ISL6440 Intersil Corporation, ISL6440 Datasheet
ISL6440
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ISL6440 Summary of contents
Page 1
... RMS input current and ripple voltage. The ISL6440 incorporates several protection features. An adjustable overcurrent protection circuit monitors the output current by sensing the voltage drop across the lower MOSFET. Hiccup mode overcurrent operation protects the DC/DC components from damage during output overload/short circuit conditions ...
Page 2
... C2 4.7µF VIN VCC5 SS1 SS2 0.1µF BOOT1 BOOT2 23 2 UGATE1 UGATE2 22 3 PHASE2 PHASE1 ISEN1 ISEN2 20 5 1.4K ISL6440IA LGATE1 LGATE2 24 1 PGND FB2 19 11 FB1 OCSET1 14 15 SD1 18 OCSET2 10 SD2 SGND PGOOD BIAS R9 10K VCC5 C1 + 56µF ...
Page 3
Block Diagram BOOT1 UGATE1 PHASE1 ADAPTIVE DEAD-TIME DIODE EMULATION VCC_5V V/I SAMPLE TIMING LGATE1 PGND FB3 18.5pF 1400kΩ 180kΩ FB1 - 16kΩ 0.8V ERROR AMP 1 REF SS1 ISEN1 - CURRENT SAMPLE CURRENT + SAMPLE OCSET1 + 0.8V ...
Page 4
... PWM CONVERTERS Output Voltage FB Pin Bias Current Maximum Duty Cycle Minimum Duty Cycle 4 ISL6440 Thermal Information Thermal Resistance (Typical) 24 Lead QSOP (Note 1 Maximum Junction Temperature (Plastic Package) . -55°C to 150°C Maximum Storage Temperature Range . . . . . . . . . . . -65°C to 150°C Maximum Lead Temperature (Soldering 10s 300°C Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . -40° ...
Page 5
... Guaranteed by design; not production tested. 8. Not production tested; guaranteed by characterization only. 9. Guaranteed by design. The full scale current of 32µA is recommended for optimum current sample and hold operation. See the Feedback Loop Compensation Section below. 5 ISL6440 = 5.6V to 24V, or VCC5 = 5V ±10 25°C (Continued) ...
Page 6
... Typical Performance Curves (Oscilloscope Plots Are Taken Using the ISL6440EVAL1B Evaluation Board, VIN = 12V, Unless Otherwise Noted) 3.4 3.39 3.38 3.37 3.36 3.35 3.34 3.33 3.32 3.31 3.3 0 0.5 1 1.5 2 2.5 LOAD CURRENT (A) FIGURE 1. PWM1 LOAD REGULATION 0.85 0.84 0.83 0.82 0.81 0.8 0.79 0.78 0.77 0.76 0.75 -40 - TEMPERATURE (°C) FIGURE 3. REFERENCE VOLTAGE VARIATION OVER TEMPERATURE V 20mV/DIV, AC COUPLED OUT1 I 0.5A/DIV, AC COUPLED L1 PHASE1 10V/DIV FIGURE 5 ...
Page 7
... Typical Performance Curves (Oscilloscope Plots Are Taken Using the ISL6440EVAL1B Evaluation Board, VIN = 12V, Unless Otherwise Noted) V 200mV/DIV OUT1 AC COUPLED I 1A/DIV OUT1 FIGURE 7. LOAD TRANSIENT RESPONSE VOUT1 (3.3V) VCC_5V 1V/DIV V 1V/DIV OUT1 FIGURE 9. PWM SOFT-START WAVEFORM 100 LOAD CURRENT (A) FIGURE 11 ...
Page 8
... Bypass the regulator’s output (VCC5) with a 4.7µF capacitor to ground. The dropout voltage for this LDO is typically 600mV, so when VIN is greater then 5.6V, VCC5V is +5V. The ISL6440 also employs an undervoltage lockout circuit that disables both regulators when VCC5 falls below 4.4V. ...
Page 9
... R1 is the top resistor of the feedback divider network and R2 is the resistor connected from FB1 or FB2 to ground. Out-of-Phase Operation The two PWM controllers in the ISL6440 operate 180 of-phase to reduce input ripple current. This reduces the input capacitor ripple current requirements, reduces power supply-induced noise, and improves EMI ...
Page 10
... Input Voltage Range The ISL6440 is designed to operate from input supplies ranging from 4.5V to 24V. However, the input voltage range can be effectively limited by the available maximum duty cycle (D = 93%). MAX OUT d1 -------------------------------- – V min d2 d1 0.93 where, Vd1 = Sum of the parasitic voltage drops in the inductor discharge path, including the lower FET, inductor and PC board ...
Page 11
... Layout Guidelines Careful attention to layout requirements is necessary for successful implementation of a ISL6440 based DC/DC converter. The ISL6440 switches at a very high frequency and therefore the switching times are very short. At these switching frequencies, even the shortest trace has significant impedance. Also the peak gate drive current rises significantly in extremely short time ...
Page 12
... One of the parameters limiting the converter’s response to a load transient is the time required for the inductor current to slew to it’s new level. The ISL6440 will provide either 0% or 71% duty cycle in response to a load transient. , gate supply requirements, ) ...
Page 13
... For the ISL6440, use Inductor values between 4.7µH to 10µH when using the component values in the Typical Application Schematic for optimal compensation. Other inductor values can be used but with a more rigorous design for compensation. Input Capacitor Selection The important parameters for the bulk input capacitor(s) are the voltage rating and the RMS current rating ...
Page 14
... For surface mount designs, solid tantalum capacitors can be used, but caution must be exercised with regard to the capacitor surge current rating. These capacitors must be capable of handling the surge- current at power-up. The TPS series available from AVX is surge current tested. 14 ISL6440 5V 3. FN9040.2 ...
Page 15
... 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 15 ISL6440 M24.15 24 LEAD SHRINK SMALL OUTLINE PLASTIC PACKAGE M ...