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ht7936a/ht7936b white led step-up charge pump converter selection table part no. output voltage tolerance package marking ht7936a 5.0v 4% sot23-6 936a ht7936b 4.5v 4% sot23-6 936b rev 1.30 1 june 25, 2016 features input voltage range: 2.8v to v out driving current: 110ma (ht7936a), 150ma (ht7936b) fixed output voltage: 5v (ht7936a), 4.5v (ht7936b) oscillator frequency: 1mhz soft start function, current limit, short circuit protection small outline sot23-6 package applications cellular phones pdas dscs handheld devices white led display backlighting general description the ht7936a and ht7936b are charge-pump type dc-dc step-up converter devices, which can generate regulated fixed output voltages of 5.0v and 4.5v. their high degree of functional integration requires only the addition of three external capacitors, namely a flying ca - pacitor and an input and output capacitor, to implement a full step-up conversion function. the devices have the additional benefit of an integrated soft start function to reduce the level of in-rush current during device power on. the operating voltage range is from 2.8v to the full output voltage value, v out . to meet the demands of today s power sensitive appli - cations, the devices, have a very low standby current value as well as the extra safety features of current limit and short circuit protection. this range of device fea- tures, supplied in 6-pin sot-23-6 package type, will en- sure that these device will find excellent use in a wide range of dc-dc step-up converter applications.
block diagram pin assignment pin description pin no. pin name description 1 vout regulated output voltage. v out should be bypassed with a 1 fto10 f low esr ceramic capacitor placed as close as possible to the pin for best performance. 2 gnd ground. this pin is the voltage reference for the regulator output voltage. 3en device on/off control 1: enable 0: disable pin must not be left floating. 4 c- capacitor negative pin. flying capacitor negative terminal. 5 vin input supply voltage. v in should be bypassed with a 1 fto10 f low esr ceramic capacitor. 6 c+ capacitor positive pin. flying capacitor positive terminal. ht7936a/ht7936b rev 1.30 2 june 25, 2016
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absolute maximum ratings input supply voltage..................................................6v other pins voltage ......................................... ...........6v operating temperature range ............... 40 cto85 c maximum junction temperature..........................125 c note: these are stress ratings only. stresses exceeding the range specified under absolute maximum ratings may cause substantial damage to the device. functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability. electrical characteristics v in =v en =3.7v, c in =c pump =c out =1 f, ta=25 c, unless otherwise specified. symbol parameter test conditions min. typ. max. unit v in input supply voltage ht7936a 2.8 5.0 v ht7936b 2.8 4.5 v v out output voltage ht7936a, v in >3.2v, i o
110ma 4.80 5.20 v ht7936b, v in >3.2v, i o
140ma 4.32 4.68 v i shdn shutdown current v en =0 0.1 1.0 a i q operation current 2.0 4.0 ma i o output current ht7936a 110 ma ht7936b 150 ma i short short circuit current 60 90 ma i limit current limit 370 500 ma f osc switching frequency 0.8 1.0 1.3 mhz v enh en pin voltage high 2.8v
v in
5.0v 1.5 v v enl en pin voltage low 2.8v
v in
5.0v 0.4 v v ripple output ripple voltage i o =60ma, c out =2.2 f 30 mv efficiency ht7936a, v in =3.0v, i o =50ma 80 % ht7936b, v in =2.8v, i o =70ma 80 % note: absolute maximum ratings indicate limits beyond which damage to the device may occur. operating ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. the guaranteed specifications apply only for the test conditions listed. specifications are production tested at ta=25 c. specifications over 40 cto+85 c operating temperature range are assured by design. ht7936a/ht7936b rev 1.30 3 june 25, 2016
ht7936a/ht7936b rev 1.30 4 june 25, 2016 functional description these dc-dc step-up converters can generate fixed level output voltages higher than their input supply volt - age. operation utilising a charge pump method with three external ca - pacitors to store and transfer energy, the devices can transfer electrical energy from input to output at different voltage levels. since the capacitors are not able to change their voltage level abruptly, the v out /v in voltage ratio of v out over v in is limited within a fixed range. ca - pacitive voltage conversion is obtained by the periodic switching of a capacitor. it first charges the capacitor c pump by connecting it across a voltage source after which it is connected to the output. referring to fig - ure.1, during the on state of the internal clock, m1 and m3 are closed, m2 and m4 are opened, which charges c pump to a v in level. during the off state of the internal clock, m2 and m4 are closed, m1 and m3 are opened, which transfers the energy to the output. the output voltage is therefore v in plus v cpump , which is in effect equal to 2v in . shutdown the devices can be shutdown by setting the en input pin to a low level. in the shutdown mode, the output is disconnected from the input. the input current will re- duce to an extremely low level as most of the internal cir - cuitry is inactive. as the en pin is a high impedance input, it must not be allowed to float. short circuit protection the devices contain integrated short circuit protection circuits with current limiting protection. during a short circuit condition, the output current is automatically lim - ited to a typical value of approximately 60ma. if the fault does not clear itself, the protect operation will repeat continuously. this protection feature allows the devices to operate indefinitely under short circuit conditions without damaging the device. capacitor selection careful selection of the three external capacitors c in , c out and c pump is important because they will affect ramp-up time, output ripple and transient performance. optimum performance will be obtained when low esr (<100m ) ceramic capacitors are used for c in and c out and c pump . in general, a low esr may be defined as less than 100m . in all cases, x7r or x5r dielectrics are recom - mended. for certain applications, low esr tantalum capacitors may be substituted, however optimum output ripple performance may not be attainable. aluminum electrolytic capacitors are not recommended for use with these devices due to their inherent high esr char - acteristics. in general the c in ,c out and c pump capacitors may range from 1 fto10 f for heavy output load condi - tions. if the c pump capacitor is increased, then c out should also be increased by the same ratio to minimise output ripple. lowering the values of c in ,c out and c pump may decrease the ramp-up time of v out , but it will inversely increase the output ripple. efficiency the efficiency of the charge pump regulator varies with the output voltage type, the applied input voltage, the load current and the internal operation mode of the de- vice. the approximate device efficiency is given by: due to internal switching losses and ic quiescent cur - rent consumption, the actual measured efficiency will decrease. ( ( ( ( / ( / figure.1
typical operating characteristics for ht7936a, c in =c out =2.2 f, c pump =0.22 f, ta=25 c, unless otherwise specified ht7936a/ht7936b rev 1.30 5 june 25, 2016 ht7936a output voltage vs. output current 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5.0 5.1 10 20 30 40 50 60 70 80 90 100 110 output current(ma) output voltage(v) vin=2.8v vin=3v vin=3.2v vin=3.7v vin=4.2v vin=5v ht7936a operation current vs. input voltage 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 input voltage(v) quiescent current(ma) iq i q
ht7936a/ht7936b rev 1.30 6 june 25, 2016

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for ht7936b, c in =c out =2.2 f, c pump =0.22 f, ta=25 c, unless otherwise specified ht7936a/ht7936b rev 1.30 7 june 25, 2016 ht7936b output voltage vs. output current 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 10 25 40 55 70 85 100 115 130 145 output current(ma) output voltage(v) vin=2.8v vin=3v vin=3.2v vin=3.7v vin=4.5v ht7936b operation current vs. input voltage 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 input voltage(v) quiescent current(ma) iq i q
ht7936a/ht7936b rev 1.30 8 june 25, 2016 ht7936b output voltag e vs. supply voltage 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 supply voltage(v) output voltage(v) io=10ma io=20ma io=30ma io=40ma io=50ma io=60ma io=70ma io=80ma io=90ma io=100ma io=110ma io=120ma io=130ma io=140ma io=150ma ht7936b efficiency vs. output current 40% 45% 50% 55% 60% 65% 70% 75% 80% 85% 10 25 40 55 70 85 100 115 130 145 output current(ma) efficiency vin=2.8v vin=3v vin=3.2v vin=3.7v vin=4.5v ht7936b efficiency vs. input voltage 40% 45% 50% 55% 60% 65% 70% 75% 80% 85% 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 input voltage(v) efficiency io=10ma io=20ma io=30ma io=40ma io=50ma io=60ma io=70ma io=80ma io=90ma io=100ma io=110ma io=120ma io=130ma io=140ma io=150ma
inrush current ht7936a/ht7936b rev 1.30 9 june 25, 2016 ht7936b v in =2.8v, c in =c out =2.2mf , c pump =0.22mf ht7936b v in =4.5v, c in =c out =2.2mf , c pump =0.22mf ht7936a v in =2.8v, c in =c out =2.2mf , c pump =0.22mf ht7936a v in =5.0v, c in =c out =2.2mf , c pump =0.22mf
normal operation ht7936a/ht7936b rev 1.30 10 june 25, 2016 ht7936b v in =2.8v, c in =c out =2.2mf , c pump =0.22mf ht7936b v in =4.5v, c in =c out =2.2mf , c pump =0.22mf ht7936a v in =2.8v, c in =c out =2.2mf , c pump =0.22mf ht7936a v in =5.0v, c in =c out =2.2mf , c pump =0.22mf
dimming operation ht7936a, refer to figure.2 ht7936a/ht7936b rev 1.30 11 june 25, 2016 v i n 3 . 7 v c i n 1 m f c o u t 1 m f l e d l e d l e d c + c - v i n e n v o u t g n d h t 7 9 3 6 a c p u m p 1 m f r 1 1 0 0 w r 2 1 0 0 w r 3 1 0 0 w p w m 1 0 0 h z ~ 1 5 k h z q 1 0 v 3 v figure.2
ht7936a, refer to figure.3 application circuits ht7936a/ht7936b rev 1.30 12 june 25, 2016 v i n 3 . 7 v c i n 1 m f c o u t 1 m f l e d l e d l e d c + c - v i n e n v o u t g n d h t 7 9 3 6 a c p u m p 1 m f r 1 1 0 0 w r 2 1 0 0 w r 3 1 0 0 w 0 v p w m 5 0 0 h z 3 v figure.3 v i n 2 . 8 v t o v o u t c i n c o u t l e d l e d l e d n o t e : c i n = c p u m p = c o u t = 1 m f ( t a i y o y u d e n j m k 1 0 7 b j 1 0 5 k a ) c + c - v i n e n v o u t g n d h t 7 9 3 6 a h t 7 9 3 6 b c p u m p r
package information ht7936a/ht7936b rev 1.30 13 june 25, 2016 note that the package information provided here is for consultation purposes only. as this information may be updated at regular intervals users are reminded to consult the holtek website for the latest version of the package/carton information . additional supplementary information with regard to packaging is listed below. click on the relevant section to be transferred to the relevant website page. ? package information (include outline dimensions, product tape and reel specifications) ? the operation instruction of packing materials ? carton information
6-pin sot23-6 outline dimensions symbol dimensions in inch min. nom. max. a 0.057 a1 0.006 a2 0.035 0.045 0.051 b 0.012 0.020 c 0.003 0.009 d 0.114 bsc e 0.063 bsc e 0.037 bsc e1 0.075 bsc h 0.110 bsc l 0.024 bsc 0 8 symbol dimensions in mm min. nom. max. a 1.45 a1 0.15 a2 0.90 1.15 1.30 b 0.30 0.50 c 0.08 0.22 d 2.90 bsc e 1.60 bsc e 0.95 bsc e1 1.90 bsc h 2.80 bsc l 0.60 bsc 0 8 ht7936a/ht7936b rev 1.30 14 june 25, 2016
ht7936a/ht7936b rev 1.30 15 june 25, 2016 copyright 2016 by holtek semiconductor inc. the information appearing in this data sheet is believed to be accurate at the time of publica - tion. however, holtek assumes no responsibility arising from the use of the specifications de - scribed. the applications mentioned herein are used solely for the purpose of illustration and holtek makes no warranty or representation that such applications will be suitable without fur - ther modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. holtek s products are not authorized for use as critical components in life support devices or systems. holtek reserves the right to alter its products without prior notification. for the most up-to-date information, please visit our web site at http://www.holtek.com.tw.

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