Datasheet AD1580 (Analog Devices) - 7

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AD1580 1.2258 REVERSE VOLTAGE HYSTERESIS (VMAX – VO) 1.2256 SLOPE = TC = (+85°C – +25°C) × 1.225 × 10–6
A major requirement for high performance industrial
1.2254 VMAX
equipment manufacturers is a consistent output voltage at
) V ( 1.2252
nominal temperature following operation over the operating
GE 1.2250
temperature range. This characteristic is generated by measur-
VO OLTA 1.2248
ing the difference between the output voltage at +25°C after
T V U 1.2246
operation at +85°C and the output, at +25°C after operation
TP
at −40°C. Figure 15 displays the hysteresis associated with the
1.2244 OU (V
AD1580. This characteristic exists in all references and has been
1.2242 MIN – VO) SLOPE = TC = (–40°C – +25°C) × 1.225 × 10–6
minimized in the AD1580.
1.2240
013
V 40 MIN 1.2238
00700-
–55 –35 –15 5 25 45 65 85 105 125 35 TEMPERATURE (°C)
Figure 13. Output Voltage vs. Temperature
30
For example, the AD1580BRT initial tolerance is ±1 mV;
25
a ±50 ppm/°C temperature coefficient corresponds to an
TITY N 20
error band of ±4 mV (50 × 10−6 × 1.225 V × 65°C). Thus, the
A QU
unit is guaranteed to be 1.225 V ± 5 mV over the operating
15
temperature range.
10
Duplication of these results requires a combination of high
5
accuracy and stable temperature control in a test system. 015 Evaluation of the AD1580 produces a curve similar to that
0
00700-
–400 –300 –200 –100 0 100 200 300 400
in Figure 5 and Figure 13.
HYSTERESIS VOLTAGE (µV) VOLTAGE OUTPUT NONLINEARITY vs.
Figure 15. Reverse Voltage Hysteresis Distribution
TEMPERATURE OUTPUT IMPEDANCE vs. FREQUENCY
When a reference is used with data converters, it is important to Understanding the effect of the reverse dynamic output imped- understand how temperature drift affects the overall converter ance in a practical application may be important to successfully performance. The nonlinearity of the reference output drift apply the AD1580. A voltage divider is formed by the AD1580 represents an additional error that is not easily calibrated out of output impedance and the external source impedance. When the system. This characteristic (see Figure 14) is generated by an external source resistor of about 30 kΩ (IR = 100 μA) is used, normalizing the measured drift characteristic to the end point 1% of the noise from a 100 kHz switching power supply is devel- average drift. The residual drift error of approximately 500 ppm oped at the output of the AD1580. Figure 16 shows how a 1 µF shows that the AD1580 is compatible with systems that require load capacitor connected directly across the AD1580 reduces 10-bit accurate temperature performance. the effect of power supply noise to less than 0.01%.
600 1k 500 m) p p 100 Ω) R ( 400 C ( L = 0 RRO E T DANCE 300 F E 10 P M DRI I 200 UT ΔIR = 0.1IR P I IDUAL R = 100µA UT C S L = 1µF O 1 RE 100 IR = 1mA
014 016
0
00700-
–55 –35 –15 5 25 45 65 85 105 125 0.1
00700-
10 100 1k 10k 100k 1M TEMPERATURE (°C) FREQUENCY (Hz)
Figure 14. Residual Drift Error Figure 16. Output Impedance vs. Frequency Rev. F | Page 7 of 12 Document Outline Features Applications General Description Pin Configurations Revision History Specifications Absolute Maximum Ratings ESD Caution Typical Performance Characteristics Theory of Operation Applying the AD1580 Temperature Performance Voltage Output Nonlinearity vs. Temperature Reverse Voltage Hysteresis Output Impedance vs. Frequency Noise Performance and Reduction Turn-On Time Transient Response Precision Micropower Low Dropout Reference Using the AD1580 with 3 V Data Converters Outline Dimensions Ordering Guide Package Branding Information