LT6660KCDC-5#TRPBF

LT6660 Tiny Micropower Precision Series References in 2mm × 2mm DFN DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ U ■ No Output Capacitor Required Low Drift: 20ppm/°C Max High Accuracy: 0.2% Max Low Supply Current 20mA Output Current Guaranteed Reverse-Battery Protection Low IR Reflow Induced Stress: 0.02% Typ Voltage Options: 2.5V, 3V, 3.3V, 5V and 10V Space-Saving Alternative to the LT1460 3-Lead 2mm × 2mm × 0.75mm DFN Package The LT®6660 is a family of micropower series references that combine high accuracy and low drift with low power dissipation and extremely small package size. These series references use curvature compensation to obtain low temperature coefficient, and laser trimmed precision thin-film resistors to achieve high output accuracy. The LT6660 will supply up to 20mA with excellent line regulation characteristics, making it ideal for precision regulator applications. The LT6660 family of series references provide supply current and power dissipation advantages over shunt references that must idle the entire load current to operate. Additionally, the LT6660 does not require an output compensation capacitor. This feature is important in applications where PC board space is a premium, fast settling is demanded, or total capacitance must be kept to a minimum, as in intrinsic safety applications. Reverse-battery protection keeps these references from conducting reverse current. U APPLICATIO S ■ ■ ■ ■ ■ ■ Handheld Instruments Precision Regulators A/D and D/A Converters Power Supplies Hard Disk Drives Sensor Modules , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATIO U LT6660H VOUT Shift Due to IR Reflow 32 28 Basic Connection LT6660 VOUT + 0.9V ≤ VIN ≤ 20V IN C1 0.1µF OUT VOUT GND 6660 TA01 DISTRIBUTION (%) 24 20 16 12 8 4 0 –0.09 –0.05 –0.01 0.01 0.05 CHANGE IN VOUT (%) 0.09 6660 TA01b 6660fa 1 LT6660 AXI U RATI GS U W W W ABSOLUTE (Note 1) Input Voltage.............................................................30V Reverse Voltage ......................................................–15V Output Short-Circuit Duration, TA = 25°C ................5 sec Specified Temperature Range ...................... 0°C to 70°C Operating Temperature Range (Note 2) ............................................... –40°C to 85°C Storage Temperature Range (Note 3)..... –65°C to 150°C Lead Temperature (Soldering, 10 sec) .................. 300°C U W U PACKAGE/ORDER I FOR ATIO ORDER PART NUMBER DFN PART MARKING* LT6660HCDC-2.5 LT6660JCDC-2.5 LT6660KCDC-2.5 LT6660HCDC-3 LT6660JCDC-3 LT6660KCDC-3 LT6660HCDC-3.3 LT6660JCDC-3.3 LT6660KCDC-3.3 LT6660HCDC-5 LT6660JCDC-5 LT6660KCDC-5 LT6660HCDC-10 LT6660JCDC-10 LT6660KCDC-10 LBXN LBXN LBXN LBYV LBYV LBYV LBYW LBYW LBYW LBYT LBYT LBYT LBYX LBYX LBYX TOP VIEW 1 2 3 OUT GND IN 4 DC PACKAGE 3-LEAD (2mm × 2mm) PLASTIC DFN TJMAX = 125°C, θJA = 102°C/W EXPOSED PAD IS GND, MUST BE SOLDERED TO PCB Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. AVAILABLE OPTIONS OUTPUT VOLTAGE (V) SPECIFIED TEMPERATURE RANGE ACCURACY (%) TEMPERATURE COEFFICIENT (ppm/°C) PART ORDER NUMBER 2.5 2.5 2.5 0°C to 70°C 0°C to 70°C 0°C to 70°C 0.2 0.4 0.5 20 20 50 LT6660HCDC-2.5 LT6660JCDC-2.5 LT6660KCDC-2.5 3 3 3 0°C to 70°C 0°C to 70°C 0°C to 70°C 0.2 0.4 0.5 20 20 50 LT6660HCDC-3 LT6660JCDC-3 LT6660KCDC-3 3.3 3.3 3.3 0°C to 70°C 0°C to 70°C 0°C to 70°C 0.2 0.4 0.5 20 20 50 LT6660HCDC-3.3 LT6660JCDC-3.3 LT6660KCDC-3.3 6660fa 2 LT6660 AVAILABLE OPTIONS OUTPUT VOLTAGE (V) SPECIFIED TEMPERATURE RANGE ACCURACY (%) TEMPERATURE COEFFICIENT (ppm/°C) PART ORDER NUMBER 5 5 5 0°C to 70°C 0°C to 70°C 0°C to 70°C 0.2 0.4 0.5 20 20 50 LT6660HCDC-5 LT6660JCDC-5 LT6660KCDC-5 10 10 10 0°C to 70°C 0°C to 70°C 0°C to 70°C 0.2 0.4 0.5 20 20 50 LT6660HCDC-10 LT6660JCDC-10 LT6660KCDC-10 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = VOUT + 2.5V, IOUT = 0 unless otherwise specified. PARAMETER Output Voltage Tolerance Output Voltage Temperature Coefficient (Note 4) Line Regulation CONDITIONS LT6660HCDC LT6660JCDC LT6660KCDC LT6660HCDC LT6660JCDC LT6660KCDC VOUT + 0.9V ≤ VIN ≤ VOUT + 2.5V VOUT + 2.5V ≤ VIN ≤ 20V Load Regulation Sourcing (Note 5) IOUT = 100µA IOUT = 10mA IOUT = 20mA Thermal Regulation (Note 6) Dropout Voltage (Note 7) ΔP = 200mW VIN – VOUT, ΔVOUT ≤ 0.2%, IOUT = 0 VIN – VOUT, ΔVOUT ≤ 0.2%, IOUT = 10mA Output Current Reverse Leakage Short VOUT to GND VIN = –15V Output Voltage Noise (Note 8) 0.1Hz ≤ f ≤ 10Hz 10Hz ≤ f ≤ 1kHz Long-Term Stability of Output Voltage (Note 9) Hysteresis (Note 10) Supply Current ΔT = 0°C to 70°C ΔT = –40°C to 85°C MIN –0.2 –0.4 –0.5 MAX 0.2 0.4 0.5 20 20 50 UNITS % % % ppm/°C ppm/°C ppm/°C ● 800 1000 100 130 3000 4000 200 300 70 100 10 0.9 ppm/V ppm/V ppm/V ppm/V ppm/mA ppm/mA ppm/mA ppm/mA ppm/mA ppm/mA ppm/mW V ● 1.3 1.4 ● ● ● TYP 10 10 25 150 ● 50 ● 1000 ● 50 ● 20 ● 2.5 ● 40 0.5 ● ● 4 4 100 50 250 LT6660-2.5 115 ● LT6660-3 145 ● LT6660-3.3 145 ● LT6660-5 160 ● LT6660-10 215 ● 10 V V mA µA ppm (P-P) ppm (RMS) ppm/√kHr ppm ppm 145 175 180 220 180 220 200 240 270 350 µA µA µA µA µA µA µA µA µA µA 6660fa 3 LT6660 ELECTRICAL CHARACTERISTICS Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LT6660 is guaranteed functional over the operating temperature range of –40°C to 85°C. Note 3: If the parts are stored outside of the specified temperature range, the output may shift due to hysteresis. Note 4: Temperature coefficient is measured by dividing the change in output voltage by the specified temperature range. Incremental slope is also measured at 25°C. Note 5: Load regulation is measured on a pulse basis from no load to the specified load current. Output changes due to die temperature change must be taken into account separately. Note 6: Thermal regulation is caused by die temperature gradients created by load current or input voltage changes. This effect must be added to normal line or load regulation. This parameter is not 100% tested. Note 7: Excludes load regulation errors. Note 8: Peak-to-peak noise is measured with a single pole highpass filter at 0.1Hz and 2-pole lowpass filter at 10Hz. The unit is enclosed in a still-air environment to eliminate thermocouple effects on the leads. The test time is 10 sec. RMS noise is measured with a single pole highpass filter at 10Hz and a 2-pole lowpass filter at 1kHz. The resulting output is full wave rectified and then integrated for a fixed period, making the final reading an average as opposed to RMS. A correction factor of 1.1 is used to convert from average to RMS and a second correction of 0.88 is used to correct for the nonideal bandpass of the filters. Note 9: Long-term stability typically has a logarithmic characteristic and therefore, changes after 1000 hours tend to be much smaller than before that time. Total drift in the second thousand hours is normally less than one third that of the first thousand hours with a continuing trend toward reduced drift with time. Long-term stability will also be affected by differential stresses between the IC and the board material created during board assembly. Note 10: Hysteresis in output voltage is created by package stress that differs depending on whether the IC was previously at a higher or lower temperature. Output voltage is always measured at 25°C, but the IC is cycled to 70°C or 0°C before successive measurements. Hysteresis is roughly proportional to the square of the temperature change. For instruments that are stored at well-controlled temperatures (within 20 or 30 degrees of operational temperature) hysteresis is not a problem. TYPICAL PERFOR A CE CHARACTERISTICS U W Characteristic curves are similar for all voltage options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic curves for other output voltages fall between these curves, and can be estimated based on their voltage output. 2.5V Minimum Input-Output Voltage Differential 2.5V Load Regulation, Sourcing 25°C – 55°C 1 0 0.5 1.0 1.5 2.0 INPUT-OUTPUT VOLTAGE (V) 2.5 6660 G01 – 0.5 – 1.0 – 1.5 OUTPUT VOLTAGE CHANGE (mV) 125°C 10 0.1 2.5V Load Regulation, Sinking 120 0 OUTPUT VOLTAGE CHANGE (mV) OUTPUT CURRENT (mA) 100 – 55°C – 2.0 25°C – 2.5 – 3.0 125°C – 3.5 – 4.0 0.1 1 10 OUTPUT CURRENT (mA) 100 6660 G02 100 80 60 25°C 40 125°C – 55°C 20 0 0 1 2 3 4 OUTPUT CURRENT (mA) 5 6660 G03 6660fa 4 LT6660 TYPICAL PERFOR A CE CHARACTERISTICS U W Characteristic curves are similar for all voltage options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic curves for other output voltages fall between these curves, and can be estimated based on their voltage output. 2.5V Output Voltage Temperature Drift THREE TYPICAL PARTS 2.502 2.501 2.500 2.499 2.501 25°C 200 SUPPLY CURRENT (µA) OUTPUT VOLTAGE (V) 2.5V Line Regulation 2.502 250 125°C – 55°C 150 100 50 2.498 2.497 –50 –25 50 25 75 0 TEMPERATURE (°C) 100 0 125 – 55°C 2.499 2.498 125°C 2.497 2.496 5 0 10 2.494 15 20 0 2 4 INPUT VOLTAGE (V) 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 6660 G06 6660 G05 2.5V Power Supply Rejection Ratio vs Frequency 2.5V Output Impedance vs Frequency 2.5V Transient Response 1000 80 CL = 0µF OUTPUT IMPEDANCE (Ω) 60 50 40 30 20 20 LOAD CURRENT (mA) 70 CL = 0.1µF 100 10 CL = 1µF 10 1 0.1 1 200µs/DIV 10 6660 G09 CLOAD = 0µF 10 100 FREQUENCY (kHz) 1000 0.1 0.01 0.1 1 10 FREQUENCY (kHz) 100 6660 G07 1000 6660 G08 2.5V Output Voltage Noise Spectrum 2.5V Output Noise 0.1Hz to 10Hz 1000 OUTPUT NOISE (20µV/DIV) 1 NOISE VOLTAGE (nV/√Hz) POWER SUPPLY REJECTION RATIO (dB) 25°C 2.500 2.495 6660 G04 0 0.1 OUTPUT VOLTAGE (V) 2.503 2.5V Supply Current vs Input Voltage 100 10 100 1k 10k FREQUENCY (Hz) 100k 6660 G10 TIME (2 SEC/DIV) 6660 G11 6660fa 5 LT6660 TYPICAL PERFOR A CE CHARACTERISTICS U W Characteristic curves are similar for all voltage options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic curves for other output voltages fall between these curves, and can be estimated based on their voltage output. 10V Minimum Input-Output Voltage Differential 10V Load Regulation, Sourcing 25°C – 55°C 30 25 20 15 10 5 – 55°C 0 –5 0 0.5 1.0 1.5 2.0 INPUT-OUTPUT VOLTAGE (V) 125°C –10 0.1 2.5 1 10 OUTPUT CURRENT (mA) 10V Output Voltage Temperature Drift 10.004 100 –55°C 50 SUPPLY CURRENT (µA) 9.998 9.996 9.994 9.992 9.990 9.988 9.986 100 125 6660 G15 3 4 2 OUTPUT CURRENT (mA) 6660 G14 10.005 25°C 250 125°C 200 – 55°C 150 100 0 5 10V Line Regulation 25°C 10.000 – 55°C 9.995 125°C 9.990 9.985 50 9.984 1 0 10.010 300 10.000 OUTPUT VOLTAGE (V) 25°C 0 100 350 10.002 50 25 0 75 TEMPERATURE (°C) 150 10V Supply Current vs Input Voltage THREE TYPICAL PARTS 9.982 – 50 – 25 125°C 6660 G13 6660 G12 10.006 200 25°C OUTPUT VOLTAGE (V) 1 250 OUTPUT VOLTAGE CHANGE (mV) 125°C 10 0.1 10V Load Regulation, Sinking 35 OUTPUT VOLTAGE CHANGE (mV) OUTPUT CURRENT (mA) 100 0 2 4 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 6660 G16 9.980 6 8 14 12 16 10 INPUT VOLTAGE (V) 18 20 6660 G17 6660fa 6 LT6660 TYPICAL PERFOR A CE CHARACTERISTICS U W Characteristic curves are similar for all voltage options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic curves for other output voltages fall between these curves, and can be estimated based on their voltage output. 10V Power Supply Rejection Ratio vs Frequency 10V Output Impedance vs Frequency 10V Transient Response 1000 90 20 OUTPUT IMPEDANCE (Ω) 80 70 60 50 40 30 20 100 LOAD CURRENT (mA) CL = 0µF CL = 0.1µF 10 CL = 1µF 1 1 200µs/DIV 1 10 100 FREQUENCY (kHz) 1000 6660 G20 CLOAD = 0µF 0.1 0.01 0.1 1 10 FREQUENCY (kHz) 100 6660 G18 1000 6660 G19 10V Output Voltage Noise Spectrum 10V Output Noise 0.1Hz to 10Hz 10 OUTPUT NOISE (20µV/DIV) 0 0.1 10 0.1 10 NOISE VOLTAGE (µV/√Hz) POWER SUPPLY REJECTION RATIO (dB) 100 1 0.1 0.01 0.1 1 10 FREQUENCY (kHz) 100 6660 G21 TIME (2 SEC/DIV) 6660 G22 6660fa 7 LT6660 APPLICATIO S I FOR ATIO U U W U Longer Battery Life Series references have a large advantage over older shunt style references. Shunt references require a resistor from the power supply to operate. This resistor must be chosen to supply the maximum current that can ever be demanded by the circuit being regulated. When the circuit being controlled is not operating at this maximum current, the shunt reference must always sink this current, resulting in high dissipation and short battery life. The LT6660 series references do not require a current setting resistor and can operate with any supply voltage from VOUT + 0.9V to 20V. When the circuitry being regulated does not demand current, the LT6660s reduce their dissipation and battery life is extended. If the references are not delivering load current, they dissipate only several mW, yet the same connection can deliver 20mA of load current when demanded. Capacitive Loads The LT6660 family of references are designed to be stable with a large range of capacitive loads. With no capacitive load, these references are ideal for fast settling or applications where PC board space is a premium. The test circuit shown in Figure 1 is used to measure the response time and stability of various load currents and load capacitors. This circuit is set for the 2.5V option. For other voltage options, the input voltage must be scaled up and the output voltage generator offset voltage must be adjusted. The 1V step from 2.5V to 1.5V produces a current step of 10mA or 1mA for RL = 100Ω or RL = 1k. Figure 2 shows the response of the reference to these 1mA and 10mA load steps with no load capacitance, and Figure 3 shows a 1mA and 10mA load step with a 0.1µF output capacitor. Figure 4 shows the response to a 1mA load step with CL = 1µF and 4.7µF. VIN = 2.5V CIN 0.1µF LT6660-2.5 VGEN CL 2.5V 1.5V VOUT 1mA VOUT 10mA 1µs/DIV 6660 F02 Figure 2. CL = 0µF 2.5V VGEN 1.5V VOUT 1mA VOUT 10mA 100µs/DIV 6660 F03 Figure 3. CL = 0.1µF 2.5V VGEN 1.5V VOUT 1µF VOUT 4.7µF 100µs/DIV 6660 F04 Figure 4. IOUT = 1mA RL VOUT VGEN 2.5V 1.5V 6660 F01 Figure 1. Response Time Test Circuit 6660fa 8 LT6660 APPLICATIO S I FOR ATIO U U U Table 1. Maximum Output Capacitance VOLTAGE OPTION IOUT = 100µA IOUT = 1mA IOUT = 10mA IOUT = 20mA 2.5V >10µF >10µF 2µF 0.68µF 3V >10µF >10µF 2µF 0.68µF 3.3V >10µF >10µF 1µF 0.68µF 5V >10µF >10µF 1µF 0.68µF 10V >10µF 1µF 0.15µF 0.1µF Long-Term Drift Long-term drift cannot be extrapolated from accelerated high temperature testing. This erroneous technique gives drift numbers that are wildly optimistic. The only way long-term drift can be determined is to measure it over the time interval of interest. The LT6660 long-term drift data was taken on over 100 parts that were soldered into PC boards similar to a “real world” application. The boards were then placed into a constant temperature oven with TA = 30°C, their outputs were scanned regularly and measured with an 8.5 digit DVM. Figure 5 shows typical long-term drift of the LT6660s. Hysteresis Hysteresis data shown in Figure 6 and Figure 7 represents the worst-case data taken on parts from 0°C to 70°C and from –40°C to 85°C. The output is capable of dissipating relatively high power, i.e., for the LT6660-2.5, PD = 17.5V • 20mA = 350mW. The thermal resistance of the DFN package is 102°C/W and this dissipation causes a 36°C internal rise. This elevated temperature may cause the output to shift due to thermal hysteresis. For highest performance in precision applications, do not let the LT6660’s junction temperature exceed 85°C. Input Capacitance It is recommended that a 0.1µF or larger capacitor be added to the input pin of the LT6660. This can help with stability when large load currents are demanded. 18 16 WORST-CASE HYSTERESIS ON 40 UNITS 14 NUMBER OF UNITS W Table 1 gives the maximum output capacitance for various load currents and output voltages to avoid instability. Load capacitors with low ESR (effective series resistance) cause more ringing than capacitors with higher ESR such as polarized aluminum or tantalum capacitors. 12 10 8 70°C TO 25°C 0°C TO 25°C 6 4 2 0 150 –240 –200 –160 –120 – 80 –40 0 40 HYSTERESIS (ppm) 80 120 160 200 240 6660 F06 Figure 6. 0°C to 70°C Hysteresis 100 9 8 0 7 – 50 –100 –150 0 100 200 300 400 500 600 700 800 900 1000 HOURS 6660 F05 Figure 5. Typical Long-Term Drift NUMBER OF UNITS ppm 50 6 WORST-CASE HYSTERESIS ON 34 UNITS 85°C TO 25°C –40°C TO 25°C 5 4 3 2 1 0 –600 –500 –400 –300 –200 –100 0 100 200 300 400 500 600 HYSTERESIS (ppm) 6660 F07 Figure 7. – 40°C to 85°C Hysteresis 6660fa 9 LT6660 APPLICATIO S I FOR ATIO U W U U Output Accuracy Like all references, either series or shunt, the error budget of the LT6660s is made up of primarily three components: initial accuracy, temperature coefficient and load regulation. Line regulation is neglected because it typically contributes only 150ppm/V. The LT6660s typically shift 0.02% when soldered into a PCB, so this is also neglected. The output errors are calculated as follows for a 100µA load and 0°C to 70°C temperature range: Total worst-case output error is: 0.2% + 0.04% + 0.14% = 0.380% Table 2 gives the worst-case accuracy for LT6660HC, LT6660JC and LT6660KC from 0°C to 70°C, and shows that if the LT6660HC is used as a reference instead of a regulator, it is capable of 8 bits of absolute accuracy over temperature without a system calibration. Table 2. Worst-Case Output Accuracy over Temperature IOUT LT6660HCDC LT6660JCDC LT6660KCDC Initial Accuracy = 0.2% 0µA 0.340% 0.540% 0.850% 100µA 0.380% 0.580% 0.890% For IOUT = 100µA 10mA 0.640% 0.840% 1.15% 20mA 0.540% 0.740% 1.05% LT6660HCDC ΔVOUT = (4000ppm/mA)(0.1mA) = 0.04% For Temperature 0°C to 70°C the maximum ΔT = 70°C ΔVOUT = (20ppm/°C)(70°C) = 0.14% 6660fa 10 LT6660 PACKAGE DESCRIPTIO U DC Package 3-Lead Plastic DFN (2mm × 2mm) (Reference LTC DWG # 05-08-1717 Rev Ø) 1.35 ±0.05 (2 SIDES) 1.00 ±0.05 1.30 ±0.05 (2 SIDES) 2.00 ±0.05 PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 1.35 ± 0.05 (2 SIDES) 2.00 ±0.10 (4 SIDES) PIN 1 BAR TOP MARK (SEE NOTE 6) 1.00 ± 0.05 (2 SIDES) 0.40 ±0.05 0.200 REF 0.75 ±0.05 R = 0.05 TYP 0.70 ±0.05 PIN 1 NOTCH R = 0.20 OR 0.25 × 45° CHAMFER 3 R = 0.115 TYP 1 0.25 ± 0.05 0.50 BSC BOTTOM VIEW—EXPOSED PAD (DC3) DFN 1205 REV Ø 0.00 – 0.05 NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (W-TBD) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 6660fa Information 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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 11 LT6660 TYPICAL APPLICATIO U Handling Higher Load Currents V+ + 40mA 3 47µF IN R1* LT6660 OUT 1 10mA VOUT GND 2 RL TYPICAL LOAD CURRENT = 50mA *SELECT R1 TO DELIVER 80% OF TYPICAL LOAD CURRENT. LT6660 WILL THEN SOURCE AS NECESSARY TO MAINTAIN PROPER OUTPUT. DO NOT REMOVE LOAD AS OUTPUT WILL BE DRIVEN UNREGULATED HIGH. LINE REGULATION IS DEGRADED IN THIS APPLICATION Boosted Output Current with No Current Limit V + ≥ (VOUT + 1.8V) + R1 220Ω R1 = V + – VOUT 40mA 6660 TA02 Boosted Output Current with Current Limit V+ ≥ VOUT + 2.8V D1* LED 47µF + R1 220Ω 8.2Ω 2N2905 3 2N2905 3 IN 47µF IN LT6660 OUT 1 GND + 2 2µF SOLID TANT LT6660 VOUT 100mA OUT 1 GND 2 6660 TA03 + 2µF SOLID TANT VOUT 100mA * GLOWS IN CURRENT LIMIT, DO NOT OMIT 6660 TA04 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1019 Precision Bandgap Reference 0.05% Max, 5ppm/°C Max LT1027 Precision 5V Reference 0.02%, 2ppm/°C Max LT1236 Precision Low Noise Reference 0.05% Max, 5ppm/°C Max, SO Package LT1460 Micropower Series References 0.075% Max, 10ppm/°C Max, 20mA Output Current LT1461 Micropower Precision Low Dropout 0.04% Max, 3ppm/°C Max, 50mA Output Current LT1634 Micropower Precision Shunt Reference 1.25V, 2.5V Output 0.05%, 25ppm/°C Max LT1790 Micropower Precision Series References 0.05% Max, 10ppm/°C Max, 60µA Supply, SOT23 Package LTC 1798 Micropower Low Dropout Reference, Fixed or Adjustable 0.15% Max, 40ppm/°C, 6.5µA Max Supply Current ® 6660fa 12 Linear Technology Corporation LT 0406 REV A PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com  LINEAR TECHNOLOGY CORPORATION 2006