1 rev.1.1 parameter symbol limit unit vin power supply voltage vin -0.3 to +6.5 v apply voltage to sw vsw gnd-0.3 to vin+0.3 v apply voltage to en ven gnd-0.3 to vin+0.3 v apply voltage to fb vfb gnd-0.3 to vin+0.3 v sw peak current isw 1.7 a power dissipation pd 200 mw operating temperature range top -40 to +85 c storage temperature range tstg -65 to +150 c general description features maximum absolute ratings ? cellular phone ? pda and smart phone ? mp3 player ? digital camera ? wireless and dsl card ? microcomputer and dsp power supply ? portable machine application ? current mode operation ? thermal shutdown protection and short circuit protection ? constant frequency : typ.1.4mhz ? output current : 800ma ? high ef?ciency : max.95% ? shutdown current : max.1a(ven=0v, vin=6v) ? supply voltage : 2.5v to 6v ? low quiescent current : typ.200a ? full duty ratio : 0 to 100% (in dropout) ? package : tsot-25 elm600la is high ef?ciency synchronous step down dc/dc converter operated with current mode and 1.4mhz constant frequency; internal switch and synchronous recti?er are integrated for high ef?ciency. in application, elm600la does not require any external schottky diode. internal current consumption under operation of elm600la is as low as 200a and drops to less than 1a in shutdown mode. with supply voltage from 2.5v to 6v, elm600la can supply load current of 800ma; the output voltage can be regulated as low as 0.6v. with 1.4mhz switching frequency, elm600la makes it possible to adopt small surface amount inductors and capacitors. switch duty cycle would be on continuously and 100% at maximum when input voltage is set be to lower than output voltage. caution:permanent damage to the device may occur when ratings above maximum absolute ones are used. * taping direction is one way. elm600la-s, elm600la-xx-s symbol a package l: tsot-25 b product version a c, d output voltage e.g. : 12: vout=1.2v, 18: vout=1.8v e taping direction s: refer to pkg file elm600 la - x x - s a b c d e elm600la - s a b e selection guide ? fixed version ? adj. version elm600la 800ma 1.4mhz high ef?ciency synchronous pwm step down dc/dc converter 10 -
2 rev.1.1 block diagram standard circuit vin 5 4 1 3 2 fb sw en gnd r1 r2 cin=10f vin vout cout=22f l=2.2h elm600la enable + _ + _ + _ reference en 0.6v fb oscillator error ampli?er slope comp pwm comparator clock pwm logic vin m1 m2 sw gnd current sense ampli?er zero-current comparator shut down control ? adjustable output voltage vout=0.6(1+r1/r2) vout=3.3v, r1=300k, r2=68k vout=1.8v, r1=1m, r2=499k tsot-25(top view) 1 2 3 5 4 pin configuration pin no. pin name pin description 1 en enable control input 2 gnd ground 3 sw power switch output 4 vin main supply 5 fb voltage feedback elm600la 800ma 1.4mhz high ef?ciency synchronous pwm step down dc/dc converter 10 -
3 rev.1.1 vout=1.2v/1.8v l=2.2h cout=22f vin 5 4 1 3 2 fb sw en gnd elm60012la elm60018la vin cin=10f enable * passive components without speci?ed values in the above ?gure are optional. ? fixed output voltage electrical characteristics (adjustable output voltage ) parameter symbol test condition min. typ. max. unit supply voltage vin 2.5 6.0 v output voltage vout adjustable 0.6 6.0 v feedback current ifb -30.0 30.0 na regulated feedback voltage vfb -40c top +85c 0.582 0.600 0.618 v reference voltage line regulation ?vfb/?vin vin=2.5v to 6v 0.04 0.40 %/v output voltage line regulation ?vout/?vin vin=2.5v to 6v 0.04 0.40 %/v output voltage load regulation vlr 0.5 % shutdown current is ven=0v, vin=6v 0.01 1.00 a quiescent current iq ven=vin, vfb=0.65v no switching 200 a sw leakage current ileak ven=0v , vfb=0.65v vsw=0v or 6v -1 1 a pmosfet on resistance rdsonp isw=100ma 0.35 nmosfet on resistance rdsonn isw=-100ma 0.24 pmosfet current limit ipcl duty cycle=100% current pulse width<1ms 0.8 1.1 1.5 a oscillator frequency fosc 1.12 1.40 1.68 mhz thermal shutdown threshold ts d 145 c en high level input voltage venh -40c t op +85c 1.1 v en low level input voltage venl -40c t op +85c 0.3 v en input current ien ven=0v to vin -1 1 a vin=3.6v , typical values are at top=25c, unless otherwise noted. elm600la 800ma 1.4mhz high ef?ciency synchronous pwm step down dc/dc converter 10 -
4 rev.1.1 parameter symbol test condition min. typ. max. unit supply voltage vin 2.5 6.0 v feedback current ifb -30.0 30.0 na regulated feedback voltage vfb -40c t op +85c 0.582 0.600 0.618 v reference voltage line regulation ?vfb/?vin vin=2.5v to 6v 0.04 0.40 %/ v output voltage line regulation ?vout/?vin vin=2.5v to 6v 0.04 0.40 %/ v output voltage load regulation vlr 0.5 % output range (fixed voltage) vout vin=2.5v to 6v 1.164 1.200 1.236 v shutdown current is ven=0v , vin=6v 0.01 1.00 a quiescent current iq ven=vin,vfb=0.65v, no switching 200 a sw leakage current ileak ven=0v , vfb=0.65v vsw=0v or 6v -1 1 a pmosfet on resistance rdsonp isw=100ma 0.35 nmosfet on resistance rdsonn isw=-100ma 0.24 pmosfet current limit ipcl duty cycle=100% current pulse width < 1ms 0.8 1.1 1.5 a oscillator frequency fosc 1.12 1.40 1.68 mhz thermal shutdown threshold ts d 145 c en high level input voltage venh -40c t op +85c 1.1 v en low level input voltage venl -40c t op +85c 0.3 v en input current ien ven=0v to vin -1 1 a electrical characteristics (fixed output voltage) vin=3.6v, typical values are at top=25c, unless otherwise noted. vout=1.2v test circuits (adjustable output voltage ) g n d v i n s w f b e n v i n l = 2 .2 h c o u t= 2 2 f e l m 6 0 0 l a r 1 r 2 r l v o u t c i n = 1 0 f elm600l a 800ma 1.4mhz high ef?ciency synchronous pwm step down dc/dc converter 10 -
5 rev.1.1 parameter symbol test condition min. typ. max. unit supply voltage vin 2.5 6.0 v feedback current ifb -30.0 30.0 na regulated feedback voltage vfb -40c t op +85c 0.582 0.600 0.618 v reference voltage line regulation ?vfb/?vin vin=2.5v to 6v 0.04 0.40 %/ v output voltage line regulation ?vout/?vin vin=2.5v to 6v 0.04 0.40 %/ v output voltage load regulation vlr 0.5 % output range (fixed voltage) vout vin=2.5v to 6v 1.764 1.800 1.836 v shutdown current is ven=0v , vin=6v 0.01 1.00 a quiescent current iq ven=vin,vfb=0.65v, no switching 200 a sw leakage current ileak ven=0v , vfb=0.65v vsw=0v or 6v -1 1 a pmosfet on resistance rdsonp isw=100ma 0.35 nmosfet on resistance rdsonn isw=-100ma 0.24 pmosfet current limit ipcl duty cycle=100% current pulse width<1ms 0.8 1.1 1.5 a oscillator frequency fosc 1.12 1.40 1.68 mhz thermal shutdown threshold ts d 145 c en high level input voltage venh -40c t op +85c 1.1 v en low level input voltage venl -40c t op +85c 0.3 v en input current ien ven=0v to vin -1 1 a vin=3.6v , typical values are at top=25c, unless otherwise noted. vout=1.8v a b c d e tsot-25 a to e : assembly lot no. a to z (i, o, x excepted) and 0 to 9 marking elm600la 800ma 1.4mhz high ef?ciency synchronous pwm step down dc/dc converter 10 -
6 rev.1.1 elm600la is constant frequency current mode pwm step down converter which is suitable for applications that require high ef?ciency and small assembly area and use low voltage, such as li-ion battery. by external resistor divider, output voltage of elm600la can be set within the range from 0.6v to 6v. to provide opera - tion with high ef?ciency, elm600la consists of main switch and synchronous recti?er while external schottky diode is not necessary. duty cycle of elm600la can reach upto 100%. duty cycle d of step down converter is de?ned as follows: d = ton fosc 100% (vout/vin) 100% ton=main switch on time; fosc=oscillator frequency (1.4mhz); vout=output voltage;vin=input voltage 1) current mode pwm control slope compensated current mode control pwm provides superior load and line response, and protection of in - ternal main switch and synchronous recti?er to current limit by stable switching and switch cycle. elm600la switches at a constant frequency (1.4mhz) and regulates output voltage. during each cycle, the pwm compara - tor modulates the power transferred to load by changing inductor peak current which is based on the feedback error voltage. under normal operation, the main switch is turned on for a certain time to ramp the inductor current at each rising edge of the internal oscillator, and off when inductor peak current is above error voltage. when the main switch is turned off, the synchronous recti?er will be turned on immediately and stay on until either the next cycle begins or the inductor current drops to zero. with light load, elm600la would skip pulses to improve ef?ciency. 2) dropout operation elm600la allows the main switch to remain on for more than one switching cycle and increases the duty cycle while the input voltage is dropping under the output voltage. when duty cycle reaches 100%, the main switch transistor would be on continuously to supply current to output until current limit generates. output volt - age then is input voltage minus voltage drop across main switch and inductor . 3) short circuit protection elm600la consists of short circuit protection; when output is short to ground, the oscillator frequency is re - duced to prevent the inductor current from increasing beyond the p mosfet current limit. the frequency will return to normal values once the short circuit condition is recovered and the feedback voltage goes back to 0.6v . 4) maximum load current elm600la can operate when input voltage is down to 2.5v; however, the maximum load current would de - scend because of the increase ir drop which results from the on resistor of main switch and synchronous recti - ?er along with the drop of input voltage. the slope compensation signal would reduce the peak inductor current to avoid sub-harmonic oscillations when duty cycles is larger than 50%; on the contrary, it would increase the peak inductor current when duty cycle is decreased, as which is shown in the graph. application notes elm600la 800ma 1.4mhz high ef?ciency synchronous pwm step down dc/dc converter 10 -
7 rev.1.1 typical characteristics ? elm600la(adj.version) : unless otherwise noted vout=1.8v, cin=10 f, cout=22 f, l=2.2h, r1=22k , r2=11k, top=25c 0 1 2 3 4 5 6 0.4 0.8 1.2 1.6 2.0 2.4 iout=1ma 100ma vin (v) vout (v) vout-vin ? v=1.8v(adj.) 0.1 1 10 100 1000 0 20 40 60 80 100 vin=5v iout (ma) efficiency (%) efficiency-iout 0 0.5 1 1.5 2 0 1 2 0 1 2 3 4 5 time (ms) start response vout (v) ven (v) ven=vin=5v, no load 1 10 100 1000 1.7 1.8 1.9 vin=5v iout (ma) vout (v) vout-iout 0 0.5 1 1.5 2 2.5 3 3.5 4 1.5 2 2.5 0 1 2 time (ms) load transient response vout (v) iout (a) vin=5v, iout=10ma ? 600ma 0 0.5 1 1.5 2 2.5 3 3.5 4 1.5 2 2.5 0 1 2 time (ms) load transient response vout (v) iout (a) vin=5v, iout=100ma ? 600ma elm600l a 800ma 1.4mhz high ef?ciency synchronous pwm step down dc/dc converter 10 -
8 rev.1.1 ? v=3.3v(adj.) 0 1 2 3 4 5 6 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 iout=1ma 100ma vin (v) vout (v) vout-vin 0.1 1 10 100 1000 0 20 40 60 80 100 vin=5v iout (ma) efficiency (%) efficiency-iout 0 0.5 1 1.5 2 0 1 2 3 0 1 2 3 4 5 time (ms) start response vout (v) ven (v) ven=vin=5v, no load 3.5 1 10 100 1000 3.1 3.2 3.3 3.4 3.5 vin=5v iout (ma) vout (v) vout-iout 0 0.5 1 1.5 2 3 3.5 4 0 1 2 time (ms) load transient response vout (v) iout (a) vin=5v, iout=10ma ? 600ma 0 0.5 1 1.5 2 3 3.5 4 0 1 2 time (ms) load transient response vout (v) iout (a) vin=5v, iout=100ma ? 600ma ? elm600la(adj.version) : unless otherwise noted vout=3.3v, cin=10 f, cout=22 f, l=2.2h, r1=47k, r2=10.4k, top=25c elm600la 800ma 1.4mhz high ef?ciency synchronous pwm step down dc/dc converter 10 -
9 rev.1.1 ? elm600la-12(fixed version) : unless otherwise noted vout=1.2v, cin=10 f, cout=22 f, l=2.2 h, top=25c 10 - elm600la 800ma 1.4mhz high ef?ciency synchronous pwm step down dc/dc converter 0 1 2 3 4 5 6 0.2 0.4 0.6 0.8 1.0 1.2 1.4 iout=1ma 100ma vin (v) vout (v) vout-vin ? v=1.2v(fixed) 0.1 1 10 100 1000 0 20 40 60 80 100 vin=5v iout (ma) efficiency (%) efficiency-iout 0 0.2 0.4 0.6 0.8 1 0 1 2 0 1 2 3 4 5 time (s) start response vout (v) ven (v) ven=vin=5v, no load 1 10 100 1000 1.1 1.15 1.2 1.25 1.3 vin=5v iout (ma) vout (v) vout-iout 0 2 4 6 8 10 12 1 1.5 2 0 1 2 time (ms) load transient response vout (v) iout (a) vin=5v, iout=10ma ? 600ma 0 2 4 6 8 10 12 1 1.5 2 0 1 2 time (ms) load transient response vout (v) iout (a) vin=5v, iout=100ma ? 600ma
10 rev.1.1 10 - 0 1 2 3 4 5 6 0.4 0.8 1.2 1.6 2.0 2.4 iout=1ma 100ma vin (v) vout (v) vout-vin ? v=1.8v(fixed) 0.1 1 10 100 1000 0 20 40 60 80 100 iout (ma) vin=5v efficiency-iout efficiency (%) 0 0.2 0.4 0.6 0.8 1 0 1 2 0 1 2 3 4 5 time (s) start response vout (v) ven (v) ven=vin=5v, no load 1 10 100 1000 1.7 1.75 1.8 1.85 1.9 vin=5v vout-iout iout (ma) vout (v) 0 2 4 6 8 10 12 1.5 2 2.5 0 1 2 time (ms) load transient response vout (v) iout (a) vin=5v, iout=10ma ? 600ma 0 2 4 6 8 10 12 1.5 2 2.5 0 1 2 time (ms) load transient response vout (v) iout (a) vin=5v, iout=100ma ? 600ma ? elm600la-18(fixed version) : unless otherwise noted vout=1.8v, cin=10 f, cout=22 f, l=2.2 h, top=25c elm600la 800ma 1.4mhz high ef?ciency synchronous pwm step down dc/dc converter
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