ltc1142 Linear Technology Corporation, ltc1142 Datasheet
ltc1142
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ltc1142 Summary of contents
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... R MOSFET and resistance of the inductor and current sense resistor. The LTC1142 series is ideal for applications requiring dual output voltages with high conversion efficiencies over a wide load current range in a small amount of board space. , LTC and LT are registered trademarks of Linear Technology Corporation. ...
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... LTC1142/LTC1142L/LTC1142HV ABSOLUTE AXI U RATI GS Input Supply Voltage (Pins 10, 24) LTC1142, LTC1142L-ADJ ..................... 16V to – 0.3V LTC1142HV, LTC1142HV-ADJ ............. 20V to – 0.3V Continuous Output Current (Pins 6, 9, 20, 23) .... 50mA Sense Voltages (Pins 1, 14, 15, 28) V > 13V .............................................. 13V to – 0. < 13V .................................. ( PACKAGE/ORDER I FOR ATIO TOP VIEW – ...
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... SHDN 10 24 LTC1142HV-ADJ, LTC1142HV 4V < < 18V < V < 18V, 6V < V < 18V 2.1V, 4V < < 12V SHDN 10 24 LTC1142L-ADJ (Note 6) 3.5V < < 12V 10 24 3.5V < < 12V 2.1V, 3.5V < < 12V SD1 SD2 10 24 LTC1142HV-ADJ, LTC1142L-ADJ V ...
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... and are designed, characterized and expected to meet these extended temperature limits, but are not tested at – and 85 C. Guaranteed I-grade parts are available, consult the factory. Note 6: The LTC1142L-ADJ allows operation down to V 3.3V Output Efficiency 100 V ...
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... SHDN3 (Pin 2): When grounded, the 3.3V section oper- ates normally. Pulling Pin 2 high holds both MOSFETs off and puts the 3.3V section in micropower shutdown mode. Requires CMOS logic-level signal with t “float” Pin 2. LTC1142/LTC1142L/LTC1142HV Supply Current in Shutdown 20 PER REGULATOR BLOCK 18 PINS 10, 24 ...
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... SENSE 3 (Pin 28): Connects to internal resistive divider which sets the output voltage for the 3.3V section. Pin 28 is also the (–) input for the current comparator on the 3.3V section. LTC1142HV-ADJ/LTC1142L-ADJ + SENSE 1 (Pin 1): The (+) Input to the Section 1 Current Comparator. A built-in offset between Pins 1 and 28 in conjunction with R for this section ...
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... Requires CMOS logic signal with Pin 17. LTC1142/LTC1142L/LTC1142HV SGND2 (Pin 18): The section 2 small-signal ground must be routed separately from other grounds to the (–) termi- nal of the section 2 output capacitor. PGND2 (Pin 19): The section 2 driver power ground connects to source of the N-channel MOSFET and the (– ...
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... LTC1142/LTC1142L/LTC1142HV CTIO AL DIAGRA Only one regulator block shown. Pin numbers are for 3.3V (5V) sections for LTC1142/LTC1142HV, and for LTC1142L-ADJ/LTC1142HV-ADJ. OUT1 OUT2 PIN NUMBERS FOR 2(16) LTC1142, LTC1142HV LTC1142-ADJ PIN NUMBERS 3(17) FOR LTC1142L-ADJ LTC1142HV-ADJ SLEEP + S – TH1 TH2 25(11 OPERATIO Refer to Functional Diagram ...
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... MOSFETs and D1 are selected. Finally are selected and the loop is compensated. Since the OUT 3.3V and 5V sections in the LTC1142 are identical and similarly section 1 and section 2 in the LTC1142HV-ADJ/ LTC1142L-ADJ are identical, the process of component selection is the same for both sections. The circuit shown in Figure 1 can be configured for operation input voltage of 20V ...
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... MAXIMUM OUTPUT CURRENT (A) Figure 2. Selecting R L and C Selection for Operating Frequency T Each regulator section of the LTC1142 uses a constant off- time architecture with t determined by an external OFF timing capacitor C . Each time the P-channel MOSFET T switch turns on, the voltage reset to approximately T 3 ...
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... APPLICATIO S I FOR ATIO eased at the expense of efficiency. If too small an inductor is used, the inductor current will decrease past zero and change polarity. A consequence of this is that the LTC1142 may not enter Burst Mode operation and efficiency will be severely degraded at low currents. Inductor Core Selection Once the minimum value for L is known, the type of inductor must be selected ...
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... Figure 4). When C output ripple at low frequencies will be large enough to trip the voltage comparator. This causes Burst Mode opera- tion to be activated when the LTC1142 would normally be in continuous operation. The output remains in regulation at all times. must be less ...
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... U shifts by an section) less the gate charge current. For V OUT LTC1142 DC supply current for each section is 160 A with no load, and increases proportionally with load up also begins to charge to a constant 1.6mA after the LTC1142 has entered continuous mode. Because the DC bias current is ...
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... C and L can SENSE T component values shown in Figure 14. LTC1142HV-ADJ/LTC1142L-ADJ Adjustable Applications When an output voltage other than 3. required, the LTC1142 adjustable version is used with an external resistive divider from V lated output voltage is determined by: V OUT = 0.007(63 – 25) = 0.27. The required ...
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... Check the following in your layout: returned OUT 1. Are the signal and power grounds segregated? The LTC1142 signal ground [Pin 3 (17) for the LTC1142, Pin 4 (18) for LTC1142-ADJ] must return to the (–) plate of R SENSE C . The power ground returns to the source of the ...
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... AC current to the P-channel MOSFET the input decoupling capacitor (1 F/0.22 F) con- nected closely between Pin 24 (10) and power ground [Pin 4 (18) for the LTC1142, Pin 5 (19) for the LTC1142- ADJ]? This capacitor carries the MOSFET driver peak currents. ...
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... R1 52.3k 100pF DALE WSL-2010-.05 SENSE1, SENSE2 L1: SUMIDA CDRH125-270 L2: SUMIDA CDRH125-330 Figure 11. LTC1142HV-ADJ Dual Regulator with 3.6V/2A and 5V/2A Outputs LTC1142/LTC1142L/LTC1142HV W U With the addition current is generated through R1 causing an offset of: V OFFSET If V OFFSET Burst Mode operation is prevented from occurring. Since > 5A) ...
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... OUT1 2.5V/1.5A 1000pF + C OUT1 220 F 10V D1 N- MBRS130T3 Si9410DY 49. 49.9k 100pF IRC L1206-01-R075-J SENSE1 R : IRC L1206-01-R050-J SENSE2 Figure 12. LTC1142HV-ADJ High Efficiency Regulator with 3.3V/2A and 2.5V/1.5A Outputs C + IN3 22 F 0.22 F 25V 2 P-CH Si9433DY L1 R SENSE3 0.033 OUT3 3.3V/3A 1000pF D1 MBRS130T3 N- OUT3 Si9410DY 100 F ...
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... SENSE2 L1: COILTRONICS CTX50-4 L2: COILTRONICS CTX25-4 Figure 15. LTC1142HV-ADJ High Efficiency Power Supply Providing 3.3V/2A with Built-In Battery Charger Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...
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... LTC1142/LTC1142L/LTC1142HV U TYPICAL APPLICATIO S Figure 16. LTC1142HV-ADJ Output Current vs Trickle Charge Set Resistance (R ) for the Circuit in Figure 15 Using a 0.1 Current Sense Resistor R X PACKAGE DESCRIPTIO 5.20 – 5.38** (0.205 – 0.212) 0 – 8 0.13 – 0.22 0.55 – 0.95 (0.005 – 0.009) (0.022 – 0.037) NOTE: DIMENSIONS ARE IN MILLIMETERS * DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.152mm (0.006" ...