sc1402 Semtech Corporation, sc1402 Datasheet
sc1402
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sc1402 Summary of contents
Page 1
... The MOSFET drivers provide 1A peak drive current for fast MOSFET switching. The SC1402 includes a PSAVE enable input to select a pulse skipping mode for high efficiency or a fixed fre- quency mode for low noise operation. TYPICAL APPLICATION CIRCUIT © ...
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... Either SMPS, 6V < V+ < 30V CSH3-CSL3 or CSH5-CSL5 PSAVE = VL or V12OUT < 11.9V PSAVE = 0V, not tested From enable to 95% full current limit with respect to f Note 2. OSC SYNC = VL SYNC = 0V SYNC = VL SYNC = 0V 652 MITCHELL ROAD SC1402 MAXIMUM UNITS -0.3, +36 V ± 0 +0 -0.3 to (VL+.3V) V -0.3 to (V+ + 0.3V ...
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... LOAD < 5mA Falling edge VL switched over to CSL5, 5V SMPS 30V, SMPS off, includes current into SHDN 30V, SHDN = 0V SMPS enabled, FB3 = FB5 = 0V, CSL3 = CSH 3 = 3.5V, CSL5 = CSH5 = 5.5V Table 2 652 MITCHELL ROAD SC1402 = -40 to +85°C A MIN TYP MAX UNITS 300 300 ns 200 ...
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... With respect to fOSC SHDN, SYNC SHDN, SYNC SHDN, SYNC, SEQ = 0V or 3.3V RESET, ISINK = 4mA RESET = 3.5V SEQ = TIME/ON5 = 0V, SEQ = TIME/ON5, RUN/ON3 = 0V, SEQ = DL3, DH3, DL5, DH5, forced to 2V High or low 652 MITCHELL ROAD SC1402 = -40 to +85°C A MIN TYP MAX UNITS 3 1.5 µ ...
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... December 15, 2000 BLOCK DIAGRAM VL © 2000 SEMTECH CORP. Multi-Output, Low-Noise Power Supply Controller for Notebook Computers 652 MITCHELL ROAD SC1402 5 NEWBURY PARK CA 91320 ...
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... December 15, 2000 FUNCTIONAL BLOCK DIAGRAM PWM CONTROLLER DIAGRAM (Fig. 1) © 2000 SEMTECH CORP. Multi-Output, Low-Noise Power Supply Controller for Notebook Computers PIN CONFIGURATION 652 MITCHELL ROAD SC1402 Top View SSOP-28 6 NEWBURY PARK CA 91320 ...
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... ON/OFF Control Input of 3.3V SMPS. Note: All logic level inputs and outputs are open collector TTL compatible. © 2000 SEMTECH CORP. Multi-Output, Low-Noise Power Supply Controller for Notebook Computers 652 MITCHELL ROAD SC1402 . Bypass 12 OUT to GND with 1µ NEWBURY PARK CA 91320 ...
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... PSAVE, will not cause as large a negative dip in the output voltage. Gate Drive/Control The gate driver on the SC1402 are designed to switch large MOSFETs up to 350kHz. The high side gate driver is required to drive the gates of the high side MOSFET above the V+ input ...
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... SHDN or RUN/ON3 is toggled or the V+ input is brought below 1V. Shutdown and Operating Modes Holding the SHDN pin low disables the SC1402, reduc- ing the V+ input current to <10uA. When SHDN goes high, the part enters a standby mode where the VL regulator and VREF are enabled. Turning on either SMPS will put the SC1402 in run mode ...
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... If the VDD input is above 19V, an over-voltage is de- tected and a 10mA current shunt load is applied to VDD. The over-voltage threshold has 0.5V of hystere- sis. Power up Controls and Soft Start The user has control of the SC1402 startup sequence by setting the SEQ, RUN/ON3 and TIME/ON5 pins as described in the following table. SEQ RUN/ON3 ...
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... December 15, 2000 APPLICATION INFORMATION Introduction The SC1402 is a versatile dual switching regulator ad- justable from 2.5V to 5.5V with fixed 5V and 3.3V modes. In addition, there are two on-chip 12V & 5V lin- ear regulators capable of supplying 120mA & 50mA of output current, respectively. The SC1402 is designed for notebook applications but has applications any- where high efficiency, small size and low cost are re- quired ...
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... Now that the basic output filter has been designed time to check if the output filter will allow stable opera- tion. Since the control loop is internal to the SC1402, the output filter capacitor and its associated equivilant series resistance (ESR), will effect stability impor- tant to choose a capacitor with its ESR for stable SMPS operation ...
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... Conduction Losses Upper FET 3.3 P 0.011 CU 12 Conduction Losses Lower FET æ ç è P 0.011 1 CL 652 MITCHELL ROAD SC1402 2 1.98A 0 C ambient temperature 50°C 1. 0.027W 2 I ö 3 0.072W 12 13 NEWBURY PARK CA 91320 ...
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... FET will turn on prior to the lower FET turning on. Where Ig is the gate driver current. This is equal to 1A for the SC1402. Crss is the reverse transfer capacitance of the FET; in this case it equals 240pF for the IRF7413. ...
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... GND and power GND then tie the two together at one point. Be sure that high current paths have low inductance by making track widths wide where possible. We recommend the following layout for the SC1042 shown below. This layout has been optimized for having tight loop areas and bypassing the SC1402 properly. © 2000 SEMTECH CORP. ...
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... D7 R10 C18 C19 C20 10.7K 140T3 GND 1 C29 R12 REF 10.7K 100pF JU7 VL REF 1 R18 100K SYNC 1 JP6 2 1 GND 1 RESET 1 Title SC1402 Eval Board Size Document Number B RTP00005 Thursday, April 13, 2000 Date: Sheet 1 NEWBURY PARK CA 91320 Rev ...
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... MITCHELL ROAD SC1402 3.3V LINE REGULATION 7.5 0 2.5 5 7.5 20 22.5 25 Vin i INPUT VOLTAGE (V) ILOAD = 0.5A ILOAD = A ILOAD = 3A 3.3V LOAD REGULATION 0 0.3 0.6 0.9 .2 .5 .8 2. Iout Iout i j ...
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... December 15, 2000 OUTLINE DRAWING - SSOP-28 ECN00-004 © 2000 SEMTECH CORP. Multi-Output, Low-Noise Power Supply Controller for Notebook Computers 652 MITCHELL ROAD SC1402 Ref. MO-150AH 18 NEWBURY PARK CA 91320 ...