View ME2139F_7858250.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

v1.0 page 1 of 11 me21 39 ultra-small package pwm/pfm switching control step-up switching regulator selection guide description the me2139 series is a cmos step-up switching regulator which mainly consists of a reference voltage source, an oscillation circuit, an error amplifier, a phase compensation circuit, a pwm/pfm switching control circuit. with an external low- on -resistance nch power mos, this product is applicable to application s requiring high efficiency and high output current. the me2139 series switches its operation to the pfm control circuit whose duty ratio is 15 % with to the pwm/pfm switching control circuit under a light load and to prevent decline in the efficiency by ic operation current. feature ? low voltage operation: start-up is guaranteed from 0.9 v(i out =1 ma ) ? duty ratio: built-in pwm/pfm switching control circuit 15 to 78 % . ? oscillator frequency 1.0m hz ? external parts: coil, diode, capacitor, and transistor ? output voltage range: 1.5v ~6.5 v ? output voltage accuracy 2 % ? soft start function: 2 ms. ? package sot 23 - 5 typical application ? mp3 players, digital audio players ? digital cameras, gps, wireless transceiver ? portable devices v?mw`r?y?b? www.gofotech.com
v1.0 page 2 of 11 me21 39 pin configuration type posfix package swiching transistor ce function vdd function fb function feature me 2139f m5 sot23-5 external tr ansistor yes yes yes ext+fb sot- 23 -5 pin information pin number pin name function sot23-5 1 fb feed back voltage pin 2 vdd ic power supply pin 3 ce shutdown pin 4 gnd gnd pin 5 ext external transistor connection pin me 2139f n~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? www.gofotech.com
v1.0 page 3 of 11 me21 39 block diagram absolute maximum rang parameter symbol rating unit v dd pin voltage v dd -0.3 6.5 v ext pin voltage ext -0.3 vdd + 0.3 v ce pin voltage v ce -0.3 vin + 0.3 v ext pin current i ext 1000 ma power dissipation (sot23- 5) pd 250 mw operating temperature r ange t opr -25~+85 storage temperature range t stg -40~+125 n~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? www.gofotech.com
v1.0 page 4 of 11 me21 39 electrical characteristics me 2139f measuring conditions v dd = v ce = 3.3v topt=25 unless otherwise specified parameter symbol condition min typ max unit circuit feedback voltage v fb - 1.2 25 1.25 1.2 75 v 2 input voltage v in - - 6 v 2 operation start voltage v st1 i out =1ma - - 0.9 v 2 oscillation start voltage v st2 no external parts, voltage applied to v out - - 0.7 v 1 operation holding voltage v hld i out =1ma measured by de creasing vin voltage gradually 0.7 - - v 2 current consumption 1 i ss1 v fb =v fb (s) 0.95 - 2 00 - a 1 current consumption 2 i ss2 v fb =1.5v - 15 - a 1 current consumption during shutdown i sss v ce =0v - 0.02 0.5 a 1 ext pin output current i exth v ext =v out -0.4v - -25 - ma 1 i extl v ext =0.4v - 40 - ma 1 feed back voltagetemperature coefficient ta=- 25-85 - 50 - ppm/ 2 oscillation frequency f osc - 0.8 1.0 1.2 m hz 1 max. duty ratio maxduty v fb =v fb (s) 0.95 - 78 - 1 pwm/pfm switchingduty ratio pfmduty v fb =v fb (s) 1.5, no load - 15 - 1 shutdown pin input voltage v sh measured the oscillation at ext pin 0.75 - - v 1 v sl1 judged the stop of oscillation at ext pin v out 1.5v - - 0.3 v 1 v sl2 v out <1.5v - - 0.2 v 1 shutdown pin input voltage i sh v ce =v fb (s)0.95 -0.1 - 0.1 a 1 i sl v ce =0v -0.1 - 0.1 a 1 soft start time tss - - 2 - ms 2 efficiency effi - - 90 - 2 n~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? www.gofotech.com
v1.0 page 5 of 11 me21 39 note: 1. v out (s) is the set output voltage value, and v out is the typical value of the output voltage. 2. v out (s) can be set by using the rate of v fb and output voltage setting resistors (r1, r2). 3. v fb (s) is the set output voltage value. 4. vdd/v out separate type: 1.8v Q vdd<6v is recommended to stabilize the output voltage and oscillation frequency. test circuit 1. 2. external parts suggest 1 diode use schottky diode such as in5817 or in5819 (forward voltage drop:0.2v) 2 inductor 3.3 h r< 3 0m 3 capacitor ceramic capacitor 22 f it is best to us e two parallel connection ceramic capacitors 4 feed back resistors:r1+r2<50k n~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? www.gofotech.com
v1.0 page 6 of 11 me21 39 external parts selection for dc/dc converter the relationship between major characteristics of the step-up circuit and characteristics parameters of the external parts are shown in figure 1. for larger output current? for high efficiency? for smaller ripple voltage? operation effi ci ency stand-by efficiency figure 1 relationship between major characteristics of the step-up circuit and external parts 1. inductor an inductance has strong influence on maximum output curren t i out and efficiency . 1. figure 2 shows the relation between i out , and characteristics to l of me 2139f. figure 2 l i out and characteristics the peak current (i pk ) increases by decreasing l and the stability of a circuit improves and i out increas es. if l is furthermore made small, efficiency falls and in running short, i out decreases. ( based on the current drive capability smaller inductance larger inductance smaller dc resistance of inductor large output capacitance large output capacitance with mosfet, smaller on resistance with mosfet, smaller input capacitance with bipolar transistor, smaller external resisitance rb with bipolar transistor, larger external resistance rb n~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? www.gofotech.com
v1.0 page 7 of 11 me21 39 of external switching transistor.) the loss of i pk by the switching transistor decreases by increasing l and the efficiency becomes maximum at a certain l value. further increasing l decreases efficiency due to the loss of dc resistance of the coil. also, i out decreases, too. oscillation frequency is higher, smaller one can be cho se and also makes coil smaller. the recommende d inductances are 2.2 to 4.7 h inductor for ME2139F. choose a value for l by referring to the reference data because the maximum output current is due to the input voltage in an actual case. choose an inductor so that i pk does not exceed the allowable current. exceeding the allowable current of the inductor causes magnetic saturation, remarkable low efficiency and destruction of the ic chip due to a large current. i pk in uncontinuous mode is calculated from the following equati on : )( . ) (2 a lf vvvi i o sc n id ou t o ut pk ?? ? fosc = oscillation frequency, v dd =0.4 v. use an external diode that meets the following requirements: ? low forward voltage: (v f <0.3 v) ? high switching speed: (50 ns max.) ? reverse voltage: v out + v f or more ? rated current: i pk or more to improve efficiency, an input capacitor (c in ) lowers the power supply impedance and averages the input current. select c in according to the impedance of the power supply used. the recommended capacitance is 10 f for the ME2139F. an output capacitor (c out ), which is used to smooth the output voltage, requires a capacitance larger than that of the step-down type because the current is intermittently supplied from the input to the output side in the step- up type. a 22f ceramic capacitor is recommended for the ME2139F. however, a higher capacitance is recommended if the output voltage is high or the load current is large. if the output voltage or load current is low, about 10f can be used without problems. se lect c out after sufficient evaluation with actual application. a ceramic capacitor can be used for both the input and output. n~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? www.gofotech.com
v1.0 page 8 of 11 me21 39 4. enhancement mos fet type for a mos fet, an n-channel power mos fet should be used. because the gate voltage and current of the external power mos fet are supplied from the stepped up output voltage v out , the mos fet is driven more effectively. depending on the mos fet you use in your device, there is a chance of a current overrun at power on. thoroughly test all settings with your device before deciding on which one to use. also, try to use a mos fet with the input capacitance of 700 pf or less. since the on resistor of the mos fet might depend on the difference between the output voltage v out and the threshold voltage of mos fet, and affect the output current as well as the efficiency, the threshold voltage should be low. when the output voltage is low, the circuit operates only when the mos fet has the threshold voltage lower than the output voltage. 5. precautions mount external capacitors, a diode, and a coil as close as possible to the ic. unique ripple voltage and spike noise occur in switching regulators. because they largely depend on the coil and the capacitor used, check them using an actually mounted model. make sure dissipation of the switching transistor (especially at a high temperature) does not exceed the allowable power dissipation of the package. the performance of this ic varies depending on the design of the pcb patterns, peripheral circuits and external parts. thoroughly test all settings with your device. also, try to use recommended external parts. typical application circuit for fb and external 1 for fb and external 2 n~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? www.gofotech.com
v1.0 page 9 of 11 me21 39 typical performance characteristics vin=3.6v vin=3v vin=4.2v vin=3v vin=3.6v vin=4.2v n~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? www.gofotech.com
v1.0 page 10 of 11 me21 39 package dimension package type:sot23-5 unit:mm(inch) dim millimeters inches min max min max a 0.9 1.45 0.0354 0.0570 a1 0 0.15 0 0.0059 a2 0.9 1.3 0.0354 0.0511 b 0.2 0.5 0.0078 0.0196 c 0.09 0.26 0.0035 0.0102 d 2.7 3.10 0.1062 0.1220 e 2.2 3.2 0.0866 0.1181 e1 1.30 1.80 0.0511 0.0708 e 0.95ref 0.0374ref e1 1.90ref 0.0748ref l 0.10 0.60 0.0039 0.0236 a 0 0 0 30 0 0 0 30 0 n~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? www.gofotech.com
v1.0 page 11 of 11 me21 39 the inform ation described herein is subject to change without notice. nanjing micro one electronics inc is not responsible for any problems caused by circuits or diagrams described herein whose related industrial properties, patents, or other rights belong to thi rd parties. the application circuit examples explain typical applications of the products, and do not guarantee the success of any specific mass - production design. use of the information described herein for other purposes and/or reproduction or copyin g without the express permission of nanjing micro one electronics inc is strictly prohibited. the products described herein cannot be used as part of any device or equipment affecting the human body, such as exercise equipment, medical equipment, securi ty systems, gas equipment, or any apparatus installed in airplanes and other vehicles, without prior written permission of nanjing micro one electronics inc. although nanjing micro one electronics inc exerts the greatest possible effort to ensure high q uality and reliability, the failure or malfunction of semiconductor products may occur. the user of these products should therefore give thorough consideration to safety design, including redundancy, fire - prevention measures, and malfunction prevention, t o prevent any accidents, fires, or community damage that may ensue. n~n?t?m?w3^v?mw`r?y?b?g ?pqls? tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com v?mw`r?y?b? www.gofotech.com

▲Up To Search▲

Price & Availability of ME2139F

	To Download ME2139F Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .