plessey semiconductors ltd, tamerton road, roboroug h, plymouth, uk pl6 7bq data sheet 292205 issue 1 tel: +44 (0)1752 693000 fax: +44 (0)1752 693200 w eb: www.plesseysemiconductors.com email: sales@plesseysemi.com ; october 12, 2010 1 PS22924 12v, 2a fast transient response linear regulator preliminary data sheet 292205 issue 1 typical application vin = 1.7 ? 12v description the PS22924 is a high performance, precision linear regulator with very low dropout voltage and excellent transie nt response. it is designed to operate with wide input voltage r ange of 1.7 ? 12 volts making it ideal for two step conversion. the device is capable of supplying 2a of output current with a ty pical dropout voltage of 350mv. the output voltage is available i n either fixed or adjustable options. for fixed option, the inter nal resistor network can be set in 100mv increment ranging from 0.5 to 5.0 volts. the product includes an enable pin for electrical o n/off of the regulator. forcing the enable pin to logic low shu ts down the ldo and reduces the supply current below 1 a. the PS22924 features fast transient response and low self outpu t noise. connecting a capacitor form bypass to gnd further e nhances the psrr and the output noise. an open collector power good flag with 500s delay is available for systems requiring supply monitoring and sequenc ing of other supplies. the regulator features the full su ite of protection with a combination of current limit and thermal ove rload protection. the PS22924 is available in a thermally enhanced soic-8 edp packages, and it is rated for -40c to +125c junct ion temperature range. features ? v in range 1.7 ? 12v ? fixed and adjustable output voltage ? 2a maximum output current ? 350mv typical dropout voltage ? bypass output for low psrr and output noise ? power good pin with 500s delay ? low self noise ? shutdown mode for longer battery life ? high psrr typically 60db at 100hz ? stable with a wide range of ceramic, tantalum or electrolytic capacitors ? current limit protection ? thermal shutdown ? -40c to 125c temperature range ? available in soic-8 package applications ? set top boxes ? digital audio systems ? dsp ? pol regulators ? smps post regulator
PS22924 plessey semiconductors ltd, tamerton road, roboroug h, plymouth, uk pl6 7bq data sheet 292205 issue 1 tel: +44 (0)1752 693000 fax: +44 (0)1752 693200 w eb: www.plesseysemiconductors.com email: sales@plesseysemi.com; october 12, 2010 2 pin description symbol pin number description en 1 enable pin. it controls the electrical on/off of t he device. when connected to logic low, the device shuts off and consumes 1 a of current. logic high will resume normal operat ion. bypass 2 bypass pin. connect an external capacitor from byp to ground to bypass the noise generated by the internal bandgap. this improves power supply r ejection ratio and output noise. a minimum capacitor of 220pf is recommended. v in 3 input supply pin. connect a 10 f capacitor between this pin and ground. nc 4 no connect. fb 5 feedback voltage. for preset vout devices an on-chi p resistor network of two resistors is used to set-up the output voltage. in this case fb needs to be connected externally to vout. for adjustable vout devices the centre of an external r esistive chain needs to be connected to this fb pin. v out 6 regulated output voltage. connect a 10 f capacitor from this pin to ground. pg 7 power good. it is an open collector, active high o utput that indicates the status of the output voltage. when output voltage (v out ) exceeds the pg trip threshold, the pg pin goes in to a high impedance state. when the device is out of regulati on or shutdown, the pg pin is pulled low. a 10k to 1m resistor should be connected from pg to v out . gnd 8 ground connection. edp expose pad. connected to pcb ground plane for good thermal dissipation. nb: n/a = not available in the shown package type pin configuration soic-8 (top view)
PS22924 plessey semiconductors ltd, tamerton road, roboroug h, plymouth, uk pl6 7bq data sheet 292205 issue 1 tel: +44 (0)1752 693000 fax: +44 (0)1752 693200 w eb: www.plesseysemiconductors.com email: sales@plesseysemi.com; october 12, 2010 3 absolute maximum ratings (1) maximum input supply voltage??????........?.? -0.8 to 15v enable voltage????????????????.... -0.8 to 15v power good????????????????? ..... -0.8 to 15v feedback voltage???? ???????????...... -0.8 to 5v bypass voltage?????????????????. -0.8 to 5v recommended operating conditions input voltage?????????????.????.. 1.7 to 12v enable input voltage?????????.?????.. 0v to v in junction operating temperature??????..?? -40 ? c to 125 ? c thermal information (2) soic-8 1 ja ................................................... .............................36 ? c/w storage temperature range?????..................... .... -65 to 150 ? c lead temperature???????..???? .?????? 260 ? c junction temperature? ???????? .???? ... -40 to 125 ? c electrical characteristics unless otherwise noted: v in =5.0v; v o =3.3v; c in =c out =22f; -40 ? c to t j(max.) = 125 c; typical values are t a = 25 c parameter symbol conditions min. typ. max. units fixed option; 100mv increment 0.5 5.0 v output voltage range v o adjustable 0.5 v o +v do output voltage tolerance tbd % feedback voltage v fb 0.494 0.50 0.506 v maximum output current i o 2 a shutdown current i shd v en =gnd 0.1 1.0 a current limit i lim 2.2 3.2 a supply current i q i out = 2a tbd ma load regulation 3 i out = 0.1ma ? 2a -1.0 1.0 % line regulation v in = vo+1v to 12v; i out =10ma -0.5 0.5 % i out = 1a tbd i out = 1.5a tbd dropout voltage v do i out = 2a tbd mv enable threshold low v en(l) 0.8 v enable threshold high v en(h) 1.4 v input enable low current i en(l) v en = 0v 0.01 2.0 a input enable high current i en(h) v en =2v 5.0 8.0 a freq=100hz 62 ripple rejection ratio psrr i o =50ma freq=10khz 60 db c byp = open tbd output noise e n bw; 10hz ? 100khz io=100ma c out = 10f c byp =100nf tbd nv/ hz power good low threshold v ol_pg i pg =200 a 400 mv power good delay v pg_delay 500 s thermal shutdown t sd 140 ?c thermal shutdown hys. t sd_hys 15 ?c notes: 1. stresses above those listed in absolute maximum rat ings may cause permanent damage to the device. meas ured on approximately 1? square of 1oz copper. 2. the PS22924 is guaranteed to meet performance speci fications over the -40c to +125c junction operati ng temperature range and is assured by design, characterization, and correla tion with statistical process control. 3. load regulation is measured using pulse techniques with duty cycle <5%.
PS22924 plessey semiconductors ltd, tamerton road, roboroug h, plymouth, uk pl6 7bq data sheet 292205 issue 1 tel: +44 (0)1752 693000 fax: +44 (0)1752 693200 w eb: www.plesseysemiconductors.com email: sales@plesseysemi.com; october 12, 2010 4 typical dropout voltage vs iout(a) typical line regulation vs vin (v)
PS22924 plessey semiconductors ltd, tamerton road, roboroug h, plymouth, uk pl6 7bq data sheet 292205 issue 1 tel: +44 (0)1752 693000 fax: +44 (0)1752 693200 w eb: www.plesseysemiconductors.com email: sales@plesseysemi.com; october 12, 2010 5 typical load regulation vs iout(a) functional block diagram
plessey semiconductors ltd, tamerton road, roboroug h, plymouth, uk pl6 7bq data sheet 292205 issue 1 tel: +44 (0)1752 693000 fax: +44 (0)1752 693200 w eb: www.plesseysemiconductors.com email: sales@plesseysemi.com ; october 12, 2010 6 application hint input capacitor (c in ) input capacitor may be required when the device is not near the source power supply or when supplied b y a battery. this capacitor will reduce the circuit?s sensitivity whe n powered from complex source impedance and signifi cantly enhance the output transient response. the input bypass should be mounted with the short possible track directly across the regulator?s input and ground terminals. a 10 f ceramic capacitor should be adequate for most app lications. output capacitor (c out ) the output capacitor provides not only stability to the regulator, but also, enhances the load transie nt response. a minimum capacitance of 10 f is required. when selecting a ceramic capacitor, only x5r and x7r dielectric types should be used. other types such as z5u and y5f have such severe lo ss of capacitance due to effects of temperature var iation and applied voltage, they may provide as little as 20% of rated capacitance in many typical applications. always consult capacitor manufacturer?s data curves before selecting a capacitor. high-quality ceramic capacitors can be obtained from taiyo-yuden, avx, and murata. higher values of the output capacitance can be used to en hance loop stability and transient response. output voltage the adjustable output voltage option allows the use r to select an output voltage by using an external resistor divider. PS22924 uses a 0.5v reference voltage at the positive termi nal of the error amplifier. to set the output volta ge a programming resistor from the feedback pin (fb) to ground must be select ed. a 10k resistor is a good selection for a programming res istor r2. a higher value may result in an excessively sensitive feedback node while a lower value will draw more c urrent and degrade the light load efficiency. the equation for selecting t he voltage specific resistor is: fb o v r r v * 2 1 1 ?? ? ?? ? + = for the fixed output devices, r1 and r2 are include d within the device. bypass capacitor connecting a capacitor between the byp pin and grou nd can significantly reduce output noise. values ca n range from 0pf to 100nf, depending on the sensitivity to output noise in the application. the start up speed of the ps22 294 is inversely proportional to the size of the bypass capacitor. a pplications requiring a slow ramp-up of output volt age should consider larger values of bypass capacitance. likewise, if rapid tu rn on is necessary, consider omitting c byp . enable/shutdown the enable (en) pin is active high and is compatibl e with standard digital signalling levels. when v en below 0.8v, it turns the regulator off while v en above 1.4v turns the regulator on. if not used, en can be connected to the input voltage. if en is connected to v in , it should be connected as close as possible to th e largest capacitance on the input to prevent volta ge droops on that line from triggering the enable circuit. thermal consideration the ps22294 is designed to provide 2a of continuous current in a very small package. maximum power dis sipation can be calculated based on the output current and the volt age drop across the part. to determine the maximum power dissipation of the package, use the junction-to-ambient thermal re sistance of the device and the following basic equa tion: ? ?? ? ? ?? ? ? = ja a j d t t p (max) (max) where t j(max) is the maximum junction temperature of the die, t a is the ambient operating temperature, and ja is layout dependent. the actual power dissipation of the reg ulator circuit can be determined using the equation : p d = (v in ? v out )*i out + v in *i sup
PS22924 plessey semiconductors ltd, tamerton road, roboroug h, plymouth, uk pl6 7bq data sheet 292205 issue 1 tel: +44 (0)1752 693000 fax: +44 (0)1752 693200 w eb: www.plesseysemiconductors.com email: sales@plesseysemi.com; october 12, 2010 7 substituting pd(max) for pd and solving for the ope rating conditions that are critical to the applicat ion will give the maximum operating conditions for the regulator. the thermal resistance of the so8-edp is 36 (c/w) junction to ambient, and 5.5 (c/w) junction to cas e. ordering information device operating junction temp. package output voltage PS22924c1s4a3 -40c to +125c soic-8 adjustable PS22924tms4a3 -40c to +125c soic-8 2.5v PS22924tus4a3 -40c to +125c soic-8 3.3v n.b for other values of output voltage please conta ct your local plessey semiconductors sales represen tative
PS22924 plessey semiconductors ltd, tamerton road, roboroug h, plymouth, uk pl6 7bq data sheet 292205 issue 1 tel: +44 (0)1752 693000 fax: +44 (0)1752 693200 w eb: www.plesseysemiconductors.com email: sales@plesseysemi.com; october 12, 2010 8 outline drawing and landing pattern (soic-8)
PS22924 plessey semiconductors ltd, tamerton road, roboroug h, plymouth, uk pl6 7bq data sheet 292205 issue 1 tel: +44 (0)1752 693000 fax: +44 (0)1752 693200 w eb: www.plesseysemiconductors.com email: sales@plesseysemi.com; october 12, 2010 9 for further information about this and other produc ts, please visit: www.plesseysemiconductors.com legal notice product information provided by plessey semiconduct ors limited (?plessey?) in this document is believe d to be correct and accurate. plessey reserves the right to change/ correct the specifica tions and other data or information relating to pro ducts without notice but plessey accepts no liability for errors that may appear in this docume nt, howsoever occurring, or liability arising from the use or application of any information or data provided herein. neither the supply of such in formation, nor the purchase or use of products conv eys any licence or permission under patent, copyright, trademark or other intellectual property right of plessey or third parties. products sold by plessey are subject to its standar d terms and conditions of sale that are available o n request. no warranty is given that products do not infringe the intellectual property rights of third parties, and furthermore, the use o f products in certain ways or in combination with plessey, or non-plessey furnished equipments/c omponents may infringe intellectual property rights of plessey. the purpose of this document is to provide informat ion only and it may not be used, applied or reprodu ced (in whole or in part) for any purpose nor be taken as a representation relating to the pr oducts in question. no warranty or guarantee expres s or implied is made concerning the capability, performance or suitability of any produ ct, and information concerning possible application s or methods of use is provided for guidance only and not as a recommendation. the use r is solely responsible for determining the perform ance and suitability of the product in any application and checking that any specification or data it seeks to rely on has not been supersede d. products are intended for normal commercial applica tions. for applications requiring unusual environme ntal requirements, extended temperature range, or high reliability capability ( e.g. military, or medical applications), special pr ocessing/testing/conditions of sale may be available on application to plessey.
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