vishay siliconix sip2800/01/02/03/04/05 new product document number: 72660 s-71497-rev. d, 23-jul-07 www.vishay.com 1 low power consumption current mode controller features ? pin-for-pin compatible with ucc280x controllers ? enhanced performance uc284x for new designs ? 100 a typical start-up current ? 500 a typical operating current ? internal soft start at power-on and after fault ? 100 ns internal leading edge blanking applications ? efficiency-enhanced dc/dc converter modules ? low quiescent current standby power supplies ? offline (ac/dc) power supplies ? universal input power supplies ? buck, boost, and buck-boost converters description the sip280x family includes six high-speed, low power consumption, bicmos current mode controllers. these integrated circuits contain all of the control and drive functions required for off-line and dc-to-dc current-mode switching power supplies. their advanced architecture enables the implementation of full-featured designs with minimal external parts count. the sip280x family controllers are available in both standard and lead (pb)-free, so-8 and tssop-8 packages, and are rated for operation over the industrial temperature range of - 40 to 85 c. part number maximum duty cycle reference voltage turn-on threshold turn-off threshold sip2800 100 % 5 v 7.2 v 6.9 v sip2801 50 % 5 v 9.4 v 7.4 v sip2802 100 % 5 v 12.5 v 8.3 v sip2803 100 % 4 v 4.1 v 3.6 v sip2804 50 % 5 v 12.5 v 8.3 v sip2805 50 % 4 v 4.1 v 3.6 v typical application circuit * pb containing terminations are not rohs compliant, exemptions may apply. v cc ref gnd rc out + 48 v gnd comp fb cs sip2801 12 v/3 a + + + flyback converter for point of load application available pb-free rohs* compliant
www.vishay.com 2 document number: 72660 s-71497-rev. d, 23-jul-07 vishay siliconix sip2800/01/02/03/04/05 new product notes: a. currents are positive into, negativ e out of the specificed terminal. b. in normal operation v cc is powered through a current limiting resistor . an absolute maximum of 12 v applies when v cc is driven from a low impedance source such that i cc does not exceed 30 ma. stresses beyond those listed under ?absolute maximum ratings? ma y cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other condit ions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. absolute maximum ratings a parameter limit unit v cc b 12 v fb, comp, cs - 0.3 to 6 power dissipation so-8 1w power dissipation tssop-8 830 mw storage temperature - 55 to 150 c recommended operating range parameter limit unit operating temperature range - 40 to 85 c specifications parameter symbol test conditions unless specified v cc = 10 v, r t = 100 k ., c t = 330 pf c ref = 0.1 f, - 40 c < t a < 85 c limits unit min a typ b max a reference reference voltage v ref i load = 0.2 ma, t a = 25 c sip2800/1/2/4 4.925 5.000 5.075 v sip2803/5 3.940 4.000 4.06 sip2800/1/2/4 4.88 5.00 5.10 sip2803/5 3.90 4.00 4.08 load regulation v load 0.2 ma < i load < 5 ma 10 30 mv line regulation v line v cc = 10 v to clamp, t a = 25 c 1.9 mv/v v cc = 10 v to clamp 2.5 noise v noise 10 hz < f < 10 khz, t a = 25 c 130 v short circuit current i sc - 5 - 35 ma oscillator frequency f osc sip2800/1/2/4 40 46 52 khz sip2803/5 26 31 36 temperature stability 2.5 % amplitude v p-p 2.25 2.40 2.55 v peak voltage v p 2.45 error amplifier input voltage v in comp = 2.5 v sip2800/1/2/4 2.44 2.50 2.56 v comp = 2.0 v sip2803/5 1.95 2.00 2.05 input bias current i bias1 - 1 1 a open loop gain a v 60 80 db comp sink current i sink fb = 2.7 v, comp = 1.1 v 0.3 3.5 ma comp source current i source fb = 1.8 v, comp = v ref - 1.2 v - 0.2 - 0.5 - 0.8 gain bandwidth b w 2mhz
document number: 72660 s-71497-rev. d, 23-jul-07 www.vishay.com 3 vishay siliconix sip2800/01/02/03/04/05 new product notes: a. the algebraic convention whereby the most negative value is a minimum and the most positive a maximum (- 40 to 85 c). b. typical values are for design aid only, not guarant eed nor subject to production te sting and are measured at v cc = 12 v unless otherwise noted. c. gain is defined by a = v comp / v cs , 0 v v cs 0.8 v. d. start, stop, and zener voltages track each other. specifications parameter symbol test conditions unless specified v cc = 10 v, r t = 100 k ., c t = 330 pf c ref = 0.1 f, - 40 c < t a < 85 c limits unit min a typ b max a pwm and overcurrent comparator maximum duty cycle d max sip2800/2/3 97 99 100 % sip2801/4/5 48 49 50 minimum duty cycle d min comp = 0 v 0 gain c a v 0 < v cs < 0.8 v 1.2 1.65 1.9 v/v max. input signal v imax comp = 5 v 0.9 1.0 1.1 v input bias current 2 i bias2 - 200 200 na comp to cs offset cs = 0 v 0.45 0.90 1.35 v cs pin blanking time 50 100 150 ns overcurrent comparator fault threshold 1.47 1.73 output output voltage v ol i = 20 ma all parts 0.1 0.40 v i = 200 ma 0.35 0.90 i = 50 ma, v cc = 5 v sip2803/5 0.15 0.40 i = 20 ma, v cc = 0 v all parts 0.70 1.20 v cc - v oh i = - 20 ma all parts 0.15 0.40 i = - 200 ma 1.00 1.90 i = - 50 ma, v cc = 5 v sip2803/5 0.40 0.90 rise time t r cl = 1 nf 41 70 ns fall time t f 44 75 undervoltage lockout start threshold d v start sip2800 6.6 7.2 7.8 v sip2801 8.6 9.4 10.2 sip2802/4 11.5 12.5 13.5 sip2803/5 3.7 4.1 4.5 stop threshold d v stop sip2800 6.3 6.9 7.5 sip2801 6.8 7.4 8.0 sip2802/4 7.6 8.3 9.0 sip2803/5 3.2 3.6 4.0 start to stop hysteresis v hys sip2800 0.05 0.30 0.48 sip2801 1.5 2.0 2.4 sip2802/4 3.0 4.2 5.1 sip2803/5 0.2 0.5 0.8 soft-start comp rise time ss fb = 1.8 v, rise from 0.5 v to v ref - 1 v 410ms overall start-up current i start v cc < start threshold 0.1 0.2 ma operating supply current i cc fb = 0 v, cs = 0 v 0.5 1.0 v cc internal zener voltage d v z i cc = 10 ma 12.0 13.5 15.0 v v cc internal zener voltage minus start threshold voltage d v z - v start sip2802/04 0.5 1.0
www.vishay.com 4 document number: 72660 s-71497-rev. d, 23-jul-07 vishay siliconix sip2800/01/02/03/04/05 new product typical characteristics sip2800/01/02/04 oscillator frequency vs. r t and c t oscillator dead time vs. c t r t (k ) oscillator fr equency (khz) c t = 100 pf 1000 100 10 10 100 1000 c t = 200 pf c t = 330 pf c t = 1000 pf 0 50 100 150 200 250 300 350 400 450 500 100 200 300 400 500 600 700 800 900 100 0 r t = 100 k c t (pf) dead time (ns) sip2803/05 sip2800/01/02/04 sip2803/05 oscillator frequency vs. r t and c t comp to cs offset vo ltage vs. temperature r t (k ) oscillator fr equency (khz) 1000 100 10 10 100 1000 c t = 100 pf c t = 200 pf c t = 330 pf c t = 1000 pf 0.7 0.8 0.9 1.0 1.1 1.2 1.3 - 50 - 25 0 25 50 75 100 125 150 cs = 0 v temperature ( c) comp to cs offset (v) error amplifier gain and phase vs. frequency 1 - 3 0 80 10 10000 frequency (khz) gain (db) 100 70 60 50 40 30 20 10 0 - 1 0 - 2 0 1000 135 45 0 -45 90 phase ( ) phase gain
document number: 72660 s-71497-rev. d, 23-jul-07 www.vishay.com 5 vishay siliconix sip2800/01/02/03/04/05 new product pin configuration additional voltage options are available. 5 comp ref fb v cc cs out rc gnd soic-8 6 7 8 2 3 4 1 to p v i e w comp fb cs rc 1 2 3 4 8 7 6 5 ref v cc out gnd tssop-8 to p v i e w ordering information soic-8 tssop-8 part number lead (pb)-free part number marking temperature part number lead (pb)-free part number marking temperature sip2800dy-t1 sip2800dy-t1-e3 2800 - 40 to 85 c sip2800dq-t1 sip2800dq-t1-e3 2800 - 40 to 85 c sip2801dy-t1 sip2801dy-t1-e3 2801 SIP2801DQ-T1 SIP2801DQ-T1-e3 2801 sip2802dy-t1 sip2802dy-t1-e3 2802 sip2802dq-t1 sip2802dq-t1-e3 2802 sip2803dy-t1 sip2803dy-t1-e3 2803 sip2803dq-t1 sip2803dq-t1-e3 2803 sip2804dy-t1 sip2804dy-t1-e3 2804 sip2804dq-t1 sip2804dq-t1-e3 2804 sip2805dy-t1 sip2805dy-t1-e3 2805 sip2805dq-t1 sip2805dq-t1-e3 2805 pin description pin number name function 1 comp output of the voltage error amplifier, and the inverting input to the pwm?s current sense comparator 2 fb inverting input of the voltage error amplifier 3cs non-inverting input of the pwm current sense compar ator, and inverting input of the overcurrent fault comparator (both comparators are fed from the output of the internal 100 ns leading edge blanking circuit) 4 rc connection for the pwm oscillator?s timing resistor and timing capacitor 5 gnd ground pin 6 out pwm output signal (capable of driving 750 ma into the gate of an external mosfet power switch) 7 v cc positive supply voltage for the ic 8 ref ic reference voltage
www.vishay.com 6 document number: 72660 s-71497-rev. d, 23-jul-07 vishay siliconix sip2800/01/02/03/04/05 new product detailed pin description comp comp is the output of the voltage error amplifier (vea). the vea is a low output impedance operational amplifier, providing the input to the pwm cycle-by-cycle current limit comparator. as the sip280x series of parts use a true operational amplifie r for the vea, the co mp terminal can both source and sink current. to add flexibility to these parts, the vea is internally current lim ited, which allows out to be forced to zero duty cycle by taking the comp pin to gnd. the voltage on comp is passed through an internal diode to develop an offset voltage of approximately 0.6 v, and then through a resistive divider wit h a gain of 0.606 v/v, before being presented to the control input of the cycle-by-cycle current limit comparator. clamping the comp pin to less than the diode?s forward voltage (i.e., < 0.5 v) will command the current loop to deliver 0 a, by holding the control input of the cycle-by-cycle current comparator at 0 v. similarly, the current loop will command the maximum inductor current on each cycle when comp is at 2.25 v or greater, which drives the control input of the cycle-by -cycle current comparator to 1 v (since [2.25 v - 0.6 v] x 0.606 v/v = 1 v). the sip280x series additionally features a built-in soft-start function, which functions by clamping the output level of the vea to an internally generated voltage. this clamp will hold comp at a low voltage (v comp 0 v) until v cc and v ref are at their proper levels. when these levels are appropriate for circuit operation, the internal voltage will begin rising, at the rate of 1 v/ms. this rising clamp level allows the voltage on the comp pin to rise, which in turn allows the voltage at the control input of th e cycle-by-cycle current comparator to increase. the maximum soft-start interval occurs under conditions requiring full duty cycle (50 % or 100 %, depending upon the part type), and is given by the time required for the voltage on the cycle-by-cycle current comparator?s control input to reach 1 v. since 1 v at the control input to the comparator requires that the comp pin be at 2.25 v, the maximum soft-start interval is approximately 2.25 ms. cs input to both the cycle-by-cycle and overcurrent fault current sense comparators. the cy cle-by-cycle current limit comparator is the mechani sm by which the vea?s output voltage commands the level of inductor or transformer current during a given "on" interval, thereby regulating the overall circuit?s output.this co mparator forms the inner loop of the two loops used in current-mode regulation. the overcurrent comparator has a trip threshold that is 50 % higher than that of the cycl e-by-cycle comparator. under normal operating conditions, this comparator will not trip: its purpose is to provide enhanced protection of the power path components during severe faults (e.g., a short circuit). if the overcurrent comparator is trippe d by a fault condition, it will command the sip280x to do a "f ull-cycle restart". during this restart, the power supply will be quickly driven to the "off" state, and will be required to wait for five milliseconds (typical) before restarting. when the supply does restart, it will do so using the built-in soft-start function of the sip280x. the sip280x family incorporates internal leading-edge blanking on the cs pin, to keep any spurious voltages on the cs pin from reaching the comparator inputs during the 100 ns interval immediately following the rising edge on out (for example, voltages due to capacitive charging currents). because of this internal leading-edge blanking, many applications require no external rc filter on the cs input. compared to circuits requiring the use of an external rc filter circuit, leading-edge blanking provides a shorter effective cs to out propagation delay. fb fb is the inverting input of the vea. internally compared against v ref /2 appearing on the vea?s non-inverting input. to avoid stability problems, keep lead lengths to fb as short as possible, and use good layout practices to minimize the stray capacitances of components connected to this pin. gnd the gnd pin is both the reference ground and the power ground for this part. out out is the output of a high-current driver capable of peak currents in excess of 750 ma. out is therefore well suited to driving the gates of power mosfets. this pin is specifically held low when v cc is below the sip280x?s uvlo threshold, to ensure a predictable system turn-on. since the out pin is internally connected to a low impedance cmos buffer, it is capable of rapid ra il-to-rail transitions. this output topology also mitigates the effects of undershoot and overshoot. for this reason, external schottky clamp diodes are generally not required on this pin. rc rc is the oscillator frequency programming pin. f osc is set by the combination of r t and c t . the charging current for c t is provided through r t , which is normally connected between ref and the sip280x rc pin. c t then connects from rc to gnd. due to the high impedances encountered in low power control circuits, this connection must be a short and quiet return to gnd (preferably by means of a dedicated signal trace, separated from all other circuit functions). the oscillator frequency for the sip280x family of parts is approximated by the following formulas: for the sip2800, sip2801, sip2802, and sip2804: ?f osc (1.5)/r t c t for the sip2803 and sip2805: ?f osc (1.0)/r t c t here r t is in ohms and c t is in farads.
document number: 72660 s-71497-rev. d, 23-jul-07 www.vishay.com 7 vishay siliconix sip2800/01/02/03/04/05 new product more accurate formulas for f osc are: for the sip2800, sip2801, sip2802 and sip2804: ?f osc = 1/{[(c t + c stray ) x r t x 0.652] + [(c t + c stray ) x r disch x 2.53] + t delay } for the sip2803 and sip2805: ?f osc = 1/{[(c t + c stray ) x r t x 0.93] + [(c t + c stray ) x r disch x 2.53] + t delay } here r t is in ohms and c t is in farads, r disch is the value of the resistor through which c t is discharged (normally an on-chip 130 resistor, unless the circuit is configured with additional external discharge-path resistance), and t delay is an inherent internal comparat or delay time of 100 ns. the capacitance associated with the rc pin is approximately 7.5 pf, and should be included as a part of c stray . note that the sip2801, si p2804, and sip2805 have an internal toggle flip-flop at the output of the oscillator, to ensure that the output duty cycle never exceeds 50 %. this divides the frequency appearing at the out pin to one-half of the oscillator frequency for these three parts. values of r t below 10 k are not recommended. low values of r t cause high circuit operating currents, and very low values will prevent the oscillator from properly discharging c t . ref the reference generator bloc k of the si280x provides an accurate and stable 4.0 v or 5.0 v (depending upon part number), which is available at this pin of the ic. this voltage is also used internally for other functions on the ic. one of these uses is as the logic power supply for high speed switching logic on the ic; this, and stability concerns, make it important to bypass v ref to gnd with a good quality 0.1 f ceramic capacitor, as close to the part as possible. an electrolytic or tantalum capacitor may be used in addition to the ceramic capacitor. when 1 v < v cc < the uvlo threshold, ref is pulled to ground through a 5 k resistor. hence, ref can also be used as an output to indicate the part?s v cc status. v cc v cc is the positive power connection for the sip280x controller ic, and should be the most positive terminal on the part. in normal operation, v cc is powered through a current limiting resistor. the required start-up supply current will generally be on the order of 100 a with v cc below the uvlo voltage of the sip280x, and can remain at or below 500 a total supply current once the part starts switching. to prevent the ic from being damaged by overvoltage conditions, each of the sip 2800 family of parts has an internal clamp (effectively a 13.5 v zener diode) between v cc and gnd. if the part?s v cc pin is current-fed through an appropriate dropping resistor, the v cc pin will never exceed its rated voltage, nor will the device as a whole exceed its rated power dissipation. this does require knowing what the operating current of the ic will be, so that the value of the dropping resistor can be calculated. a good estimate of the actual operating current (i cc ) may be made by summing three components: (a) any external current loading on the v cc or ref pins (b) the operating current required by the ic itself, and (c) the drive current (i drive ) required by the external power switch. item (a) in the above list is a static dc value, and can generally be calculated with good accuracy. item (b) will increase with operating frequency, but will be fixed for a given value of f osc . item (c) is usually the dominant term in the calculation of i cc , as the power required to drive the external power switch will typically increase as f out is increased. the most common example of this is seen in driving the gate of a power mosfet. in such applications, the gate capacitances must be charged once each switching cycle. this calculation is simp lified by using the gate charge term given by most mosfet manufacturers, allowing the use of the formula: i drive = f out x q g of the chosen mosfet. a first approximation of t he necessary dropping resistor value is then given by: r = [(nominal v supply ) - 12 v]/(nominal i cc ) here r is in ohms and i cc is in amperes. the resistor limiting the current into the v cc pin should be selected such that i cc(min) equals the worst-case maximum sum of the above currents, while holding i cc(max) to as low a value above that number as practicable (for best overall efficiency), and nevermore than 25 ma above that number (to avoid exceeding the ic?s internal clamp diode ratings). v cc must be bypassed to gnd with a good quality 0.1 f ceramic capacitor, as close to the part as possible. this will help avoid problems created by high-frequency noise on the power supply of the part. an electrolytic or tantalum capacitor may be placed in parallel with the ceramic capacitor if more capacitance is needed or desired.
www.vishay.com 8 document number: 72660 s-71497-rev. d, 23-jul-07 vishay siliconix sip2800/01/02/03/04/05 new product functional block diagram vishay siliconix maintains worldwide manufacturing capability. products may be manufactured at one of several qualified locatio ns. reliability data for silicon technology and package reliability represent a composite of all qualified locations. for related documents such as package/tape drawings, part marking, and reliability data, see http://www.vishay.com/ppg?72660 . cs out rc comp v cc fb gnd tq sq r osc leading edge blanking reference voltage uvlo soft-start ref sip2801/4/5 only 1.5 v ref/2 overcurrent comparator - + + - voltage error amplifier pwm comparator 13.5 v - +
document number: 91000 www.vishay.com revision: 18-jul-08 1 disclaimer legal disclaimer notice vishay all product specifications and data are subject to change without notice. vishay intertechnology, inc., its affiliates, agents, and employees, and all persons acting on its or their behalf (collectively, ?vishay?), disclaim any and all liability fo r any errors, inaccuracies or incompleteness contained herein or in any other disclosure relating to any product. vishay disclaims any and all li ability arising out of the use or application of any product describ ed herein or of any information provided herein to the maximum extent permit ted by law. the product specifications do not expand or otherwise modify vishay?s terms and conditions of purcha se, including but not limited to the warranty expressed therein, which apply to these products. no license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document or by any conduct of vishay. the products shown herein are not designed for use in medi cal, life-saving, or life-sustaining applications unless otherwise expressly indicated. customers using or selling vishay products not expressly indicated for use in such applications do so entirely at their own risk and agree to fully indemnify vishay for any damages arising or resulting from such use or sale. please contact authorized vishay personnel to obtain written terms and conditions regarding products designed for such applications. product names and markings noted herein may be trademarks of their respective owners.
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