LT6660HCDC-3

■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 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 c ompensation 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. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. APPLICATIO S ■ ■ ■ ■ ■ ■ Handheld Instruments Precision Regulators A/D and D/A Converters Power Supplies Hard Disk Drives Sensor Modules Basic Connection DISTRIBUTION (%) LT6660 VOUT + 0.9V ≤ VIN ≤ 20V C1 0.1µF IN GND 6660 TA01 U TYPICAL APPLICATIO LT6660H VOUT Shift Due to IR Reflow 32 28 24 20 16 12 8 4 0 –0.09 –0.05 –0.01 0.01 0.05 CHANGE IN VOUT (%) 0.09 6660 TA01b OUT VOUT U FEATURES LT6660 Tiny Micropower Precision Series References in 2mm × 2mm DFN DESCRIPTIO U 6660fa 1 LT6660 (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 TOP VIEW 4 1 OUT 2 GND 3 IN 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) 2.5 2.5 2.5 3 3 3 3.3 3.3 3.3 SPECIFIED TEMPERATURE RANGE 0°C to 70°C 0°C to 70°C 0°C to 70°C 0°C to 70°C 0°C to 70°C 0°C to 70°C 0°C to 70°C 0°C to 70°C 0°C to 70°C ACCURACY (%) 0.2 0.4 0.5 0.2 0.4 0.5 0.2 0.4 0.5 TEMPERATURE COEFFICIENT (ppm/°C) 20 20 50 20 20 50 20 20 50 PART ORDER NUMBER LT6660HCDC-2.5 LT6660JCDC-2.5 LT6660KCDC-2.5 LT6660HCDC-3 LT6660JCDC-3 LT6660KCDC-3 LT6660HCDC-3.3 LT6660JCDC-3.3 LT6660KCDC-3.3 2 U PACKAGE/ORDER I FOR ATIO W U U WW W ABSOLUTE AXI U RATI GS 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 ORDER PART NUMBER 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 DFN PART MARKING* LBXN LBXN LBXN LBYV LBYV LBYV LBYW LBYW LBYW LBYT LBYT LBYT LBYX LBYX LBYX 6660fa LT6660 AVAILABLE OPTIONS OUTPUT VOLTAGE (V) 5 5 5 10 10 10 SPECIFIED TEMPERATURE RANGE 0°C to 70°C 0°C to 70°C 0°C to 70°C 0°C to 70°C 0°C to 70°C 0°C to 70°C ACCURACY (%) 0.2 0.4 0.5 0.2 0.4 0.5 TEMPERATURE COEFFICIENT (ppm/°C) 20 20 50 20 20 50 PART ORDER NUMBER LT6660HCDC-5 LT6660JCDC-5 LT6660KCDC-5 LT6660HCDC-10 LT6660JCDC-10 LT6660KCDC-10 ELECTRICAL CHARACTERISTICS PARAMETER Output Voltage Tolerance 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. CONDITIONS LT6660HCDC LT6660JCDC LT6660KCDC LT6660HCDC LT6660JCDC LT6660KCDC VOUT + 0.9V ≤ VIN ≤ VOUT + 2.5V VOUT + 2.5V ≤ VIN ≤ 20V MIN –0.2 –0.4 –0.5 ● ● ● ● 50 ● 1000 ● 50 ● 20 ● 2.5 ● ● ● 40 0.5 4 4 100 50 250 115 ● LT6660-3 ● LT6660-3.3 ● LT6660-5 ● LT6660-10 ● 215 160 145 145 145 175 180 220 180 220 200 240 270 350 TYP MAX 0.2 0.4 0.5 20 20 50 800 1000 100 130 3000 4000 200 300 70 100 10 0.9 1.3 1.4 10 UNITS % % % ppm/°C ppm/°C ppm/°C ppm/V ppm/V ppm/V ppm/V ppm/mA ppm/mA ppm/mA ppm/mA ppm/mA ppm/mA ppm/mW V V V mA µA ppm (P-P) ppm (RMS) ppm/√kHr ppm ppm µA µA µA µA µA µA µA µA µA µA 6660fa Output Voltage Temperature Coefficient (Note 4) Line Regulation 10 10 25 150 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 Output Voltage Noise (Note 8) Long-Term Stability of Output Voltage (Note 9) Hysteresis (Note 10) Supply Current Short VOUT to GND VIN = –15V 0.1Hz ≤ f ≤ 10Hz 10Hz ≤ f ≤ 1kHz ΔT = 0°C to 70°C ΔT = –40°C to 85°C LT6660-2.5 ● ● 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. 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 100 OUTPUT VOLTAGE CHANGE (mV) 0 OUTPUT VOLTAGE CHANGE (mV) – 0.5 – 1.0 – 1.5 – 2.0 – 2.5 – 3.0 – 3.5 – 4.0 0.1 1 10 OUTPUT CURRENT (mA) 100 6660 G02 TYPICAL PERFOR A CE CHARACTERISTICS UW 2.5V Load Regulation, Sourcing 120 100 80 60 40 20 0 2.5V Load Regulation, Sinking OUTPUT CURRENT (mA) 10 125°C – 5 5° C 25°C 1 – 5 5 °C 25°C 125°C 25°C 125°C – 55°C 0.1 0 0.5 1.0 1.5 2.0 INPUT-OUTPUT VOLTAGE (V) 2.5 6660 G01 0 1 2 3 4 OUTPUT CURRENT (mA) 5 6660 G03 6660fa 4 LT6660 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 2.503 2.502 SUPPLY CURRENT (µA) OUTPUT VOLTAGE (V) 2.501 2.500 2.499 2.498 2.497 –50 –25 THREE TYPICAL PARTS 250 200 25°C OUTPUT VOLTAGE (V) 125°C – 5 5°C TYPICAL PERFOR A CE CHARACTERISTICS UW 100 6660 G07 2.5V Supply Current vs Input Voltage 2.502 2.501 2.500 2.499 2.498 2.497 2.496 2.495 0 5 10 INPUT VOLTAGE (V) 6660 G04 6660 G05 2.5V Line Regulation 25°C – 5 5° C 150 100 125°C 50 50 25 75 0 TEMPERATURE (°C) 125 0 15 2.494 20 0 2 4 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 6660 G06 2.5V Power Supply Rejection Ratio vs Frequency 80 POWER SUPPLY REJECTION RATIO (dB) 70 OUTPUT IMPEDANCE (Ω) 60 50 40 30 20 10 0 0.1 1 10 100 FREQUENCY (kHz) 1000 100 1000 2.5V Output Impedance vs Frequency CL = 0µ F CL = 0.1µF LOAD CURRENT (mA) 20 10 1 0.1 2.5V Transient Response 10 C L = 1 µF 1 200µs/DIV CLOAD = 0µF 0.1 0.01 0.1 1 10 FREQUENCY (kHz) 100 1000 6660 G08 6660 G09 2.5V Output Voltage Noise Spectrum 1000 2.5V Output Noise 0.1Hz to 10Hz NOISE VOLTAGE (nV/√Hz) 100 10 OUTPUT NOISE (20µV/DIV) 100 1k 10k FREQUENCY (Hz) 100k 6660 G10 TIME (2 SEC/DIV) 6660 G11 6660fa 5 LT6660 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 100 OUTPUT VOLTAGE CHANGE (mV) 35 OUTPUT VOLTAGE CHANGE (mV) 30 25 20 15 10 5 0 –5 0.1 0 0.5 1.0 1.5 2.0 INPUT-OUTPUT VOLTAGE (V) 2.5 6660 G12 TYPICAL PERFOR A CE CHARACTERISTICS UW 100 10V Load Regulation, Sourcing 250 10V Load Regulation, Sinking 200 125°C 150 25°C 100 –55°C 50 OUTPUT CURRENT (mA) 10 125°C 25°C 1 – 5 5 °C – 5 5 °C 125°C 25°C 100 6660 G13 –10 0.1 1 10 OUTPUT CURRENT (mA) 0 0 1 3 4 2 OUTPUT CURRENT (mA) 5 6660 G14 10V Output Voltage Temperature Drift 10.006 10.004 10.002 SUPPLY CURRENT (µA) OUTPUT VOLTAGE (V) 10.000 9.998 9.996 9.994 9.992 9.990 9.988 9.986 9.984 9.982 – 50 – 2 5 50 25 0 75 TEMPERATURE (°C) 125 THREE TYPICAL PARTS 350 300 250 200 150 100 50 0 10V Supply Current vs Input Voltage 10.010 10.005 OUTPUT VOLTAGE (V) 10.000 9.995 9.990 9.985 9.980 10V Line Regulation 25°C 125°C – 55°C 25°C – 55°C 125°C 0 2 4 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 6660 G16 6 8 14 12 16 10 INPUT VOLTAGE (V) 18 20 6660 G15 6660 G17 6660fa 6 LT6660 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 100 POWER SUPPLY REJECTION RATIO (dB) 90 80 OUTPUT IMPEDANCE (Ω) 70 60 50 40 30 20 10 0 0.1 1 10 100 FREQUENCY (kHz) 1000 6660 G18 TYPICAL PERFOR A CE CHARACTERISTICS UW 0.1 10V Output Impedance vs Frequency 1000 CL = 0µF 100 CL = 0.1µF 20 LOAD CURRENT (mA) 10 10V Transient Response 10 C L = 1 µF 1 0.1 200µs/DIV 6660 G20 1 0.1 0.01 CLOAD = 0µF 0.1 1 10 FREQUENCY (kHz) 100 1000 6660 G19 10V Output Voltage Noise Spectrum 10 10V Output Noise 0.1Hz to 10Hz 1 0.1 0.01 1 10 FREQUENCY (kHz) 100 6660 G21 OUTPUT NOISE (20µV/DIV) NOISE VOLTAGE (µV/√Hz) TIME (2 SEC/DIV) 6660 G22 6660fa 7 LT6660 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 VOUT CL RL VGEN 2.5V 1.5V 6660 F01 Figure 1. Response Time Test Circuit 8 U VGEN 2.5V 1.5V VOUT 1mA VOUT 10mA 1µs/DIV 6660 F02 APPLICATIO S I FOR ATIO W U U Figure 2. CL = 0µF VGEN 2.5V 1.5V VOUT 1mA VOUT 10mA 100µs/DIV 6660 F03 Figure 3. CL = 0.1µF VGEN 2.5V 1.5V VOUT 1µF VOUT 4.7µF 100µs/DIV 6660 F04 Figure 4. IOUT = 1mA 6660fa LT6660 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. Table 1. Maximum Output Capacitance VOLTAGE OPTION 2.5V 3V 3.3V 5V 10V IOUT = 100µA >10µF >10µF >10µF >10µF >10µF IOUT = 1mA >10µF >10µF >10µF >10µF 1µF IOUT = 10mA 2µF 2µF 1µF 1µF 0.15µF IOUT = 20mA 0.68µF 0.68µF 0.68µF 0.68µF 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. 150 100 50 ppm 0 NUMBER OF UNITS NUMBER OF UNITS – 50 –100 –150 0 100 200 300 400 500 600 700 800 900 1000 HOURS 6660 F05 Figure 5. Typical Long-Term Drift U 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 14 12 10 8 6 4 2 0 –240 –200 –160 –120 – 80 –40 0 40 HYSTERESIS (ppm) 80 120 160 200 240 6660 F06 APPLICATIO S I FOR ATIO W U U WORST-CASE HYSTERESIS ON 40 UNITS 70°C TO 25°C 0°C TO 25°C Figure 6. 0°C to 70°C Hysteresis 9 8 7 6 5 4 3 2 1 0 – 600 – 500 – 400 – 300 – 200 – 100 0 100 200 300 400 500 600 HYSTERESIS (ppm) 6660 F07 WORST-CASE HYSTERESIS ON 34 UNITS 85°C TO 25°C – 40°C TO 25°C Figure 7. – 40°C to 85°C Hysteresis 6660fa 9 LT6660 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: LT6660HCDC Initial Accuracy = 0.2% For IOUT = 100µA 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% 10 U 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 0µA 100µA 10mA 20mA LT6660HCDC 0.340% 0.380% 0.640% 0.540% LT6660JCDC 0.540% 0.580% 0.840% 0.740% LT6660KCDC 0.850% 0.890% 1.15% 1.05% 6660fa APPLICATIO S I FOR ATIO W U U LT6660 U DC Package 3-Lead Plastic DFN (2mm × 2mm) (Reference LTC DWG # 05-08-1717 Rev Ø) 1.35 ± 0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 1.35 ± 0.05 (2 SIDES) R = 0.05 TYP PIN 1 NOTCH R = 0.20 OR 0.25 × 45° CHAMFER 3 1 R = 0.115 TYP 0.25 ± 0.05 0.50 BSC (DC3) DFN 1205 REV Ø PACKAGE DESCRIPTIO 1.00 ± 0.05 1.30 ± 0.05 (2 SIDES) 2.00 ± 0.05 PIN 1 BAR TOP MARK (SEE NOTE 6) 2.00 ± 0.10 (4 SIDES) 1.00 ± 0.05 (2 SIDES) 0.40 ± 0.05 0.200 REF 0.75 ± 0.05 0.70 ± 0.05 BOTTOM VIEW—EXPOSED PAD 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 U Handling Higher Load Currents V+ 40mA TYPICAL APPLICATIO + 47µF 3 IN LT6660 OUT GND 2 RL TYPICAL LOAD CURRENT = 50mA 1 10mA VOUT R1* *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 R1 = V + – VOUT 40mA 6660 TA02 Boosted Output Current with No Current Limit V + ≥ (VOUT + 1.8V) R1 220Ω 3 IN LT6660 OUT GND 2 1 VOUT 100mA 2N2905 Boosted Output Current with Current Limit V+ ≥ VOUT + 2.8V D1* LED R1 220Ω 3 IN LT6660 OUT GND 2 * GLOWS IN CURRENT LIMIT, DO NOT OMIT 1 VOUT 100mA + 47µF + 8.2Ω 2N2905 47µF + 2µ F SOLID TANT + 2 µF SOLID TANT 6660 TA03 6660 TA04 RELATED PARTS PART NUMBER LT1019 LT1027 LT1236 LT1460 LT1461 LT1634 LT1790 LTC 1798 ® DESCRIPTION Precision Bandgap Reference Precision 5V Reference Precision Low Noise Reference Micropower Series References Micropower Precision Low Dropout Micropower Precision Shunt Reference 1.25V, 2.5V Output Micropower Precision Series References Micropower Low Dropout Reference, Fixed or Adjustable COMMENTS 0.05% Max, 5ppm/°C Max 0.02%, 2ppm/°C Max 0.05% Max, 5ppm/°C Max, SO Package 0.075% Max, 10ppm/°C Max, 20mA Output Current 0.04% Max, 3ppm/°C Max, 50mA Output Current 0.05%, 25ppm/°C Max 0.05% Max, 10ppm/°C Max, 60µA Supply, SOT23 Package 0.15% Max, 40ppm/°C, 6.5µA Max Supply Current 6660fa 12 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● LT 0406 REV A PRINTED IN USA www.linear.com  LINEAR TECHNOLOGY CORPORATION 2006