SC4910A/B High Performance Secondary Side Controller with Synchronous Rectifier POWER MANAGEMENT Description Features The SC4910A/B is an integrated, full featured, secondary side controller designed for use in single ended and isolated switch mode power supplies with synchronous rectification where efficiency and fast transient response are of primary concern. The SC4910A/B has outputs for both primary FET and secondary synchronous rectification. The primary drive output is designed to drive a small and low cost pulse transformer to isolate the primary FET driver. The secondary control makes it much easier to monitor and control the system load with tight control loops and implement load current sharing and synchronous rectification. Synchronous rectification with adaptive control Programmable secondary side delay Programmable switching frequency Programmable max. duty cycle Remote voltage sense capability Close-loop soft start with active low shutdown 0.75V precision reference for low output applications Oscillator sychronization Undervoltage Lockout Operation to 1MHz Current-mode or voltage-mode operation Single stage power conversion with multiphase link capability (with SC4201) Monotonic start-up with pre-biased output Active current sharing capability 20 pin TSSOP package The SC4910A/B features synchronous rectification, multiphase link capability, programmable secondary side delay, programmable switching frequency and programmable maximum duty cycle. It is designed for either current mode or voltage mode operation. Applications The SC4910A has a typical turn-on threshold of 9V and the SC4910B has a threshold of 4.5V. Typical Application Circuit Telecom isolated DC to DC converters Isolated VRMS Networking power supplies Industrial power supplies Distributed power architectures High density power modules L1 +Vin T1 C3 R2 R1 C1 LOAD C2 M1 D1 M2 SC1301 SC1301 +12V SC1301 C4 M3 SC4910 12 T2 D2 4 10 R3 R4 20 R5 19 3 15 5 PVCC CS C8 T3 C10 14 AVCC 16 ISHARE PVCC OUTA PHASE RT1 OUTB RT2 COMP SS FB SYNC/EN DELAY VREF AGND C9 13 7 -SENSE PGND 8 6 11 C5 17 18 C6 R6 R7 2 1 R8 PGND 9 R9 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. Parameter Symbol Maximum Units V cc 18 V Output Voltage V cc V Phase V cc V -0.3 to 7 V 150 mA Supply Voltage FB, COMP, SYNC/EN, ISHARE OUTA & OUTB Current Source or Sink Junction Temperature Range TJ -40 to +150 C Storage Temperature Range TSTG -60 to +150 C Lead Temperature (Soldering) 10 Sec. TLEAD 260 C Electrical Characteristics Unless specified: TA = T = -40C to 125C , VCC = 12V, R = R = 50K, R J Parameter T1 T2 DELAY Test Conditions = 50K, C SS = 0.1F. Min Typ Max Unit 10 15 mA Pow er Supply Operating Current SYNC/EN = Low Undervoltage Lockout Start Threshold UVLO Hysteresis S C 4910A 8.7 9.0 9.3 V S C 4910B 4.35 4.50 4.75 V S C 4910A 400 550 700 mV S C 4910B 200 300 375 mV S C 4910A 4.75 5.0 5.25 V S C 4910B 2.97 3.30 3.63 V VREF Reference Output Voltage Line Regulation 9.3V < Vcc < 15V 15 30 mV Load Regulation 0mA < IREF < 5mA 2 10 mV Soft Start SS Output 0.75 Voltage Accuracy Line Regulation Impedance TA = TJ = 25C 9.3V < Vcc < 15V 2005 Semtech Corp. -1 +1 -1.5 +1.5 -5 0 7K (2) 2 V +5 % mV www.semtech.com SC4910A/B POWER MANAGEMENT Electrical Characteristics (Cont.) Unless specified: TA = T = -40C to 125C , VCC = 12V, R = R = 50K, R J T1 Parameter T2 DELAY = 50K, C SS = 0.1F. Test Conditions Min Typ Max Unit 0.1 5 A Offset Voltage 2 7 mV Open Loop Gain 80 dB CMRR 70 dB 70 dB 1.9 V Error Amplifier Input Bias Current PSRR (1) (1) Output High Voltage ICOMP = 1.0mA Output Low Voltage ICOMP = 1.0mA Unity Gain Bandwidth (1) 1.75 0.9 1.0 MHz 5.0 Slew Rate (1) V 2.0 V/S Min. Frequency RT1 = RT2 = 500K 50 KHz Max. Frequency RT1 = RT2 = 25K 1000 Oscillator Frequency Range Frequency Peak Voltage 450 (1) Valley Voltage (1) Enable Input High 500 550 KHz 2.5 V 1.0 V V 2.0 Enable Input Low 0.8 V Duty Cycle Maximum Duty Cycle (2) Minimum Duty Cycle Duty Cycle Tolerance 90 % 0 % -5 +5 % Current Limit Cycle by Cycle Threshold Shutdown Threshold 0.975 1.025 1.075 V 1.1 1.25 1.4 V Delay to Output (2) 100 nS Input Impedance 20 k (2) 2005 Semtech Corp. 3 www.semtech.com SC4910A/B POWER MANAGEMENT Electrical Characteristics (Cont.) Unless specified: TA = T = -40C to 125C , VCC = 12V, R = R = 50K, R J T1 Parameter T2 DELAY = 50K, C Test Conditions SS = 0.1F. Min Typ Max Unit 1 1.3 V OUTA and OUTB Output Low IOUTPUT = 100mA Output High IOUTPUT = 100mA Rise Time (2) Fall Time (2) 10 V COUT = 100pF 20 nS COUT = 100pF 20 nS RDELAY = 50K 70 nS PHASE > 1.5V 220 nS PHASE < 1.5V 30 9.75 Delay OUTB Falling to OUTA Rising OUTA Falling to OUTB Rising (2) (2) Current Share Error Amplifier Transconductance (1) Output Source or Sink Current (1) 0.18 mS 10 A 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 Part Number TOP VIEW SC4910AITSTRT(2) -SENSE 1 20 RT1 SYNC/EN 2 19 RT2 SS 3 18 FB CS 4 17 COMP VREF 5 16 ISHARE PHASE 6 15 DELAY AGND 7 14 AVCC PGND 8 13 PVCC PGND 9 12 PVCC OUTA 10 11 OUTB SC4910BITSTRT(2) P ackag e TSSOP-20(1) Notes: (1) Only available in tape and reel packaging. A reel contains 2500 devices. (2) Lead free product. This product is fully WEEE and RoHS compliant. (20 Pin TSSOP) Marking Information Part Number (Example: 1471) yyww = Date Code (Example: 0012) xxxxx = Semtech Lot No. (Example: P94A01) Part Number (Example: 1471) yyww = Date Code (Example: 0012) xxxxx = Semtech Lot No. (Example: P94A01) 2005 Semtech Corp. 5 www.semtech.com SC4910A/B POWER MANAGEMENT Pin Descriptions Pin # Pin Name 1 -SENSE Remote voltage sense return. 2 SYNC/EN Bidirectional synchronization and enable /disable pin. Referenced to -SENSE. 3 SS Soft start. 4 CS Current sense input. 5 VREF 6 PHASE Phase node for synchronous rectification. 7 AGND Analog ground. 8 PGND Power ground for OUTA. 9 PGND Power ground for OUTB. 10 OUTA Output driver for primary MOSFET and secondary forward MOSFET. Low during UVLO. 11 OUTB Output the MOSFET driving signal for forward rectifier. Low during UVLO. 12 PVC C Power supply for OUTB. 13 PVC C Power supply for OUTA. 14 AVCC Analog supply voltage. 15 DELAY 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. 16 ISHARE Current share bus. 17 COMP 18 FB F e e d b a ck. 19 RT2 Connect to timing resistor RT2 to control the negative ramp of the internal oscillator. 20 RT1 Connect to timing resistor RT1 to control the positive ramp of the internal oscillator. 2005 Semtech Corp. Pin Function 5V internal reference output. Feedback compensation. 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 working either in current mode or voltage mode mainly for applications of forward converters with synchronous rectification. While the OUTA drives the primary MOSFET through transformer and the secondary forward rectifier, the OUTB drives the secondary freewheeling rectifier. The switching frequency and maximum duty cycle can be programmable with two resistors. The delay time from the falling edge of OUTA to the rising edge of OUTB is adaptive by monitoring the phase node voltage. The delay time from the falling edge of OUTB to the rising edge of OUTA is determined by a programming resistor from the DELAY pin to ground. The ISHARE pin allows for current sharing among the parallel operating units to make current equally distribute load. The -SENSE pin separated from GND pin provides true output voltage remote sense capability. Other features include soft start, sychronization or enable/disable by user, provided 5V reference voltage. SYNC/EN The enable function looks at the SYNC/EN pin and an internal timing capacitor. If the SYNC/EN pin is low and the internal timing capacitor voltage is high, then the SC4910 is disabled with OUTA, OUTB and SS pulled low. When the SYNC/EN pin is held high, the device is enabled and runs off of the internal oscillator. When a rising signal is detected on the SYNC/EN pin a one-shot is triggered and discharges the internal timing capacitor. As long as the internal timing capacitor is below an internal reference level, the device will synchronize with the external pulse. If the internal timing capacitor is allowed to charge up to the internal reference level before another SYNC pulse is detected, the device will switch back to the internal oscillator. Soft Start The SS pin is connected to the internal reference, 0.75V, through an internal 6K ohm resistor. The SS pin is also connected to the non-inverting input of the error amplifier. With an external capacitor connected to this pin, the soft start timing will be determined by this RC time constant. During start-up, the SS pin is held low until the undervoltage lockout threshold is reached. Once the UVLO threshold is reach, the SS pin is released and the device will regulate to the voltage on this pin. Oscillator The frequency and duty cycle of the oscillator is controlled by placing two resistors from the RT1 and RT2 pins to ground. The resistor at RT1 controls the maximum "on" duty cycle and the resistor at RT2 controls the "off" portion of a cycle. When the resistor at RT1 is equal to that at RT2, the maximum duty cycle will be approximately 50%. The following formula is used to determine the time duration of the "on" and "off" portions: t = RT x 20 x 10 Undervoltage Lockout -12 When the supply voltage VCC is below the undervoltage lockout threshold, both OUTA and OUTB are held low. The SS pin and the COMP pin are also held low. Once the undervoltage lockout threshold has been surpassed, OUTA, OUTB, SS and COMP are released for normal operation. Current Sense and Current Limit The CS pin has an input impedance of 20K ohms and swings from 1.0V to 2.5V. With a 5K ohm resistor from 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 NS - Secondary turns of current sense transformer Io(pk) - Peak inductor current SC4910 is for single ended topologies with secondary side synchronous rectification. It provides outputs to drive the primary MOSFET through a small pulse transformer and the secondary synchronous rectifiers directly. To avoid cross conduction and optimize performance, adjustable delay is necessary between forwarding and freewheeling switches. The delay from falling edge of OUTB to rising edge of OUTA is determined by a resistor from the DELAY pin to ground. The following formula is used to calculate the delay time: An example of choosing a current sense resistor is given below. Assume the converter full load current is 20A and peak inductor current is 23A, the power transformer primary to secondary turns ratio is 6:1 and the current sense transformer primary to secondary turns ratio is 1:100, then, t DELAY = R * 1 - 12 + 20nS Rs = where, R is the delay time setting resistor. R should be between 20K and 200K. Slope Compensation Slope compensation is needed to prevent sub-harmonic oscillation at duty cycle higher than 50% and to compensate the peak to average difference in peak current mode control. The following equation can be used to calculate the external slope. If negative Se is obtained by the equation, no slope compensation is needed. The delay time from falling edge of OUTA to rising edge of OUTB is adaptive and is triggered when the PHASE node falls below 1.5V. If after 220nS the PHASE node has still not fallen, the device will automatically switch. Operation Mode SC4910 could be configured either current mode or voltage mode operation. In current mode, the current 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 resistor for voltage mode operation while current limit signal comes to the same pin. In current mode, which is preferred for application of SC4910, current is sensed by a current transformer for current feedback and over current protection. The current in the primary switch is sensed and controlled by 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 limit threshold in the current sense pin of the SC4910 is 1.0V. The over current limit is assumed typical 120% of full load current. Then the current sense resistor can be calculated by the following equation: Rs = 2005 Semtech Corp. 1.0 * 6 * 100 21 120% * 23 Se 2VOn - VIN VIN * IL RS * * 2( VIN - VOn) VOn n * NS where Se - External slope magnitude Vin - Low input line voltage Vo - Output voltage n - Power transformer primary to secondary turns ratio NS - Secondary turns of current sense transformer IL - Peak-to-peak Inductor current ripple For example, if the low input line voltage is 36V, output voltage is 3.3V, power transformer primary to secondary turns ratio is 6:1; the peak-to-peak inductor current ripple is 6A, and current sense gain RS is 21W, then the external slope needed is: 1.0 * n * NS 120 % * IO (pk ) Se 9 2 * 3.3 * 6 - 36 36 * 6 21 * * 85mV 2(36 - 3.3 * 6) 3.3 * 6 6 * 100 www.semtech.com SC4910A/B POWER MANAGEMENT Applications Information (Cont.) Closed-Loop Compensation This is the minimum external slope required to avoid subharmonic oscillation at low input line. The simplified control-to-output transfer function for the forward converter with current mode control, for small value of external slope ( Se Sn, Sn is on-time slope of sensed current waveform) is given by: With SC4910, the external slope is very easy to implement. Referring to Figure 2, R12 is the current sense resistor. R10 and the internal 20K resistor divide the internal slope 1.0V - 2.5V down to the required compensation slope. G vg where where: G vgo = LM - Power transformer magnetizing inductance fS = Switching frequency In the example, 36 * 21 ) * 20 450 E - 6 * 100 * 250E3 R10 = = 240 36 * 21 (2.5 - 1.0) - (0.085 - ) 450E - 6 * 100 * 250E3 (0.085 - 5 C22 R25 12 PVCC 13 RT1 PHASE U5 SC4910 RT2 OUTB SS COMP FB DELAY VREF C36 PGND 15 SY NC/EN PGND 3 ISHARE P = 1 Do min ant pole of power stage with current loop closed RC Z = 1 ESR zero of power stage R ESR C -SENSE For the given example above, at low line and R = 0.165, C = 2 x 680uF = 1360uF, RESR = 17m, therefore: 16 2 6 11 G vgo = 17 18 6 * 100 * 3.3 = 4.71 = 13dB 20 * 21 1 = 4456 rad / s = 710Hz 0.165 X 1360E - 6 1 Z = = 43253 rad / s = 6887Hz 17E - 3 X 1360E - 6 P = 1 9 R22 OUTA 8 19 PVCC 14 20 AGND R21 CS 7 4 10 AVCC C13 nNS VO DC gain of power stage with current loop closed IOR S where R - Load resistance C - Output capacitance RESR - Output capacitors ESR R10 R12 s z = G vgo s 1+ p 1+ VIN * R S ) * 20 (Se - L M * NS * fS R10 = VIN * R S (2.5 - 1.0) - (Se - ) L M * NS * f S Figure 2 2005 Semtech Corp. 10 www.semtech.com SC4910A/B POWER MANAGEMENT Applications Information (Cont.) The goal of the compensation design is to shape the loop with high DC gain, high bandwidth, enough phase margin, and high attenuation for high frequency noises. Figure 4 gives the asymptotic diagrams of the power stage with current loop closed and its loop gain. One integrator is added to increase the DC gain. Wzc is used to cancel the power stage pole wp so that the loop gain has -20dB rate when it reaches 0 dB line. wpc is placed at output capacitor ESR or half switching frequency, whichever is lower. Arbitrarily choose R2, then Type 2 compensator (Figure 3) is needed for the above current mode control. The compensation network gives the following characteristics: C3 s z = 1 s s 1+ p 1+ C1 R1 - GCOMP R2 + V ref Figure 3 C1 = 1 R 2P where 1 = PC = 1 R 2 C1 Synchronization 1 CC R2 1 3 C1 + C 3 Synchronization of oscillators in multiphase operation allows for reduced size of filtering components and improved dynamic response. SC4910 provides single stage conversion where SC4201 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 SC4910's. Both power supplies operate 180 degrees apart. SC4201 can be configured up to 4 phase operation. The loop gain will be given by: s s 1+ V z 1 ZC = G vgo * * ref s s s VO 1+ 1+ p PC 1+ T = G vg GCOMPK FB C1 1 ,R1 = PC ( C I 1 + C3 ) -1 ZC I is adjusted for satisfactory phase margin and crossover frequency. 1 R 1 ( C1 + C 3 ) ZC = , C3 = Loop gain T(s) zc Compensator Power stage pc fs C P Z Figure 4 2005 Semtech Corp. 11 www.semtech.com SC4910A/B POWER MANAGEMENT Applications Information (Cont.) Load Remote Sensing Load Current Sharing Dedicated -SENSE pin provides true remote sensing of the regulated supply's output terminal voltage for high current applications. As shown in Figure 5, the bandgap reference "ground " is brought out as -Sense, which is connected to the "load ground" and to the local analog ground by the resistor R10. With this way combined with upper side R1, the voltage drop on power line is offset and the load voltage is truly sensed. A single wire connected between the ISHARE pins will force current sharing between parallel units for paralleling or n+1 redundant operation. The ISHARE pin allows for current sharing between several parallel units. The ISHARE pin connects internally to the non-inverting input of ISHARE amplifier. An internal 4K 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 all devices are sharing the load current equally, the COMP pin voltages on each units should be approximately equal. If one of the devices begins to take on too much or too little of the load, the difference in COMP pin voltage will cause the ISHARE amplifier to adjust the SS (0.75V ref) voltage accordingly. In the event of ISHARE pulled down below 1V, the ISHARE amplifier is disabled to prevent output voltage of the unit lower than specification. R1 15 14 AVCC 13 PVCC RT1 OUTB RT2 COMP SS FB DELAY SY NC/EN VREF -SENSE 7 AGND 5 PHASE PGND 3 ISHARE OUTA PGND 19 SC4910 16 6 11 C5 17 C6 R7 R6 18 2 R8 1 R10 9 20 CS 8 4 10 PVCC 12 LOAD Figure 5 2005 Semtech Corp. 12 www.semtech.com SC4910A/B POWER MANAGEMENT Typical Characteristics Icc vs Temperature Icc vs Vcc 25.00 20.00 16.00 Syn/En = High Sync/En = High Icc (mA) Icc (mA) Vcc = 12V TA = 25C 18.00 14.00 12.00 Sync/En = Low 10.00 15.00 Syn/En = Low 10.00 5.00 8.00 0.00 4.5 6.5 8.5 10.5 12.5 14.5 -40 -20 0 Vcc (V) 60 80 100 120 (Sc4910A) UVLO High Threshold vs Temperature 8.98 UVLO High Thre shold (V) 580.00 UVLO Hysteresis (mV) 40 Temperature (C) (Sc4910A) UVLO Hysteresis vs Temperature 575.00 570.00 565.00 560.00 555.00 550.00 8.97 8.96 8.95 8.94 8.93 8.92 8.91 8.90 -40 -20 0 20 40 60 80 100 120 -40 -20 0 Temperature (C) 20 40 60 80 100 120 Temperature (C) (Sc4910B) UVLO Hysteresis vs Temperature (Sc4910B) UVLO High Threshold vs Temperature 302.00 4.56 300.00 4.55 UVLO High Thre shold (V) UVLO Hyste resis (mV) 20 298.00 296.00 294.00 292.00 290.00 288.00 286.00 284.00 4.55 4.54 4.54 4.53 4.53 4.52 4.52 -40 -20 0 20 40 60 80 100 120 -40 Temperature (C) 2005 Semtech Corp. -20 0 20 40 60 80 100 120 Temperature (C) 13 www.semtech.com SC4910A/B POWER MANAGEMENT Typical Characteristics (Cont.) Bandgap Voltage vs Vcc 0.7505 TA = 25C Iout = 0mA 0.753 Vcc = 12V Bandgap Voltage (V) Bandgap Voltage (V) 0.755 Bandgap Voltage vs Temperature 0.751 0.749 0.747 0.745 0.7500 0.7495 0.7490 0.7485 0.7480 0.7475 9 10 11 12 13 14 15 -40 -20 0 20 Vcc (V) 140.00 TA = 25C Vfb = 5V 100.00 80.00 60.00 40.00 20.00 Vfb = 0V 0.00 4.5 6.5 8.5 10.5 12.5 600.00 Vcc = 12V 200.00 Vfb = 5V 100.00 0.00 Vfb = 0V -100.00 -200.00 -40 -20 0 20 10.5 Error Amp Offset Voltage (mV) 60 80 100 120 Error Amp Offset Voltage vs Temperature 12.5 14.5 1.50 Vcc = 12V 1.40 1.30 1.20 1.10 1.00 0.90 0.80 -40 Vcc (V) 2005 Semtech Corp. 40 Temperature (C) Error Amp Offset Voltage (mV) 8.5 120 300.00 14.5 TA = 25C 6.5 100 400.00 Error Amp Offset Voltage vs Vcc 4.5 80 500.00 Vcc (V) 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00 -0.20 -0.40 -0.60 60 Error Amp Input Bias Current vs Temperature Error Amp Input Bias Curre nt (nA) Error Amp Input Bias Curre nt (nA) Error Amp Input Bias Current vs Vcc 120.00 40 Temperature (C) -20 0 20 40 60 80 100 120 Temperature (C) 14 www.semtech.com SC4910A/B POWER MANAGEMENT Typical Characteristics (Cont.) Oscillator Frequency vs Temperature 3.00 Oscillator Frequency (kHz) Error Amp Output Voltage (V) Error Amp Output Voltage vs Temperature Vcc = 12V Icomp = 1mA 2.50 2.00 High 1.50 1.00 Low 0.50 -40 -20 0 20 40 60 80 100 120 525 520 515 510 505 500 495 490 485 480 475 Rt1 = Rt2 = 50kohm -40 -20 0 20 Temperature (C) Enable Voltage vs Temperature Vcc = 12V 2.50 High 2.00 1.50 Low 1.00 0.50 -40 -20 0 20 40 60 60 80 100 120 Max Duty Cycle vs Temperature Max Duty Cycle (%) Enable Voltage (V) 3.00 40 Temperature (C) 80 100 120 91.00 90.80 90.60 90.40 90.20 90.00 89.80 89.60 89.40 89.20 89.00 Output A -40 Temperature (C) -20 0 20 40 60 80 100 120 Temperature (C) Progammable Delay vs Temperature Progammable De lay (nS) 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 Vin- C3 1u,100V C4 1u,100V C5 1u,100V C33 1u,100V C34 1u,100V M5 si4490dy R53 8 Q3 FMMT718 D9 1N4148WS D3 1N4148WS 0 C18 0.1uF Q4 Not Populated R17 1K 3 T3 C19 0.1uF 6 PE68386 1 4 1 3 7 R37 5.1 8 7 6 5 R12 22 R10 1.5K R33 100K R31 470K C37 470pF C28 100pF R5 4.7 R35 20K C30 47nF 4 3 COMP FB R30 100K R28 2.7MEG 0.1uF C22 R22 75K R25 62K R27 100K f s=250KHz R36 100K 4 7 C16 0.1uF ILIM OUT 5 7 M4 si4842dy 10 R51 U5 SC4910 C31 1000pF 51 R32 C29 150pF R29 68 4 3 1 2 8 5 R34 1.00 16 2 1 18 17 11 6 R26 10.0 D15 SMAZ20 R38 10K R18 10K C21 C24 47uF C25 47uF +12V 43K R23 C20 100pF 1.0nF D12 1N4148WS Q1 Si2320DS PB2090 T4 -SENSE FB COMP OUTB PHASE SY NC/EN ISHARE C17 0.1uF +12V R4 10K C11 0.1uF +12V 4 2 D10 1N4148WS C23 47uF C27 10uF 0.1uF C36 VREF DELAY SS RT2 RT1 OUTA CS R8 4.7 5 U2 SC1302A Q2 FMMT718 U6 SC4911 5 15 3 19 20 10 D21* 1N5819HW R21 124K D11 1N4148WS C12 0.1uF +12V C13 150pF R3 5.1 C1 2.2nF D5 1N4148WS D14 B130L D22* 1N5819HW Q5 FMMT718 R6 10K Ilim=24A +12PRI 4 2 R11 10K D6 1N4148WS D2 1N4148WS M2si4842dy 1 2 3 4 M1 si4842dy 8 1 7 2 6 3 5 4 C32 2.2nF C26 0.47uF +Vin 5 U4 SC1302A 10 D20* 1N5819HW R50 8 10 M6 si4490dy P8208T 7 T2 2 5 5 6 7 8 4 3 2 1 ES1D D1 C2 0.1uF,100V 5 6 7 8 4 3 2 1 M7 Not populated R1 39K 5 6 7 8 4 3 2 1 M3 si4842dy 8 Vin+ 8 8 7 6 5 1 2 3 4 1 6 3 T1 1 6 3 14 AVCC AGND 7 PA0168A 8 VCC GND 1 LUVLO RT 2 16 6 8 7 6 5 1 2 3 4 12 PVCC 13 PVCC PGND 8 PGND 9 R52 1K C50 22nF C51 10uF L1 1.3uH R13 10.0K 5 C14 0.1uF +12V C7 100uF R24 2.0K R19 6.8K U3 SC4431 C6 100uF 1 +Vin C8 680uF V re f 2005 Semtech Corp. 2 CON1 4 R15 18.2K R14 37.4K C9 680uF * : Optional R2 10.0 7 6 5 4 3 1 Vout- EN Ishare Sense Sense Vout+ CON2 3.3V/20A SC4910A/B POWER MANAGEMENT Evaluation Board Schematics www.semtech.com SC4910A/B POWER MANAGEMENT Evaluation Board Bill of Materials Item Quantity Reference 3 2 C1,C32 4 1 C2 5 5 6 Part Manufacturer # 2.2nF Foot Print SM/C_0805 0.1uF,100V TDK, C3216X7R2A104M SM/C_1206 C3,C4,C5,C33,C34 1uF,100V Murata, GRM55RR72A105KA01B SM/C_2220 4 C6,C7,C8,C9 680uF, 4V Sanyo, 4TPB680 SM/CT_7343 7 10 C11,C12,C14,C16,C17,C18,C19, C22,C36, C51 0.1uF SM/C_0805 8 2 C13,C29 150pF SM/C_0805 9 1 C 20 560pF SM/C_0805 10 1 C 21 1.5nF SM/C_0805 11 3 C23,C24,C25 12 1 C 26 0.47uF 13 1 C 27 10uF, 10V 14 1 C 28 100pF SM/C_0805 15 1 C 30 47nF SM/C_0805 16 1 C 31 1000pF SM/C_0805 17 1 C 37 470pF SM/C_0805 18 1 C 50 22nF SM/C_0805 19 1 D1 E S 1D 20 10 21 1 D 14 B 130L 22 1 D 15 23 1 L1 24 4 M1,M2,M3,M4 25 2 26 D2,D5,D6,D9, D10,D11,D12,D20,D21,D22 47uF, 16V Sanyo, 16TPB47 SM/CT_7343 SM/C_1206 Murata, GRM32ER61C106KC31L Diodes Inc. ES1D-13 1N5819HW Diodes Inc. 1N5819HW-7 SM/C_1210 SM/_SMA SOD123 Diodes Inc. B130L-13 SMA SMAJ20A Diodes Inc. SMAJ120A-13 SMA 1.3uH Panasonic, ETQPAF1R3E PCC-S1 si 4 8 4 2 d y Vishay SO-8 M5,M6 si 4 4 9 0 d y Vishay SO-8 1 Q1 S i 2320D S Vishay SM/SOT23_123 27 1 R1 39K SM/R_0805 28 2 R2,R26 10 SM/R_0805 29 2 R3,R37 5.1 SM/R_0805 30 6 R4,R6,R11,R17,R18,R38 10K SM/R_0805 31 2 R5, R8 4.7 SM/R_0805 2005 Semtech Corp. 17 www.semtech.com SC4910A/B POWER MANAGEMENT Evaluation Board Bill of Materials Item Quantity Reference Part Manufacturer # Foot Print 32 1 R10 412 SM/R_0805 33 1 R12 22 SM/R_0805 34 1 R13 10.0K SM/R_0805 35 1 R14 37.4K SM/R_0805 36 1 R15 18.2K SM/R_0805 37 1 R19 21.5K SM/R_0805 38 1 R21 160K SM/R_0805 39 1 R22 40.2K SM/R_0805 40 1 R23 43K SM/R_0805 41 1 R24 6.19K SM/R_0805 42 1 R25 110K SM/R_0805 43 3 R27,R30,R33 100K SM/R_0805 44 1 R28 2.7MEG SM/R_0805 45 3 R29 68 SM/R_0805 46 1 R31 383K SM/R_0805 47 1 R32 51 SM/R_0805 48 1 R34 1 SM/R_0805 49 1 R35 4.7K SM/R_0805 50 1 R36 130K SM/R_0805 51 2 R50,R51 10 SM/R_0805 52 1 R52 1.0K SM/R_0805 53 1 T1 PA0168 Pulse XP4 54 1 T2 P 8208T Pulse P 8208 55 1 T3 P E 68386 Pulse P E 68386 56 1 T4 31414R Midcom 57 2 U2, U4 S C 1302A Semtech SOT23_5PIN 58 1 U3 S C 4431 Semtech SOT23_5PIN 59 1 U5 S C 4910 Semtech TSSOP-20 60 1 U6 SC4911 Semtech MSOP-8 2005 Semtech Corp. 18 www.semtech.com SC4910A/B POWER MANAGEMENT Outline Drawing - TSSOP-20 A D e 2X E/2 E PIN 1 INDICATOR ccc C 1 2 3 2X N/2 TIPS e/2 B 1.20 0.15 0.05 1.05 0.80 0.19 0.30 0.20 0.09 6.40 6.50 6.60 4.30 4.40 4.50 6.40 BSC 0.65 BSC 0.45 0.60 0.75 (1.0) 20 0 8 0.10 0.10 0.20 D aaa C SEATING PLANE .047 .006 .002 .042 .031 .007 .012 .007 .003 .251 .255 .259 .169 .173 .177 .252 BSC .026 BSC .018 .024 .030 (.039) 20 8 0 .004 .004 .008 A A1 A2 b c D E1 E e L L1 N 01 aaa bbb ccc N E1 DIMENSIONS MILLIMETERS INCHES MIN NOM MAX MIN NOM MAX DIM A2 A C H A1 bxN bbb C A-B D c GAGE PLANE 0.25 SIDE VIEW SEE DETAIL L (L1) DETAIL A 01 A NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE-H- 3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. 4. REFERENCE JEDEC STD MO-153, VARIATION AC. Land Pattern - TSSOP-20 F DIM (C) H G C F G H P X Y Z Z Y P NOTES: 1. DIMENSIONS INCHES MILLIMETERS (.222) .157 .161 .126 .026 .016 .061 .283 (5.65) 4.00 4.10 3.20 0.65 0.40 1.55 7.20 X 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 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Semtech: SC4910AITSTRT SC4910BITSTRT