6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)(2)
| Input Voltage |
−0.4 V ≤ VIN ≤ 45 V |
| Switch Voltage |
−0.4 V ≤ VSW ≤ 65 V |
| Switch Current (3) |
Internally Limited |
| Compensation Pin Voltage |
−0.4 V ≤ VCOMP ≤ 2.4 V |
| Feedback Pin Voltage |
−0.4 V ≤ VFB ≤ 2 V |
| Storage Temperature Range |
−65°C to +150°C |
| Lead Temperature |
(Soldering, 10 sec.) |
260°C |
| Maximum Junction Temperature(4) |
150°C |
| Power Dissipation (4) |
Internally Limited |
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions the device is intended to be functional, but device parameter specifications may not be specified under these conditions. For specifications and test conditions see
Electrical Characteristics: All Versions.
(2) If Military/Aerospace specified devices are required, contact the Texas Instruments Sales Office/ Distributors for availability and specifications.
(3) Note that switch current and output current are not identical in a step-up regulator. Output current cannot be internally limited when the LM2585 is used as a step-up regulator. To prevent damage to the switch, the output current must be externally limited to 3 A. However, output current is internally limited when the LM2585 is used as a flyback regulator (see
Typical Flyback Regulator Applications for more information).
(4) The junction temperature of the device (TJ) is a function of the ambient temperature (TA), the junction-to-ambient thermal resistance (θJA), and the power dissipation of the device (PD). A thermal shutdown will occur if the temperature exceeds the maximum junction temperature of the device: PD × θJA + TA(MAX) ≥ TJ(MAX). For a safe thermal design, check that the maximum power dissipated by the device is less than: PD ≤ [TJ(MAX) − TA(MAX))]/θJA. When calculating the maximum allowable power dissipation, derate the maximum junction temperature—this ensures a margin of safety in the thermal design.