Datasheet LTM8020 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | 200mA, 36V DC/DC µModule Regulator |
| Pages / Page | 16 / 10 — APPLICATIONS INFORMATION. High Temperature Considerations. BIAS Pin … |
| File Format / Size | PDF / 406 Kb |
| Document Language | English |
APPLICATIONS INFORMATION. High Temperature Considerations. BIAS Pin Considerations. (4a). (4b). (4c)
Model Line for this Datasheet
Text Version of Document
LTM8020
APPLICATIONS INFORMATION High Temperature Considerations
Finally, be aware that at high ambient temperatures the The die temperature of the LTM8020 must be lower than internal Schottky diode will have significant leakage current the maximum rating of 125°C, so care should be taken increasing the quiescent current of the LTM8020. in the layout of the circuit to ensure good heat sinking of
BIAS Pin Considerations
the LTM8020. To estimate the junction temperature, ap- proximate the power dissipation within the LTM8020 by The BIAS pin is used to provide drive power for the internal applying the typical efficiency stated in this data sheet to power switching stage and operate internal circuitry. For the desired output power, or, if you have an actual module, proper operation, it must be powered by at least 3V. If the by taking a power measurement. Then calculate the inter- output voltage is programmed to be 3V or higher, simply nal temperature rise of the LTM8020 above the surface tie BIAS to VOUT. If VOUT is less than 3V, BIAS can be tied of the printed circuit board by multiplying the module’s to VIN or some other voltage source. In all cases, ensure power dissipation by the thermal resistance. The actual that the maximum voltage at the BIAS pin is both less than thermal resistance of the LTM8020 to the printed circuit 25V and the sum of VIN and BIAS is less than 47V. If BIAS board depends upon the layout of the circuit board, but the power is applied from a remote or noisy voltage source, it thermal resistance given in the Pin Configuration, which is may be necessary to apply a decoupling capacitor locally based upon a 25cm2 4-layer FR4 PC board, and the Typical to the LTM8020. Performance Characteristics can be used a guide. CLOSING SWITCH SIMULATES HOT PLUG IIN VIN LTM8020 VIN + 10V/DIV 2.2µF IIN 10A/DIV LOW STRAY IMPEDANCE INDUCTANCE 10µs/DIV ENERGIZED DUE TO 6 FEET 24V SUPPLY (2 METERS) OF TWISTED PAIR
(4a)
LTM8020 VIN 10µF + 10V/DIV 35V 2.2µF AI.EI. IIN 10A/DIV
(4b)
10µs/DIV 1Ω LTM8020 VIN 10V/DIV 0.1µF 2.2µF IIN 10A/DIV
(4c)
10µs/DIV 8020 F04
Figure 4. A Well Chosen Input Network Prevents Input Voltage Overshoot and Ensures Reliable Operation When the LTM8020 is Connected to a Live Supply
8020fe 10 For more information www.linear.com/LTM8020
APPLICATIONS INFORMATION High Temperature Considerations
Finally, be aware that at high ambient temperatures the The die temperature of the LTM8020 must be lower than internal Schottky diode will have significant leakage current the maximum rating of 125°C, so care should be taken increasing the quiescent current of the LTM8020. in the layout of the circuit to ensure good heat sinking of
BIAS Pin Considerations
the LTM8020. To estimate the junction temperature, ap- proximate the power dissipation within the LTM8020 by The BIAS pin is used to provide drive power for the internal applying the typical efficiency stated in this data sheet to power switching stage and operate internal circuitry. For the desired output power, or, if you have an actual module, proper operation, it must be powered by at least 3V. If the by taking a power measurement. Then calculate the inter- output voltage is programmed to be 3V or higher, simply nal temperature rise of the LTM8020 above the surface tie BIAS to VOUT. If VOUT is less than 3V, BIAS can be tied of the printed circuit board by multiplying the module’s to VIN or some other voltage source. In all cases, ensure power dissipation by the thermal resistance. The actual that the maximum voltage at the BIAS pin is both less than thermal resistance of the LTM8020 to the printed circuit 25V and the sum of VIN and BIAS is less than 47V. If BIAS board depends upon the layout of the circuit board, but the power is applied from a remote or noisy voltage source, it thermal resistance given in the Pin Configuration, which is may be necessary to apply a decoupling capacitor locally based upon a 25cm2 4-layer FR4 PC board, and the Typical to the LTM8020. Performance Characteristics can be used a guide. CLOSING SWITCH SIMULATES HOT PLUG IIN VIN LTM8020 VIN + 10V/DIV 2.2µF IIN 10A/DIV LOW STRAY IMPEDANCE INDUCTANCE 10µs/DIV ENERGIZED DUE TO 6 FEET 24V SUPPLY (2 METERS) OF TWISTED PAIR
(4a)
LTM8020 VIN 10µF + 10V/DIV 35V 2.2µF AI.EI. IIN 10A/DIV
(4b)
10µs/DIV 1Ω LTM8020 VIN 10V/DIV 0.1µF 2.2µF IIN 10A/DIV
(4c)
10µs/DIV 8020 F04
Figure 4. A Well Chosen Input Network Prevents Input Voltage Overshoot and Ensures Reliable Operation When the LTM8020 is Connected to a Live Supply
8020fe 10 For more information www.linear.com/LTM8020
