ly1152 rev. 1.2 inverting dc/dc controller (sop) lyontek inc. reserves the rights to change the specifications and products without notice. 5f, no. 2, lndustry e . rd. ix, science-ba sed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 1 ? features ? 2.4v ~ 7.0v power supply. ? low shutdown current at 0.1ua (typical). ? low quiescent current at 90.0ua (typical). ? adjustable output voltage to -40v. ? 60khz ~ 160khz switching frequency. ? high efficiency with low cost external pnp bipolar transistor. ? pulse frequency modulation maintains high efficiency (80%). ? lead free and green package available. (rohs compliant) ? space saving packag e - 8-pin sop package. application ? negative voltage supply. ? negative lcd contrast bias for - portable data collection terminals. - notebook computers. general description the ly1152 is a high performance inverting dc/dc controller, and the ly1152 designed to drive an external power switch to generate adjustable negative voltages. output voltage can be scaled to -40v. the ly1152 quiescent current is about 90.0ua and shutdown mode current can be reduced to 0.1ua. in the lcd bias contrast a pplication, efficiency of 80% can be achieved with low cost pnp bipolar transistor drivers. the ly1152 switching frequency can be around 60khz to 160khz range, and small size package is ideally suited for powered portable equipments. pin configuration ly1152 sop8 (top view)
ly1152 rev. 1.2 inverting dc/dc controller (sop) lyontek inc. reserves the rights to change the specifications and products without notice. 5f, no. 2, lndustry e . rd. ix, science-ba sed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 2 ? pin description symbol pin no description vin 1 power supply input vref 2 reference output (1.22v). (*1) shutdown 3 shutdown the device.(when low level is enable) (*2) fb 4 feedback signal input to sense ground. (*3) gnd 5 ground. dlow 6 driver sinking output. (*4) dhi 7 driver sourcing output. (*5) cl 8 current-limit input. (*6) (*1 ) bypass with 0.047uf capacitor to gnd, sourcing capability is guaranteed to be greater than 250ua. (*2 ) >1.5v = operation mode, gnd = shutdown, in shutdow n mode dlow and dhi pins are at high level. (*3 ) connecting a resistor r2 to v out and a resistor r1 to v ref pin yields the output voltage: v out = -(r2/r1 ) x v ref (*4 ) when using an external pnp bipolar transistor, conn ect a resistor r3 from this pin to dhi. r3 value depends on v in , inductor and pnp bipolar transistor. by adjusting the r3 value, efficiency can be optimized. (*5 ) connect to base of the pnp bipolar transistor. (*6 ) this pin clamps the switch peak current to prev ent over-current damage to the external switch. the r cl resistor equation: r = v / i = 100mv(cl threshold) / 100ma(the current(100ma) depend on user) r= 1 ? , (so the r cl resistor use 1 ? ). application circuit figure 1. application sche matic for negative lcd contrast bios power supply
ly1152 rev. 1.2 inverting dc/dc controller (sop) lyontek inc. reserves the rights to change the specifications and products without notice. 5f, no. 2, lndustry e . rd. ix, science-ba sed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 3 ? ordering information ly 1 152 vv absolute maximum ratings* parameter symbol rating unit supply voltage v dd 7.0 v operating temperature t a -40 to 85 (i grade) storage temperature t stg -65 to 150 junction temperature t jmax 125 soldering temperature (under 10 sec) t solder 260 electrical characteristics (v in =5.0v, t a = 25 ) refer to typical application circuit. parameter test condition min. typ. max. unit input voltage - 2.4 - 7.0 v quiescent current v fb = -50mv - 90 - ua shutdown current v shutdow n = 0v - 0.1 1.0 a shutdown threshold - - 1.5 - v cl threshold - - 100 - mv v ref voltage - 1.22 - v v ref source current - 250 - - ua vv : package type sl : 8-pin sop product name a : product line ly : lyontek product number prefix
ly1152 rev. 1.2 inverting dc/dc controller (sop) lyontek inc. reserves the rights to change the specifications and products without notice. 5f, no. 2, lndustry e . rd. ix, science-ba sed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 4 ? typical performanc e characteristics fig.1 shutdown current vs vin fig.2 efficiency vs vin fig.3 frequency vs vin fig.4 duty cycle vs vin
ly1152 rev. 1.2 inverting dc/dc controller (sop) lyontek inc. reserves the rights to change the specifications and products without notice. 5f, no. 2, lndustry e . rd. ix, science-ba sed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 5 ? package outline dimension 8-pin sop (150 mil) pack age outline dimension
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