isl6744a Intersil Corporation, isl6744a Datasheet
isl6744a
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isl6744a Summary of contents
Page 1
... It provides precise control of switching frequency, adjustable soft-start, precise deadtime control with deadtimes as low as 35ns, and overcurrent shutdown. The ISL6744A is identical to the ISL6744, but is optimized for higher noise environments. Low start-up and operating currents allow for easy biasing in both AC/DC and DC/DC applications. This advanced ...
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Internal Architecture V DD UVLO + - INTERNAL BG OT SHUTDOWN 130 - 150 C GND R 2 RTD V BIAS 160 PEAK 2 VALLEY 0 ...
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... Typical Application using ISL6744A - 48V Input DC Transformer, 12V @ 8A Output VIN CR3 VIN- R7 TP6 C13 TP1 R10 T2 QL C14 CR1 R5 U4 TP4 ISL6700 TP5 D2 C15 D1 R12 C6 QR1 C11 QR3 QR2 ...
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... Charged Device Model (Per EOS/ESD DS5.3, 4/14/93 .1000V Operating Conditions Temperature Range ISL6744AAxx . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +105°C Supply Voltage Range (Typical 9VDC to 16VDC CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and result in failures not covered by warranty ...
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... Thermal Shutdown Clear Hysteresis, Internal Protection NOTES: 3. Specifications at -40°C and +105°C are guaranteed by +25°C test with margin limits. 4. Limits established by characterization and are not production tested. 5 ISL6744A < 16V 51.1kΩ 470pF -40°C to +105°C (Note 3), Typical values are at D ...
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... RTD CURRENT (mA) FIGURE 1. OSCILLATOR CT DISCHARGE CURRENT GAIN 600 500 400 300 200 100 0 100 200 300 400 500 600 CT (pF) FIGURE 3. CAPACITANCE vs OSCILLATOR FREQUENCY (RTD = 49.9kΩ) 6 ISL6744A 1-10 1-10 100 0.07 0.08 0.09 0.10 700 800 900 1000 1.07 1.06 1.05 1.04 1.03 1.02 1.01 1.00 0.99 0. RTD (kΩ) FIGURE 5. TIMING CAPACITOR VOLTAGE vs RTD ...
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... DD protection and internal thermal protection, allowing a highly flexible design with minimal external components. Oscillator The ISL6744A has an oscillator with a frequency range to (EQ. 1) 2MHz, programmable using a resistor R The switching period may be considered to be the sum of the timing capacitor charge and discharge durations. The ...
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... Soft-start occurs during start-up and after recovery from an overcurrent shutdown. The soft-start voltage is clamped to 4V. Gate Drive The ISL6744A is capable of sourcing and sinking 1A peak current, and may also be used in conjunction with a MOSFET driver such as the ISL6700 for level shifting. To limit the peak current through the IC, an external resistor may be placed between the totem-pole output of the IC (OUTA or OUTB pin) and the gate of the MOSFET ...
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... ISL6744A Since the converter is operating open loop at nearly 100% duty cycle, the turns ratio simply the ratio of the input voltage to the output voltage divided by 2. ...
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... DC power loss for the secondary at 20°C is 486mW. 10 ISL6744A The primary windings have an RMS current of approximately OUT configured as 2 layers, 2 turns per layer to minimize the winding stack height ...
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... FIGURE 7C. INT. LAYER 2: 2 TURNS PRIMARY WINDING FIGURE 7D. INT. LAYER 3: 2 TURNS PRIMARY WINDING FIGURE 7E. INT. LAYER 4: 1 TURN SECONDARY WINDING FIGURE 7F. BOTTOM LAYER: 1 TURN SECONDARY AND SR WINDINGS 11 ISL6744A ∅0.358 0.000 0.184 0.479 FIGURE 7G. PWB DIMENSIONS MOSFET Selection The criteria for selection of the primary side half-bridge FETs and the secondary side synchronous rectifier FETs is largely based on the current and voltage rating of the device ...
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... Ichg t • Cfet ------------------- - ISL6744A Once the estimated transition time is determined, it must be verified directly in the application. The transformer leakage inductance was measured at 125nH and the combined capacitance was estimated at 2000pF. Calculations indicate a transition period of ~25ns. Verification of the performance yielded a value of T The remainder of the switching half-period is the charge ...
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... The peak current limit causes the duty cycle to decrease resulting ISL6744A reduction of the average current through the inductor. The implication is that the converter can not supply the same output current in current limit that it can supply under steady state conditions. The peak current limit setpoint must take this behavior into consideration. A 5.11Ω ...
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... The deadtime duration of 46.9ns is clearly shown. A 2.7V zener is added between the Vdd pins of ISL6700 and ISL6744, in order to ensure that the PWM turns on only after the driver has turned on, thereby ensuring the soft-start function. Figure 17 shows the soft-start operation. 14 ISL6744A OUT FIGURE 15 ...
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... Diode, Schottky, SMA, 100V, 2.1A D1 Zener, 10V,Zetex BZX84C10ZXCT-ND D2 Zener, 2.7V, BZX84C2V7 L1 190nH Pulse, P2004T L2 1.5µH Bitech, HM73-301R5 L3 Short Jumper or Optional Discrete Leakage Inductance P1, P2, P3, P4 Keystone, 1514-2 Q5 NPN Transistor, ON MJD31C QL, QH FET, Fairchild FDS3672, 100V 15 ISL6744A FIGURE 17. OUTPUT SOFT-START DESCRIPTION FN6554.0 October 8, 2007 ...
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... Resistor, 0805, 1% R10 18 Resistor, 2512, 1% R11 100 Resistor, 0603, 1% R12 10.0K Resistor, 0603 Custom Midcom 31718 T2 Custom Midcom 31719R TP1, TP2, TP4, 5002 Keystone TP5, TP6 SP1 Tektronix Scope Jack, 131-4353-00 U1 Intersil ISL6744AAUZ, MSOP8 U4 Intersil ISL6700IB, SOIC 16 ISL6744A DESCRIPTION FN6554.0 October 8, 2007 ...
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... B - 10. Datums -A - and to be determined at Datum plane . - H - 11. Controlling dimension: MILLIMETER. Converted inch dimen- sions are for reference only. 17 ISL6744A M8.118 (JEDEC MO-187AA) 8 LEAD MINI SMALL OUTLINE PLASTIC PACKAGE SYMBOL θ ...
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... 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 18 ISL6744A M8.15 (JEDEC MS-012-AA ISSUE C) 8 LEAD NARROW BODY SMALL OUTLINE PLASTIC PACKAGE ...