Datasheet LM4041 (Analog Devices) - 5
| Manufacturer | Analog Devices |
| Description | Improved Precision Micropower Shunt Voltage Reference |
| Pages / Page | 7 / 5 — Improved Precision Micropower. Shunt Voltage Reference. LM4041. Pin … |
| File Format / Size | PDF / 141 Kb |
| Document Language | English |
Improved Precision Micropower. Shunt Voltage Reference. LM4041. Pin Description. PIN. NAME. FUNCTION. Detailed Description
Model Line for this Datasheet
- LM4041AEM3-1.2+ LM4041AEM3-1.2+T LM4041AIM3-1.2+ LM4041AIM3-1.2+T LM4041BEM3-1.2+ LM4041BEM3-1.2+T LM4041BEX3-1.2+ LM4041BEX3-1.2+T LM4041BIM3-1.2+ LM4041BIM3-1.2+T LM4041BIX3-1.2+ LM4041BIX3-1.2+T LM4041CEX3-1.2+ LM4041CEX3-1.2+T LM4041CIM3-1.2+ LM4041CIM3-1.2+T LM4041CIX3-1.2+ LM4041CIX3-1.2+T LM4041DEX3-1.2+ LM4041DEX3-1.2+T LM4041DIM3-1.2+ LM4041DIM3-1.2+T LM4041DIX3-1.2+ LM4041DIX3-1.2+T
Text Version of Document
Improved Precision Micropower Shunt Voltage Reference LM4041 Pin Description PIN NAME FUNCTION
1 + Positive Terminal of the Shunt Reference 2 − Negative Terminal of the Shunt Reference 3 N.C. Leave this pin unconnected, or connect to pin 2.
Detailed Description
The LM4041 shunt references use the bandgap princi- VS ple to produce a stable, accurate voltage. The device behaves similarly to an ideal zener diode; a fixed volt- ISHUNT + ILOAD age of +1.225V is maintained across its output termi- RS nals when biased with 60µA to 12mA of reverse ILOAD current. The LM4041 behaves similarly to a silicon VR diode when biased with forward currents up 10mA. Figure 3 shows a typical operating circuit. The LM4041 ISHUNT is ideal for providing a stable reference from a high- voltage power supply.
Applications Information
LM4041 The LM4041’s internal pass transistor is used to main- tain a constant output voltage (VSHUNT) by sinking the necessary amount of current across a source resistor. The source resistance (RS) is determined from the load current (ILOAD) range, supply voltage (VS) variations, VSHUNT, and desired quiescent current. Figure 3. Typical Operating Circuit Choose the value of RS when VS is at a minimum and ILOAD is at a maximum. Maintain a minimum ISHUNT of 60µA at all times. The R used. Ensure that the resistor’s power rating is ade- S value should be large enough to keep I quate, using the following general power equation: SHUNT less than 12mA for proper regulation when VS is maximum and ILOAD is at a minimum. To PR = ISHUNT ✕ (VS(MAX) - VR) prevent damage to the device, ISHUNT should never exceed 20mA.
Output Capacitance
The LM4041 does not require an external capacitor for Therefore, the value of RS is bounded by the following frequency stability and is stable for any output capaci- equation: tance. [VS(MIN) - VR ] / [60µA + ILOAD(MAX)] > RS > [V
Temperature Performance
S(MAX) - VR ] / [20mA + ILOAD(MIN)] The LM4041 typically exhibits an output voltage tem- Choosing a larger resistance minimizes the total power perature coefficient within ±15ppm/°C. The polarity of dissipation in the circuit by reducing the shunt current the temperature coefficient may be different from one (PD(TOTAL) = VS ✕ ISHUNT). Provide a safety margin to device to another; some may have positive coefficients, incorporate the worst-case tolerance of the resistor and others may have negative coefficients.
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1 + Positive Terminal of the Shunt Reference 2 − Negative Terminal of the Shunt Reference 3 N.C. Leave this pin unconnected, or connect to pin 2.
Detailed Description
The LM4041 shunt references use the bandgap princi- VS ple to produce a stable, accurate voltage. The device behaves similarly to an ideal zener diode; a fixed volt- ISHUNT + ILOAD age of +1.225V is maintained across its output termi- RS nals when biased with 60µA to 12mA of reverse ILOAD current. The LM4041 behaves similarly to a silicon VR diode when biased with forward currents up 10mA. Figure 3 shows a typical operating circuit. The LM4041 ISHUNT is ideal for providing a stable reference from a high- voltage power supply.
Applications Information
LM4041 The LM4041’s internal pass transistor is used to main- tain a constant output voltage (VSHUNT) by sinking the necessary amount of current across a source resistor. The source resistance (RS) is determined from the load current (ILOAD) range, supply voltage (VS) variations, VSHUNT, and desired quiescent current. Figure 3. Typical Operating Circuit Choose the value of RS when VS is at a minimum and ILOAD is at a maximum. Maintain a minimum ISHUNT of 60µA at all times. The R used. Ensure that the resistor’s power rating is ade- S value should be large enough to keep I quate, using the following general power equation: SHUNT less than 12mA for proper regulation when VS is maximum and ILOAD is at a minimum. To PR = ISHUNT ✕ (VS(MAX) - VR) prevent damage to the device, ISHUNT should never exceed 20mA.
Output Capacitance
The LM4041 does not require an external capacitor for Therefore, the value of RS is bounded by the following frequency stability and is stable for any output capaci- equation: tance. [VS(MIN) - VR ] / [60µA + ILOAD(MAX)] > RS > [V
Temperature Performance
S(MAX) - VR ] / [20mA + ILOAD(MIN)] The LM4041 typically exhibits an output voltage tem- Choosing a larger resistance minimizes the total power perature coefficient within ±15ppm/°C. The polarity of dissipation in the circuit by reducing the shunt current the temperature coefficient may be different from one (PD(TOTAL) = VS ✕ ISHUNT). Provide a safety margin to device to another; some may have positive coefficients, incorporate the worst-case tolerance of the resistor and others may have negative coefficients.
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