general description the RT9261 series are vfm step-up dc/dc ics with ultra low supply current by cmos process and suitable for use with battery-powered instruments. the RT9261 ic consists of an oscillator, a vfm control circuit, a driver transistor (lx switch), a reference voltage unit, an error amplifier, resistors for voltage detection, and a lx switch protection circuit. a low ripple and high efficiency step-up dc/dc converter can be constructed of this RT9261 ic with only three external components. the RT9261a ic provides with a drive pin (ext) for an external transistor, so that a power transistor can be externally applied. therefore, the RT9261a ic is recommended for applications where large currents are required. ce pin enables circuit to set the standby supply current at a maximum of 0.5 a. ordering information RT9261a- ? ? ? ? features z minimal number of external components ( only an inductor, a diode, and a capacitor) z ultra low input current ( 5 a at switch off) z 2% high output voltage accuracy z low ripple and low noise z low start-up voltage, 0.85v at 1ma z 75% efficiency with low cost inductor z +50 ppm/ c low temperature-drift z sot-89 and sot-25 small packages applications z power source for battery-powered equipment z power source for cameras, camcorders, vcrs, pdas, pagers, electronic data banks, and hand- held communication equipment z power source for applications, which require higher voltage than that of batteries used in the appliances pin configurations part number pin configurations RT9261- ? ? cx (plastic sot-89) top view 1. gnd 2. vout (tab) 3. lx RT9261a- ? ? cx (plastic sot-89) top view 1. gnd 2. vout (tab) 3. ext RT9261- ? ? cb (plastic sot-25) top view 1. ce 2. vout 3. nc 4. gnd 5. lx RT9261a- ? ? cb (plastic sot-25) top view 1. ce 2. vout 3. nc 4. gnd 5. ext operating temperature range c: commercial standard package type b : sot-25 x : sot-89 output voltage 15 : 1.5v 16 : 1.6v : 49 : 4.9v 50 : 5.0v a : use external switch use internal switch 123 123 54 3 2 1 54 3 2 1 RT9261/a product specification 1 of 5 4008-318-123 sales@twtysemi.com http://www.twtysemi.com
absolute maximum ratings z output voltage 8v z lx pin voltage (1) 8v z ext pin voltage (2) -0.3 to v out +0.3v z ce pin voltage (3) -0.3 to v out +0.3v z lx pin output current (1) 250ma z ext pin current (2) 50ma z power dissipation, p d @ t a = 25 c z sot-89 0.5w sot-25 0.25w z package thermal resistance sot-89, jc 100 c/w sot-89, ja 300 c/w sot-25, ja 250 c/w z operating temperature range -20 to +85 c z storage temperature range 165 c z lead temperature (soldering, 10 sec.) 260 c notes: (1) applicable to RT9261- ? ? cx and RT9261- ? ? cb (2) applicable to RT9261a- ? ? cx and RT9261a- ? ? cb (3) applicable to RT9261- ? ? cb and RT9261a- ? ? cb electrical characteristics (refer to fig. 1) parameter symbol test conditions min typ max units output voltage accuracy ? v out -2 -- +2 % input voltage v in -- -- 7 v start-up voltage v st i out = 1ma, v in : 0 2v -- 0.85 1.0 v hold-on voltage v ho i out = 1ma, v in : 2 0v 0.7 -- -- v v out 3.5v (1) -- 15 18 input current 1 3.5v < v out 5v (2) to be measured at v in at no load -- 18 24 a input current 2 to be measured at v out in switch off condition -- 5 8 a v out 3.5v (1) 60 -- -- lx switching current 3.5v < v out 5v (2) i switching v lx = 0.4v 80 -- -- ma lx leakage current i leakage v lx = 6v -- -- 0.5 a maximum oscillator f max 80 120 160 khz oscillator duty cycle d osc on ( v lx ? l ? ) side 65 75 85 % efficiency -- 75 -- % v lx voltage limit l x switch on 0.65 0.8 1.0 v notes: (1) v in = 1.8v, vss = 0v, i out = 10ma, t opt = 25 c, and external circuit of typical application (2) v in = 3v, vss = 0v, i out = 10ma, t opt = 25 c, and external circuit of typical application RT9261/a product specification 2 of 5 4008-318-123 sales@twtysemi.com http://www.twtysemi.com
electrical characteristics (refer to fig. 2) parameter symbol test conditions min typ max units output voltage accuracy ? v out -2 -- +2 % input voltage v in -- -- 7 v start-up voltage v st i out = 1ma, v in : 0 2v -- 0.85 1.0 v v out 3.5v (1) -- 30 50 input current 1 3.5v < v out 5v (2) to be measured at v in at no load -- 60 90 a v out 3.5v (1) input current 2 3.5v < v out 5v (2) to be measured at v out in switch off condition -- 6 10 a v out 3.5v (1) -1.5 -- -- ext ?h? output current 3.5v < v out 5v (2) v ext = v out ? 0.4v -2 -- -- ma v out 3.5v (1) 1.5 -- -- ext ?l? output current 3.5v < v out 5v (2) v ext = 0.4v 2---- ma maximum oscillator frequency f max 80 120 160 khz oscillator duty cycle d osc v ext ? h ? side 65 75 85 % notes: (1) unless otherwise provided, v in = 1.8v, vss = 0v, i out = 10ma, t opt = 25 c, and use external circuit of typical application (2) unless otherwise provided, v in = 3v, vss = 0v, i out = 10ma, t opt = 25 c, and external circuit of typical application RT9261/a product specification 3 of 5 4008-318-123 sales@twtysemi.com http://www.twtysemi.com
electrical characteristics (refer to fig. 3) parameter symbol test conditions min typ max units output voltage accuracy ? v out -2 -- +2 % input voltage v in -- -- 7 v start-up voltage v st i out = 1ma, v in : 0 2v -- 0.85 1.0 v hold-on voltage v ho i out = 1ma, v in : 2 0v 0.7 -- -- v v out 3.5v (1) -- 75 -- efficiency 3.5v < v out 5v (2) -- 85 -- % v out 3.5v (1) -- 15 18 input current 1 3.5v < v out 5v (2) to be measured at v in at no load -- 18 24 a v out 3.5v (1) -- 5 8 input current 2 3.5v < v out 5v (2) to be measured at v out in switch off condition -- 6 10 a v out 3.5v (1) 60 -- -- lx switching current 3.5v < v out 5v (2) i switching v lx = 0.4v 80 -- -- ma lx leakage current i leakage v lx = 6v -- -- 0.5 a ce ?h? level v in = v out 0.9 0.4 v out -- -- v ce ? l? level v in = v out 0.9 -- -- 0.2 v ce ? h? input current ce = v out -- -- 0.5 a ce ? l? input current ce = 0v -0.5 -- -- a maximum oscillator frequency f max 80 120 160 khz oscillator duty cycle d osc on (v lx ? l? ) side 65 75 85 % v lx voltage limit lx switch on 0.65 0.8 1.0 v notes: (1) unless otherwise provided, v in = 1.8v, vss = 0v, i out = 10ma, t opt = 25 c, and use external circuit of typical application (2) unless otherwise provided, v in = 3v, vss = 0v, i out = 10ma, t opt = 25 c, and external circuit of typical application RT9261/a product specification 4 of 5 4008-318-123 sales@twtysemi.com http://www.twtysemi.com
electrical characteristics (refer to fig. 4) parameter symbol test conditions min typ max units output voltage accuracy ? v out -2 -- +2 % input voltage v in -- -- 7 v start-up voltage v st i out = 1ma, v in : 0 2v -- 0.85 1.0 v v out 3.5v (1) -- 75 -- efficiency 3.5v < v out 5v (2) -- 85 -- % v out 3.5v (1) -- 30 50 input current 1 3.5v < v out 5v (2) to be measured at v in at no load -- 60 90 a v out 3.5v (1) input current 2 3.5v < v out 5v (2) to be measured at v out in switch off condition -- 6 10 a v out 3.5v (1) -1.5 -- -- ext ?h? output current 3.5v < v out 5v (2) v ext = v out ? 0.4v -2 -- -- ma v out 3.5v (1) 1.5 -- -- ext ?l? output current 3.5v < v out 5v (2) v ext = 0.4v 2---- ma ce ?h? level v in = v out 0.9 0.4 v out -- -- v ce ? l? level v in = v out 0.9 -- -- 0.2 v ce ? h? input current ce = v out -- -- 0.5 a ce ? l? input current ce = 0v -0.5 -- -- a maximum oscillator frequency f max 80 120 160 khz oscillator duty cycle d osc on (v lx ? l? ) side 65 75 85 % v lx voltage limit lx switch on 0.65 0.8 1.0 v notes: (1) unless otherwise provided, v in = 1.8v, vss = 0v, i out = 10ma, t opt = 25 c, and use external circuit of typical application (2) unless otherwise provided, v in = 3v, vss = 0v, i out = 10ma, t opt = 25 c, and external circuit of typical application RT9261/a product specification 5 of 5 4008-318-123 sales@twtysemi.com http://www.twtysemi.com
|
