Datasheet LTC1151 (Analog Devices) - 8
| Manufacturer | Analog Devices |
| Description | Dual ±15V Zero-Drift Operational Amplifier |
| Pages / Page | 12 / 8 — APPLICATI. S I FOR ATIO. ALIASING. Table 1. Resistor Thermal EMF. … |
| File Format / Size | PDF / 190 Kb |
| Document Language | English |
APPLICATI. S I FOR ATIO. ALIASING. Table 1. Resistor Thermal EMF. RESISTOR TYPE. THERMAL EMF/. C GRADIENT
Model Line for this Datasheet
Text Version of Document
LTC1151
O U U W U APPLICATI S I FOR ATIO
Resistors are another source of thermal EMF errors. they are outside the LTC1151’s offset nulling loop and Table 1 shows the thermal EMF generated for different cannot be cancelled. The input offset voltage specification resistors. The temperature gradient across the resistor is of the LTC1151 is actually set by the package-induced important, not the ambient temperature. There are two warm-up drift rather than by the circuit itself. The thermal junctions formed at each end of the resistor and if these time constant ranges from 0.5 to 3 minutes, depending on junctions are at the same temperature, their thermal EMFs package type. will cancel each other. The thermal EMF numbers are approximate and vary with resistor value. High values give
ALIASING
higher thermal EMF. Like all sampled data systems, the LTC1151 exhibits
Table 1. Resistor Thermal EMF
aliasing behavior at input frequencies near the sampling frequency. The LTC1151 includes a high frequency cor-
RESISTOR TYPE THERMAL EMF/
°
C GRADIENT
rection loop which minimizes this effect. As a result, Tin Oxide >1mV/°C aliasing is not a problem for many applications. Carbon Composition ∼450µV/°C Metal Film ∼20µV/°C For a complete discussion of the correction circuitry and Wire Wound aliasing behavior, please refer to the LTC1051/LTC1053 Evenohm, Manganin ∼2µV/°C data sheet.
PACKAGE-INDUCED OFFSET VOLTAGE LOW SUPPLY OPERATION
Package-induced thermal EMF effects are another impor- The minimum supply for proper operation of the LTC1151 tant source of errors. They arise at the junctions formed is typically 4.0V (±2.0V). In single supply applications, when wire or printed circuit traces contact a package lead. PSRR is guaranteed down to 4.7V (±2.35V) to ensure Like all the previously mentioned thermal EMF effects, proper operation at minimum TTL supply voltage of 4.75V. NOMINALLY UNNECESSARY LEAD WIRE/SOLDER RESISTOR USED TO COPPER TRACE JUNCTION THERMALLY BALANCE OTHER INPUT RESISTOR + LTC1151 OUTPUT – RESISTOR LEAD, SOLDER, COPPER TRACE JUNCTION 1151 F01
Figure 1. Extra Resistors Cancel Thermal EMF
1151fa 8
O U U W U APPLICATI S I FOR ATIO
Resistors are another source of thermal EMF errors. they are outside the LTC1151’s offset nulling loop and Table 1 shows the thermal EMF generated for different cannot be cancelled. The input offset voltage specification resistors. The temperature gradient across the resistor is of the LTC1151 is actually set by the package-induced important, not the ambient temperature. There are two warm-up drift rather than by the circuit itself. The thermal junctions formed at each end of the resistor and if these time constant ranges from 0.5 to 3 minutes, depending on junctions are at the same temperature, their thermal EMFs package type. will cancel each other. The thermal EMF numbers are approximate and vary with resistor value. High values give
ALIASING
higher thermal EMF. Like all sampled data systems, the LTC1151 exhibits
Table 1. Resistor Thermal EMF
aliasing behavior at input frequencies near the sampling frequency. The LTC1151 includes a high frequency cor-
RESISTOR TYPE THERMAL EMF/
°
C GRADIENT
rection loop which minimizes this effect. As a result, Tin Oxide >1mV/°C aliasing is not a problem for many applications. Carbon Composition ∼450µV/°C Metal Film ∼20µV/°C For a complete discussion of the correction circuitry and Wire Wound aliasing behavior, please refer to the LTC1051/LTC1053 Evenohm, Manganin ∼2µV/°C data sheet.
PACKAGE-INDUCED OFFSET VOLTAGE LOW SUPPLY OPERATION
Package-induced thermal EMF effects are another impor- The minimum supply for proper operation of the LTC1151 tant source of errors. They arise at the junctions formed is typically 4.0V (±2.0V). In single supply applications, when wire or printed circuit traces contact a package lead. PSRR is guaranteed down to 4.7V (±2.35V) to ensure Like all the previously mentioned thermal EMF effects, proper operation at minimum TTL supply voltage of 4.75V. NOMINALLY UNNECESSARY LEAD WIRE/SOLDER RESISTOR USED TO COPPER TRACE JUNCTION THERMALLY BALANCE OTHER INPUT RESISTOR + LTC1151 OUTPUT – RESISTOR LEAD, SOLDER, COPPER TRACE JUNCTION 1151 F01
Figure 1. Extra Resistors Cancel Thermal EMF
1151fa 8
