IRU3037ACS

Data Sheet No. PD94173 IRU3037 / IRU3037A 8-PIN SYNCHRONOUS PWM CONTROLLER FEATURES Synchronous Controller in 8-Pin Package Operating with single 5V or 12V supply voltage Internal 200KHz Oscillator (400KHz for IRU3037A) Soft-Start Function Fixed Frequency Voltage Mode 500mA Peak Output Drive Capability Protects the output when control FET is shorted DESCRIPTION The IRU3037 controller IC is designed to provide a low cost synchronous Buck regulator for on-board DC to DC converter applications. With the migration of today’s ASIC products requiring low supply voltages such as 1.8V and lower, together with currents in excess of 3A, traditional linear regulators are simply too lossy to be used when input supply is 5V or even in some cases with 3.3V input supply. The IRU3037 together with dual N-channel MOSFETs such as IRF7313, provide a low cost solution for such applications. This device features an internal 200KHz oscillator (400KHz for "A" version), under-voltage lockout for both Vcc and Vc supplies, an external programmable soft-start function as well as output under-voltage detection that latches off the device when an output short is detected. APPLICATIONS DDR memory source sink Vtt application Low cost on-board DC to DC such as 5V to 3.3V, 2.5V or 1.8V Graphic Card Hard Disk Drive TYPICAL APPLICATION 5V 12V C3 1uF C4 1uF C2 10TPB100M, 100uF, 55mV L1 1uH C1 47uF Vcc Vc HDrv Q1 1/2 of IRF7313 L2 1.5V/5A C7 2x 6TPC150M, 150uF, 40mV C8 0.1uF SS/SD U1 IRU3037 LDrv D05022P-562, 5.6uH, 5.3A Q2 1/2 of IRF7313 R3 C9 2200pF R4 24k Comp Fb Gnd R5 1.24K, 1% 249, 1% Figure 1 - Typical application of IRU3037 or IRU3037A. PACKAGE ORDER INFORMATION TA (°C) 0 To 70 0 To 70 0 To 70 0 To 70 DEVICE IRU3037CF IRU3037CS IRU3037ACF IRU3037ACS PACKAGE 8-Pin Plastic TSSOP (F) 8-Pin Plastic SOIC NB (S) 8-Pin Plastic TSSOP (F) 8-Pin Plastic SOIC NB (S) FREQUENCY 200KHz 200KHz 400KHz 400KHz Rev. 2.8 03/10/03 www.irf.com 1 IRU3037 / IRU3037A ABSOLUTE MAXIMUM RATINGS Vcc Supply Voltage .................................................. Vc Supply Voltage ...................................................... Storage Temperature Range ...................................... Operating Junction Temperature Range ..................... 25V 30V (not rated for inductive load) -65°C To 150°C 0°C To 125°C CAUTION: Stresses above those listed in "Absolute Maximum Ratings" may cause permanent damage to the device. PACKAGE INFORMATION 8-PIN PLASTIC TSSOP (F) 8-PIN PLASTIC SOIC (S) Fb 1 Vcc 2 LDrv 3 Gnd 4 8 SS/SD 7 Comp 6 Vc 5 HDrv Fb 1 Vcc 2 LDrv 3 Gnd 4 8 SS/SD 7 Comp 6 Vc 5 HDrv θJA=124°C/W θJA=160°C/W ELECTRICAL SPECIFICATIONS Unless otherwise specified, these specifications apply over Vcc=5V, Vc=12V and TA=0 to 70°C. Typical values refer to TA=25°C. Low duty cycle pulse testing is used which keeps junction and case temperatures equal to the ambient temperature. PARAMETER Reference Voltage Fb Voltage Fb Voltage Line Regulation UVLO UVLO Threshold - Vcc UVLO Hysteresis - Vcc UVLO Threshold - Vc UVLO Hysteresis - Vc UVLO Threshold - Fb UVLO Hysteresis - Fb Supply Current Vcc Dynamic Supply Current Vc Dynamic Supply Current Vcc Static Supply Current Vc Static Supply Current Soft-Start Section Charge Current SYM V FB LREG TEST CONDITION IRU3037 IRU3037A 5 > 2 gm gmZf >> 1 and gmZIN >>1 ---(14) By replacing ZIN and Zf according to Figure 7, the transformer function can be expressed as: H(s)= 1 3 sR6(C12+C11) [ (1+sR7C11)3[1+sC10(R6+R8)] C123C11 1+sR7 3(1+sR8C10) C12+C11 3) Place first zero before LC’s resonant frequency pole. FZ1 ≅ 75% FLC 1 C11 = 2p 3 FZ1 3 R7 4) Place third pole at the half of the switching frequency. FP3 = fS 2 1 2p 3 R7 3 FP3 ( )] As known, transconductance amplifier has high impedance (current source) output, therefore, consider should be taken when loading the E/A output. It may exceed its source/sink output current capability, so that the amplifier will not be able to swing its output voltage over the necessary range. The compensation network has three poles and two zeros and they are expressed as follows: C12 = C12 > 50pF If not, change R7 selection. 5) Place R7 in (15) and calculate C10: C10 [ 2p 3 Lo 3 Fo 3 Co VOSC 3 R7 VIN Rev. 2.8 03/10/03 www.irf.com 9 IRU3037 / IRU3037A 6) Place second pole at the ESR zero. FP2 = FESR 1 R8 = 2p 3 C10 3 FP2 Check if R8 > 1 gm Start to place the power components, make all the connection in the top layer with wide, copper filled areas. The inductor, output capacitor and the MOSFET should be close to each other as possible. This helps to reduce the EMI radiated by the power traces due to the high switching currents through them. Place input capacitor directly to the drain of the high-side MOSFET, to reduce the ESR replace the single input capacitor with two parallel units. The feedback part of the system should be kept away from the inductor and other noise sources, and be placed close to the IC. In multilayer PCB use one layer as power ground plane and have a control circuit ground (analog ground), to which all signals are referenced. The goal is to localize the high current path to a separate loop that does not interfere with the more sensitive analog control function. These two grounds must be connected together on the PC board layout at a single point. Figure 8 shows a suggested layout for the critical components, based on the schematic on page 14. PGnd C1 C2A, B If R8 is too small, increase R7 and start from step 2. 7) Place second zero around the resonant frequency. FZ2 = FLC 1 R6 = - R8 2p 3 C10 3 FZ2 8) Use equation (1) to calculate R5. R5 = VREF 3 R6 VOUT - VREF These design rules will give a crossover frequency approximately one-tenth of the switching frequency. The higher the band width, the potentially faster the load transient speed. The gain margin will be large enough to provide high DC-regulation accuracy (typically -5dB to 12dB). The phase margin should be greater than 458 for overall stability. IC Quiescent Power Dissipation Power dissipation for IC controller is a function of applied voltage, gate driver loads and switching frequency. The IC's maximum power dissipation occurs when the IC operating with single 12V supply voltage (Vcc=12V and Vc≅ 24V) at 400KHz switching frequency and maximum gate loads. Figures 9 and 10 show voltage vs. current, when the gate drivers loaded with 470pF, 1150pF and 1540pF capacitors. The IC's power dissipation results to an excessive temperature rise. This should be considered when using IRU3037A for such application. Layout Consideration The layout is very important when designing high frequency switching converters. Layout will affect noise pickup and can cause a good design to perform with less than expected results. PGnd L1 PGnd C7A, B Vin Vout 8 7 6 5 L2 Q1 1 2 3 4 D 3 DD 21 C 5 5 4 C4 6 PGnd R4 C9 7 U1 IRU3037 3 Single Point Analog Gnd Connect to Power Ground plane Analog Gnd 2 C3 R5 C8 8 1 R6 Analog Gnd Figure 8 - Suggested layout. (Topside shown only) 10 www.irf.com Rev. 2.8 05/10/04 IRU3037 / IRU3037A TYPICAL PERFORMANCE CHARACTERISTICS IRU3037A Vcc vs. Icc @470PF, 1150PF and 1540PF Gate Load TA = 258C 14 12 10 8 6 4 2 0 0 2 4 6 Vcc (V) 8 CLOAD =1540pF CLOAD =1150pF Icc (mA) CLOAD =470pF 10 12 14 Figure 9 - Vcc vs. Icc IRU3037A Vc vs. Ic @470PF, 1150PF and 1540PF Gate Load TA = 258C 30 25 Ic (ma) 20 15 10 5 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Vc (V) Figure 10 - Vc vs. Ic CLOAD =470pF CLOAD =1540pF CLOAD =1150pF Rev. 2.8 03/10/03 www.irf.com 11 IRU3037 / IRU3037A TYPICAL PERFORMANCE CHARACTERISTICS IRU3037 Output Voltage 1.3 240 IRU3037 Output Frequency 230 1.28 220 Max Max 210 1.26 Kilo Hertz Volts 200 1.24 190 Min 180 Min 1.22 170 1.2 -40°C 0°C Output Voltage +50°C Spec Max. +100°C Spec Min. +150°C 160 -40°C 0°C Oscillation Frequency +50°C +100°C Spec Min. +150°C Spec Max. Figure 11 - Output Voltage Figure 12 - Output Frequency IRU3037 Maximum Duty Cycle 92.0% 90.0% 88.0% Percent Duty Cycle 86.0% 84.0% 82.0% 80.0% -40°C -25°C 0°C +25°C +50°C +75°C +100°C +125°C +150°C Max Duty Cycle Figure 13 - Maximum Duty Cycle 12 www.irf.com Rev. 2.8 05/10/04 IRU3037 / IRU3037A TYPICAL PERFORMANCE CHARACTERISTICS IRU3037A Output Voltage 820 IRU3037A Output Frequency 460 Max 440 810 Max 420 800 400 790 Kilo Hertz milli Volts 380 Min 780 360 Min 340 770 320 760 -40°C -25°C 0°C +25°C +50°C Spec Max. +75°C +100°C +150°C 300 -40°C -25°C 0°C +25°C +50°C +75°C +100°C +150°C Output Voltage Spec Min. Oscillation Frequency Spec Max. Spec Min. Figure 14 - Output Voltage Figure 15 - Output Frequency IRU3037 / IRU3037A Transconductance ( GM ) IRU3037 / IRU3037A Rise Time / Fall Time CL=1500pF 1000 50 900 45 800 40 700 35 600 nano Seconds micro Mho's 30 500 25 400 20 300 15 200 10 100 5 0 -40°C -25°C 0°C +25°C +50°C Negative load GM +75°C +100°C 0 -40°C -25°C 0°C +25°C Rise Time +50°C Fall time +75°C +100°C Positive load GM Figure 16 - Transconductance Figure 17 - Rise Time and Fall Time Rev. 2.8 03/10/03 www.irf.com 13 IRU3037 / IRU3037A TYPICAL APPLICATION Single Supply 5V Input 5V D1 1N4148 D3 1N4148 D2 1N4148 C4 1uF C5 0.1uF L1 1uH C2 2x 10TPB100ML, 100uF, 55mV C1 47uF Tantalum C3 1uF Vcc Vc HDrv Q1 1/2 of IRF7301 L2 3.3V @ 4A C7 2x 6TPC150M, 150uF, 40mV SS/SD C8 0.1uF U1 IRU3037 LDrv D05022P-103, 10uH, 4.3A Q2 1/2 of IRF7301 R6 Fb 1.65K, 1% R5 1K, 1% Comp C9 680pF R4 105K Gnd Figure 18 - Typical application of IRU3037 in an on-board DC-DC converter using a single 5V supply. 14 www.irf.com Rev. 2.8 05/10/04 IRU3037 / IRU3037A TYPICAL APPLICATION Dual Supply, 5V Bus and 12V Bias Input 5V L1 12V 1uH C2 10TPB100M, 100uF, 55mV, 1.5A rms C1 47uF 1.8V/1A IRU1206-18 Vcc Vc HDrv C4 1uF C1 1uF Q1 1/2 of IRF7752 C3 47uF L2 C6 6TPB150M, 150uF, 55mV 2.5V/2A C7 0.1uF SS/SD U1 IRU3037 LDrv CTX5-2P, 3.5uH @ 2.5A Q2 1/2 of IRF7752 R1 C8 2200pF R2 14K Comp Gnd Fb R3 1K 1% 1K, 1% L2 CTX5-2P, 3.5uH @ 2.5A CTX10-5P, 5.7uH @ 2.5A C6 6TPB150M, 150uF, 55mV (Qty 2) 6TPB150M, 150uF, 55mV (Qty 1) C9 10TPB100M, 100uF, 55mV, 1.5A rms C10 1uF C11 1uF Vcc Vc HDrv Q3 1/2 of IRF7752 SS/SD C13 0.1uF U2 IRU3037 L3 C12 6TPB150M, 150uF, 55mV 3.3V/1.8A LDrv CTX5-1P, 3.4uH @ 2A Q4 1/2 of IRF7752 R4 1.65K, 1% R6 1K, 1% C14 2200pF R5 14K Comp Gnd Fb Figure 19 - Typical application of IRU3037 or IRU3037A in an on-board DC-DC converter providing the Core, GTL+, and Clock supplies for the Pentium II microprocessor. Rev. 2.8 03/10/03 www.irf.com 15 IRU3037 / IRU3037A TYPICAL APPLICATION 1.8V to 7.5V / 0.5A Boost Converter Vpwr (1.5V Min) L1 1uH (CoilTronics UP2B-1R0) Vc/Vcc C5 1uF C1 2x 68uF D1 1N5817 VOUT (7.5V / 0.5A) C9 2x 47uF R1 20K R2 10K Q1 2N2222 R3 20K Q2 2N2222 C10 100pF C4 0.01uF R4 25K C5 0.1uF Q3 IRF7402 SS/SD Comp Vc U1 HDrv IRU3037 Fb Vcc LDrv Gnd C8 1uF Gnd R5 1K, 1% R6 5K, 1% Figure 20 - Typical application of IRU3037 as a boost converter. 16 www.irf.com Rev. 2.8 05/10/04 IRU3037 / IRU3037A DEMO-BOARD APPLICATION 5V or 12V to 3.3V @ 10A L1 VIN 5V or 12V 1uH C1 33uF 16V D4 LL4148 C2A 47uF 16V C2B 47uF 16V D2 LL4148 C3 1uF C19 1uF D1 LL4148 Gnd Vcc C8 1uF Vc HDrv Q1 IRF7457 C6 0.1uF L2 3.3uH C7 470pF R4 4.7V C13 1uF SS/SD C5 0.1uF U1 IRU3037 LDrv Q2 IRF7460 VOUT 3.3V @ 10A C9B C9C 150uF 150uF 6.3V 6.3V Comp C4 2200pF R3 20K R6 Gnd Gnd Fb R5 1K 1.65K Figure 21 - Demo-board application of IRU3037. Application Parts List Ref Desig Q1 Q2 U1 D1, D2, D4 L1 L2 C1 C2A, C2B C9B, C9C C5, C6 C3 C4 C7 C8, C13, C19 R3 R4 R5 R6 Rev. 2.8 03/10/03 Description MOSFET MOSFET Controller Diode Inductor Inductor Capacitor, Tantalum Capacitor, Poscap Capacitor, Poscap Capacitor, Ceramic Capacitor, Ceramic Capacitor, Ceramic Capacitor, Ceramic Capacitor, Ceramic Resistor Resistor Resistor Resistor Value Qty Part# 20V, 7mV, 15A 1 IRF7457 20V, 10mV, 12A 1 IRF7460 Synchronous PWM 1 IRU3037 Fast Switching 3 LL4148 1m H, 10A 1 D03316P-102HC 3.3m H, 12A 1 D05022P-332HC 33m F, 16V 1 ECS-T1CD336R 47m F, 16V, 70mV 2 16TPB47M 150m F, 6.3V, 40mV 2 6TPC150M 0.1m F, Y5V, 25V 2 ECJ-2VF1E104Z 1m F, X7R, 25V 1 ECJ-3YB1E105K 2200pF, X7R, 50V 1 ECJ-2VB1H222K 470pF, X7R 1 ECJ-2VB2D471K 1m F, Y5V, 16V 3 ECJ-2VF1C105Z 20K, 5% 1 4.7V, 5% 1 1K, 1% 1 1.65K, 1% 1 www.irf.com Manuf IR IR IR Coilcraft Coilcraft Panasonic Sanyo Sanyo Panasonic Panasonic Panasonic Panasonic Panasonic 17 IRU3037 / IRU3037A DEMO-BOARD WAVEFORMS IRU3037 VIN=5.0V, V OUT =3.3V 100 V IN Efficiency (%) 90 V OUT 80 70 0 1 2 3 4 5 6 7 8 9 10 11 Output Current (A) Figure 22 - Efficiency for IRU3037 Evaluation Board. Figure 23 - Start-up time @ IOUT=5A. Vss IRU3037 IRU3037 V OUT IOUT = 5V Figure 24 - Shutdown the output by pulling down the soft-start. Figure 25 - 3.3V output voltage ripple @ IOUT=5A. IRU3037 IRU3037 2A 4A 0A 0A Figure 26 - Transient response @ IOUT = 0 to 2A. Figure 27 - Transient response @ IOUT = 0 to 4A. Rev. 2.8 05/10/04 18 www.irf.com IRU3037 / IRU3037A (F) TSSOP Package 8-Pin A L Q R1 1.0 DIA B C R E M O F PIN NUMBER 1 G J K H DETAIL A D DETAIL A P N SYMBOL DESIG A B C D E F G H J K L M N O P Q R R1 MIN 4.30 0.19 2.90 --0.85 0.05 08 0.50 0.09 0.09 8-PIN NOM 0.65 BSC 4.40 6.40 BSC --1.00 1.00 3.00 --0.90 --128 REF 128 REF --1.00 REF 0.60 0.20 ----- MAX 4.50 0.30 3.10 1.10 0.95 0.15 88 0.75 ----- NOTE: ALL MEASUREMENTS ARE IN MILLIMETERS. Rev. 2.8 03/10/03 www.irf.com 19 IRU3037 / IRU3037A (S) SOIC Package 8-Pin Surface Mount, Narrow Body H A B C E DETAIL-A PIN NO. 1 D 0.386 0.015 x 458 TF K L DETAIL-A I J G 8-PIN SYMBOL A B C D E F G H I J K L T MIN MAX 4.80 4.98 1.27 BSC 0.53 REF 0.36 0.46 3.81 3.99 1.52 1.72 0.10 0.25 78 BSC 0.19 0.25 5.80 6.20 08 88 0.41 1.27 1.37 1.57 NOTE: ALL MEASUREMENTS ARE IN MILLIMETERS. 20 www.irf.com Rev. 2.8 05/10/04 IRU3037 / IRU3037A PACKAGE SHIPMENT METHOD PKG DESIG F S PACKAGE DESCRIPTION TSSOP Plastic SOIC, Narrow Body PIN COUNT 8 8 PARTS PER TUBE 100 95 PARTS PER REEL 2500 2500 T&R Orientation Fig A Fig B 1 1 1 1 1 1 Feed Direction Figure A Feed Direction Figure B IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310) 252-7105 TAC Fax: (310) 252-7903 Visit us at www.irf.com for sales contact information Data and specifications subject to change without notice. 02/01 Rev. 2.8 03/10/03 www.irf.com 21