LTC6655



6655fa

l

denotes the specifications which apply over the full operating

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Output Voltage Noise (Note 7)

0.1Hz ≤ f ≤ 10Hz

10Hz ≤ f ≤ 1kHz

0.25

0.67

Turn-On Time

400

µs

Long-Term Drift of Output Voltage (Note 8)

60

ppm/√kHr

Hysteresis (Note 9)

∆T = –0°C to 70°C

∆T = –40°C to 85°C

∆T = –40°C to 125°C

30

35

60

ppm

ppm

ppm

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: Precision may be affected if the parts are stored outside of the

specified temperature range. Large temperature changes may cause

changes in device performance due to thermal hysteresis. For best

performance, extreme temperatures should be avoided whenever possible.

Note 3: The stated temperature is typical for soldering of the leads during

manual rework. For detailed IR reflow recommendations, refer to the

Applications Information section.

Note 4: Temperature coefficient is measured by dividing the maximum

change in output voltage by the specified temperature range.

Note 5: Load regulation is measured on a pulse basis from no load to

the specified load current. Load current does not include the 2mA sense

current. Output changes due to die temperature change must be taken into

account separately.

Note 6: Excludes load regulation errors. Minimum supply for the

LTC6655-1.25, LTC6655-2.048 and LTC6655-2.5 is set by internal circuitry

supply requirements, regardless of load condition. Minimum supply for

the LTC6655-3, LTC6655-3.3, LTC6655-4.096 and LTC6655-5 is specified

by load current.

Note 7: Peak-to-peak noise is measured with a 2-pole highpass filter at

0.1Hz and 3-pole lowpass filter at 10Hz. The unit is enclosed in a still-air

environment to eliminate thermocouple effects on the leads, and the

test time is 10 seconds. Due to the statistical nature of noise, repeating

noise measurements will yield larger and smaller peak values in a given

measurement interval. By repeating the measurement for 1000 intervals,

each 10 seconds long, it is shown that there are time intervals during

which the noise is higher than in a typical single interval, as predicted by

statistical theory. In general, typical values are considered to be those for

which at least 50% of the units may be expected to perform similarly or

better. For the 1000 interval test, a typical unit will exhibit noise that is

less than the typical value listed in the Electrical Characteristics table in

more than 50% of its measurement intervals. See Application Note 124 for

noise testing details. RMS noise is measured with a spectrum analyzer in a

shielded environment.

Note 8: 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 is also affected by differential

stresses between the IC and the board material created during board

assembly.

Note 9: Hysteresis in output voltage is created by mechanical 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 the hot or cold temperature limit 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 usually not a significant error source.