LTC1261 Linear Technology, LTC1261 Datasheet
LTC1261
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LTC1261 Summary of contents
Page 1
... Output ripple is typically as low as 5mV. Quiescent current is typically 600 A when operating and shutdown. The LTC1261 is available in a 14-pin narrow body SO package and an 8-pin SO package. , LTC and LT are registered trademarks of Linear Technology Corporation. ...
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... S8 PART MARKING S8 PACKAGE 8-LEAD PLASTIC SO 1261 *FOR FIXED VERSIONS 12614 = 150 C, = 150 C/W JA 126145 ORDER PART TOP VIEW NUMBER SHDN LTC1261CS 3 12 REG 4 11 OUT 5 10 ADJ ADJ PACKAGE 14-LEAD PLASTIC SO = 150 C, = 110 C unless otherwise specified. ...
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... With supplies higher than 5V, the output should never be set to exceed V Note 6: For output voltages below – 4.5V the LTC1261 may reach 50% duty cycle and fall out of regulation with heavy load or low input voltages. Beyond this point, the output will follow the input with no regulation. ...
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... TEMPERATURE (˚C) Tripler Mode ADJ 3 9 – ADJ LTC1261CS – –4V 5% OUT OUT GND 3 LTC1261 • TC02 7 LTC1261 • TPC03 = 3.3V 80 100 LTC1261 • TPC06 ...
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... The voltage at REG may exceed V pulled up to 12V above ground without damage. SHDN (Pin 13/Pin 8): Shutdown. When this pin is at ground the LTC1261 operates normally. An internal 5 A pull-down keeps SHDN low left floating. When SHDN is pulled high, the LTC1261 enters shutdown mode ...
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... LTC1261CS8 DOUBLER MODE THEORY OF OPERATION A block diagram of the LTC1261 is shown in Figure 2. The heart of the LTC1261 is the charge pump core shown in the dashed box. It generates a negative output voltage by first charging the flying capacitors between V ground. It then stacks the flying capacitors on top of each ...
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... REG output will stay low. LTC1261 OUT + C OUT 124k R * ADJ 226k R1* INTERNALLY 100k CONNECTED FOR R0* FIXED OUTPUT VOLTAGE PARTS 50k ADJ/COMP REG *LTC1261CS14 ONLY LTC1261 • F02 and 8mA with the drain can be pulled above V CC without 7 ...
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... U U APPLICATIONS INFORMATION OUTPUT RIPPLE Output ripple in the LTC1261 comes from two sources; voltage droop at the output capacitor between clocks and frequency response of the regulation loop. Voltage droop is easy to calculate. With a typical clock frequency of 550kHz, the charge on the output capacitor is refreshed once every 1 ...
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... Figure 4. Output Filter Cuts Ripple Below 3mV CAPACITOR SELECTION Capacitor Sizing The performance of the LTC1261 can be affected by the capacitors it is connected to. The LTC1261 requires by- pass capacitors to ground for both the V The input capacitor provides most of LTC1261’s supply current while it is charging the flying capacitors. This ...
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... As soon as the RC time constant approaches half of a clock period (the time the capacitors have to share charge at full duty cycle) the output current capability of the LTC1261 will begin to diminish. For 0.1 F flying capacitors, this gives a maximum total series resis- tance of: ...
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... ADJ and shorting out some of the internal resistors. If one of these combinations gives you the output voltage you want, by all means use it! The internal resistor values are the same for the fixed output versions of the LTC1261 as they are for the adjust- U TYPICAL APPLICATIONS V BAT 3 ...
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... OUT 4 5 3.3 F GND ADJ + P-CHANNEL POWER SWITCH 10k SHDN REG LTC1261-4 100 – C2 OUT GND COMP + 100pF GaAs TRANSMITTER LTC1261 • TA04 GaAs TRANSMITTER LTC1261 • TA05 – 4V BIAS GaAs 10 F TRANSMITTER + LTC1261 • TA06 ...
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... LTC1261 GaAs TRANSMITTER LTC1261 • TA07 – 5V Supply Generator 100pF + C1 ADJ 3 9 – ADJ LTC1261 – –5V 5% OUT AT 10mA GND 3 LTC1261 • TA09 V = –4V OUT at 10mA 3 LTC1261 • TA12 13 ...
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... LTC1261 U TYPICAL APPLICATIONS This circuit uses the LTC1261CS8 to generate a – 1.24V output at 20mA. Attached to this output is a 312 resistor to make the current/voltage conversion. 4mA through 312 generates 1.24V, giving a net 0V output. 20mA through 312 gives 6.24V across the resistor, giving a net 5V output ...
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... TYP 0.014 – 0.019 (0.355 – 0.483) LTC1261 0.150 – 0.157** (3.810 – 3.988 0.004 – 0.010 (0.101 – 0.254) 0.050 (1.270) TYP ...
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... COMMENTS GaAs FET Bias with Linear Regulator 1mV Ripple GaAs FET Bias 0.4V Dropout Voltage at 150mA, Low Noise, Switched Capacitor Regulated Voltage Inverter –0.5V BIAS 5.5% GaAs TRANSMITTER 3.3 F LTC1261 • TA08 1261fa LT/TP 0198 REV A 4K • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 1994 ...