Datasheet LT6660 (Analog Devices) - 9
| Manufacturer | Analog Devices |
| Description | Tiny Micropower Precision Series References in 2mm × 2mm DFN |
| Pages / Page | 12 / 9 — APPLICATIO S I FOR ATIO. Hysteresis. Table 1. Maximum Output Capacitance. … |
| File Format / Size | PDF / 415 Kb |
| Document Language | English |
APPLICATIO S I FOR ATIO. Hysteresis. Table 1. Maximum Output Capacitance. VOLTAGE. OPTION
Model Line for this Datasheet
- LT6660HCDC-10#PBF LT6660HCDC-10#TRMPBF LT6660HCDC-10#TRPBF LT6660HCDC-2.5#PBF LT6660HCDC-2.5#TRMPBF LT6660HCDC-2.5#TRPBF LT6660HCDC-3#PBF LT6660HCDC-3#TRMPBF LT6660HCDC-3#TRPBF LT6660HCDC-3.3#PBF LT6660HCDC-3.3#TRMPBF LT6660HCDC-3.3#TRPBF LT6660HCDC-5#PBF LT6660HCDC-5#TRMPBF LT6660HCDC-5#TRPBF LT6660JCDC-10#PBF LT6660JCDC-10#TRMPBF LT6660JCDC-10#TRPBF LT6660JCDC-2.5#PBF LT6660JCDC-2.5#TRMPBF LT6660JCDC-2.5#TRPBF LT6660JCDC-3#PBF LT6660JCDC-3#TRMPBF LT6660JCDC-3#TRPBF LT6660JCDC-3.3#PBF LT6660JCDC-3.3#TRMPBF LT6660JCDC-3.3#TRPBF LT6660JCDC-5#PBF LT6660JCDC-5#TRMPBF LT6660JCDC-5#TRPBF LT6660KCDC-10#PBF LT6660KCDC-10#TRMPBF LT6660KCDC-10#TRPBF LT6660KCDC-2.5#PBF LT6660KCDC-2.5#TRMPBF LT6660KCDC-2.5#TRPBF LT6660KCDC-3#PBF LT6660KCDC-3#TRMPBF LT6660KCDC-3#TRPBF LT6660KCDC-3.3#PBF LT6660KCDC-3.3#TRMPBF LT6660KCDC-3.3#TRPBF LT6660KCDC-5#PBF LT6660KCDC-5#TRMPBF LT6660KCDC-5#TRPBF
Text Version of Document
LT6660
U U W U APPLICATIO S I FOR ATIO
Table 1 gives the maximum output capacitance for vari-
Hysteresis
ous load currents and output voltages to avoid instability. Hysteresis data shown in Figure 6 and Figure 7 represents Load capacitors with low ESR (effective series resistance) the worst-case data taken on parts from 0°C to 70°C and cause more ringing than capacitors with higher ESR such from –40°C to 85°C. The output is capable of dissipat- as polarized aluminum or tantalum capacitors. ing relatively high power, i.e., for the LT6660-2.5, PD =
Table 1. Maximum Output Capacitance
17.5V • 20mA = 350mW. The thermal resistance of the
VOLTAGE
DFN package is 102°C/W and this dissipation causes a
OPTION IOUT = 100µA IOUT = 1mA IOUT = 10mA IOUT = 20mA
36°C internal rise. This elevated temperature may cause 2.5V >10µF >10µF 2µF 0.68µF the output to shift due to thermal hysteresis.
For highest
3V >10µF >10µF 2µF 0.68µF
performance in precision applications, do not let the
3.3V >10µF >10µF 1µF 0.68µF
LT6660’s junction temperature exceed 85°C.
5V >10µF >10µF 1µF 0.68µF 10V >10µF 1µF 0.15µF 0.1µF
Input Capacitance
It is recommended that a 0.1µF or larger capacitor be
Long-Term Drift
added to the input pin of the LT6660. This can help with stability when large load currents are demanded.
Long-term drift cannot be extrapolated from accelerated
18
high temperature testing. This erroneous technique
WORST-CASE HYSTERESIS 16 ON 40 UNITS
gives drift numbers that are wildly optimistic. The only
14
way long-term drift can be determined is to measure it over the time interval of interest.
The LT6660 long-term 12 drift data was taken on over 100 parts that were soldered 10 70°C TO 25°C 0°C TO 25°C into PC boards similar to a “real world” application. The 8 boards were then placed into a constant temperature oven NUMBER OF UNITS 6 with TA = 30°C, their outputs were scanned regularly and 4 measured with an 8.5 digit DVM. Figure 5 shows typical 2 long-term drift of the LT6660s. 0 –240 –200 –160 –120 –80 –40 0 40 80 120 160 200 240 HYSTERESIS (ppm) 150 6660 F06 100
Figure 6. 0°C to 70°C Hysteresis
50 9 WORST-CASE HYSTERESIS 8 ON 34 UNITS ppm 0 7 85°C TO 25°C –40°C TO 25°C –50 6 5 –100 4 –150 NUMBER OF UNITS 3 0 100 200 300 400 500 600 700 800 900 1000 HOURS 2 6660 F05 1
Figure 5. Typical Long-Term Drift
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
U U W U APPLICATIO S I FOR ATIO
Table 1 gives the maximum output capacitance for vari-
Hysteresis
ous load currents and output voltages to avoid instability. Hysteresis data shown in Figure 6 and Figure 7 represents Load capacitors with low ESR (effective series resistance) the worst-case data taken on parts from 0°C to 70°C and cause more ringing than capacitors with higher ESR such from –40°C to 85°C. The output is capable of dissipat- as polarized aluminum or tantalum capacitors. ing relatively high power, i.e., for the LT6660-2.5, PD =
Table 1. Maximum Output Capacitance
17.5V • 20mA = 350mW. The thermal resistance of the
VOLTAGE
DFN package is 102°C/W and this dissipation causes a
OPTION IOUT = 100µA IOUT = 1mA IOUT = 10mA IOUT = 20mA
36°C internal rise. This elevated temperature may cause 2.5V >10µF >10µF 2µF 0.68µF the output to shift due to thermal hysteresis.
For highest
3V >10µF >10µF 2µF 0.68µF
performance in precision applications, do not let the
3.3V >10µF >10µF 1µF 0.68µF
LT6660’s junction temperature exceed 85°C.
5V >10µF >10µF 1µF 0.68µF 10V >10µF 1µF 0.15µF 0.1µF
Input Capacitance
It is recommended that a 0.1µF or larger capacitor be
Long-Term Drift
added to the input pin of the LT6660. This can help with stability when large load currents are demanded.
Long-term drift cannot be extrapolated from accelerated
18
high temperature testing. This erroneous technique
WORST-CASE HYSTERESIS 16 ON 40 UNITS
gives drift numbers that are wildly optimistic. The only
14
way long-term drift can be determined is to measure it over the time interval of interest.
The LT6660 long-term 12 drift data was taken on over 100 parts that were soldered 10 70°C TO 25°C 0°C TO 25°C into PC boards similar to a “real world” application. The 8 boards were then placed into a constant temperature oven NUMBER OF UNITS 6 with TA = 30°C, their outputs were scanned regularly and 4 measured with an 8.5 digit DVM. Figure 5 shows typical 2 long-term drift of the LT6660s. 0 –240 –200 –160 –120 –80 –40 0 40 80 120 160 200 240 HYSTERESIS (ppm) 150 6660 F06 100
Figure 6. 0°C to 70°C Hysteresis
50 9 WORST-CASE HYSTERESIS 8 ON 34 UNITS ppm 0 7 85°C TO 25°C –40°C TO 25°C –50 6 5 –100 4 –150 NUMBER OF UNITS 3 0 100 200 300 400 500 600 700 800 900 1000 HOURS 2 6660 F05 1
Figure 5. Typical Long-Term Drift
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
