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january 2011 ? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers fan3226 / fan3227 / fan3228 / fan3229 dual 2a high-speed, low-side gate drivers features ? industry-standard pinouts ? 4.5 to 18v operating range ? 3a peak sink/source at v dd = 12v ? 2.4a sink / 1.6a source at v out = 6v ? choice of ttl or cmos input thresholds ? four versions of dual independent drivers: - dual inverting + enable (fan3226) - dual non-inverting + enable (fan3227) - dual inputs in two pin-out configurations: o compatible with fan3225x (fan3228) o compatible with tps2814d (fan3229) ? internal resistors turn driver off if no inputs ? millerdrive? technology ? 12ns / 9ns typical rise/fall times with 1nf load ? typical propagation delay under 20ns matched within 1ns to the other channel ? double current capability by paralleling channels ? 8-lead 3x3mm mlp or 8-lead soic package ? rated from ?40c to +125c ambient applications ? switch-mode power supplies ? high-efficiency mosfet switching ? synchronous rectifier circuits ? dc-to-dc converters ? motor control ? servers description the fan3226-29 family of dual 2a gate drivers is designed to drive n-channel enhancement-mode mosfets in low-side switching applications by providing high peak current pulses during the short switching intervals. the driver is available with either ttl or cmos input thresh olds. internal circuitry provides an under-voltage lockout function by holding the output low until the supply voltage is within the operating range. in addition, the drivers feature matched internal propagation delays between a and b channels for applications requiring dual gate drives with critical timing, such as synchronous rectifiers. this enables connecting two drivers in parallel to effectively double the current capability driving a single mosfet. the fan322x drivers incorporate millerdrive? architecture for the final output stage. this bipolar- mosfet combination provides high current during the miller plateau stage of the mosfet turn-on / turn-off process to minimize switching loss, while providing rail- to-rail voltage swing and reverse current capability. the fan3226 offers two inverting drivers and the fan3227 offers two non-inverting drivers. each device has dual independent enable pins that default to on if not connected. in the fan3228 and fan3229, each channel has dual inputs of opposite polarity, which allows configuration as non-inverting or inverting with an optional enable function using the second input. if one or both inputs are left unconnected, internal resistors bias the inputs such that the output is pulled low to hold the power mosfet off. related resources ? an-6069: application review and comparative evaluation of low-side gate drivers fan3226 fan3227 fan3228 fan3229 figure 1. pin configurations
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 2 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers ordering information part number logic input threshold package packing method quantity per reel fan3226cmpx dual inverting channels + dual enable cmos 3x3mm mlp-8 tape & reel 3,000 fan3226cmx soic-8 tape & reel 2,500 fan3226tmpx ttl 3x3mm mlp-8 tape & reel 3,000 fan3226tmx soic-8 tape & reel 2,500 fan3227cmpx dual non-inverting channels + dual enable cmos 3x3mm mlp-8 tape & reel 3,000 fan3227cmx soic-8 tape & reel 2,500 fan3227tmpx ttl 3x3mm mlp-8 tape & reel 3,000 fan3227tmx soic-8 tape & reel 2,500 fan3228cmpx dual channels of two-input / one-output drivers, pin configuration 1 cmos 3x3mm mlp-8 tape & reel 3,000 fan3228cmx soic-8 tape & reel 2,500 fan3228tmpx ttl 3x3mm mlp-8 tape & reel 3,000 fan3228tmx soic-8 tape & reel 2,500 fan3229cmpx dual channels of two-input / one-output drivers, pin configuration 2 cmos 3x3mm mlp-8 tape & reel 3,000 fan3229cmx soic-8 tape & reel 2,500 fan3229tmpx ttl 3x3mm mlp-8 tape & reel 3,000 fan3229tmx soic-8 tape & reel 2,500 package outlines figure 2. 3x3mm mlp-8 (top view) figure 3. soic-8 (top view) thermal characteristics (1) package ? jl (2) ? jt (3) ? ja (4) ? jb (5) ? jt (6) units 8-lead 3x3mm molded leadless package (mlp) 1.6 68 43 3.5 0.8 c/w 8-pin small outline integrated circuit (soic) 40 31 89 43 3.0 c/w notes: 1. estimates derived from thermal simulati on; actual values depend on the application. 2. theta_jl ( ? jl ): thermal resistance between the semi conductor junction and the bottom surfac e of all the leads (including any thermal pad) that are typically soldered to a pcb. 3. theta_jt ( ? jt ): thermal resistance between the semi conductor junction and the top surface of the package, assuming it is held at a uniform temperature by a top-side heatsink. 4. theta_ja ( ja ): thermal resistance between junction and ambient, dependent on the pcb design, heat sinking, and airflow. the value given is for natural convecti on with no heatsink using a 2s2p board, as specified in jedec standards jesd51-2, jesd51-5, and jesd51-7, as appropriate. 5. psi_jb ( ? jb ): thermal characterization parameter providing corre lation between semiconductor junction temperature and an application circuit board reference point fo r the thermal environment defined in note 4. for the mlp-8 package, the board reference is defined as the pcb copper connected to the therma l pad and protruding from either end of the package. for the soic-8 package, the board reference is defi ned as the pcb copper adjacent to pin 6. 6. psi_jt ( ? jt ): thermal characterization parameter providing corre lation between the semiconductor junction temperature and the center of the top of the package for the thermal environment defined in note 4.
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 3 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers fan3226 fan3227 fan3228 fan3229 figure 4. pin configurations (repeated) pin definitions name pin description ena enable input for channel a . pull pin low to inhibit driver a. ena has ttl thresholds for both ttl and cmos inx threshold. enb enable input for channel b . pull pin low to inhibit driver b. enb has ttl thresholds for both ttl and cmos inx threshold. gnd ground . common ground reference for input and output circuits. ina input to channel a . ina+ non-inverting input to channel a . connect to vdd to enable output. ina- inverting input to channel a . connect to gnd to enable output. inb input to channel b . inb+ non-inverting input to channel b . connect to vdd to enable output. inb- inverting input to channel b . connect to gnd to enable output. outa gate drive output a : held low unless required input(s) are present and v dd is above uvlo threshold. outb gate drive output b : held low unless required input(s) are present and v dd is above uvlo threshold. outa gate drive output a (inverted from the input): held low unless required input is present and v dd is above uvlo threshold. outb gate drive output b (inverted from the input): held low unless required input is present and v dd is above uvlo threshold. p1 thermal pad (mlp only). exposed metal on the bottom of the package; may be left floating or connected to gnd; not suitable for carrying current. vdd supply voltage . provides power to the ic. output logic fan3226 ( x =a or b) fan3227 ( x =a or b) fan3228 and fan3229 ( x =a or b) enx inx outx enx inx outx inx+ inx ? outx 0 0 0 0 0 (7) 0 0 (7) 0 0 0 1 (7) 0 0 1 0 0 (7) 1 (7) 0 1 (7) 0 1 1 (7) 0 (7) 0 1 0 1 1 (7) 1 (7) 0 1 (7) 1 1 1 1 (7) 0 note: 7. default input signal if no external connection is made.
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 4 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers block diagrams 6 vdd 7 v dd_ok 5 ina 2 100k ena 1 gnd 3 v dd uvlo 100k 8 v dd enb inb 4 outa outb 100k 100k 100k 100k v dd v dd figure 5. fan3226 block diagram figure 6. fan3227 block diagram
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 5 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers block diagrams figure 7. fan3228 block diagram figure 8. fan3229 block diagram
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 6 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers absolute maximum ratings stresses exceeding the absolute maximum ratings may dam age the device. the device may not function or be operable above the recommended operating conditions and st ressing the parts to these levels is not recommended. in addition, extended exposure to stresses above the recomm ended operating conditions may affect device reliability. the absolute maximum ratings are stress ratings only. symbol parameter min. max. unit v dd vdd to pgnd -0.3 20.0 v v en ena and enb to gnd gnd - 0.3 v dd + 0.3 v v in ina, ina+, ina?, inb, inb+ and inb? to gnd gnd - 0.3 v dd + 0.3 v v out outa and outb to gnd gnd - 0.3 v dd + 0.3 v t l lead soldering temperature (10 seconds) +260 oc t j junction temperature -55 +150 oc t stg storage temperature -65 +150 oc esd electrostatic discharge protection level human body model, jedec jesd22-a114 4 kv charged device model, jedec jesd22-c101 1 kv recommended operating conditions the recommended operating conditions table defines th e conditions for actual device operation. recommended operating conditions are specified to en sure optimal performance to the datash eet specifications. fairchild does not recommend exceeding them or designing to absolute maximum ratings. symbol parameter min. max. unit v dd supply voltage range 4.5 18.0 v v en enable voltage ena and enb 0 v dd v v in input voltage ina, ina+, ina?, inb, inb+ and inb? 0 v dd v t a operating ambient temperature -40 +125 oc
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 7 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers electrical characteristics unless otherwise noted, v dd =12v, t j =-40c to +125c. currents are defined as positive into the device and negative out of the device. symbol parameter conditions min. typ. max. unit supply v dd operating range 4.5 18.0 v i dd supply current inputs / en not connected ttl 0.75 1.20 ma cmos (8) 0.65 1.05 ma v on turn-on voltage ina=ena=v dd , inb=enb=0v 3.5 3.9 4.3 v v off turn-off voltage ina=ena=v dd , inb=enb=0v 3.3 3.7 4.1 v inputs (fan322xt) (9) v inl_t inx logic low threshold 0.8 1.2 v v inh_t inx logic high threshold 1.6 2.0 v i in+ non-inverting input in from 0 to v dd -1.5 175.0 a i in- inverting input in from 0 to v dd -175.0 1.5 a v hys_t ttl logic hysteresis voltage 0.2 0.4 0.8 v inputs (fan322xc) (9) v inl_c inx logic low threshold 30 38 %v dd v inh_c inx logic high threshold 55 70 %v dd i inl in current, low in from 0 to v dd -1 175 a i inh in current, high in from 0 to v dd -175 1 a v hys_c cmos logic hysteresis voltage 17 %v dd enable (fan3226c, fan3226t, fan3227c, fan3227t) v enl enable logic low threshold en from 5v to 0v 0.8 1.2 v v enh enable logic high threshold en from 0v to 5v 1.6 2.0 v v hys_t ttl logic hysteresis voltage (10) 0.4 v r pu enable pull-up resistance (10) 100 k ? t d3 en to output propagation delay (12) 0v to 5v en, 1v/ns slew rate 10 19 34 ns t d4 0v to 5v en, 1v/ns slew rate 10 18 32 ns continued on the following page?
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 8 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers electrical characteristics (continued) unless otherwise noted, v dd =12v, t j =-40c to +125c. currents are defined as positive into the device and negative out of the device. symbol parameter conditions min. typ. max. unit output i sink out current, mid-voltage, sinking (10) out at v dd /2, c load =0.1f, f=1khz 2.4 a i source out current, mid-voltage, sourcing (10) out at v dd /2, c load =0.1f, f=1khz -1.6 a i pk_sink out current, peak, sinking (10) c load =0.1f, f=1khz 3 a i pk_source out current, peak, sourcing (10) c load =0.1f, f=1khz -3 a t rise output rise time (12) c load =1000pf 12 22 ns t fall output fall time (12) c load =1000pf 9 17 ns t d1 output propagation delay, cmos inputs (12) cmos input 7 15 30 ns t d2 cmos input 6 15 29 t d1 output propagation delay, ttl inputs (12) ttl input 10 19 34 ns t d2 ttl input 10 18 32 t del.match propagation matching between channels ina=inb, outa and outb at 50% point 1 2 ns i rvs output reverse current withstand (10) 500 ma notes: 8. lower supply current due to inactive ttl circuitry. 9. en inputs have ttl thresholds ; refer to the enable section. 10. not tested in production. 11. see timing diagrams of figure 11 and figure 12. 12. see timing diagrams of figure 9 and figure 10.
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 9 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers timing diagrams 90% 10% output input t d1 t d2 t rise t fall v inl v inh 90% 10% output t d1 t d2 t fall t rise v inl v inh input figure 9. non-inverting (en high or floating) figure 10. inverting (en high or floating) figure 11. non-inverting (in high) figure 12. inverting (in low)
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 10 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers typical performance characteristics typical characteristics are provided at 25c and v dd =12v unless otherwise noted. figure 13. i dd (static) vs. supply voltage (13) figure 14. i dd (static) vs. supply voltage (13) figure 15. i dd (static) vs. supply voltage ( 13 ) figure 16. i dd (no-load) vs. frequency figure 17. i dd (no-load) vs. frequency 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 4 6 8 1012141618 v dd - supply voltage (v) i dd (ma) fan3228c, 29c all inputs floating, outputs low 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 4 6 8 1012141618 supply voltage (v) i dd (ma) ttl input inputs and enables floatin g, out p uts low 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 4 6 8 1012141618 supply voltage (v) i dd (ma) fan3226c , 27c inputs and enables floatin g, out p uts
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 11 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers typical performance characteristics typical characteristics are provided at 25c and v dd =12v unless otherwise noted. figure 18. i dd (1nf load) vs. frequency figure 19. i dd (1nf load) vs. frequency figure 20. i dd (static) vs. temperature (13) figure 21. i dd (static) vs. temperature (13) figure 22. i dd (static) vs. temperature ( 13 ) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 -50-250 255075100125 temperature (c) i dd (ma) fan3228c, 29c a ll inputs floating, outputs low 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 -50 -25 0 25 50 75 100 125 temperature (c) i dd (ma) ttl input inputs and enables floatin g, out p uts 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 -50 -25 0 25 50 75 100 125 temperature (c) i dd (ma) fan3226c, 27c inputs and enables floatin g, out p uts
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 12 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers typical performance characteristics typical characteristics are provided at 25c and v dd =12v unless otherwise noted. figure 23. input thresholds vs. supply voltage figure 24. input thresholds vs. supply voltage figure 25. input threshold % vs. supply voltage figure 26. input thresholds vs. temperature figure 27. input thresholds vs. temperature
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 13 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers typical performance characteristics typical characteristics are provided at 25c and v dd =12v unless otherwise noted. figure 28. uvlo thresholds vs. temperature figure 29. uvlo threshold vs. temperature figure 30. propagation delays vs. supply voltage figure 31. propagation delays vs. supply voltage figure 32. propagation delays vs. supply voltage figure 33. propagation delays vs. supply voltage
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 14 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers typical performance characteristics typical characteristics are provided at 25c and v dd =12v unless otherwise noted. figure 34. propagation delays vs. temperature figure 35. propagation delays vs. temperature figure 36. propagation delays vs. temperature figure 37. propagation delays vs. temperature figure 38. fall time vs. supply voltage figure 39. rise time vs. supply voltage
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 15 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers typical performance characteristics typical characteristics are provided at 25c and v dd =12v unless otherwise noted. figure 40. rise and fall times vs. temperature figure 41. rise/fall waveforms with 1nf load figure 42. rise/fall waveforms with 10nf load figure 43. quasi-static source current with v dd =12v figure 44. quasi-static sink current with v dd =12v
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 16 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers typical performance characteristics typical characteristics are provided at 25c and v dd =12v unless otherwise noted. figure 45. quasi-static source current with v dd =8v figure 46. quasi-static sink current with v dd =8v note: 13. for any inverting inputs pulled low, non-inverting inputs pulled high, or output s driven high, static i dd increases by the current flowing through the corresponding pull- up/down resistor shown in the block diagram. test circuit figure 47. quasi-static i out / v out test circuit
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 17 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers applications information input thresholds each member of the fan322x driver family consists of two identical channels that may be used independently at rated current or connected in parallel to double the individual current capacity. in the fan3226 and fan3227, channels a and b can be enabled or disabled independently using ena or enb, respectively. the en pin has ttl thresholds for parts with either cmos or ttl input thresholds. if ena and enb are not connected, an internal pull-up resistor enables the driver channels by default. if the channel a and channel b inputs and outputs are connected in parallel to increase the driver current capacity, ena and enb should be connected and driven together. the fan322x family offers versions in either ttl or cmos input thresholds. in the fan322xt, the input thresholds meet industry-standard ttl-logic thresholds independent of the v dd voltage, and there is a hysteresis voltage of approx imately 0.4v. these levels permit the inputs to be driven from a range of input logic signal levels for which a voltage over 2v is considered logic high. the driving signal for the ttl inputs should have fast rising and falling edges with a slew rate of 6v/s or faster, so a rise time from 0 to 3.3v should be 550ns or less. with reduced slew rate, circuit noise could cause the driver input voltage to exceed the hysteresis voltage and retrigger the driver input, causing erratic operation. in the fan322xc, the logic input thresholds are dependent on the v dd level and, with v dd of 12v, the logic rising edge threshold is approximately 55% of v dd and the input falling edge threshold is approximately 38% of v dd . the cmos input configuration offers a hysteresis voltage of approximately 17% of v dd . the cmos inputs can be used with relatively slow edges (approaching dc) if good decoupling and bypass techniques are incorporated in the system design to prevent noise from violating the input voltage hysteresis window. this allows setting precise timing intervals by fitting an r-c circuit between the controlling signal and the in pin of the driver. t he slow rising edge at the in pin of the driver introduces a delay between the controlling signal and the out pin of the driver. static supply current in the i dd (static) typical performance characteristics (see figure 13 - figure 15 and figure 20 - figure 22) , the curve is produced with all inputs / enables floating (out is low) and indicates the lowest static i dd current for the tested configuration. for other states, additional current flows through the 100k ? resistors on the inputs and outputs shown in the block diagram of each part (see figure 5 - figure 8) . in these cases, the actual static i dd current is the value obt ained from the curves plus this additional current. millerdrive? gate drive technology fan322x gate drivers incorporate the millerdrive? architecture shown in figur e 48. for the output stage, a combination of bipolar and mos devices provide large currents over a wide range of supply voltage and temperature variations. the bipolar devices carry the bulk of the current as out swings between 1/3 to 2/3 v dd and the mos devices pull the output to the high or low rail. the purpose of the millerdrive? architecture is to speed up switching by providing high current during the miller plateau region when the gate-drain capacitance of the mosfet is being charged or discharged as part of the turn-on / turn-off process. for applications that have ze ro voltage switching during the mosfet turn-on or turn-off interval, the driver supplies high peak current for fast switching even though the miller plateau is not present. this situation often occurs in synchronous rectifier applications because the body diode is generally conducting before the mosfet is switched on. the output pin slew rate is determined by v dd voltage and the load on the output. it is not user adjustable, but a series resistor can be added if a slower rise or fall time at the mosfet gate is needed. figure 48. millerdrive? output architecture under-voltage lockout the fan322x startup logic is optimized to drive ground- referenced n-channel mosfets with an under-voltage lockout (uvlo) function to ensure that the ic starts up in an orderly fashion. when v dd is rising, yet below the 3.9v operational level, this circuit holds the output low, regardless of the status of the input pins. after the part is active, the supply voltage must drop 0.2v before the part shuts down. this hysteresis helps prevent chatter when low v dd supply voltages have noise from the power switching. this config uration is not suitable for driving high-side p-channel mosfets because the low output voltage of t he driver would turn the p-channel mosfet on with v dd below 3.9v.
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 18 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers v dd bypass capacitor guidelines to enable this ic to turn a device on quickly, a local high-frequency bypass capacitor c byp with low esr and esl should be connected between the vdd and gnd pins with minimal trace length. this capacitor is in addition to bulk electrolytic ca pacitance of 10f to 47f commonly found on driver and controller bias circuits. a typical criterion for choosing the value of c byp is to keep the ripple voltage on the v dd supply to 5%. this is often achieved with a value 20 times the equivalent load capacitance c eqv , defined here as q gate /v dd . ceramic capacitors of 0.1f to 1f or larger are common choices, as are diel ectrics, such as x5r and x7r with good temperature characteristics and high pulse current capability. if circuit noise affects normal operation, the value of c byp may be increased to 50-100 times the c eqv , or c byp may be split into two capacitors. one should be a larger value, based on equivalent load capacitance, and the other a smaller value, such as 1-10nf mounted closest to the vdd and gnd pins to carry the higher frequency components of the current pulses. the bypass capacitor must provid e the pulsed current from both of the driver channels and, if the drivers are switching simultaneously, the combined peak current sourced from the c byp would be twice as large as when a single channel is switching. layout and connection guidelines the fan3226-26 family of gate drivers incorporates fast-reacting input circuits, short propagation delays, and powerful output stages c apable of delivering current peaks over 2a to facilitate voltage transition times from under 10ns to over 150ns. the following layout and connection guidelines are strongly recommended: ? keep high-current output and power ground paths separate logic and enable input signals and signal ground paths. this is especially critical when dealing with ttl-level logic thresholds at driver inputs and enable pins. ? keep the driver as close to the load as possible to minimize the length of high-current traces. this reduces the series inductance to improve high- speed switching, while reducing the loop area that can radiate emi to the driver inputs and surrounding circuitry. ? if the inputs to a channel are not externally connected, the internal 100k ? resistors indicated on block diagrams command a low output. in noisy environments, it may be necessary to tie inputs of an unused channel to vdd or gnd using short traces to prevent noise from causing spurious output switching. ? many high-speed power circuits can be susceptible to noise injected from their own output or other external sources, possibly causing output re- triggering. these effects can be obvious if the circuit is tested in breadboard or non-optimal circuit layouts with long input, enable, or output leads. for best results, make connections to all pins as short and direct as possible. ? the fan322x is compatible with many other industry-standard drivers. in single input parts with enable pins, there is an internal 100k ? resistor tied to v dd to enable the driver by default; this should be considered in the pcb layout. ? the turn-on and turn-off current paths should be minimized, as discussed in the following section. figure 49 shows the pulsed gate drive current path when the gate driver is supplying gate charge to turn the mosfet on. the current is supplied from the local bypass capacitor, c byp , and flows through the driver to the mosfet gate and to gr ound. to reach the high peak currents possible, the re sistance and inductance in the path should be minimized. the localized c byp acts to contain the high peak current pulses within this driver- mosfet circuit, preventing them from disturbing the sensitive analog circuitry in the pwm controller. pwm v ds v dd c byp fan322x figure 49. current path for mosfet turn-on figure 50 shows the current path when the gate driver turns the mosfet off. ideally, the driver shunts the current directly to the source of the mosfet in a small circuit loop. for fa st turn-off times, the resistance and inductance in this path should be minimized. pwm v ds v dd c byp fan322x figure 50. current path for mosfet turn-off
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 19 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers truth table of logic operation the fan3228/fan3229 truth table indicates the operational states using the dua l-input configuration. in a non-inverting driver configur ation, the in- pin should be a logic low signal. if the in- pin is connected to logic high, a disable function is real ized, and the driver output remains low regardless of the state of the in+ pin. in+ in- out 0 0 0 0 1 0 1 0 1 1 1 0 in the non-inverting driver c onfiguration in figure 51, the in- pin is tied to ground and the input signal (pwm) is applied to in+ pin. the in- pin can be connected to logic high to disable the driver and the output remains low, regardless of the stat e of the in+ pin. vdd gnd in- in+ out pwm fan3228/9 figure 51. dual-input driver enabled, non-inverting configuration in the inverting driver application in figure 52, the in+ pin is tied high. pulling the in+ pin to gnd forces the output low, regardless of t he state of the in- pin. figure 52. dual-input driver enabled, inverting configuration operational waveforms at power-up, the driver output remains low until the v dd voltage reaches the turn-on threshold. the magnitude of the out pulses rises with v dd until steady-state v dd is reached. the non-inverting operation illustrated in figure 53 shows that the output remains low until the uvlo threshold is reached, the output is in-phase with the input. figure 53. non-inverting startup waveforms for the inverting configurat ion of figure 52, startup waveforms are shown in figur e 54. with in+ tied to v dd and the input signal applied to in?, the out pulses are inverted with respect to the input. at power-up, the inverted output remains low until the v dd voltage reaches the turn-on threshold, then it follows the input with inverted phase. figure 54. inverting startup waveforms
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 20 thermal guidelines gate drivers used to switch mosfets and igbts at high frequencies can dissipate significant amounts of power. it is important to determine the driver power dissipation and the resulting junction temperature in the application to ensure that th e part is operating within acceptable temperature limits. the total power dissipation in a gate driver is the sum of two components, p gate and p dynamic : p total = p gate + p dynamic (1) gate driving loss: the most significant power loss results from supplying gate current (charge per unit time) to switch the load mosfet on and off at the switching frequency. the power dissipation that results from driving a mo sfet at a specified gate- source voltage, v gs , with gate charge, q g , at switching frequency, f sw , is determined by: p gate = q g ? v gs ? f sw ? n (2) n is the number of driver channels in use (1 or 2). dynamic pre-drive / shoot-through current: a power loss resulting from internal current consumption under dynamic operating conditions, including pin pull-up / pull-down resistors, can be obtained using the ?i dd (no-load) vs. frequency? graphs in typical performance characteristics to determine the current i dynamic drawn from v dd under actual operating conditions: p dynamic = i dynamic ? v dd ? n (3) once the power dissipated in the driver is determined, the driver junction rise with respect to circuit board can be evaluated using the following thermal equation, assuming ? jb was determined for a similar thermal design (heat sinking and air flow): t j = p total ? ? jb + t b (4) where: t j = driver junction temperature ? jb = (psi) thermal characterization parameter relating temperature rise to total power dissipation t b = board temperature in location defined in note 1 under thermal resistance table. in the forward converter with synchronous rectifier shown in the typical application diagrams, the fdms8660s is a reasonable mosfet selection. the gate charge for each sr mosfet would be 60nc with v gs = v dd = 7v. at a switching frequency of 500khz, the total power dissipation is: p gate = 60nc ? 7v ? 500khz ? 2 = 0.42w (5) p dynamic = 3ma ? 7v ? 2 = 0.042w (6) p total = 0.46w (7) the soic-8 has a junction-to-board thermal characterization parameter of ? jb = 43c/w. in a system application, the lo calized temperature around the device is a function of the layout and construction of the pcb along with airflow across the surfaces. to ensure reliable operation, the maximum junction temperature of the devic e must be prevented from exceeding the maximum rating of 150c; with 80% derating, t j would be limited to 120c. rearranging equation 4 determines the board temperature required to maintain the junction temperature below 120c: t b = t j - p total ? ? jb (8) t b = 120c ? 0.46w ? 43c/w = 100c (9) for comparison, replace the soic-8 used in the previous example with the 3x3mm mlp package with ? jb = 3.5c/w. the 3x3mm mlp package could operate at a pcb temperature of 118c, while maintaining the junction temperature below 120c. this illustrates that the physically smaller mlp package with thermal pad offers a more conductive path to remove the heat from the driver. consider tradeoffs between reducing overall circuit size with junction temperature reduction for increased reliability.
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 21 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers typical application diagrams figure 55. forward converter with synchronous rectification figure 56. primary-side dual driver in a push-pull converter figure 57. phase-shifted full-bridge with two gate drive transformers (simplified)
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 22 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers table 1. related products type part number gate drive (14) (sink/src) input threshold logic package single 1a fan3111c +1.1a / -0.9a cmos single channel of dual-input/single-output sot23-5, mlp6 single 1a fan3111e +1.1a / -0.9a external (15) single non-inverting channel with external reference sot23-5, mlp6 single 2a fan3100c +2.5a / -1.8a cmos single channel of two-input/one-output sot23-5, mlp6 single 2a fan3100t +2.5a / -1.8a ttl single channel of two-input/one-output sot23-5, mlp6 dual 2a fan3216t +2.4a / -1.6a ttl dual inverting channels soic8 dual 2a fan3217t +2.4a / -1.6a ttl dual non-inverting channels soic8 dual 2a fan3226c +2.4a / -1.6a cmos dual inverting channels + dual enable soic8, mlp8 dual 2a fan3226t +2.4a / -1.6a ttl dual inverting channels + dual enable soic8, mlp8 dual 2a fan3227c +2.4a / -1.6a cmos dual non-inverting channels + dual enable soic8, mlp8 dual 2a fan3227t +2.4a / -1.6a ttl dual non-inverting channels + dual enable soic8, mlp8 dual 2a fan3228c +2.4a / -1.6a cmos dual channels of two-input/one-output, pin config.1 soic8, mlp8 dual 2a fan3228t +2.4a / -1.6a ttl dual channels of two-input/one-output, pin config.1 soic8, mlp8 dual 2a fan3229c +2.4a / -1.6a cmos dual channels of two-input/one-output, pin config.2 soic8, mlp8 dual 2a fan3229t +2.4a / -1.6a ttl dual channels of two-input/one-output, pin config.2 soic8, mlp8 dual 2a fan3268t +2.4a / -1.6a ttl 20v non-inverting channel (nmos) and inverting channel (pmos) + dual enables soic8 dual 2a FAN3278T +2.4a / -1.6a ttl 30v non-inverting channel (nmos) and inverting channel (pmos) + dual enables soic8 dual 4a fan3213t +2.5a / -1.8a ttl dual inverting channels soic8 dual 4a fan3214t +2.5a / -1.8a ttl dual non-inverting channels soic8 dual 4a fan3223c +4.3a / -2.8a cmos dual inverting channels + dual enable soic8, mlp8 dual 4a fan3223t +4.3a / -2.8a ttl dual in verting channels + dual enable soic8, mlp8 dual 4a fan3224c +4.3a / -2.8a cmos dual n on-inverting channels + dual enable soic8, mlp8 dual 4a fan3224t +4.3a / -2.8a ttl dual non- inverting channels + dual enable soic8, mlp8 dual 4a fan3225c +4.3a / -2.8a cmos dual channels of two-input/one-output soic8, mlp8 dual 4a fan3225t +4.3a / -2.8a ttl dual channels of two-input/one-output soic8, mlp8 single 9a fan3121c +9.7a / -7.1a cmos singl e inverting channel + enable soic8, mlp8 single 9a fan3121t +9.7a / -7.1a ttl singl e inverting channel + enable soic8, mlp8 single 9a fan3122t +9.7a / -7.1a cmos single non-inverting channel + enable soic8, mlp8 single 9a fan3122c +9.7a / -7.1a ttl single non-inverting channel + enable soic8, mlp8 notes: 14. typical currents with outx at 6v and v dd= 12v. 15. thresholds proportional to an externally supplied reference voltage.
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 23 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers physical dimensions figure 58. 3x3mm, 8-lead molded leadless package (mlp) package drawings are provided as a service to customers considering fairchild comp onents. drawings may change in any manner without notice. please note the revision and/or date on the drawin g and contact a fairchild semiconductor representative to ver ify or obtain the most recent revision. package s pecifications do not expand the terms of fa irchild?s worldwide terms and conditions, specifically the warranty therein, which covers fairchild products. always visit fairchild semiconductor?s online packa ging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/ . b. dimensions are in millimeters. c. dimensions and tolerances per a. conforms to jedec registration mo-229, variation veec, dated 11/2001 asme y14.5m, 1994 recommended land pattern 0.05 0.00 2x 2x 0.8 max seating plane d. filename: mkt-mlp08drev2
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 24 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers physical dimensions (continued) figure 59. 8-lead, small outline integrated curcuit (soic) package drawings are provided as a service to customers considering fairchild comp onents. drawings may change in any manner without notice. please note the revision and/or date on the drawin g and contact a fairchild semiconductor representative to ver ify or obtain the most recent revision. package s pecifications do not expand the terms of fa irchild?s worldwide terms and conditions, specifically the warranty therein, which covers fairchild products. always visit fairchild semiconductor?s online packa ging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/ . 8 0 see detail a notes: unless otherwise specified a) this package conforms to jedec ms-012, variation aa, issue c, b) all dimensions are in millimeters. c) dimensions do not include mold flash or burrs. d) landpattern standard: soic127p600x175-8m. e) drawing filename: m08arev13 land pattern recommendation seating plane 0.10 c c gage plane x 45 detail a scale: 2:1 pin one indicator 4 8 1 c m ba 0.25 b 5 a 5.60 0.65 1.75 1.27 6.20 5.80 3.81 4.00 3.80 5.00 4.80 (0.33) 1.27 0.51 0.33 0.25 0.10 1.75 max 0.25 0.19 0.36 0.50 0.25 r0.10 r0.10 0.90 0.406 (1.04) option a - bevel edge option b - no bevel edge
? 2007 fairchild semiconductor corporation www.fairchildsemi.com fan3226 / fan3227 / fan3228 / fan3229 ? rev. 1.0.7 25 fan3226 / fan3227 / fan3228 / fan3229 ? du al 2a high-speed, low-side gate drivers

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