ISL6729 ® Data Sheet July 2004 Low-Cost Single-Ended Current-Mode PWM for Microcontroller Based Power Converters Features • 5V Operation The ISL6729 pulse width modulating (PWM) current mode controller is designed for power conversion applications that are based on a microcontroller or other device which can generate a digital clock signal at the desired switching frequency. Similar to the ISL684x family of products, the ISL6729 provides the basic current mode PWM control features, but eliminates the error amplifier, the oscillator, and the reference. An external clock signal applied to the oscillator input provides the time base and sets the maximum duty cycle. The reduced feature set is ideal for those applications where a microcontroller is available to provide the monitor and control functions. The analog PWM provides the cycle by cycle peak current mode control, leaving the monitor and control overhead to the microcontroller. • 1A MOSFET gate driver • 400µA startup current • 30ns propagation delay current sense to output • Fast transient response with peak current mode control • Switching frequency to 2MHz • 20ns rise and fall times with 1nF output load • Maximum Duty Cycle Determined by Clock Input Duty Cycle • Tight tolerance current limit threshold • Pb-free available Applications • Telecom and Datacom Power Ordering Information PART NUMBER • Wireless Base Station Power TEMP. RANGE (°C) PACKAGE PKG. DWG. # • File Server Power ISL6729IB -40 to 105 8 Ld SOIC M8.15 • Industrial Power Systems ISL6729IBZ (See Note) -40 to 105 8 Ld SOIC (Pb-free) M8.15 • PC Power Supplies ISL6729IU -40 to 105 8 Ld MSOP M8.118 ISL6729IUZ (See Note) -40 to 105 8 Ld MSOP (Pb-free) M8.118 • Isolated Buck and Flyback Regulators • Boost Regulators Pinout Add -T to part number for Tape and Reel packaging. NOTE: Intersil Pb-free products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which is compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J Std-020B. PART NUMBER RISING UVLO MAX. DUTY CYCLE ISL6729 4.75V 100% 1 FN9152.1 ISL6729 (8-PIN SOIC, MSOP) TOP VIEW COMP 1 8 N/C N/C 2 7 VDD CS 3 6 OUT CLKS 4 5 GND CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright © Intersil Americas Inc. 2004 All Rights Reserved. All other trademarks mentioned are the property of their respective owners. Functional Block Diagram VDD START/STOP UV COMPARATOR VDDOK + - 2 BG + - GND + - + - CS 100mV PWM COMPARATOR OUT ISL6729 2R 1.1V CLAMP COMP R CLK S Q R Q Typical Application - Interleaved Multi-Phase Isolated Converter VOLTAGE FEEDBACK ERROR AMPLIFIER 5V 1 COMP 3 CLOCK φ1 ISOLATION 8 2 VDD 7 3 CS OUT 6 POWER STAGE VOUT 4 CLK GND 5 ISL6729 CURRENT FEEDBACK 1 COMP MICROCONTROLLER 2 VDD 7 3 CS OUT 6 POWER STAGE ISL6729 CLOCK φ2 8 4 CLK GND 5 ISL6729 CURRENT FEEDBACK 1 COMP 2 8 VDD 7 POWER STAGE 3 CS OUT 6 CLOCK φ3 4 CLK GND 5 ISL6729 CURRENT FEEDBACK ISL6729 Absolute Maximum Ratings Thermal Information Supply Voltage, VDD . . . . . . . . . . . . . . . . . . . . GND - 0.3V to +6.5V OUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to VDD + 0.3V Signal Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to 6.5V Peak GATE Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1A ESD Classification Human Body Model (Per MIL-STD-883 Method 3015.7) . . .2000V Charged Device Model (Per EOS/ESD DS5.3, 4/14/93) . . .1000V Thermal Resistance (Typical, Note 1) θJA (°C/W) SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 MSOP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 Maximum Junction Temperature . . . . . . . . . . . . . . . . -55°C to 150°C Maximum Storage Temperature Range . . . . . . . . . . . -65°C to 150°C Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300°C (SOIC- Lead Tips Only) Operating Conditions Temperature Range ISL6729Ix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to 105°C Supply Voltage Range (Typical) ISL6729 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.75V-5.25V CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. NOTES: 1. θJA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details. 2. All voltages are with respect to GND. Electrical Specifications Recommended operating conditions unless otherwise noted. Refer to Block Diagram and Typical Application schematic. VDD = 5V, CLK = 50kHz, TA = -40 to 105°C (Note 3), Typical values are at TA = 25°C PARAMETER TEST CONDITIONS MIN TYP MAX UNITS START Threshold 4.15 4.50 4.75 V STOP Threshold 4.00 4.30 4.60 - 0.2 - V UNDERVOLTAGE LOCKOUT Hysteresis Start-Up Current, IDD VDD < START Threshold - 420 800 µA Operating Current, IDD (Note 4) - 3.3 5.5 mA Operating Supply Current, ID Includes 1nF GATE loading - 4.1 6.0 mA -1.0 - 1.0 µA CURRENT SENSE Input Bias Current VCS = 1V CS Offset Voltage VCS = 0V (Note 5) 95 100 105 mV COMP to PWM Comparator Offset Voltage VCS = 0V (Note 5) 0.80 1.15 1.30 V 0.91 0.97 1.03 V 2.5 3.0 3.5 V/V - 25 40 ns Input High Voltage Level, VIH - 2.8 - V Input Low Voltage Level, VIL - 2.7 - V (Note 5) 2 - - MHz Gate VOH VDD - OUT, IOUT = -200mA - 1.0 2.0 V Gate VOL OUT - GND, IOUT = 200mA - 1.0 2.0 V Peak Output Current COUT = 1nF (Note 5) 1.0 - - A Rise Time COUT = 1nF (Note 5) - 20 40 ns Fall Time COUT = 1nF (Note 5) - 20 40 ns CS Input Signal, Maximum Gain, ACS = ∆VCOMP/∆VCS 0 < VCS < 910mV, VFB = 0V. (Note 5) CS to OUT Delay (Note 5) CLOCK Maximum Clock Rate OUTPUT 4 ISL6729 Electrical Specifications Recommended operating conditions unless otherwise noted. Refer to Block Diagram and Typical Application schematic. VDD = 5V, CLK = 50kHz, TA = -40 to 105°C (Note 3), Typical values are at TA = 25°C (Continued) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Maximum Duty Cycle - 99 - % Minimum Duty Cycle - - 0 % PWM NOTES: 3. Specifications at -40°C are guaranteed by design, not production tested. 4. This is the VDD current consumed when the device is active but not switching. Does not include gate drive current. 5. Guaranteed by design, not 100% tested in production. Pin Descriptions Ground Plane Requirements CLK - This is the oscillator timing control pin. The operational frequency and maximum duty cycle are set by applying a 5V amplitude clock signal to CLK. The logic high duration defines the maximum ON time for the output. A maximum clock rate up to 2.0MHz is possible. Careful layout is essential for satisfactory operation of the device. A good ground plane must be employed. A unique section of the ground plane must be designated for high di/dt currents associated with the output stage. VDD should be bypassed directly to GND with good high frequency capacitors. COMP - COMP is the input to the PWM comparator and is typically controlled through an external error amplifier. CS - This is the current sense input to the PWM comparator. The range of the input signal is nominally 0 to 1.0V and has an internal offset of 100mV. GND - GND is the power and small signal reference ground for all functions. OUT - This is the drive output to the power switching device. It is a high current output capable of driving the gate of a power MOSFET with peak currents of 1.0A. This GATE output is actively held low when VDD is below the UVLO threshold. VDD - VDD is the 5V power connection for the IC. The IC will operate from 4.75V to 5.25V. However, the accuracy of the voltage clamp on the COMP signal, which determines the over current threshold, is dependent on the accuracy of VDD. A tight tolerance on VDD will result in a tight over current threshold. The total supply current will depend on the load applied to OUT. Total IDD current is the sum of the operating current and the average output current. Knowing the operating frequency, f, and the MOSFET gate charge, Qg, the average output current can be calculated from: I OUT = Qg × f (EQ. 1) To optimize noise immunity, bypass VDD to GND with a ceramic capacitor as close to the VDD and GND pins as possible. 5 Applications Information Microcontrollers are becoming more popular for monitoring and supervisory functions in power converters due to their flexibility, capability, and declining prices. Many applications would like to take advantage of this flexibility and use them to perform the control loop function as well. There are many examples of voltage mode control using digital signal processing techniques. However, microcontrollers available today do not have the execution speed required for peak current mode control at the operational frequencies of modern switch-mode power supplies. As such, they are unable to detect the peak current and terminate the switching cycle within the few nanosecond window required. The ISL6729 provides the analog circuitry required to perform peak current control, but delegates the oscillator function to the microcontroller. This arrangement allows the microcontroller to control soft-start, maximum duty cycle, and operational frequency of the power converter, as well as performing the traditional overhead functions such as fault monitoring and system interface. Application of the ISL6729 is similar to the ISL684x family of PWM converters except that the input bias voltage has been changed to 5V and the oscillator, reference, and error amplifier functions have been removed. An external digital clock signal, such as the PWM output of a microcontroller, must be supplied to control the frequency and maximum duty cycle. The frequency of the applied clock signal and the frequency of operation of the PWM are identical. The duty cycle of the clock is the maximum duty cycle of the PWM. Soft-start may be accomplished by incrementing the duty cycle of the applied clock signal from zero to the maximum desired value in a time frame appropriate for the application. ISL6729 The Typical Application block diagram illustrates how the ISL6729 may be used for an interleaved power converter. In this example, three clock signals of equal duty cycle, but phased 120º apart, are applied to separate power stages. Each phase shares a common voltage feedback signal, but uses separate current feed back signals from each power stage for regulation. Excellent current sharing behavior is assured since each phase must produce the same peak current. Accuracy is determined by the variation of the output inductor value and the feedback components. Multiple output power supplies can be created in a similar fashion. Only one clock signal is required if in-phase operation is desired. Each stage may be independently controlled using separate voltage and current feedback loops. 6 ISL6729 Small Outline Plastic Packages (SOIC) M8.15 (JEDEC MS-012-AA ISSUE C) N INDEX AREA 0.25(0.010) M H 8 LEAD NARROW BODY SMALL OUTLINE PLASTIC PACKAGE B M E INCHES -B- 1 2 SYMBOL 3 L SEATING PLANE -A- h x 45o A D -C- e µα A1 B 0.25(0.010) M C C A M B S 1. Symbols are defined in the “MO Series Symbol List” in Section 2.2 of Publication Number 95. 2. Dimensioning and tolerancing per ANSI Y14.5M-1982. 3. Dimension “D” does not include mold flash, protrusions or gate burrs. Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006 inch) per side. 4. Dimension “E” does not include interlead flash or protrusions. Interlead flash and protrusions shall not exceed 0.25mm (0.010 inch) per side. 5. The chamfer on the body is optional. If it is not present, a visual index feature must be located within the crosshatched area. 6. “L” is the length of terminal for soldering to a substrate. 7. “N” is the number of terminal positions. 8. Terminal numbers are shown for reference only. 9. The lead width “B”, as measured 0.36mm (0.014 inch) or greater above the seating plane, shall not exceed a maximum value of 0.61mm (0.024 inch). 10. Controlling dimension: MILLIMETER. Converted inch dimensions are not necessarily exact. 7 MILLIMETERS MIN MAX NOTES A 0.0532 0.0688 1.35 1.75 - 0.0040 0.0098 0.10 0.25 - B 0.013 0.020 0.33 0.51 9 C 0.0075 0.0098 0.19 0.25 - D 0.1890 0.1968 4.80 5.00 3 E 0.1497 0.1574 3.80 4.00 4 0.050 BSC 1.27 BSC - H 0.2284 0.2440 5.80 6.20 - h 0.0099 0.0196 0.25 0.50 5 L 0.016 0.050 0.40 1.27 6 8o 0o N NOTES: MAX A1 e 0.10(0.004) MIN α 8 0o 8 7 8o Rev. 0 12/93 ISL6729 Mini Small Outline Plastic Packages (MSOP) N M8.118 (JEDEC MO-187AA) 8 LEAD MINI SMALL OUTLINE PLASTIC PACKAGE E1 INCHES E -B- INDEX AREA 1 2 0.20 (0.008) A B C TOP VIEW 4X θ 0.25 (0.010) R1 R GAUGE PLANE SEATING PLANE -CA 4X θ A2 A1 b -H- 0.10 (0.004) L SEATING PLANE C MIN MAX MIN MAX NOTES A 0.037 0.043 0.94 1.10 - A1 0.002 0.006 0.05 0.15 - A2 0.030 0.037 0.75 0.95 - b 0.010 0.014 0.25 0.36 9 c 0.004 0.008 0.09 0.20 - D 0.116 0.120 2.95 3.05 3 E1 0.116 0.120 2.95 3.05 4 0.026 BSC 0.20 (0.008) C C a SIDE VIEW CL E1 0.20 (0.008) C D - 0.187 0.199 4.75 5.05 - L 0.016 0.028 0.40 0.70 6 0.037 REF N -A- 0.65 BSC E L1 e D SYMBOL e L1 MILLIMETERS 0.95 REF 8 R 0.003 R1 0 α - 8 - 0.07 0.003 - 5o 15o 0o 6o 7 - - 0.07 - - 5o 15o - 0o 6o -B- Rev. 2 01/03 END VIEW NOTES: 1. These package dimensions are within allowable dimensions of JEDEC MO-187BA. 2. Dimensioning and tolerancing per ANSI Y14.5M-1994. 3. Dimension “D” does not include mold flash, protrusions or gate burrs and are measured at Datum Plane. Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006 inch) per side. 4. Dimension “E1” does not include interlead flash or protrusions and are measured at Datum Plane. - H - Interlead flash and protrusions shall not exceed 0.15mm (0.006 inch) per side. 5. Formed leads shall be planar with respect to one another within 0.10mm (0.004) at seating Plane. 6. “L” is the length of terminal for soldering to a substrate. 7. “N” is the number of terminal positions. 8. Terminal numbers are shown for reference only. 9. Dimension “b” does not include dambar protrusion. Allowable dambar protrusion shall be 0.08mm (0.003 inch) total in excess of “b” dimension at maximum material condition. Minimum space between protrusion and adjacent lead is 0.07mm (0.0027 inch). 10. Datums -A -H- . and - B - to be determined at Datum plane 11. Controlling dimension: MILLIMETER. Converted inch dimensions are for reference only. All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 8