SC1401 Semtech Corporation, SC1401 Datasheet
SC1401
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SC1401 Summary of contents
Page 1
... November 21, 2000 DESCRIPTION The SC1401 is a synchronous buck regulator designed to power the latest generation microprocessors in battery operated systems. The SC1401 may be used to provide both the I/O and core voltages utilizing synchronous rectification for the core supply voltage and an LDO N-Channel MOSFET controller for the I/O supply voltage. A 1.25 volt reference allows lower output voltages required by today’ ...
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... CSH Non-Inverting input to current sense amplifier. Current limit level is 120mV referenced to CSL. 8 V5V 5 volt external supply used to power the gate drives, internal control and reference of the SC1401 Gate drive output for low side synchronous rectifier MOSFET. 10 PGND Device power ground. ...
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... Typical values are MIN TYP MAX 6.0 30.0 VREF 5.5 1.225 1.250 1.275 2 0.03 100 130 160 30 512 265 300 335 165 200 235 NEWBURY PARK CA 91320 SC1401 = +25°C. A UNITS %/ clks kHz % 3 ...
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... A CONDITIONS DL, DH, forced to 2V High or low CSL = CSH = 5. 1.25V VDD2=12V, GATEIO=0V IOS = 1.25V ILOAD=0.5A Vin=12V, ILOAD = 0. VDD1 = 6V to 30V, V5V = 5V, SHDN = 0V V5V = 5V, no load on DH/DL, PSAVE = 0V VDD2 = 12V 652 MITCHELL ROAD SC1401 = +25°C. A MIN TYP MAX UNITS 2.0 A 1.0 200 200 ns 200 240 ...
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... CONDITIONS Typical hysteresis = +10°V Falling edge of VDD1, hysteresis = 1% Falling edge of V5V, hysteresis = 1% Hysteresis = 1% Hysteresis = 1% FB Over/Under Voltage condition With respect to f OSC SHDN,ENABLEIO PSAVE,SYNC SHDN,ENABLEIO, PSAVE, SYNC RESET, ISINK = 4mA 652 MITCHELL ROAD SC1401 = +25°C. A MIN TYP MAX UNITS 150 °C 4.2 4.5 4.8 V 3.75 4 ...
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... SEMTECH CORP. HIGH PERFORMANCE SYNCHRONOUS BUCK CONTROLLER WITH LDO FOR PORTABLE POWER LINE REGULATION (SMPS 7.0A 2.2V 6.0 9.0 12.0 15.0 18.0 21.0 INPUT VOLTAGE (V) 0.5 1.0 2.0 3.0 4.0 5.0 LOAD CURRENT (A) EFFICIENCY vs LOAD CURRENT 0.1 1.0 2.0 3.0 4.0 5.0 LOAD CURRENT (A) 652 MITCHELL ROAD SC1401 24.0 27.0 30.0 6.0 7.0 VIN = 6V VIN = 10V VIN = 14V VIN = 18V VIN = 22V 6.0 7.0 NEWBURY PARK CA 91320 6 ...
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... November 21, 2000 LOAD TRANSIENT: Vin = 16V 2.0V © 2000 SEMTECH CORP. HIGH PERFORMANCE SYNCHRONOUS BUCK CONTROLLER WITH LDO FOR PORTABLE POWER RIPPLE VOLTAGE: 200KHZ RIPPLE VOLTAGE: 300KHZ 652 MITCHELL ROAD SC1401 7 NEWBURY PARK CA 91320 ...
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... SSOP) V (SMPS 1. © 2000 SEMTECH CORP. HIGH PERFORMANCE SYNCHRONOUS BUCK CONTROLLER WITH LDO FOR PORTABLE POWER V (Linear) O (current sense resistor) 120mV 1. Table 1 652 MITCHELL ROAD SC1401 R7 R10 5 I MAX NEWBURY PARK CA 91320 8 ...
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... November 21, 2000 TYPICAL NOTEBOOK CPU APPLICATION CIRCUIT FOR V © 2000 SEMTECH CORP. HIGH PERFORMANCE SYNCHRONOUS BUCK CONTROLLER WITH LDO FOR PORTABLE POWER CORE BAT42W 0.1uF D1 652 MITCHELL ROAD SC1401 = 2.2V & 3.3V I ...
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... EVALUATION BOARD SCHEMATIC © 2000 SEMTECH CORP. HIGH PERFORMANCE SYNCHRONOUS BUCK CONTROLLER WITH LDO FOR PORTABLE POWER BAT42W 0.1uF D1 652 MITCHELL ROAD SC1401 NEWBURY PARK CA 91320 ...
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... COUNTER ENABLEIO DAC POWER RESET GOOD Figure 2: Main PWM Modulator Control Block © 2000 SEMTECH CORP. HIGH PERFORMANCE SYNCHRONOUS BUCK CONTROLLER WITH LDO FOR PORTABLE POWER Figure 1: SC1401 Block Diagram V5V BG REF DIGITAL CONTROLLER BG REF 652 MITCHELL ROAD SC1401 VDD1 VDD2 ...
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... An LDO NMOS linear regulator is also generated by the SC1401. A block diagram of the SC1401 is shown in Figure 1. PWM Control Block The SC1401 employs peak-current-mode control with slope compensation to provide fast output response to load and line transients ...
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... November 21, 2000 Gate Drive and Control The gate drivers on the SC1401 are designed to switch large MOSFETs 350kHz. The high- side gate drivers are required to drive the gates of the high-side MOSFETs above the V5V input. The supply for these gate drivers is generated by charging a bootstrap capacitor from a supply when the low side driver is on ...
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... HIGH PERFORMANCE SYNCHRONOUS BUCK CONTROLLER WITH LDO FOR PORTABLE POWER efficiency, small size and low cost are required. The Semtech SC1401 EVAL board consists of a 2.0V, 7A switcher and a 1.5V, 1A linear regulator. Design Guidelines The schematic for the EVAL board is shown on page 10. The EVAL board is configured as follows: ...
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... The current carrying capability of the inductor and MOSFETs should be sized to handle the maximum current of the supply set by the current sense resistor. For the SC1401 EVAL board Rsense equals the parallel combination of R7A & R7B. Here we use the minimum current threshold value: ...
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... CONTROLLER WITH LDO FOR PORTABLE POWER P = 0.065W SU Crss is the reverse transfer capacitance of the FET; in this case it equals 215pF for the IRF7805. Where Ig is the gate driver current. This is equal to 2A for the SC1401 C/W So the total FET losses equate to 0.09 + 0.225 + 0.065 = 0.38W. ...
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... November 21, 2000 OUTLINE DRAWING - SSOP-20 © 2000 SEMTECH CORP. HIGH PERFORMANCE SYNCHRONOUS BUCK CONTROLLER WITH LDO FOR PORTABLE POWER 652 MITCHELL ROAD SC1401 Jedec MO-150AE 17 NEWBURY PARK CA 91320 ...