Datasheet ADR280 (Analog Devices) - 7
| Manufacturer | Analog Devices |
| Description | 1.2 V Ultralow Power High PSRR Voltage Reference |
| Pages / Page | 12 / 7 — ADR280. THEORY OF OPERATION. R12. Q10. R13. PNP3. R10. Q18. Q17. VOUT. R11 |
| Revision | C |
| File Format / Size | PDF / 863 Kb |
| Document Language | English |
ADR280. THEORY OF OPERATION. R12. Q10. R13. PNP3. R10. Q18. Q17. VOUT. R11
Model Line for this Datasheet
Text Version of Document
link to page 7
ADR280 THEORY OF OPERATION
The ADR280 provides the basic core 1.2 V band gap reference.
V+
It contains two NPN transistors, Q9 and Q17, with their emitter
R1 R2 R12
areas scaled in a fixed ratio. The difference in the VBE produces
I1
a proportional to absolute temperature (PTAT) voltage that
Q2 Q1 Q7
cancels the complementary to absolute temperature (CTAT) Q9
Q10
VBE voltage. As a result, a core band gap voltage that is almost a
R3 R4
constant 1.2 V over temperature is generated (see Figure 11).
R13 C1
Precision laser trimming of the internal resistors and other
PNP3
proprietary circuit techniques are used to enhance the initial
Q3 R10
accuracy, temperature curvature, and temperature drift
Q18 Q17 Q9
performance.
Q6 VOUT R7 Q5 R5 R6 R8 R11 R9
3 -01 5
V–
06 03 Figure 11. Simplified Architecture Rev. C | Page 7 of 12 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION PIN CONFIGURATIONS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ELECTRICAL CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION APPLICATIONS INFORMATION LOW COST, LOW POWER CURRENT SOURCE Precision Low Power Current Source Boosted Current Source Negative Reference Boosted Reference with Scalable Output GSM and 3G Mobile Station Applications OUTLINE DIMENSIONS ORDERING GUIDE
ADR280 THEORY OF OPERATION
The ADR280 provides the basic core 1.2 V band gap reference.
V+
It contains two NPN transistors, Q9 and Q17, with their emitter
R1 R2 R12
areas scaled in a fixed ratio. The difference in the VBE produces
I1
a proportional to absolute temperature (PTAT) voltage that
Q2 Q1 Q7
cancels the complementary to absolute temperature (CTAT) Q9
Q10
VBE voltage. As a result, a core band gap voltage that is almost a
R3 R4
constant 1.2 V over temperature is generated (see Figure 11).
R13 C1
Precision laser trimming of the internal resistors and other
PNP3
proprietary circuit techniques are used to enhance the initial
Q3 R10
accuracy, temperature curvature, and temperature drift
Q18 Q17 Q9
performance.
Q6 VOUT R7 Q5 R5 R6 R8 R11 R9
3 -01 5
V–
06 03 Figure 11. Simplified Architecture Rev. C | Page 7 of 12 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION PIN CONFIGURATIONS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ELECTRICAL CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION APPLICATIONS INFORMATION LOW COST, LOW POWER CURRENT SOURCE Precision Low Power Current Source Boosted Current Source Negative Reference Boosted Reference with Scalable Output GSM and 3G Mobile Station Applications OUTLINE DIMENSIONS ORDERING GUIDE
