LT1307B Linear Technology Corporation, LT1307B Datasheet
LT1307B
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LT1307B Summary of contents
Page 1
... LT1307 features automatic shifting to power saving Burst Mode operation at light loads. High efficiency is main- tained over a broad 100 A to 100mA load range. The LT1307B does not shift into Burst Mode operation at light loads, eliminating low frequency output ripple at the expense of light load efficiency. The devices contain a low- battery detector with a 200mV reference and shut down to less than 5 A ...
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... LT1307CMS8 LT1307BCMS8 FB 2 SHDN 3 GND 4 N8 PACKAGE 8-LEAD PDIP T = 125 C, JMAX T = 125 C, JMAX LTIC LTIB = V , LT1307/LT1307B unless otherwise noted. SHDN IN CONDITIONS Not Switching (LT1307) Not Switching (LT1307B SHDN REF ( ( ...
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... Error Amp Transconductance m A Error Amp Voltage Gain V f Switching Frequency OSC Maximum Duty Cycle Switch V CESAT Shutdown Pin Current LBI Threshold Voltage = V , LT1307/LT1307B unless otherwise noted. SHDN IN CONDITIONS 40 75 500mA ( 500mA ( ...
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... SW Note 4: Switch current limit guaranteed by design and/or correlation to static tests. Duty cycle affects current limit due to ramp generator. Note 5: Bias current flows out of LBI pin. Note 6: The LT1307/LT1307B will withstand continuous application of 1.6V applied to the GND pin while MIN ...
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... TEMPERATURE ( C) 1307 G04 Quiescent Current in Shutdown INPUT VOLTAGE (V) 1307 G07 3.3V Output Efficiency, Circuit of Figure 1 (LT1307B 1.25V 1. 0 LOAD CURRENT (mA) Feedback Bias Current vs Temperature ...
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... OUT 6 LBI Reference vs Temperature 210 208 206 204 202 200 198 196 194 192 190 100 –50 – TEMPERATURE ( C) Transient Response (LT1307B) V OUT 200mV/DIV AC COUPLED I L 200mA/DIV 55mA I LOAD 5mA V = 1.25V 500 s/DIV 1307 G13 3.3V OUT Load Regulation (LT1307) ...
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... – ERROR + AMPLIFIER – BIAS R3 A1 30k R4 140k COMPARATOR – RAMP GENERATOR + + + A2 600kHz OSCILLATOR *HYSTERESIS IN LT1307 ONLY Figure 2. LT1307/LT1307B Block Diagram LT1307/LT1307B SHDN 3 SHUTDOWN LBI + 7 LBO 8 ENABLE – A4 200mV SW 5 DRIVER 0.15 – 4 GND 1307 F02 ...
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... The entire device is disabled when the SHDN pin is brought low. To enable the converter, SHDN must The LT1307B differs from the LT1307 in that there is no hysteresis in comparator A1. Also, the bias point set lower than on the LT1307 so that switching can occur at inductor current less than 100mA ...
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... Low Noise Performance of C OUT LT1307B Can Be Realized at Light Loads of 5mA to 10mA At light loads, the LT1307B will begin to skip alternate cycles. The load point at which this occurs can be de- creased by increasing the inductor value. However, output ripple will continue to be significantly less than the LT1307 output ripple ...
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... FREQUENCY (kHz) Figure 9. LT1307B at 5mA Load Shows No Audio Components or Sidebands About Switching Frequency, 333kHz Fundamental Amplitude is –10dBmV, or 316 eliminate the low frequency noise of Figure 6, the LT1307 can be replaced with the LT1307B. Figure 9 details the spectral noise at the output of Figure 1’ ...
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... Observant readers will notice R has been set to 100k for all the photos in Figure 11. Usable R values can be found in the 10k to 500k range, but after too many trips to the resistor bins, 100k wins. LT1307/LT1307B OUT 5ms/DIV OUT 500 s/DIV 1307 F11b ...
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... LT1307/LT1307B U U APPLICATIO S I FOR ATIO LAYOUT HINTS The LT1307 switches current at high speed, mandating careful attention to layout for proper performance. You will not get advertised performance with careless layouts. Figure 12 shows recommended component placement. Follow this closely in your PC layout. Note the direct path of the switching loops. Input capacitor C close (< ...
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... LBI pin doesn’t cause large errors. For R2, 100k is adequate. The 200mV refer- ence can also be accessed as shown in Figure 15 100k Figure 14. Setting Low-Battery Detector Trip Point > al- IN LT1307/LT1307B SHUTDOWN 400k CURRENT SHDN 200k START-UP ...
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... LT1307/LT1307B U U APPLICATIO S I FOR ATIO REVERSE BATTERY CONSIDERATIONS The LT1307 is built on a junction-isolated bipolar process. The p-type substrate is connected to the GND pin of the LT1307. Substrate diodes, normally reverse-biased, are present on the SW pin and the V pin as shown in Figure IN 16. When the battery polarity is reversed, these diodes conduct, as illustrated in Figure 17 ...
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... allowing M1’s gate voltage drops below 3V. R1 adds hysteresis, resulting in low-frequency Burst Mode operation ripple voltage at the output. By pulling the V current of the LT1307B drops resulting in accept- able efficiency at loads in the 100 A range. V OUT 100mV/DIV ...
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... LT1307/LT1307B U TYPICAL APPLICATIO 1.4V TO 3.3V + C1, C2: PANASONIC ECA0JFQ221 L1: SUMIDA CD43-100 V IN 2.1V TO 4.8V L1: COILTRONICS CTX10 MURATA ERIE LQH3C100 EFFICIENCY 70% TO 73% Constant Current NiCd Battery Charger with Overvoltage Protection CELL AA OR AAA 47k L1: COILTRONICS CTX10-1 16 Low Cost 2-Cell to 5V ...
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... FOR FLYBACK FOR OUT FOR 2V IN HIGHER VOLTAGES ACHIEVED WITH CAPACITIVE DOUBLER OR TRIPLER R2 240k 0 SNUBBER REQUIRED WITH SPECIFIED TRANSFORMER AND V 1% 1307 TA06 LT1307/LT1307B CERAMIC 40mA R1 5.1 1307 TA05 12V/30mA FROM 3V 12V/60mA FROM 5V ~250mV RIPPLE P-P 10pF 0.33 F CERAMIC ...
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... 1.5V 100 1.5V 0 CERAMIC LT1307B 10k 1 SHDN FB CELL GND V C 0 OPERATE C1: WIMA MKP- SHUTDOWN D1: MOTOROLA MBR0520L L1: SUMIDA CD54-330 T1: COILTRONICS CTX110611 Q1, Q2: ZETEX FZT-849 U MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1660) ...
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... TYP 0.016 – 0.050 0.014 – 0.019 (0.406 – 1.270) (0.355 – 0.483) TYP LT1307/LT1307B 0.400* MAX 0.130 0.005 (3.302 0.127) 0.125 0.020 (3.175) MIN (0 ...
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... LT1307/LT1307B U TYPICAL APPLICATIO CELLS L1: 3 CELL) 4 CELLS CELLS) SUMIDA CD43 MURATA-ERIE LQH3C COILCRAFT D01608 C1 FOR +OUTPUT 0.01 F FOR – OUTPUT D1 TO D3: MBR0530 OR 1N4148 RELATED PARTS PART NUMBER DESCRIPTION ® LTC 1163 Triple High Side Driver for 2-Cell Inputs ...