ISL8843 ® Data Sheet January 3, 2006 Industry Standard Single-Ended Current Mode PWM Controller The ISL8843 is an industry standard drop-in replacement for the popular 28C43 and 18C43 PWM controllers suitable for a wide range of power conversion applications including boost, flyback, and isolated output configurations. Its fast signal propagation and output switching characteristics make this an ideal product for existing and new designs. Features include 30V operation, low operating current, 90µA start-up current, adjustable operating frequency to 2MHz, and high peak current drive capability with 20ns rise and fall times. PART NUMBER RISING UVLO MAX. DUTY CYCLE ISL8843 8.4V 100% PART MARKING Features • 1A MOSFET gate driver • 90µA start-up current, 125µA maximum • 35ns propagation delay current sense to output • Fast transient response with peak current mode control • 30V operation • Adjustable switching frequency to 2MHz • 20ns rise and fall times with 1nF output load • Trimmed timing capacitor discharge current for accurate deadtime/maximum duty cycle control • 1.5MHz bandwidth error amplifier • Tight tolerance voltage reference over line, load, and temperature • ±3% current limit threshold Ordering Information PART NUMBER FN9238.1 TEMP. PKG. RANGE (°C) PACKAGE DWG. # ISL8843ABZ (See Note) 8843 ABZ -40 to 105 8 Ld SOIC (Pb-free) M8.15 ISL8843AUZ (See Note) 8843Z -40 to 105 8 Ld MSOP M8.118 (Pb-free) ISL8843MBZ 8843 MBZ (See Note) -55 to 125 8 Ld SOIC (Pb-free) ISL8843MUZ 843MZ (See Note) -55 to 125 8 Ld MSOP M8.118 (Pb-free) M8.15 • Pb-free plus anneal available and ELV, WEEE, RoHS Compliant Applications • Telecom and datacom power • Wireless base station power • File server power • Industrial power systems • PC power supplies Add -T to part number for Tape and Reel packaging. • Isolated buck and flyback regulators NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are RoHS compliant and 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-020. • Boost regulators Pinout ISL8843 (8 LD SOIC, MSOP) TOP VIEW COMP 1 1 8 VREF FB 2 7 VDD CS 3 6 OUT RTCT 4 5 GND CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright © Intersil Americas Inc. 2005, 2006 All Rights Reserved. All other trademarks mentioned are the property of their respective owners. Functional Block Diagram VREF 5.00 V VDD VREF START/STOP UV COMPARATOR ENABLE VDD OK + - VREF FAULT - 2 VREF UV COMPARATOR 4.65V ↓ 4.80V ↑ GND 2.5V A + - + + - A=0.5 PWM COMPARATOR + - CS 100mV 5% FB VF Total = 1.15V ERROR AMPLIFIER ISL8843 2R + - + - 1.1V 3% CLAMP R COMP OUT S Q R Q 36K 100 nS FALLING EDGE DELAY VREF 100K 2.9V 1.0V ON 150K OSCILLATOR COMPARATOR < 10nS - RTCT + 8.4mA FN9238.1 January 3, 2006 ON CLOCK RESET DOMINANT Typical Application - 48V Input Dual Output Flyback CR5 +3.3V C21 T1 + C16 R21 VIN+ R3 + C15 +1.8V C4 CR4 3 C2 C17 CR2 C5 + C22 + C20 C19 RETURN CR6 R1 36-75V R16 R17 C6 C1 C3 R18 R19 U2 Q1 C14 R4 R22 R15 R27 R20 U4 R26 COMP VREF CS FB V DD OUT RTCT GND ISL8843 R6 R10 CR1 Q3 C12 VR1 C8 R13 C11 ISL8843 C13 U3 VIN- FN9238.1 January 3, 2006 ISL8843 Absolute Maximum Ratings Thermal Information Supply Voltage, VDD . . . . . . . . . . . . . . . . . . . GND - 0.3V to +30.0V OUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to VDD + 0.3V Signal Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to 6.0V Peak GATE Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1A ESD Classification Human Body Model (Per JESD22-A114C.01) . . . . . . . . . . .2000V Machine Model (Per EIA/JESD22-A115-A) . . . . . . . . . . . . . .200V Charged Device Model (Per JESD22-C191-A) . . . . . . . . . .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, MSOP - Lead Tips Only) Operating Conditions Temperature Range ISL8843AxZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to 105°C ISL8843MxZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-55°C to 125°C Supply Voltage Range (Typical) ISL8843 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9V - 30V 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 ISL8843A - Recommended operating conditions unless otherwise noted. Refer to Block Diagram and Typical Application schematic. VDD = 15V, RT = 10kΩ, CT = 3.3nF, TA = -40 to 105°C (Note 3) Typical values are at TA = 25°C PARAMETER TEST CONDITIONS MIN TYP MAX UNITS START Threshold 8.0 8.4 9.0 V STOP Threshold 7.3 7.6 8.0 V - 0.8 - V UNDERVOLTAGE LOCKOUT Hysteresis Startup Current, IDD VDD < START Threshold - 90 125 µA Operating Current, IDD (Note 4) - 2.9 4.0 mA Operating Supply Current, ID Includes 1nF GATE loading - 4.75 5.5 mA 4.925 5.000 5.050 V REFERENCE VOLTAGE Overall Accuracy Over line (VDD = 12V to 18V), load, temperature Long Term Stability TA = 125°C, 1000 hours (Note 5) Current Limit, Sourcing Current Limit, Sinking - 5 - mV -20 - - mA 5 - - 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 0.97 1.00 1.03 V 2.5 3.0 3.5 V/V - 35 55 ns Input Signal, Maximum Gain, ACS = ∆VCOMP/∆VCS 0 < VCS < 910mV, VFB = 0V CS to OUT Delay ERROR AMPLIFIER Open Loop Voltage Gain (Note 5) 60 90 - dB Unity Gain Bandwidth (Note 5) 1.0 1.5 - MHz Reference Voltage VFB = VCOMP 2.475 2.500 2.530 V 4 FN9238.1 January 3, 2006 ISL8843 Electrical Specifications ISL8843A - Recommended operating conditions unless otherwise noted. Refer to Block Diagram and Typical Application schematic. VDD = 15V, RT = 10kΩ, CT = 3.3nF, TA = -40 to 105°C (Note 3) Typical values are at TA = 25°C (Continued) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS FB Input Bias Current VFB = 0V -1.0 -0.2 1.0 µA COMP Sink Current VCOMP = 1.5V, VFB = 2.7V 1.0 - - mA COMP Source Current VCOMP = 1.5V, VFB = 2.3V -0.4 - - mA COMP VOH VFB = 2.3V 4.80 - VREF V COMP VOL VFB = 2.7V 0.4 - 1.0 V PSRR Frequency = 120Hz, VDD = 12V to 18V (Note 5) 60 80 - dB Frequency Accuracy Initial, TA = 25°C 48 51 53 kHz Frequency Variation with VDD TA= 25°C, (F30V - F9V)/F30V - 0.2 1.0 % Temperature Stability (Note 5) - - 5 % Amplitude, Peak to Peak Static Test - 1.75 - V RTCT Discharge Voltage (Valley Voltage) Static Test - 1.0 - V Discharge Current RTCT = 2.0V 6.5 7.8 8.5 mA OSCILLATOR OUTPUT 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 GATE VOL UVLO Clamp Voltage VDD = 5V, ILOAD = 1mA - - 1.2 V PWM Maximum Duty Cycle COMP = VREF 93.5 95 - % Minimum Duty Cycle COMP = GND - - 0 % NOTES: 3. Specifications at -40°C and 105°C are guaranteed by 25°C test with margin limits. 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. Electrical Specifications ISL8843M - Recommended operating conditions unless otherwise noted. Refer to Block Diagram and Typical Application schematic. VDD = 15V, RT = 10kΩ, CT = 3.3nF, TA = -55 to 125°C (Note 6), Typical values are at TA = 25°C PARAMETER TEST CONDITIONS MIN TYP MAX UNITS START Threshold 8.0 8.4 9.0 V STOP Threshold 7.3 7.6 8.0 V - 0.8 - V UNDERVOLTAGE LOCKOUT Hysteresis Startup Current, IDD VDD < START Threshold - 90 125 µA Operating Current, IDD (Note 7) - 2.9 4.0 mA Operating Supply Current, ID Includes 1nF GATE loading - 4.75 5.5 mA 4.900 5.000 5.050 V REFERENCE VOLTAGE Overall Accuracy Over line (VDD = 12V to 18V), load, temperature 5 FN9238.1 January 3, 2006 ISL8843 Electrical Specifications ISL8843M - Recommended operating conditions unless otherwise noted. Refer to Block Diagram and Typical Application schematic. VDD = 15V, RT = 10kΩ, CT = 3.3nF, TA = -55 to 125°C (Note 6), Typical values are at TA = 25°C (Continued) PARAMETER Long Term Stability TEST CONDITIONS TA = 125°C, 1000 hours (Note 8) Current Limit, Sourcing Current Limit, Sinking MIN TYP MAX UNITS - 5 - mV -20 - - mA 5 - - mA CURRENT SENSE Input Bias Current VCS = 1V -1.0 - 1.0 µA CS Offset Voltage VCS = 0V (Note 8) 95 100 105 mV COMP to PWM Comparator Offset Voltage VCS = 0V (Note 8) 0.80 1.15 1.30 V 0.97 1.00 1.03 V 2.5 3.0 3.5 V/V - 35 60 ns Input Signal, Maximum Gain, ACS = ∆VCOMP/∆VCS 0 < VCS < 910mV, VFB = 0V CS to OUT Delay ERROR AMPLIFIER Open Loop Voltage Gain (Note 8) 60 90 - dB Unity Gain Bandwidth (Note 8) 1.0 1.5 - MHz Reference Voltage VFB = VCOMP 2.460 2.500 2.535 V FB Input Bias Current VFB = 0V -1.0 -0.2 1.0 µA COMP Sink Current VCOMP = 1.5V, VFB = 2.7V 1.0 - - mA COMP Source Current VCOMP = 1.5V, VFB = 2.3V -0.4 - - mA COMP VOH VFB = 2.3V 4.80 - VREF V COMP VOL VFB = 2.7V 0.4 - 1.0 V PSRR Frequency = 120Hz, VDD = 12V to 18V (Note 8) 60 80 - dB OSCILLATOR Frequency Accuracy Initial, TA = 25°C 48 51 53 kHz Frequency Variation with VDD TA = 25°C, (F30V - F9V)/F30V - 0.2 1.0 % Temperature Stability (Note 8) - - 5 % Amplitude, Peak to Peak Static Test - 1.75 - V RTCT Discharge Voltage (Valley Voltage) Static Test - 1.0 - V Discharge Current RTCT = 2.0V 6.2 8.0 8.5 mA OUTPUT 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 8) - 1.0 - A Rise Time COUT = 1nF (Note 8) - 20 40 ns Fall Time COUT = 1nF (Note 8) - 20 40 ns GATE VOL UVLO Clamp Voltage VDD = 5V, ILOAD = 1mA - - 1.2 V PWM Maximum Duty Cycle COMP = VREF 93.5 95 - % Minimum Duty Cycle COMP = GND - - 0 % NOTES: 6. Specifications at -55°C and 125°C are guaranteed by 25°C test with margin limits. 7. This is the VDD current consumed when the device is active but not switching. Does not include gate drive current. 8. Guaranteed by design, not 100% tested in production. 6 FN9238.1 January 3, 2006 ISL8843 1.001 1.01 1.000 NORMALIZED VREF NORMALIZED FREQUENCY Typical Performance Curves 1 0.99 0.999 0.998 0.997 0.996 0.98 -60 -40 -20 0 20 40 60 80 0.995 -60 -40 -20 100 120 140 0 20 40 60 80 100 120 140 TEMPERATURE (°C) TEMPERATURE (°C) FIGURE 1. FREQUENCY vs TEMPERATURE FIGURE 2. REFERENCE VOLTAGE vs TEMPERATURE 1.001 FREQUENCY (kHz) NORMALIZED EA REFERENCE 1•103 1.000 0.998 220pF 330pF 470pF 1.0nF 10 2.2nF 3.3nF 4.7nF 6.8nF 0.996 -60 -40 -20 0 20 40 60 80 100 120 140 FIGURE 3. EA REFERENCE vs TEMPERATURE RTCT - This is the oscillator timing control pin. The operational frequency and maximum duty cycle are set by connecting a resistor, RT, between VREF and this pin and a timing capacitor, CT, from this pin to GND. The oscillator produces a sawtooth waveform with a programmable frequency range up to 2.0MHz. The charge time, TC, the discharge time, TD, the switching frequency, f, and the maximum duty cycle, Dmax, can be approximated from the following equations: C ≈ 0.533 • RT • CT (EQ. 1) D 0.008 • RT – 3.83 ≈ – RT • CT • ln ---------------------------------------------- 0.008 • RT – 1.71 (EQ. 2) f = 1 ⁄ (TC + TD) (EQ. 3) D = TC • f (EQ. 4) 7 1 1 10 RT (kΩ) 100 FIGURE 4. RTCT vs FREQUENCY Pin Descriptions T 100 0.997 TEMPERATURE (°C) T CT = 100pF The formulae have increased error at higher frequencies due to propagation delays. Figure 4 may be used as a guideline in selecting the capacitor and resistor values required for a given frequency. COMP - COMP is the output of the error amplifier and the input of the PWM comparator. The control loop frequency compensation network is connected between the COMP and FB pins. FB - The output voltage feedback is connected to the inverting input of the error amplifier through this pin. The non-inverting input of the error amplifier is internally tied to a reference voltage. 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. FN9238.1 January 3, 2006 ISL8843 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 power connection for the device. 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. 5) To optimize noise immunity, bypass VDD to GND with a ceramic capacitor as close to the VDD and GND pins as possible. VREF - The 5.00V reference voltage output. +1.0/-1.5% tolerance over line, load and operating temperature. Bypass to GND with a 0.1µF to 3.3µF capacitor to filter this output as needed. Functional Description Features The ISL8843 current mode PWM makes an ideal choice for low-cost flyback and forward topology applications. With its greatly improved performance over industry standard parts, it is the obvious choice for new designs or existing designs which require updating. Oscillator The ISL8843 has a sawtooth oscillator with a programmable frequency range to 2MHz, which can be programmed with a resistor from VREF and a capacitor to GND on the RTCT pin. (Please refer to Figure 4 for the resistor and capacitance required for a given frequency.) Soft-Start Operation Soft-start must be implemented externally. One method, illustrated below, clamps the voltage on COMP. VREF R1 COMP ISL8843 D1 Q1 GND C1 The COMP pin is clamped to the voltage on capacitor C1 plus a base-emitter junction by transistor Q1. C1 is charged from VREF through resistor R1 and the base current of Q1. At power-up C1 is fully discharged, COMP is at ~0.7V, and the duty cycle is zero. As C1 charges, the voltage on COMP increases, and the duty cycle increases in proportion to the voltage on C1. When COMP reaches the steady state operating point, the control loop takes over and soft start is complete. C1 continues to charge up to VREF and no longer affects COMP. During power down, diode D1 quickly discharges C1 so that the soft start circuit is properly initialized prior to the next power on sequence. Gate Drive The ISL8843 is capable of sourcing and sinking 1A peak current. To limit the peak current through the IC, an optional external resistor may be placed between the totem-pole output of the IC (OUT pin) and the gate of the MOSFET. This small series resistor also damps any oscillations caused by the resonant tank of the parasitic inductances in the traces of the board and the FET’s input capacitance. Slope Compensation For applications where the maximum duty cycle is less than 50%, slope compensation may be used to improve noise immunity, particularly at lighter loads. The amount of slope compensation required for noise immunity is determined empirically, but is generally about 10% of the full scale current feedback signal. For applications where the duty cycle is greater than 50%, slope compensation is required to prevent instability. Slope compensation may be accomplished by summing an external ramp with the current feedback signal or by subtracting the external ramp from the voltage feedback error signal. Adding the external ramp to the current feedback signal is the more popular method. From the small signal current-mode model [1] it can be shown that the naturally-sampled modulator gain, Fm, without slope compensation, is 1 Fm = -------------------SnTsw where Sn is the slope of the sawtooth signal and Tsw is the duration of the half-cycle. When an external ramp is added, the modulator gain becomes 1 1 Fm = --------------------------------------- = ---------------------------( Sn + Se )Tsw m c SnTsw 8 (EQ. 7) where Se is slope of the external ramp and Se m c = 1 + ------Sn FIGURE 5. SOFT-START (EQ. 6) (EQ. 8) The criteria for determining the correct amount of external ramp can be determined by appropriately setting the damping factor of the double-pole located at the switching FN9238.1 January 3, 2006 ISL8843 frequency. The double-pole will be critically damped if the Q-factor is set to 1, over-damped for Q < 1, and underdamped for Q > 1. An under-damped condition may result in current loop instability. 1 Q = ------------------------------------------------π ( m c ( 1 – D ) – 0.5 ) (EQ. 9) Substituting Equations 12 and 13 into Equation 14 and solving for RCS yields 1 R CS = --------------------------------------------------------------------------------------------------------------------------------------------------------1 - + 0.5 N D ⋅ T sw ⋅ V IN -( 1 – D ) ⋅ V O ⋅ T sw π --------------------------------- ⋅ ------------------ – 1 + ------s- ⋅ I O + --------------------------------------------- N Lp 1–D 2L s p (EQ. 15) where D is the percent of on time during a switching cycle. Setting Q = 1 and solving for Se yields 1 1 S e = S n --- + 0.5 ------------- – 1 1 –D π (EQ. 10) Since Sn and Se are the on time slopes of the current ramp and the external ramp, respectively, they can be multiplied by Ton to obtain the voltage change that occurs during Ton. 1 + 0.5 ------------- – 1 Ve = Vn 1 1 –D --π Adding slope compensation is accomplished in the ISL8843 using an external buffer transistor and the RTCT signal. A typical application sums the buffered RTCT signal with the current sense feedback and applies the result to the CS pin as shown in Figure 6. (EQ. 11) VREF For a flyback converter, Vn can be solved for in terms of input voltage, current transducer components, and primary inductance, yielding D ⋅ T SW ⋅ V IN ⋅ R CS 1 1 V e = ---------------------------------------------------- --- + 0.5 ------------- – 1 1 –D π Lp R9 CS R6 ISL8843 where Vn is the change in the current feedback signal (∆I) during the on time and Ve is the voltage that must be added by the external ramp. RTCT C4 V (EQ. 12) FIGURE 6. SLOPE COMPENSATION where RCS is the current sense resistor, TSW is the switching frequency, Lp is the primary inductance, VIN is the minimum input voltage, and D is the maximum duty cycle. The current sense signal at the end of the ON time for CCM operation is: ( 1 – D ) ⋅ VO ⋅ T N S ⋅ R CS sw V CS = ------------------------ I O + --------------------------------------------- NP 2L s V ⋅ R6 V e = 2.05D ----------------------------R6 + R9 V Since the peak current limit threshold is 1.00V, the total current feedback signal plus the external ramp voltage must sum to this value when the output load is at the current limit threshold. (EQ. 14) The factor of 2.05 in Equation 16 arises from the peak amplitude of the sawtooth waveform on RTCT minus a baseemitter junction drop. That voltage multiplied by the maximum duty cycle is the voltage source for the slope compensation. Rearranging to solve for R9 yields: ( 2.05D – V e ) ⋅ R6 R9 = ---------------------------------------------Ve Ω (EQ. 17) The value of RCS determined in Equation 15 must be rescaled so that the current sense signal presented at the CS pin is that predicted by Equation 13. The divider created by R6 and R9 makes this necessary. R6 + R9 R′ CS = ---------------------- ⋅ R CS R9 9 (EQ. 16) (EQ. 13) where VCS is the voltage across the current sense resistor, Ls is the secondary winding inductance, and IO is the output current at current limit. Equation 13 assumes the voltage drop across the output rectifier is negligible. V e + V CS = 1 Assuming the designer has selected values for the RC filter (R6 and C4) placed on the CS pin, the value of R9 required to add the appropriate external ramp can be found by superposition. (EQ. 18) FN9238.1 January 3, 2006 ISL8843 Example: VIN = 12V VO = 48V Ls = 800µH Ns/Np = 10 Lp = 8.0µH IO = 200mA Switching Frequency, Fsw = 200kHz Duty Cycle, D = 28.6% R6 = 499Ω Solve for the current sense resistor, RCS, using Equation 15. RCS = 295mΩ Determine the amount of voltage, Ve, that must be added to the current feedback signal using Equation 12. Ve = 92.4mV Using Equation 17, solve for the summing resistor, R9, from CT to CS. R9 = 2.67kΩ Determine the new value of RCS, R’CS, using Equation 18. R’CS = 350mΩ Additional slope compensation may be considered for design margin. The above discussion determines the minimum external ramp that is required. The buffer transistor used to create the external ramp from RTCT should have a sufficiently high gain (>200) so as to minimize the required base current. Whatever base current is required reduces the charging current into RTCT and will reduce the oscillator frequency. Fault Conditions A Fault condition occurs if VREF falls below 4.65V. When a Fault is detected OUT is disabled. When VREF exceeds 4.80V, the Fault condition clears, and OUT is enabled. Ground Plane Requirements 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. References [1] Ridley, R., “A New Continuous-Time Model for Current Mode Control”, IEEE Transactions on Power Electronics, Vol. 6, No. 2, April 1991. 10 FN9238.1 January 3, 2006 ISL8843 Small Outline Plastic Packages (SOIC) M8.15 (JEDEC MS-012-AA ISSUE C) N INDEX AREA 8 LEAD NARROW BODY SMALL OUTLINE PLASTIC PACKAGE H 0.25(0.010) M B M INCHES E SYMBOL -B1 2 A 3 L SEATING PLANE -A- A D h x 45° -C- e A1 B 0.25(0.010) M C 0.10(0.004) C A M B S MIN MAX MIN MAX NOTES 0.0532 0.0688 1.35 1.75 - A1 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 e α 0.050 BSC - 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 α 1. Symbols are defined in the “MO Series Symbol List” in Section 2.2 of Publication Number 95. 1.27 BSC H N NOTES: MILLIMETERS 8 0° 1.27 8 8° 0° 6 7 8° Rev. 1 6/05 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. 11 FN9238.1 January 3, 2006 ISL8843 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) L1 SEATING PLANE C D 0.20 (0.008) C a CL E1 0.20 (0.008) C D MAX MIN MAX NOTES 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 0.65 BSC - E 0.187 0.199 4.75 5.05 - L 0.016 0.028 0.40 0.70 6 0.037 REF N C SIDE VIEW MIN A L1 -A- e SYMBOL e L MILLIMETERS 0.95 REF 8 R 0.003 R1 0 α - 8 7 - - 0.07 - - 5o 15o - 0o 6o - 0.07 0.003 - 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 12 FN9238.1 January 3, 2006