lt1931a Linear Technology Corporation, lt1931a Datasheet
lt1931a
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lt1931a Summary of contents
Page 1
... These high speeds enable the use of tiny, low cost capacitors and inductors 2mm or less in height. The LT1931 is capable of generating – 350mA or –12V at 150mA from a 5V supply, while the LT1931A can generate –5V at 300mA using significantly smaller induc- tors. Both parts are easy pin-for-pin upgrades for higher power LT1611 applications ...
Page 2
... SHDN Pin Bias Current V V Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT1931E/LT1931AE are guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the – 40°C to 85° PACKAGE/ORDER I FOR ATIO ...
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... Input Supply Pin. Must be locally bypassed – 6 LT1931/LT1931A Shutdown Pin Current 25° LT1931A –10 100 SHDN PIN VOLTAGE (V) 1931 G02 Oscillator Frequency 2.5 2.3 LT1931A 2.1 1.9 1.7 1.5 1.3 1.1 0.9 0.7 0.5 –50 – 1.2 TEMPERATURE (°C) 1931 G05 | V | – 255 OUT = 255 . + – ...
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... SR latch is reset regardless of the state of comparator A2. This current limit protects the power switch as well as various external components connected to the LT1931. ) and m The Block Diagram for the LT1931A is identical except that the oscillator is 2.2MHz and resistors are one-half the LT1931 values. 1 COMPARATOR – ...
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... INDUCTOR SELECTION Several inductors that work well with the LT1931 are listed in Table 1 and those for the LT1931A are listed in Table 2. Besides these, there are many other inductors that can be used. Consult each manufacturer for detailed information and for their entire selection of related parts ...
Page 6
... LT1931/LT1931A U U APPLICATIO S I FOR ATIO The inductors shown in Table 2 for use with the LT1931A were chosen for their small size. For better efficiency, use similar valued inductors with a larger volume. For in- stance, the Sumida CR43 series, in values ranging from 3.3µH to 10µH, will give a LT1931A application a few percentage points increase in efficiency ...
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... Figure 5. Transient Response of Inverting Converter with 22µF Tantalum Output Capacitor and No Phase Lead Capacitor START-UP/SOFT-START For most LT1931/LT1931A applications, the start-up in- rush current can be high. This is an inherent feature of switching regulators in general since the feedback loop is saturated due to V being far from its final value ...
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... U DIODE SELECTION A Schottky diode is recommended for use with the LT1931/ LT1931A. The Motorola MBR0520 is a very good choice. Where the input to output voltage differential exceeds 20V, use the MBR0530 (a 30V diode). These diodes are rated to handle an average forward current of 0 applications ...
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... SHDN R1 220pF LT1931 29.4k C1 4.7µF NFB GND R2 10k L2 4.7µ OUT –5V 300mA C4 180pF C3 4.7µF 1931 TA05a LT1931/LT1931A Efficiency 100 100 125 150 50 LOAD CURRENT (mA) 1931 TA03 L2 10µ OUT –5V 300mA C3 22µ ...
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... Converter Uses Tiny Chip Inductors L1 3.3µ SHDN R1 LT1931A 28.7k C1 2.2µF NFB GND C1: TAIYO YUDEN X5R JMK212BJ225MG C2: TAIYO YUDEN X5R LMK212BJ105MG C3: TAIYO YUDEN X5R JMK212BJ475MG D1: ON SEMICONDUCTOR MBR0520 L1, L2: PANASONIC ELJPC3R3MF SLIC Power Supply with – 33V and – 68V Outputs, Uses Soft-Start ...
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... C4 1µF 35V U S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 0.95 REF 1.22 REF 1.50 – 1.75 2.80 BSC 1.4 MIN (NOTE 4) PIN ONE 0.95 BSC 0.80 – 0.90 1.00 MAX 0.09 – 0.20 (NOTE 3) LT1931/LT1931A COM C5 4.7µF 1 25V V OUT1 –21.6V 48mA 4.7µF 25V 4.7µ ...
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... McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● ● C2 L1A 0.1µF 4.7µ SHDN R1 LT1931A 28.7k C1 2.2µF NFB GND R2 10k C1: TAIYO YUDEN Y5V EMK212F225ZG C2: 0.1µF 25V X5R C3: TAIYO YUDEN X5R JMK212BJ475MG D1: ON SEMICONDUCTOR MBR0520 L1: SUMIDA CLQ4D10-4R7 DRAWING #5382-T039 Efficiency ...