SEMTECH SC4910B

SC4910A/B High Performance Secondary Side Controller with Synchronous Rectifier POWER MANAGEMENT Description Features The SC4910A/B is an integrated, full featured, second- ‹ Synchronous rectification with adaptive control ary side controller designed for use in single ended and ‹ Programmable secondary side delay isolated switch mode power supplies with synchronous ‹ Programmable switching frequency rectification where efficiency and fast transient response ‹ Programmable max. duty cycle are of primary concern. The SC4910A/B has outputs for ‹ Remote voltage sense capability both primary FET and secondary synchronous rectifica- ‹ Close-loop soft start with active low shutdown tion. The primary drive output is designed to drive a small ‹ 0.75V precision reference for low output applications and low cost pulse transformer to isolate the primary ‹ Oscillator sychronization FET driver. The secondary control makes it much easier ‹ Undervoltage Lockout to monitor and control the system load with tight control ‹ Operation to 1MHz loops and implement load current sharing and synchro- ‹ Current-mode or voltage-mode operation nous rectification. ‹ Single stage power conversion with multiphase link The SC4910A/B features synchronous rectification, multi- capability (with SC4201) phase link capability, programmable secondary side ‹ Monotonic start-up with pre-biased output delay, programmable switching frequency and program- ‹ Active current sharing capability mable maximum duty cycle. It is designed for either ‹ 20 pin TSSOP package current mode or voltage mode operation. Applications The SC4910A has a typical turn-on threshold of 9V and ‹ Telecom isolated DC to DC converters the SC4910B has a threshold of 4.5V. ‹ Isolated VRMS ‹ Networking power supplies ‹ Industrial power supplies ‹ Distributed power architectures Typical Application Circuit ‹ High density power modules L1 +Vin T1 R1 R2 C1 C3 LOAD C2 M1 D1 M2 SC1301 SC1301 +12V SC1301 C4 M3 SC4910 12 13 14 D2 PVCC PVCC AVCC T2 16 4 CS ISHARE 10 6 R3 OUTA PHASE R4 20 11 OUTB RT1 C5 R5 19 17 RT2 COMP C6 R6 3 18 R7 SS FB 2 15 SYNC/EN DELAY 5 1 R8 -SENSE VREF AGND PGND PGND 7 8 9 C8 R9 C9 C10 T3 D3 Revision: June 1, 2005 1 www.semtech.com SC4910A/B POWER MANAGEMENT Absolute Maximum Ratings Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied. Exposure to Absolute Maximum rated conditions for extended periods of time may affect device reliability. Pl arameter Sm ymboMs aximu Unit Sc upply Voltage V8 c 1V Output Voltage VV cc Phase VV cc FB, COMP, SYNC/EN, ISHARE -V 0.3 to 7 OUTA & OUTB Current Source or Sink 1A 50 m JT unction Temperature Range -C 40 to +150 ° J ST torage Temperature Range -C 60 to +150 ° STG LT ead Temperature (Soldering) 10 Sec. 2C 60 ° LEAD Electrical Characteristics Unless specified: T = T = -40°C to 125°C , V = 12V, R = R = 50K, R = 50K, C = 0.1µF. A CC J T1 T2 DELAY SS Ps arameter Tn est Condition Mp i Tx y Mt a Uni Power Supply Ow perating Current S0 YNC/EN = Lo 151A m Undervoltage Lockout S7 C4910A 80 . 93 . 9V . Start Threshold S5 C4910B 40 .3 45 .5 4V .7 S0 C4910A 40 0 50 5 7V 0 m UVLO Hysteresis S0 C4910B 20 0 35 0 3V 7 m VREF Reference S5 C4910A 40 .7 55 . 5V .2 Output Voltage S7 C4910B 20 .9 33 .3 3V .6 LV ine Regulation 95 .3V < Vcc < 15 103V m LI oad Regulation 0mA <<2 5mA 1V0 m REF Soft Start SS Output 0V .75 T = T=1 25°C -1 + A J Voltage Accuracy % -5 1.5 +1. LV ine Regulation 95 .3V < Vcc < 15 -0 +V 5 m (2) Impedance 7K Ω  2005 Semtech Corp. 2 www.semtech.com SC4910A/B POWER MANAGEMENT Electrical Characteristics (Cont.) Unless specified: T = T = -40°C to 125°C , V = 12V, R = R = 50K, R = 50K, C = 0.1µF. A CC J T1 T2 DELAY SS Ps arameter Tn est Condition Mp i Tx y Mt a Uni Error Amplifier Input Bias Current 05 .1 µA Offset Voltage 27 mV Open Loop Gain dB 80 (1) CMRR dB 70 (1) PSRR dB 70 Output High Voltage V I=5 1.0mA 19 .7 1. COMP Output Low Voltage I=9 1.0mA 00 . 1. V COMP (1) Unity Gain Bandwidth 5.0 MHz (1) Slew Rate 2.0 V/µS Oscillator FR requency Range Min. Frequency = R=0 500K 5z KH T1 T2 Max. Frequency R = R=0 25K 100 T1 T2 Frequency 40 50 50 0 5z 5 KH (1) Peak Voltage 2V .5 (1) Valley Voltage 1.0 V Enable Input High 2.0 V Enable Input Low 0.8 V Duty Cycle (2) Maximum Duty Cycle 90 % Minimum Duty Cycle 0 % Duty Cycle Tolerance -5 5 + % Current Limit Cycle by Cycle Threshold 05 .97515 .02 1.07 V Shutdown Threshold 15 .1 14 .2 1. V (2) Delay to Output 100 nS (2) Input Impedance 20 kΩ  2005 Semtech Corp. 3 www.semtech.com SC4910A/B POWER MANAGEMENT Electrical Characteristics (Cont.) Unless specified: T = T = -40°C to 125°C , V = 12V, R = R = 50K, R = 50K, C = 0.1µF. A CC J T1 T2 DELAY SS Ps arameter Tn est Condition Mp i Tx y Mt a Uni OUTA and OUTB Output Low I=1 100mA 1.3 V OUTPUT Output High V I=5 100mA 90 .7 1 OUTPUT (2) Rise Time nS C=0 100pF 2 OUT (2) Fall Time C=0 100pF 2 nS OUT Delay (2) OUTB Falling to OUTA Rising R = 50KΩ 70 nS DELAY (2) OUTA Falling to OUTB RisingP0 HASE > 1.5V 22 nS P0 HASE < 1.5V 3 Current Share Error Amplifier (1) Transconductance 0.18 mS (1) Output Source or Sink Current 10 µA Notes: (1) Guaranteed by design. (2) Guaranteed by characterization. (3) This device is ESD sensitive. Use of standard ESD handling requirements are required.  2005 Semtech Corp. 4 www.semtech.com SC4910A/B POWER MANAGEMENT Pin Configurations Ordering Information Pe art Number Packag TOP VIEW (2) SC4910AITSTRT (1) TSSOP-20 (2) -SENSE 1 20 RT1 SC4910BITSTRT SYNC/EN 2 19 RT2 Notes: SS 3 18 FB (1) Only available in tape and reel packaging. A reel contains 2500 devices. CS 4 17 COMP (2) Lead free product. This product is fully WEEE and VREF 5 16 ISHARE RoHS compliant. PHASE 6 15 DELAY AGND 7 14 AVCC PGND 8 13 PVCC PGND 9 12 PVCC OUTA 10 11 OUTB (20 Pin TSSOP) Marking Information Part Number (Example: 1471) Part Number (Example: 1471) yyww = Date Code (Example: 0012) yyww = Date Code (Example: 0012) xxxxx = Semtech Lot No. (Example: P94A01) xxxxx = Semtech Lot No. (Example: P94A01)  2005 Semtech Corp. 5 www.semtech.com SC4910A/B POWER MANAGEMENT Pin Descriptions Pe in #Pn in Nam Pin Functio 1E-. SENS Remote voltage sense return 2N SYNC/E Bidirectional synchronization and enable /disable pin. Referenced to -SENSE. 3SS. Soft start 4SC. Current sense input 5FV. RE 5V internal reference output 6EP. HAS Phase node for synchronous rectification 7DA. GN Analog ground 8DP. GN Power ground for OUTA 9DP. GN Power ground for OUTB 1A 0 OUT Output driver for primary MOSFET and secondary forward MOSFET. Low during UVLO. 1B 1 OUT Output the MOSFET driving signal for forward rectifier. Low during UVLO. 1C 2P. VC Power supply for OUTB 1C 3P. VC Power supply for OUTA 1C 4A. VC Analog supply voltage 1Y 5 DELA Predictive delay between OUTA and OUTB. The delay is from turn-off of the freewheeling MOSFET to turn-on of the forward MOSFET and primary MOSFET. The delay time is 20 to 200nS programmable. 1E 6I. SHAR Current share bus 1P 7C. OM Feedback compensation 1B 8 F. Feedback 12 9 RT Connect to timing resistor RT2 to control the negative ramp of the internal oscillator. 21 0 RT Connect to timing resistor RT1 to control the positive ramp of the internal oscillator.  2005 Semtech Corp. 6 www.semtech.com SC4910A/B POWER MANAGEMENT Block Diagram Figure. 1  2005 Semtech Corp. 7 www.semtech.com SC4910A/B POWER MANAGEMENT Applications Information The SC4910A/B is a secondary side PWM controller work- SYNC/EN ing either in current mode or voltage mode mainly for applications of forward converters with synchronous rec- The enable function looks at the SYNC/EN pin and an tification. While the OUTA drives the primary MOSFET internal timing capacitor. If the SYNC/EN pin is low and through transformer and the secondary forward recti- the internal timing capacitor voltage is high, then the fier, the OUTB drives the secondary freewheeling recti- SC4910 is disabled with OUTA, OUTB and SS pulled low. fier. The switching frequency and maximum duty cycle When the SYNC/EN pin is held high, the device is enabled can be programmable with two resistors. The delay time and runs off of the internal oscillator. When a rising signal from the falling edge of OUTA to the rising edge of OUTB is detected on the SYNC/EN pin a one-shot is triggered is adaptive by monitoring the phase node voltage. The and discharges the internal timing capacitor. As long as delay time from the falling edge of OUTB to the rising the internal timing capacitor is below an internal reference edge of OUTA is determined by a programming resistor level, the device will synchronize with the external pulse. from the DELAY pin to ground. The ISHARE pin allows for If the internal timing capacitor is allowed to charge up to current sharing among the parallel operating units to the internal reference level before another SYNC pulse make current equally distribute load. The -SENSE pin is detected, the device will switch back to the internal separated from GND pin provides true output voltage oscillator. remote sense capability. Other features include soft start, sychronization or enable/disable by user, provided 5V Soft Start reference voltage. The SS pin is connected to the internal reference, 0.75V, Oscillator through an internal 6K ohm resistor. The SS pin is also connected to the non-inverting input of the error amplifier. The frequency and duty cycle of the oscillator is controlled With an external capacitor connected to this pin, the soft by placing two resistors from the RT1 and RT2 pins to start timing will be determined by this RC time constant. ground. The resistor at RT1 controls the maximum “on” During start-up, the SS pin is held low until the duty cycle and the resistor at RT2 controls the “off” undervoltage lockout threshold is reached. Once the portion of a cycle. When the resistor at RT1 is equal to UVLO threshold is reach, the SS pin is released and the that at RT2, the maximum duty cycle will be approximately device will regulate to the voltage on this pin. 50%. The following formula is used to determine the time duration of the “on” and “off” portions: Undervoltage Lockout −12 t = RT × 20× 10 When the supply voltage V is below the undervoltage CC lockout threshold, both OUTA and OUTB are held low. The Current Sense and Current Limit SS pin and the COMP pin are also held low. Once the undervoltage lockout threshold has been surpassed, The CS pin has an input impedance of 20K ohms and OUTA, OUTB, SS and COMP are released for normal swings from 1.0V to 2.5V. With a 5K ohm resistor from operation. CS to ground, the device operates in voltage mode with a ramp that will swing from 0.2V to 0.5V. When the 5K resistor is connect to a voltage that is proportional to the primary side current, the device will operate in current mode. The cycle-by-cycle current limit is triggered when the CS pin voltage rises above 1V. If CS exceeds 1.25V, the faulty latch will be set and the outputs will be driven low. The soft start capacitor is then discharged by the internal current sink. No outputs are allowed until the soft start capacitor is fully discharged to 0.15V. At this point the fault latch will be reset and the SC4910 will begin a soft start process. This results in a hiccup current limit mode for continuous fault conditions.  2005 Semtech Corp. 8 www.semtech.com SC4910A/B POWER MANAGEMENT Applications Information (Cont.) Programmable Delay where n – Power transformer primary to secondary turns ratio SC4910 is for single ended topologies with secondary N – Secondary turns of current sense transformer side synchronous rectification. It provides outputs to drive S Io(pk) – Peak inductor current the primary MOSFET through a small pulse transformer and the secondary synchronous rectifiers directly. To avoid An example of choosing a current sense resistor is given cross conduction and optimize performance, adjustable below. Assume the converter full load current is 20A and delay is necessary between forwarding and freewheeling peak inductor current is 23A, the power transformer switches. The delay from falling edge of OUTB to rising primary to secondary turns ratio is 6:1 and the current edge of OUTA is determined by a resistor from the DELAY sense transformer primary to secondary turns ratio is pin to ground. The following formula is used to calculate 1:100, then, the delay time: 1.0 • 6 •100 t = R •1Ε −12 + 20nS DELAY Rs = ≈ 21Ω 120% • 23 where, R is the delay time setting resistor. Slope Compensation R should be between 20K and 200K. Slope compensation is needed to prevent sub-harmonic The delay time from falling edge of OUTA to rising edge of oscillation at duty cycle higher than 50% and to OUTB is adaptive and is triggered when the PHASE node compensate the peak to average difference in peak falls below 1.5V. If after 220nS the PHASE node has still current mode control. The following equation can be used not fallen, the device will automatically switch. to calculate the external slope. If negative Se is obtained by the equation, no slope compensation is needed. Operation Mode 2V n − V V • ΔI R SC4910 could be configured either current mode or O IN IN L S Se ≥ • • voltage mode operation. In current mode, the current 2(V − V n) V n n • N IN O O S sense signal comes to the CS pin while an external resistor could configure slope compensation. In voltage mode, an external resistor forms sawtooth with the internal 20K where resistor for voltage mode operation while current limit Se – External slope magnitude signal comes to the same pin. Vin – Low input line voltage In current mode, which is preferred for application of Vo – Output voltage SC4910, current is sensed by a current transformer for n – Power transformer primary to secondary turns ratio current feedback and over current protection. The current N – Secondary turns of current sense transformer S in the primary switch is sensed and controlled by ΔI - Peak-to-peak Inductor current ripple L developing a voltage proportional to current across a sense resistor on the secondary. The sensed voltage is then fed into the CS pin of SC4910. The typical current For example, if the low input line voltage is 36V, output limit threshold in the current sense pin of the SC4910 is voltage is 3.3V, power transformer primary to secondary 1.0V. The over current limit is assumed typical 120% of turns ratio is 6:1; the peak-to-peak inductor current ripple full load current. Then the current sense resistor can be is 6A, and current sense gain R is 21W, then the external S calculated by the following equation: slope needed is: 1.0 • n •N 2 • 3.3 • 6 − 36 36 • 6 21 S Rs = Se ≥ • • ≈ 85mV 120% •I (pk) O 2(36 − 3.3 • 6) 3.3 • 6 6 •100  2005 Semtech Corp. 9 www.semtech.com SC4910A/B POWER MANAGEMENT Applications Information (Cont.) Closed-Loop Compensation This is the minimum external slope required to avoid sub- harmonic oscillation at low input line. The simplified control-to-output transfer function for the With SC4910, the external slope is very easy to forward converter with current mode control, for small implement. Referring to Figure 2, R12 is the current sense value of external slope ( Se ≤ Sn, Sn is on-time slope of resistor. R10 and the internal 20KΩ resistor divide the sensed current waveform) is given by: internal slope 1.0V - 2.5V down to the required compensation slope. s 1+ V • R IN S ω (Se − ) • 20 z G = G L •N • f vg vgo M S S s R10 = 1+ V •R IN S ω (2.5 −1.0) − (Se − ) p L •N • f M S S where where: nN V S O G = DC gain of power stage with current loop closed vgo I R O S LM - Power transformer magnetizing inductance fS = Switching frequency 1 In the example, ω = Dominant pole of power stage with current loop closed P RC 36 • 21 (0.085 − ) • 20 1 450E − 6 •100 • 250E3 ω = ESR zero of power stage Z R10 = = 240Ω R C ESR 36 • 21 (2.5 −1.0) − (0.085 − ) 450E − 6 •100 • 250E3 where R - Load resistance C - Output capacitance R10 RESR - Output capacitors ESR C13 R12 4 16 For the given example above, at low line and R = 0.165Ω, CS ISHARE = 17mΩ, therefore: C = 2 x 680uF = 1360uF, R 10 2 ESR OUTA SYNC/EN R21 20 6 RT1 PHASE 19 U5 11 6 •100 • 3.3 RT2 OUTB SC4910 G = = 4.71 = 13dB vgo R22 3 17 20 • 21 SS COMP 15 18 DELAY FB 1 5 1 ω = = 4456 rad/ s = 710Hz P VREF -SENSE 0.165 X 1360E − 6 1 C22 R25 C36 ω = = 43253 rad/ s = 6887Hz Z 17E − 3 X 1360E − 6 Figure 2  2005 Semtech Corp. 10 www.semtech.com 7 14 AGND AVCC 8 13 PGND PVCC 9 12 PGND PVCC SC4910A/B POWER MANAGEMENT Applications Information (Cont.) The goal of the compensation design is to shape the loop Type 2 compensator (Figure 3) is needed for the above with high DC gain, high bandwidth, enough phase margin, current mode control. The compensation network gives and high attenuation for high frequency noises. Figure 4 the following characteristics: gives the asymptotic diagrams of the power stage with current loop closed and its loop gain. C3 One integrator is added to increase the DC gain. W is zc s R2 C1 used to cancel the power stage pole w so that the loop 1+ p ω ω 1 z gain has –20dB rate when it reaches 0 dB line. w is G = pc COMP s R1 s placed at output capacitor ESR or half switching frequency, 1+ ω p whichever is lower. Arbitrarily choose R2, then Vref Figure 3 C 1 1 1 C = ,C = ,R = 1 3 1 ω R ω ω (C + C ) PC 2 P I 1 3 −1 ω ZC where ω is adjusted for satisfactory phase margin and I 1 ω = 1 crossover frequency. R (C + C ) 1 1 3 1 Synchronization ω = ZC R C 2 1 1 Synchronization of oscillators in multiphase operation ω = PC C C 1 3 allows for reduced size of filtering components and R 2 C +C improved dynamic response. 1 3 SC4910 provides single stage conversion where SC4201 The loop gain will be given by: provides the multiphase function. SC4910 and SC4201 are placed on the secondary side, outputs A and C of the SC4201 are fed into the Sync pins of 2 separate s s 1+ 1+ SC4910’s. Both power supplies operate 180 degrees ω V ω ω z 1 ZC ref T = G G K = G • • apart. SC4201 can be configured up to 4 phase vg COMP FB vgo s s s V O 1+ 1+ operation. ω ω p PC Loop gain T(s) Compensator ω Power stage zc ω pc fs ω C ω P ω Z Figure 4  2005 Semtech Corp. 11 www.semtech.com + - SC4910A/B POWER MANAGEMENT Applications Information (Cont.) Load Current Sharing Load Remote Sensing A single wire connected between the ISHARE pins will Dedicated -SENSE pin provides true remote sensing of the regulated supply’s output terminal voltage for high force current sharing between parallel units for paralleling current applications. As shown in Figure 5, the bandgap or n+1 redundant operation. reference “ground “ is brought out as –Sense, which is The ISHARE pin allows for current sharing between several connected to the “load ground” and to the local analog parallel units. The ISHARE pin connects internally to the ground by the resistor R10. With this way combined with upper side R1, the voltage drop on power line is offset non-inverting input of ISHARE amplifier. An internal 4KΩ and the load voltage is truly sensed. resistor is between the inverting and non-inverting inputs of this amplifier, with the inverting input also connected to the COMP pin. The output of the amplifier connects to the SS (0.75V ref) pin. During normal operation, when R1 all devices are sharing the load current equally, the COMP LOAD pin voltages on each units should be approximately equal. If one of the devices begins to take on too much or too SC4910 little of the load, the difference in COMP pin voltage will cause the ISHARE amplifier to adjust the SS (0.75V ref) 4 16 CS ISHARE 10 6 voltage accordingly. In the event of ISHARE pulled down OUTA PHASE 20 11 C5 RT1 OUTB below 1V, the ISHARE amplifier is disabled to prevent 19 17 R6 C6 R7 RT2 COMP output voltage of the unit lower than specification. 3 18 SS FB 15 2 R8 DELAY SYNC/EN 5 1 VREF -SENSE R10 Figure 5  2005 Semtech Corp. 12 www.semtech.com 7 12 AGND PVCC 8 13 PGND PVCC 9 14 PGND AVCC SC4910A/B POWER MANAGEMENT Typical Characteristics Icc vs Vcc Icc vs Temperature 25.00 Vcc = 12V TA = 25°C 18.00 20.00 16.00 Syn/En = High Sync/En = High 15.00 14.00 Syn/En = Low 10.00 12.00 Sync/En = Low 5.00 10.00 8.00 0.00 4.5 6.5 8.5 10.5 12.5 14.5 -40 -20 0 20 40 60 80 100 120 Vcc (V) Temperature (°C) (Sc4910A) UVLO Hysteresis vs Temperature (Sc4910A) UVLO High Threshold vs Temperature 580.00 8.98 8.97 575.00 8.96 570.00 8.95 565.00 8.94 8.93 560.00 8.92 555.00 8.91 550.00 8.90 -40 -20 0 20 40 60 80 100 120 -40 -20 0 20 40 60 80 100 120 Temperature (°C) Temperature (°C) (Sc4910B) UVLO Hysteresis vs Temperature (Sc4910B) UVLO High Threshold vs Temperature 302.00 4.56 300.00 4.55 298.00 4.55 296.00 4.54 294.00 4.54 292.00 4.53 290.00 4.53 288.00 4.52 286.00 284.00 4.52 -40 -20 0 20 40 60 80 100 120 -40 -20 0 20 40 60 80 100 120 Temperature (°C) Temperature (°C)  2005 Semtech Corp. 13 www.semtech.com UVLO Hysteresis (mV) Icc (mA) UVLO Hysteresis (mV) Icc (mA) UVLO High Threshold (V) UVLO High Threshold (V) SC4910A/B POWER MANAGEMENT Typical Characteristics (Cont.) Bandgap Voltage vs Vcc Bandgap Voltage vs Temperature 0.755 0.7505 A T = 25°C Vcc = 12V Iout = 0mA 0.7500 0.753 0.7495 0.751 0.7490 0.749 0.7485 0.747 0.7480 0.745 0.7475 9 1011 12 1314 15 -40 -20 0 20 40 60 80 100 120 Vcc (V) Temperature (°C) Error Amp Input Bias Current vs Vcc Error Amp Input Bias Current vs Temperature 140.00 600.00 Vcc = 12V TA = 25°C 120.00 500.00 Vfb = 5V 400.00 100.00 300.00 80.00 200.00 Vfb = 5V 60.00 100.00 40.00 0.00 Vfb = 0V 20.00 Vfb = 0V -100.00 0.00 -200.00 4.5 6.5 8.5 10.5 12.5 14.5 -40 -20 0 20 40 60 80 100 120 Vcc (V) Temperature (°C) Error Amp Offset Voltage vs Vcc Error Amp Offset Voltage vs Temperature 1.40 1.50 A T = 25°C Vcc = 12V 1.20 1.40 1.00 1.30 0.80 0.60 1.20 0.40 1.10 0.20 0.00 1.00 -0.20 0.90 -0.40 -0.60 0.80 4.5 6.5 8.5 10.5 12.5 14.5 -40 -20 0 20 40 60 80 100 120 Vcc (V) Temperature (°C)  2005 Semtech Corp. 14 www.semtech.com Error Amp Offset Voltage (mV) Error Amp Input Bias Current Bandgap Voltage (V) (nA) Error Amp Offset Voltage (mV) Error Amp Input Bias Current Bandgap Voltage (V) (nA) SC4910A/B POWER MANAGEMENT Typical Characteristics (Cont.) Error Amp Output Voltage vs Temperature Oscillator Frequency vs Temperature 525 3.00 Rt1 = Rt2 = 50kohm Vcc = 12V 520 Icomp = 1mA 2.50 515 510 2.00 505 High 500 1.50 495 490 1.00 485 Low 480 0.50 475 -40 -20 0 20 40 60 80 100 120 -40 -20 0 20 40 60 80 100 120 Temperature (°C) Temperature (°C) Enable Voltage vs Temperature Max Duty Cycle vs Temperature 3.00 91.00 Output A Vcc = 12V 90.80 2.50 90.60 90.40 High 2.00 90.20 90.00 1.50 89.80 89.60 Low 1.00 89.40 89.20 0.50 89.00 -40 -20 0 20 40 60 80 100 120 -40 -20 0 20 40 60 80 100 120 Temperature (°C) Temperature (°C) Progammable Delay vs Temperature 90.00 Rdelay = 50kohm 85.00 80.00 75.00 70.00 65.00 60.00 -40 -20 0 20 40 60 80 100 120 Temperature (°C)  2005 Semtech Corp. 15 www.semtech.com Progammable Delay (nS) Enable Voltage (V) Error Amp Output Voltage (V) Max Duty Cycle (%) Oscillator Frequency (kHz) SC4910A/B POWER MANAGEMENT Evaluation Board Schematics  2005 Semtech Corp. 16 www.semtech.com * : Optional 3.3V/20A CON1 M3 M4 L1 T1 CON2 +Vin si4842dy si4842dy 1.3uH PA0168A 1 Vin+ Vout+ 5 10 C32 R37 C1 C2 2.2nF 5.1 2.2nF R1 D15 0.1uF,100V 39K R2 D14 SMAZ20 M1 si4842dy C6 C7 C8 C9 C3 C4 C5 C33 C34 2 8 10.0 D1 B130L 1u,100V 1u,100V 1u,100V 1u,100V 1u,100V 8 1 R3 100uF 100uF 680uF 680uF 7 2 5.1 3 ES1D Sense 6 3 5 4 R4 10K R18 4 Sense M2si4842dy Q2 10K Vin- R6 10K 8 1 FMMT718 D5 7 2 U2 6 3 1N4148WS +12V 5 SC1302A Ishare 5 4 Q5 R38 C11 FMMT718 10K D2 0.1uF 6 EN 1N4148WS R5 4.7 7 2 7 T2 3 D22* R8 4.7 1N5819HW +12V 8 1 5 4 7 Vout- C14 P8208T M7 M5 D21* 0.1uF 1N5819HW R13 Not populated si4490dy 10.0K R14 5 37.4K M6 C50 D6 si4490dy R10 22nF 4 1N4148WS 1.5K C13 R11 R12 +12V R15 150pF R51 10K 22 18.2K R17 1K 10 C16 C17 Ilim=24A R53 0.1uF 0.1uF R52 Q3 U3 FMMT718 +12V 1K 0 SC4431 D3 C12 C51 1N4148WS 10uF 0.1uF 4 16 CS ISHARE Q4 Not Populated fs=250KHz 10 2 OUTA SYNC/EN D9 7 2 R19 R21 124K 1N4148WS 20 6 6.8K U4 RT1 PHASE C20 100pF SC1302A 19 U5 11 C18 T3 C19 RT2 OUTB SC4910 0.1uF PE68386 0.1uF R50 R22 75K C21 R23 6 1 5 4 3 17 SS COMP R24 10 1.0nF 43K D20* 15 18 2.0K DELAY FB 4 3 1N5819HW 5 1 VREF -SENSE C22 C36 R25 R26 0.1uF 0.1uF 62K 10.0 D10 +12PRI 1N4148WS T4 2 C23 47uF D12 1N4148WS +12V D11 1N4148WS 1 5 R27 +Vin 100K C24 C25 3 8 47uF 47uF R28 C26 2.7MEG R29 0.47uF 68 4 C27 R30 PB2090 C28 10uF C29 100K 150pF R31 100pF 470K U6 SC4911 Q1 3 7 Si2320DS FB OUT R32 4 5 COMP ILIM 51 R33 100K C30 C31 C37 47nF R34 1000pF 470pF 1.00 R35 20K R36 100K 4 5 3 6 2 7 1 8 4 5 3 6 2 7 1 8 4 5 3 6 2 7 1 8 1 3 6 8 2 1 RT LUVLO 6 8 GND VCC 1 8 2 7 1 3 6 3 6 4 5 7 14 AGND AVCC 8 8 13 PGND PVCC 1 8 9 12 2 7 PGND PVCC 3 6 4 5 2 1 Vref SC4910A/B POWER MANAGEMENT Evaluation Board Bill of Materials Iy temQe uantitRt eferenc P# arMt anufacturer Foot Prin 32CF 1,C32 25 .2n SM/C_080 41CV 2 0M .1uF,100T6 DK, C3216X7R2A104 SM/C_120 55CV 3,C4,C5,C33,C34 1, uF,100 Murata SM/C_2220 GRM55RR72A105KA01B 64CV 6,C7,C8,C9 60 80uF, 4S3 anyo, 4TPB68 SM/CT_734 701, C11,C12,C14,C16,C17,C18,C1905 .1uF SM/C_080 C22,C36, C51 82CF 13,C29 15 50p SM/C_080 91CF 20 55 60p SM/C_080 11 0CF 21 15 .5n SM/C_080 13 1CV 23,C24,C25 47 7uF, 16S3 anyo, 16TPB4 SM/CT_734 11 2CF 26 06 .47u SM/C_120 11 3CV 27 1, 0uF, 10 Murata SM/C_1210 GRM32ER61C106KC31L 11 4CF 28 15 00p SM/C_080 11 5CF 30 45 7n SM/C_080 11 6CF 31 15 000p SM/C_080 11 7CF 37 45 70p SM/C_080 11 8CF 50 25 2n SM/C_080 11 9DD 1 E3 S1DA iodes Inc. ES1D-1 SM/_SM 20 01, D2,D5,D6,D9 17 N5819HWD3 iodes Inc. 1N5819HW- SOD12 D10,D11,D12,D20,D21,D22 21 1DL 14 B3 130DA iodes Inc. B130L-1 SM 21 2DA 15 S3 MAJ20DA iodes Inc. SMAJ120A-1 SM 21 3LH 1 1E .3uP1 anasonic, ETQPAF1R3 PCC-S 24 4My 1,M2,M3,M4 sy i4842dV8 isha SO- 22 5My 5,M6 sy i4490dV8 isha SO- 21 6QS 1 Sy i2320DV3 isha SM/SOT23_12 21 7RK 1 35 9 SM/R_080 22 8R0 2,R26 15 SM/R_080 22 9R1 3,R37 55 . SM/R_080 36 0RK 4,R6,R11,R17,R18,R3815 0 SM/R_080 32 1R7 5, R8 45 . SM/R_080  2005 Semtech Corp. 17 www.semtech.com SC4910A/B POWER MANAGEMENT Evaluation Board Bill of Materials Iy temQe uantitRt eferenc P# arMt anufacturer Foot Prin 31 2R2 10 45 1 SM/R_080 31 3R2 12 25 SM/R_080 31 4RK 13 15 0.0 SM/R_080 31 5RK 14 35 7.4 SM/R_080 31 6RK 15 15 8.2 SM/R_080 31 7RK 19 25 1.5 SM/R_080 31 8RK 21 15 60 SM/R_080 31 9RK 22 45 0.2 SM/R_080 41 0RK 23 45 3 SM/R_080 41 1RK 24 65 .19 SM/R_080 41 2RK 25 15 10 SM/R_080 43 3RK 27,R30,R33 15 00 SM/R_080 41 4RG 28 25 .7ME SM/R_080 43 5R8 29 65 SM/R_080 41 6RK 31 35 83 SM/R_080 41 7R1 32 55 SM/R_080 41 8R1 34 SM/R_0805 41 9RK 35 45 .7 SM/R_080 51 0RK 36 15 30 SM/R_080 52 1R0 50,R51 15 SM/R_080 51 2RK 52 15 .0 SM/R_080 51 3T8 1 Pe A016 P4 uls XP 51 4TT 2 Pe 8208 P8 uls P820 51 5T6 3 Pe E6838 P6 uls PE6838 51 6TR 4 3m 1414 Midco 52 7UA 2, U4 Sh C1302SN emtec SOT23_5PI 51 8U1 3 Sh C443SN emtec SOT23_5PI 51 9U0 5 Sh C491S0 emtec TSSOP-2 61 0U1 6 Sh C491 S8 emtec MSOP-  2005 Semtech Corp. 18 www.semtech.com SC4910A/B POWER MANAGEMENT Outline Drawing - TSSOP-20 DIMENSIONS INCHES MILLIMETERS A DIM D e MIN NOM MAX MIN NOM MAX - - - - A .047 1.20 N - - A1 .002 .006 0.05 0.15 A2 .031 - .042 0.80 - 1.05 2X E/2 - - b .007 .012 0.19 0.30 c - - .003 .007 0.09 0.20 E1 D .251 .255 .259 6.40 6.50 6.60 E E1 .169 .173 .177 4.30 4.40 4.50 PIN 1 E .252 BSC 6.40 BSC INDICATOR e .026 BSC 0.65 BSC L .018 .024 .030 0.45 0.60 0.75 ccc C 1 2 3 L1 (.039) (1.0) e/2 N 20 20 2X N/2 TIPS 01 0° - 8° 0° - 8° B aaa .004 0.10 bbb .004 0.10 ccc .008 0.20 D aaa C A2 A SEATING PLANE H C A1 bxN c bbb C A-B D GAGE PLANE 0.25 L 01 (L1) DETAIL A SEE DETAIL A SIDE VIEW NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS AND TO BE DETERMINED AT DATUM PLANE -A- -B- -H- 3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. REFERENCE JEDEC STD MO-153, VARIATION AC. 4. Land Pattern - TSSOP-20 F DIMENSIONS DIM INCHES MILLIMETERS C (.222) (5.65) (C) H F .157 4.00 G Z G .161 4.10 H .126 3.20 P .026 0.65 Y X .016 0.40 Y .061 1.55 P Z .283 7.20 X NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804  2005 Semtech Corp. 19 www.semtech.com