电源片子ltc1844-byp中文资料

1、元器件交易网 Final Electrical SpecificationsLTC1844 Series150mA, Micropower, Low Noise, VLDO Linear RegulatorMay 2003DESCRIPTIOThe LTC1844 Series are low noise VLDOTM (very low dropout) linear regulators designed for low power/portable applications. These regulators can operate from input vo

2、ltages as low as 1.6V. Typical output noise is only 30mVRMS andtypicaldropoutforthe LTC1844-3.3isjust 90mV at the maximum load current of 150mA, reducing to 30mV at 50mA.The internal P-channel MOSFET pass transistor requires no base current, allowing the device to draw only 35mA during normal operat

3、ion, independent of the dropout voltage and load current. The quiescent current falls to a negligible 10nA during shutdown.Other features include high output voltage accuracy, excellent transient response, stablity with ultralow ESR ceramic capacitors as small as 1mF, reverse-battery and reverse-cur

4、rent protection, short-circuit and thermal overload protection and output current limiting.The LTC1844 regulators are available in a low profile (1mm) SOT-23 (ThinSOTTM) package.FEATURESVery Low Dropout:90mV at 150mA30mV at 50mA (LTC1844-3.3)Wide Input Voltage Range: 1.6V to 6.5V Low 35mASupply Curr

5、ent, Even in Dropout Low Noise: 30mVRMS (10Hz to 100kHz)1.75% Voltage Accuracy Over Temperature,Voltage and Current RangesFast Transient Response10nA Supply Current in ShutdownFixed Output Voltages: 1.5V, 1.8V, 2.5V, 2.8V, 3.3V Adjustable Output Voltage: 1.25V to 6V Output Current LimitReverse-Batte

6、ry and Reverse-Current Protection No Protection Diodes NeededStable with 1mF Output CapacitorStable with Ceramic CapacitorsShort-Circuit and Thermal Overload Protection Low Profile (1mm) SOT-23 PackageAPPLICATIO S, LTC and LT are registered trademarks of Linear Technology Corporation. VLDO and ThinS

7、OT are trademarks of Linear Technology Corporation.Bluetooth/802.11 CardsPDAs and Notebook ComputersPortable Instruments and Battery-Powered Systems Cellular PhonesTYPICAL APPLICATIOFixed Voltage Low Noise, VLDO Linear RegulatorLTC1844-3.3 Dropout Voltage vs Load Current1201008015VVINOUTINOUT3.3V TO

8、 6.5V3.3V1mF1mF60LTC1844-3.334OFF ONSHDNBYP40GND0.1mF2201844 TA0105075100125 150IOUT (mA)1844 TA020251844ia1Information 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 repres

9、en- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.DROPOUT VOLTAGE (mV)元器件交易网 LTC1844 SeriesABSOLUTEAXIURATI GS (Note 1)Supply Voltage (IN)Vto 7VInput VoltageSHDN,BYP, ADJV to7VOutput VoltageOUTV to 7VOUT to INV to 7VOutp

10、ut Short-Circut DurationIndefiniteOperating Junction Temperature Range(Notes 2, 10)40C to 125CStorage Temperature Range65C to 150CLead Temperature (Soldering, 10 sec)300CPACKAGE/ORDER I FORATIOConsultLTC Marketingforpartsspecifiedwithwideroperatingtemperatureranges.ELECTRICAL CHARACTERISTICS The den

11、otes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VIN = VOUT + 0.5V, unless otherwise noted. (Note 2)1844ia2SYMBOLPARAMETERCONDITIONSMINTYPMAXUNITSVINInput Voltage1.66.5VIINQuiescent CurrentSHDN = VIN355580mAmAIINSHDNVIN Shutdown Sup

12、ply CurrentSHDN = 0V0.011mAVOUT%Regulated Output Voltage (Notes 3, 4, 5)LTC1844-3.3 VIN = 3.8V to 6.5V, IOUT = 0mA to 150mA LTC1844-3.3 VIN = 3.8V to 6.5V, IOUT = 0mA to 150mA1.501.501.751.75%VOUT%VOUTLTC1844-2.8 VIN = 3.3V to 6.5V, IOUT = 0mA to 150mA LTC1844-2.8 VIN = 3.3V to 6.5V, IOUT = 0mA to 1

13、50mA1.501.501.751.75%VOUT%VOUTLTC1844-2.5 VIN = 3.0V to 6.5V, IOUT = 0mA to 150mA LTC1844-2.5 VIN = 3.0V to 6.5V, IOUT = 0mA to 150mA1.501.501.751.75%VOUT%VOUTLTC1844-1.8 VIN = 2.3V to 6.5V, IOUT = 0mA to 150mA LTC1844-1.8 VIN = 2.3V to 6.5V, IOUT = 0mA to 150mA1.501.501.751.75%VOUT%VOUTTOP VIEWIN 1

14、5 OUTGND 2SHDN 34 BYPS5 PACKAGE5-LEAD PLASTIC TSOT-23TJMAX = 150C, qJA = 250C/ W, qJC = 90C/ W SEE THE APPLICATIONS INFORMATION SECTIONTOP VIEWIN 15 OUTGND 2SHDN 34 ADJS5 PACKAGE5-LEAD PLASTIC TSOT-23TJMAX = 150C, qJA = 250C/ W, qJC = 90C/ W SEE THE APPLICATIONS INFORMATION SECTIONTOP VIEWIN 15 OUTG

15、ND 2BYP 34 ADJS5 PACKAGE5-LEAD PLASTIC TSOT-23TJMAX = 150C, qJA = 250C/ W, qJC = 90C/ W SEE THE APPLICATIONS INFORMATION SECTIONORDER PART NUMBERS5 PART MARKINGORDER PART NUMBERS5 PART MARKINGORDER PART NUMBERS5 PART MARKINGLTC1844ES5-1.5 LTC1844ES5-1.8 LTC1844ES5-2.5 LTC1844ES5-2.8 LTC1844ES5-3.3LT

16、F1 LTF2 LTF3 LTQK LTF4LTC1844ES5-SDLTE8LTC1844ES5-BYPLTE9元器件交易网 LTC1844 SeriesELECTRICAL CHARACTERISTICSThe denotes specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25C. VIN = VOUT + 0.5V, unless otherwise noted. (Note 2)1844ia3S

17、YMBOLPARAMETERCONDITIONSMINTYPMAXUNITSLTC1844-1.5 VIN= 2.0V to 6.5V, IOUT= 0mA to 150mA LTC1844-1.5 VIN= 2.2V to 6.5V, IOUT= 0mA to 150mA LTC1844-1.5 VIN=2.0Vto6.5V, IOUT =0mAto150mA1.501.502.002.002.502.00%VOUT%VOUT%VOUTLTC1844-BYP VIN = 1.75V to 6.5V, IOUT = 0mA to 150mA LTC1844-BYP VIN = 2.2V to

18、6.5V, IOUT = 0mA to 150mA LTC1844-BYP VIN = 1.75V to 6.5V, IOUT = 0mA to 150mA1.501.501.751.753.501.75%VOUT%VOUT%VOUTLTC1844-SD VIN = 1.75V to 6.5V, IOUT = 0mA to 150mA LTC1844-SD VIN=2.2Vto6.5V, IOUT =0mAto150mA LTC1844-SD VIN = 1.75V to 6.5V, IOUT = 0mA to 150mA1.501.501.751.753.501.75%VOUT%VOUT%V

19、OUTDVLNRLine Regulation (Notes 3, 5)LTC1844-3.3 VIN = 3.4V to 6.5V, IL = 1mA420mVLTC1844-2.8 VIN = 2.9V to 6.5V, IL = 1mA420mVLTC1844-2.5 VIN = 2.6V to 6.5V, IL = 1mA420mVLTC1844-1.8 VIN = 2.2V to 6.5V, IL = 1mAVIN = 1.9V to 6.5V, IL = 1mA VIN = 1.9V to 6.5V, IL = 1mA420420430mV mV mVLTC1844-1.5 VIN

20、 = 2.2V to 6.5V, IL = 1mAVIN = 1.6V to 6.5V, IL = 1mA VIN = 1.6V to 6.5V, IL = 1mA420420480mV mV mVLTC1844-BYP VIN = 2.2V to 6.5V, IL = 1mAVIN = 1.6V to 6.5V, IL = 1mA VIN = 1.6V to 6.5V, IL = 1mA420420480mV mV mVLTC1844-SDVIN = 2.2V to 6.5V, IL = 1mAVIN = 1.6V to 6.5V, IL = 1mA VIN = 1.6V to 6.5V,

21、IL = 1mA420420480mV mV mVDVLDRLoad Regulation (Notes 3, 5)LTC1844-3.3 VIN = 3.8V, IOUT = 0mA to 150mA920mVLTC1844-2.8 VIN = 3.3V, IOUT = 0mA to 150mA920mVLTC1844-2.5 VIN = 3.0V, IOUT = 0mA to 150mA920mVLTC1844-1.8 VIN = 2.3V, IOUT = 0mA to 150mA920mVLTC1844-1.5 VIN = 2.2V, IOUT = 0mA to 150mAVIN = 2

22、.0V, IOUT = 0mA to 150mA920940mV mVLTC1844-BYP VIN = 2.2V, IOUT = 0mA to 150mAVIN = 1.75V, IOUT = 0mA to 150mA920950mV mVLTC1844-SDVIN = 2.2V, IOUT = 0mA to 150mA VIN = 1.75V, IOUT = 0mA to 150mA920950mV mVDVDODropout Voltage (Notes 6, 7)LTC1844-3.3 IOUT = 50mAIOUT = 150mA305590150mV mVLTC1844-2.8 I

23、OUT = 50mAIOUT = 150mA3560105165mV mVLTC1844-2.5 IOUT = 50mAIOUT = 150mA4575135200mV mVLTC1844-1.8 IOUT = 50mAIOUT = 150mA85120230300mV mVLTC1844-1.5 IOUT = 50mAIOUT = 150mA115160350450mV mVLTC1844-BYP IOUT = 50mAIOUT = 150mA4575135200mV mVLTC1844-SDIOUT = 50mAIOUT = 150mA4575135200mV mV元器件交易网www.ce

24、 LTC1844 SeriesELECTRICAL CHARACTERISTICSThe denotes specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25C. VIN = VOUT + 0.5V, unless otherwise noted. (Note 2)Note 1: Absolute Maximum Ratings are those values beyond which the life of a

25、device may be impaired.Note 2: The LTC1844 is tested and specified under pulse load conditions such that TJ TA. The LTC1844E is guaranteed to meet performance specifications from 0C to 70C. Specifications over the 40C to 125C operating junction temperature range are assured by design, characterizati

26、on and correlation with statistical process controls.Note 3: The LTC1844 adjustable versions are tested and specifed for these conditions with the ADJ pin connected to the OUT pin for a VOUT(NOMINAL) of 1.252V.Note 4: Operating conditions are limited by maximum junction temperature. The regulated ou

27、tput voltage specification will not apply for all possible combinations of input voltage and output current. When operating at maximum input voltage, the output current range must be limited. When operating at maximum output current, the input voltage range must be limited.Note 5: The LTC1844s high

28、precision degrades slightly at high temperatures (TJ 70C) with input voltages below 2.2V. The lower output voltageversionshavebeensplitintohigher andlower accuracyinput voltage ranges to reflect this.Note 6: To ensure adequate input supply voltage, the LTC1844 adjustable versions are tested and spec

29、ified for these conditions with an external resistor divider (two 100k resistors) for an output voltage of 2.504V. The external resistor divider will add a 5mA load on the output.Note 7: Dropout voltage is (VIN VOUT) when VOUT falls to 100mV below its nominalvaluemeasuredat VIN = VOUT + 0.5V. Forexa

30、mple, the LTC1844-3.3 is tested by measuring the VOUT at VIN = 3.8V, then VIN is lowered until VOUT falls 100mV below the measured value. The difference (VIN VOUT) is then measured and defined as DVDO.Note 8: ADJ pin bias current flows into the ADJ pin.Note 9: Output reverseleakage current is tested

31、 with the IN pin grounded and the OUT pin forced to the rated output voltage.Note 10: This IC includes overtemperature protection that is intended to protect thedeviceduring momentaryoverload conditions. Junction temperature will exceed 125C when overtemperature protection is active. Continuous oper

32、ation above the specified maximum operating junction temperature may impair device reliability.1844ia4SYMBOLPARAMETERCONDITIONSMINTYPMAXUNITSILIMOutput Current Limit160350mAenOutput Voltage Noisef = 10Hz to 100kHz, CBP = 0.1mF, COUT = 1mF, IL = 150mA f = 10Hz to 100kHz, CBP = 0.1mF, COUT = 10mF, IL

33、= 150mA3530mVRMSmVRMSVSHDNSHDN Input Threshold0.350.650.9VtDELAYShutdown Exit DelayCBP = 0.01mF, COUT = 1mF, No load CBP = 0.01mF, COUT = 1mF, No load70100200msmsTSHDNThermal Shutdown Limit155CDTSHDNThermal Shutdown Hysteresis10CIADJADJ Pin Bias Current(Notes 3, 8)30100nAIIRLInput Reverse Leakage Cu

34、rrentLTC1844-3.3, LTC1844-2.8, LTC1844-2.5, LTC1844-1.8, LTC1844-1.5, VIN = 5V, VOUT = 0V200500mALTC1844-BYP, LTC1844-SD, VIN = 5V, VOUT = 0V10001500mAIORLOutput Reverse Leakage Current (Note 9)VIN = 0V, VOUT = VOUT(NOMINAL) VIN = 0V, VOUT = VOUT(NOMINAL)0.010.11.2mAmAVOSHStart-Up OvershootRL = 1k,

35、SHDN Rise Time 1ms2%VOUTVRPOutput Ripple Rejection(VIN VOUT) = 1V (Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz, ILOAD = 100mA60dB元器件交易网 LTC1844 SeriesPIFU CTIO SIN (Pin 1): Power for LTC1844 and Load. Power issupplied to the device through the IN pin. The IN pin should be locallybypassed

36、togroundifthe LTC1844ismorethana few inches away from another source of bulk capacitance. In general, the output impedance of a battery rises with frequency, so it is usually adviseable to include an input bypass capacitor in battery-powered circuits. A capacitor in the range of 0.1mF to 1mF is usua

37、lly sufficient. The LTC1844 is designed to withstand reverse voltages on the IN pin with respect to both ground and the output pin. In the case of a reversed input, which can happen if a battery is plugged in backwards, the LTC1844 will act as if there is a large resistor in series with its input wi

38、th only a small amount of current flow.GND (Pin 2): Ground and Heat Sink. Solder to a ground plane or large pad to maximize heat dissipation.SHDN (Pin 3, Fixed and SD Devices): Shutdown, ActiveADJ (Pin 4, Adjustable Devices): Output Adjust. For the adjustable versions of the LTC1844, this is the inp

39、ut to the error amplifier. It has a typical bias current of 30nA flowing into the pin. The ADJ pin reference voltage is 1.25V referenced to ground. The output voltage range is 1.25V to 6V and is typically set by connecting ADJ to a resistor divider from OUT to GND. See Figure 2.BYP (Pin 4, Fixed/Pin

40、 3, BYP Devices): Noise Bypass. The BYPpinisusedtoaugmentthe internalnoisefilterto improve low noise performance. A small low leakage bypasscapacitorfromthispintogroundwillfiltertheinput of the error amplifier to lower the output voltage noise. Any value may be used; larger values will result in low

41、er output noise, but will increase initial power-up time. Shutdown exitdelaytimeafterabriefshutdown(10ms) will not be affected. If not used, this pin must be left unconnected.OUT (Pin 5): Voltage Regulated Output. The OUT pin supplies power to the load. A minimum output capacitor of 1mFis required t

42、o ensure stability. Larger output capacitors may be required for applications with large transient loads to limit peak voltage transients. See the Applications Information section for more information on output capacitance.Low. This pin is used to put the LTC1844 into shutdown. The SHDN pin current

43、is typically less than 10nA. The SHDN pin cannot be left floating and must be tied to the input pin if not used. If reverse-battery protection is desired, the SHDN pin must be tied to the input pin through a large value resistor (10k to 1M).1844ia5元器件交易网 LTC1844 SeriesAPPLICATIO S I FO

44、R ATIOThe LTC1844 family are a series of 150mA ultralow dropout regulators with micropower quiescent current and shutdown. The devices are capable of supplying 150mAatadropout voltageof90mV(LTC1844-3.3, see Electrical Characteristics for dropout voltage of other versions). Output voltage noise is as

45、 low as 30mVRMS over a 10Hz to 100kHz bandwidth with the addition of a 0.1mF bypass capacitor. The low operating quiescent current (35mA) drops to 10nA in shutdown.In addition to the low quiescent current, the LTC1844 regulators incorporate several protection features which make them ideal for use i

46、n battery-powered systems. The devices are protected against both reverse input voltages and reverse voltages from output to input (reverse current protection). The devices also include current limit and thermal overload protection, and will survive an output short circuit indefinitely. The fast tra

47、nsient response over- comes the traditional tradeoff between dropout voltage, quiescent current and load transient response inherent in most regulators by using a proprietary new architecture (see Figure 1).Adjustable OperationThe adjustable version of the LTC1844 has an output voltagerangeof1.25Vto

48、6V. Theoutputvoltageissetby the ratio of two external resistors as shown in Figure 2. The device servosthe output to maintain the ADJpin voltage at1.25V(referencedtoground).ThecurrentinR1isthen equal to 1.25V/R1 and the current in R2 is the current in R1 plus the ADJ pin bias current. The ADJ pin bi

49、as current, 30nA at 25C, flows through R2 into the ADJ pin. The output voltage can be calculated using the formula in Figure2.ThevalueofR1shouldbenogreaterthan1Mto minimize errors in the output voltage caused by the ADJ pin bias current. Note that in shutdown the output is turnedCOUToff and the divi

50、der current will be zero once discharged.isAdjustable devices are tested and specified with the ADJ pin tied to the OUT pin for an output voltage of 1.25V. Specifications for output voltages greater than 1.25V will be proportional to the ratio of the desired output voltage to 1.25V: VOUT/1.25V. For

51、example, load regulation for an0.040.0200.020.04INOUTVOUT+ VR2CFFINLTC1844ADJGNDR11844 F02V=1.25V1+ R2+(I)(R2)500OUTADJR1VADJ = 1.25VIADJ = 30nA AT 25C OUTPUT RANGE = 1.25V TO 6V CFF OPTIONAL0 10 2030 40 5060 70 80 90 100TIME (ms)1844 F01Figure 2. Adjustable OperationFigure 1. LTC1844-2.5 Transient

52、Response 1mA to 50mA to 1mA1844ia6OUTPUT VOLTAGE DEVIATION (V)LOAD CURRENT (mA)VIN = 3V CIN = 1mF COUT = 1mF元器件交易网 LTC1844 SeriesAPPLICATIO S I FORATIOput into shutdown and thus the shutdown exit delay can be much shorter (70ms) than initial power-up time if the shutdowndurationisbrief

53、(10ms).Themaximumshut- down duration required to allow fast shutdown exit is determined by the capacitor leakage current, thus a low leakage bypass capacitor is recommended.output current change of 1mA to 100mA is 4mV typical at VOUT = 1.25V. At VOUT = 5V, load regulation is:(5V/1.25V)( 4mV) = 16mVB

54、ecause the ADJ pinisrelatively high impedance(depend- ingontheresistordividerused),straycapacitanceatthis pin can introduce significant phase shift in the error amplifier loop. The PCB layout should be designed to absolutely minimize the capacitance seen at the ADJ pin. To ensure stability over all operating conditions when utilizing large divider resistors, it may be necessary to use a small ceramic