Datasheet AD580 (Analog Devices) - 6

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AD580
The consistent voltage versus temperature performance of a
1mV
typical AD580 is shown in Figure 7. Note that the characteristic is quasi-parabolic, not the possible S type characteristics of classical Zener references. This parabolic characteristic permits
E
a maximum output deviation specification over the device’s full
100
µ
V
operating temperature range, rather than just at 3 to 5 discrete
AK NOIS
temperatures.
E 2.51 AK-TO-P 10
µ
V E P 2.50
-009 00525-B
2.49 MAXIMUM 0 VOLTAGE CHANGE 100 1k 10k 100k 1M FROM 0
°
C TO 70
°
C FREQUENCY (Hz)
Figure 9. Peak-to-Peak Output Noise vs. Frequency
2.48 OUTPUT VOLTAGE (V) 2.47
-007
2.46
00525-B
–55 –30 0 25 50 75 100 125 TEMPERATURE (
°
C)
Figure 7. Typical AD580K Output Voltage vs. Temperature The AD580M guarantees a maximum deviation of 1.75 mV over the 0°C to 70°C temperature range. This can be shown to be equivalent to 10 ppm/°C average maximum; i.e.,
500
µ
A
1.75 mV max -010 1 × = 10 ppm / C ° max average
5V
70 C ° 2. V 5 00525-B Figure 10. Input Current vs. Input Voltage (Integral Loads) The AD580 typically exhibits a variation of 1.5 mV over the power supply range of 7 V to 30 V. Figure 8 is a plot of AD580
THE AD580 AS A CURRENT LIMITER
line rejection versus frequency. The AD580 represents an excellent alternative to current limiter
NOISE PERFORMANCE
diodes that require factory selection to achieve a desired Figure 9 represents the peak-to-peak noise of the AD580 from current. This approach often results in temperature coefficients 1 Hz (3 dB point) to a 3 dB high end shown on the horizontal of 1%/C. The AD580 approach is not limited to a specially axis. Peak-to-peak noise from 1 Hz to 1 MHz is approximately selected factory set current limit; it can be programmed from 600 µV. 1 mA to 10 mA with the insertion of a single external resistor. The approximate temperature coefficient of current limit for the
140
AD580 used in this mode is 0.13%/°C for ILIM = 1 mA and
130 e = 23V p-p
0.01%/°C for ILIM = 13 mA (see Figure 11). Figure 10 displays
120
the high output impedance of the AD580 used as a current
110 k e OUT p-p E = 18.5V AD580
limiter for ILIM = 1, 2, 3, 4, and 5 mA.
100 90 E IN COMPOSITE (17V
≤
V
≤
IN 30V) 80 70 V+ , p-p (mV) 60 OUTE 50 AD580 40 OUTPUT 2.5V 30 2.5V i
≅
+ 1mA 20 R R
-008
LOAD 10 V– 0
00525-B
BOTTOM VIEW OF 10 100 1k 10k 100k
-011
2.5V PRECISION LINE FREQUENCY (Hz) REFERENCE CIRCUIT IN TO-52 CASE
Figure 8. AD580 Line Rejection Plot 00525-B Figure 11. A Two-Component Precision Current Limiter Rev. B | Page 6 of 8 Document Outline FEATURES GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM PRODUCT HIGHLIGHTS SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS AD580 CHIP DIMENSIONS AND PAD LAYOUT ESD CAUTION THEORY OF OPERATION VOLTAGE VARIATION VERSUS TEMPERATURE NOISE PERFORMANCE THE AD580 AS A CURRENT LIMITER THE AD580 AS A LOW POWER, LOW VOLTAGE, PRECISION REFERENCE F OUTLINE DIMENSIONS ORDERING GUIDE