Electronic Components Datasheet Search
 ALLDATASHEET.COM Part #DescriptionMarking X
 Preview PDF Download HTML Chat AI

## LT1074CT Datasheet(PDF) 11 Page - Linear Technology

 Part # LT1074CT Description Step-Down Switching Regulator Download 16 Pages Scroll/Zoom 100% Manufacturer LINER [Linear Technology] Direct Link http://www.linear.com Logo

## LT1074CT Datasheet(HTML) 11 Page - Linear Technology

 11 / 16 pageLT1074/LT107611Figure 8. ILIM Pin CircuitFigure 9. Foldback Current LimitDESCRIPTIO SPIILIM PINThe ILIM pin is used to reduce current limit below thepreset value of 6.5A. The equivalent circuit for this pin isshown in Figure 8.Q1R18KTO LIMITCIRCUITVIN320 AµD1D36VILIM4.3VD2LT1047•PD12When ILIM is left open, the voltage at Q1 base clamps at 5Vthrough D2. Internal current limit is determined by thecurrent through Q1. If an external resistor is connectedbetween ILIM and ground, the voltage at Q1 base can bereduced for lower current limit. The resistor will have avoltage across it equal to (320µA)(R), limited to ≈5V whenclamped by D2. Resistance required for a given currentlimit is:RLIM = ILIM(2kΩ) + 1kΩ (LT1074)RLIM = ILIM(5.5kΩ) + 1kΩ (LT1076)As an example, a 3A current limit would require3A(2k) + 1k = 7kΩ for the LT1074. The accuracy of theseformulas is±25% for 2A ≤ ILIM ≤ 5A (LT1074) and7A≤ ILIM ≤ 1.8A (LT1076), so ILIM should be set at least25% above thepeak switch current required.Foldback current limiting can be easily implemented byadding a resistor from the output to the ILIM pin as shownin Figure 9. This allows full desired current limit (with orwithout RLIM) when the output is regulating, but reducescurrent limit under short-circuit conditions. A typical valuefor RFB is 5kΩ, but this may be adjusted up or down to setthe amount of foldback. D2 prevents the output voltagefrom forcing current back into the ILIM pin. To calculate avalue for RFB, first calculate RLIM, the RFB:RIRRkIRin kFBSCLLSCL=−()( )−Ω()−Ω()044051.*.**Change 0.44 to 0.16, and 0.5 to 0.18 for LT1076.Example: ILIM = 4A, ISC = 1.5A, RLIM = (4)(2k) + 1k = 9kRkkkkFB =−() Ω()−()−Ω()15 044 905 911538.....Error AmplifierThe error amplifier in Figure 10 is a single stage designwith added inverters to allow the output to swing aboveand below the common mode input voltage. One side ofthe amplifier is tied to a trimmed internal reference voltageof 2.21V. The other input is brought out as the FB (feed-back) pin. This amplifier has a GM (voltage “in” to current“out”) transfer function of≈5000µmho. Voltage gain isdetermined by multiplying GM times the total equivalentoutput loading, consisting of the output resistance of Q4and Q6 in parallel with the series RC external frequencycompensation network. At DC, the external RC is ignored,and with a parallel output impedance for Q4 and Q6 of400kΩ, voltage gain is ≈2000. At frequencies above a fewhertz, voltage gain is determined by the external compen-sation, RC and CC.VOUTILIMFBRLIMRFBD21N4148LT1074•PD13LT1074

## Similar Part No. - LT1074CT

 Manufacturer Part # Datasheet Description Linear Technology LT1074 190Kb / 16P Step-Down Switching Regulator LT1074 190Kb / 16P Step-Down Switching Regulator LT1074I 190Kb / 16P Step-Down Switching Regulator LT1074 190Kb / 16P Step-Down Switching Regulator
More results

## Similar Description - LT1074CT

 Manufacturer Part # Datasheet Description Linear Technology LT1176 178Kb / 4P Step-Down Switching Regulator Sanyo Semicon Device LV58761MX 641Kb / 7P Step-down Switching Regulator LV5807MX 206Kb / 5P Step-down Switching Regulator Linear Technology LT1074 190Kb / 16P Step-Down Switching Regulator ON Semiconductor LV5980MD 718Kb / 20P Step-down Switching Regulator October, 2013 LV5762QA 290Kb / 6P Step-down Switching Regulator May, 2014 NCV8925 172Kb / 14P Step-down Switching Regulator April, 2008 - Rev. 0 Sanyo Semicon Device LV5809MX 120Kb / 5P Step-down Switching Regulator LV5725JA 269Kb / 8P Step-down Switching Regulator LV5803M-TE-L-E 119Kb / 6P Step-down Switching Regulator LV5858M 250Kb / 9P Step-down Switching Regulator
More results

## Link URL

 Privacy Policy ALLDATASHEET.COM
 Does ALLDATASHEET help your business so far?  [ DONATE ] About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List All Rights Reserved©Alldatasheet.com Mirror Sites English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz Family Site : ic2ic.com  |   icmetro.com