed duty cycle. this is the voltage level at which the controller can operate normally. in addition to that, the startup capability with heavy loads is also improved. oscillator the oscillator frequency is internally set to 180 khz at an accuracy of 20% and with low temperature coefficient of 0.11%/ c. regulated converter voltage (v out ) the v out is set by an integrated feedback resistor network. t his is trimmed to a selected voltage from 1.8 v to 5.0 v range in 100 mv steps with an accuracy of 2.5%. compensation the device is designed to operate in continuous conduction mode. an internal compensation circuit was designed to guarantee stability over the full input/output voltage and full output load range. enable/disable operation the ncp1450a series offer ic shutdown mode by chip enable pin (ce pin) to reduce current consumption. when voltage at pin ce is equal or greater than 0.9 v, the chip will be enabled, which means the controller is in normal operation. w hen voltage at pin ce is less than 0.3 v, the chip is disabled, which means ic is shutdown. important: do not apply a voltage between 0.3 v to 0.9 v to pin ce as this is the ce pin's hysteresis voltage range. clearly defined output states can only be obtained by applying voltage out of this range.
ncp1450a http://onsemi.com 18 application circuit information stepup converter design equations the ncp1450a pwm stepup dcdc controller is designed to operate in continuous conduction mode and can be defined by the following equations. external components values can be calculated from these equations, however, the optimized value should obtained through experimental results. calculation equation d
v out v d v in v out v d v s i l i o (1 d) l (v out v d v in )(1 d) 2 f i o dir i pk i l (1 dir 2 ) q (i l i o )(1 d) f v pp q c out (i l i o ) esr notes: d ontime duty cycle i l average inductor current i pk peak inductor current dir delta inductor current to average inductor current ratio i o desired dc output current v in nominal operating dc input voltage v out desired dc output voltage v d diode forward voltage v s saturation voltage of the external transistor switch q charge stores in the c out during charging up esr equivalent series resistance of the output capacitor design example it is supposed that a stepup dcdc controller with 3.3 v output delivering a maximum 1000 ma output current with 100 mv output ripple voltage powering from a 2.4 v input is to be designed. design parameters: v in = 2.4 v v out = 3.3 v i o = 1.0 a v pp = 100 mv f = 180 khz dir = 0.2 (typical for small output ripple voltage) assume the diode forward voltage and the transistor saturation voltage are both 0.3 v. determine the maximum steady state duty cycle at v in = 2.4 v: d 3.3v 0.3v 2.4v 3.3v 0.3v 3.0v 0.364 calculate the maximum inductance value which can generate the desired current output and the preferred delta inductor current to average inductor current ratio: l
(3.3v 0.3v 2.4v)(1 0.364) 2 180000hz 1a 0.2 13.5 h determine the average inductor current and peak inductor current: i l 1 1 0.364 1.57a i pk 1.57a (1 0.2 2 ) 1.73a therefore, a 12 h inductor with saturation current larger than 1.73 a can be selected as the initial trial. calculate the delta charge stored in the output capacitor during the charging up period in each switching cycle: q (1.57a 1a)(1 0.364) 18000hz 2.01 c determine the output capacitance value for the desired output ripple voltage: assume the esr of the output capacitor is 0.15 , c out 2.01 c 100mv (1.57a 1a) 0.15 138.6 f therefore, a tantalum capacitor with value of 150 f to 220 f and esr of 0.15 can be used as the output capacitor. however, according to experimental result, 220 f output capacitor gives better overall operational stability and smaller ripple voltage. external component selection inductor selection the ncp1450a is designed to work well with a 6.8 to 12 h inductors in most applications 10 h is a sufficiently low value to allow the use of a small surface mount coil, but large enough to maintain low ripple. lower inductance values supply higher output current, but also increase the ripple and reduce efficiency. higher inductor values reduce ripple and improve efficiency, but also limit output current. the inductor should have small dcr, usually less than 1 , to minimize loss. it is necessary to choose an inductor with a saturation current greater than the peak current which the inductor will encounter in the application.
ncp1450a http://onsemi.com 19 diode the diode is the largest source of loss in dcdc converters. the most importance parameters which affect their efficiency are the forward voltage drop, v d , and the reverse recovery time, trr. the forward voltage drop creates a loss just by having a voltage across the device while a current flowing through it. the reverse recovery time generates a loss when the diode is reverse biased, and the current appears to actually flow backwards through the diode due to the minority carriers being swept from the pn junction. a schottky diode with the following characteristics is recommended: small forward voltage, v f 0.3 v small reverse leakage current fast reverse recovery time/switching speed rated current larger than peak inductor current, i rated i pk reverse voltage larger than output voltage, v reverse v out input capacitor the input capacitor can stabilize the input voltage and minimize peak current ripple from the source. the value of the capacitor depends on the impedance of the input source used. small esr (equivalent series resistance) tantalum or ceramic capacitor with a value of 10 f should be suitable. output capacitor the output capacitor is used for sustaining the output voltage when the external mosfet or bipolar transistor is switched on and smoothing the ripple voltage. low esr capacitor should be used to reduce output ripple voltage. in general, a 100 f to 220 f low esr (0.10 to 0.30 ) tantalum capacitor should be appropriate. external switch transistor an enhancement nchannel mosfet or a bipolar npn transistor can be used as the external switch transistor. for enhancement nchannel mosfet, since enhancement mosfet is a voltage driven device, it is a more efficient switch than a bjt transistor. however, the mosfet requires a higher voltage to turn on as compared with bjt transistors. an enhancement nchannel mosfet can be selected by the following guidelines: 1. low onresistance, r ds(on) , typically < 0.1 . 2. low gate threshold voltage, v gs(th) , must be < v out , typically < 1.5 v, it is especially important for the low v out device, like v out = 1.9 v. 3. rated continuous drain current, i d , should be larger than the peak inductor current, i.e. i d > i pk . 4. gate capacitance should be 1200 pf or less. for bipolar npn transistor, medium power transistor with continuous collector current typically 1 a to 5 a and v ce(sat) < 0.2 v should be employed. the driving capability is determined by the dc current gain, h fe , of the transistor and the base resistor, rb; and the controller's ext pin must be able to supply the necessary driving current. rb can be calculated by the following equation: rb v out 0.7 ib 0.4 | i exth | ib i pk h fe since the pulse current flows through the transistor, the exact rb value should be finely tuned by the experiment. generally, a small rb value can increase the output current capability, but the efficiency will decrease due to more energy is used to drive the transistor. moreover, a speedup capacitor, cb, should be connected in parallel with rb to reduce switching loss and improve efficiency. cb can be calculated by the equation below: cb
1 2 rb f osc 0.7 it is due to the variation in the characteristics of the transistor used. the calculated value should be used as the initial test value and the optimized value should be obtained by the experiment. external component reference data device v out inductor model inductor value external transistor diode output capacitor ncp1450asn19t1 1.9 v cd54 12 h ntgs3446t1 mbrm110l 220 f ncp1450asn30t1 3.0 v cd54 10 h ntgs3446t1 mbrm110l 220 f ncp1450asn50t1 5.0 v cd54 10 h ntgs3446t1 mbrm110l 220 f ncp1450asn19t1 1.9 v cd54 12 h mmjt9410 mbrm110l 220 f ncp1450asn30t1 3.0 v cd54 10 h mmjt9410 mbrm110l 220 f ncp1450asn50t1 5.0 v cd54 10 h mmjt9410 mbrm110l 220 f
ncp1450a http://onsemi.com 20 an evaluation board of ncp1450a has been made in the small size of 89 mm x 51 mm. the artwork and the silk screen of the surfacemount evaluation board pcb are shown in figures 71 and 72. please contact your on semiconductor representative for availability. the evaluation board schematic diagrams are shown in figures 73 and 74. figure 71. ncp1450a pwm stepup dcdc controller evaluation board silkscreen 89 mm 51 mm figure 72. ncp1450a pwm stepup dcdc controller evaluation board artwork (component side) 89 mm 51 mm
ncp1450a http://onsemi.com 21 1 3 gnd ce 2 out nc 4 ext 5 ncp1450a tp1 v in tp4 gnd tp3 v out tp2 gnd c1 220 f l1 10 h jp1 c2 10 f ntgs3446t1 on off ce d1 mbrm110l q1 ic1 1 3 gnd ce 2 out nc 4 ext 5 ncp1450a tp5 v in tp6 gnd tp7 v out tp8 gnd c4 220 f l2 10 h jp2 c5 10 f on off ce d2 mbrm110l ic2 q2 mmjt9410 cb 3000 pf rb 560 figure 73. ncp1450a evaluation board schematic diagram 1 (stepup dcdc converter using external mosfet switch) figure 74. ncp1450a evaluation board schematic diagram 2 (stepup dcdc converter using external bipolar transistor switch) c3 0.1 f c6 0.1 f pcb layout hints grounding one point grounding should be used for the output power return ground, the input power return ground, and the device switch ground to reduce noise. in figure 73, e.g.: c2 gnd, c1 gnd, and ic1 gnd are connected at one point in the evaluation board. the input ground and output ground traces must be thick enough for current to flow through and for reducing ground bounce. power signal traces low resistance conducting paths should be used for the power carrying traces to reduce power loss so as to improve efficiency (short and thick traces for connecting the inductor l can also reduce stray inductance), e.g.: short and thick traces listed below are used in the evaluation board: 1. trace from tp1 to l1 2. trace from l1 to anode pin of d1 3. trace from cathode pin of d1 to tp3 output capacitor the output capacitor should be placed close to the output terminals to obtain better smoothing effect on the output ripple. switching noise decoupling capacitor a 0.1 f ceramic capacitor should be placed close to the out pin and gnd pin of the ncp1450a to filter the switching spikes in the output voltage monitored by the out pin.
ncp1450a http://onsemi.com 22 components supplier parts supplier part number description phone inductor: l1, l2 sumida electric co. ltd. cd54100mc inductor 10 h/1.44 a (852) 28806688 schottky diode: d1, d2 on semiconductor mbrm110l schottky power rectifier (852) 26890088 mosfet: q1 on semiconductor ntgs3446t1 power mosfet nchannel (852) 26890088 bjt: q2 on semiconductor mmjt9410 bipolar power transistor (852) 26890088 output capacitor: c1, c3 kemet electronics corp. t494d227k006as low esr tantalum capacitor 220 f/6.0 v (852) 23051168 input capacitor: c2, c4 kemet electronics corp. t491c106k016as low profile tantalum capacitor 10 f/16 v (852) 23051168 minimum recommended footprint for surface mounted applications surface mount board layout is a critical portion of the total design. the footprint for the semiconductor packages must be the correct size to insure proper solder connection interface between the board and the package. with the correct pad geometry, the packages will self align when subjected to a solder reflow process. inches mm 0.028 0.7 0.074 1.9 0.037 0.95 0.037 0.95 0.094 2.4 0.039 1.0 tsop5 (footprint compatible with sot235) tsop5 t1 orientation 8 mm
ncp1450a http://onsemi.com 23 package dimensions tsop5 sn suffix case 48301 issue b notes: 1. dimensioning and tolerancing per ansi y14.5m, 1982. 2. controlling dimension: millimeter. 3. maximum lead thickness includes lead finish thickness. minimum lead thickness is the minimum thickness of base material. dim min max min max inches millimeters a 2.90 3.10 0.1142 0.1220 b 1.30 1.70 0.0512 0.0669 c 0.90 1.10 0.0354 0.0433 d 0.25 0.50 0.0098 0.0197 g 0.85 1.05 0.0335 0.0413 h 0.013 0.100 0.0005 0.0040 j 0.10 0.26 0.0040 0.0102 k 0.20 0.60 0.0079 0.0236 l 1.25 1.55 0.0493 0.0610 m 0 10 0 10 s 2.50 3.00 0.0985 0.1181 0.05 (0.002) 123 54 s a g l b d h c k m j
ncp1450a http://onsemi.com 24 on semiconductor and are trademarks of semiconductor components industries, llc (scillc). scillc reserves the right to make changes without further notice to any products herein. scillc makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does scillc assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. atypicalo parameters which may be provided in scill c data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. all operating parameters, including atypicalso must be validated for each customer application by customer's technical experts. scillc does not convey any license under its patent rights nor the rights of others. scillc products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body , or other applications intended to support or sustain life, or for any other application in which the failure of the scillc product could create a sit uation where personal injury or death may occur. should buyer purchase or use scillc products for any such unintended or unauthorized application, buyer shall indemnify and hold scillc and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthori zed use, even if such claim alleges that scillc was negligent regarding the design or manufacture of the part. scillc is an equal opportunity/affirmative action employer. publication ordering information japan : on semiconductor, japan customer focus center 4321 nishigotanda, shinagawaku, tokyo, japan 1410031 phone : 81357402700 email : r14525@onsemi.com on semiconductor website : http://onsemi.com for additional information, please contact your local sales representative. ncp1450a/d literature fulfillment : literature distribution center for on semiconductor p.o. box 5163, denver, colorado 80217 usa phone : 3036752175 or 8003443860 toll free usa/canada fax : 3036752176 or 8003443867 toll free usa/canada email : onlit@hibbertco.com n. american technical support : 8002829855 toll free usa/canada

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