Datasheet ADP170, ADP171 (Analog Devices) - 5

Data Sheet ADP170/ADP171 ABSOLUTE MAXIMUM RATINGS Table 3.
maximum power dissipation exists, close attention to thermal
Parameter Rating
board design is required. The value of θJA may vary, depending on PCB material, layout, and environmental conditions. The VIN to GND −0.3 V to +3.6 V specified values of θ VOUT to GND −0.3 V to VIN JA are based on a 4-layer, 4 in. × 3 in. PCB. Refer to JESD 51-7 for detailed information regarding board EN to GND −0.3 V to +3.6 V construction. Storage Temperature Range −65°C to +150°C Operating Junction Temperature Range −40°C to +125°C ΨJB is the junction-to-board thermal characterization parameter Operating Ambient Temperature Range −40°C to +85°C with units of °C/W. The ΨJB of the package is based on modeling Soldering Conditions JEDEC J-STD-020 and calculation using a 4-layer board. The Guidelines for Reporting and Using Electronic Package Thermal Information: JESD51-12 Stresses above those listed under absolute maximum ratings states that thermal characterization parameters are not the same may cause permanent damage to the device. This is a stress as thermal resistances. ΨJB measures the component power flowing rating only and functional operation of the device at these or through multiple thermal paths rather than a single path as in any other conditions above those indicated in the operational thermal resistance, θJB. Therefore, ΨJB thermal paths include section of this specification is not implied. Exposure to absolute convection from the top of the package as well as radiation from maximum rating conditions for extended periods may affect the package—factors that make ΨJB more useful in real-world device reliability. applications. Maximum junction temperature (TJ) is calculated from the board temperature (TB) and power dissipation (PD)
THERMAL DATA
using the formula Absolute maximum ratings apply only individually, not in TJ = TB + (PD × ΨJB) combination. The ADP170/ADP171 can be damaged when the junction temperature limits are exceeded. Monitoring ambient Refer to JESD51-8 and JESD51-12 for more detailed information temperature does not guarantee that T about ΨJB. J is within the specified temperature limits. In applications with high power dissipation
THERMAL RESISTANCE
and poor thermal resistance, the maximum ambient temperature θJA and ΨJB are specified for the worst-case conditions, that is, a may have to be derated. device soldered in a circuit board for surface-mount packages. In applications with moderate power dissipation and low PCB thermal resistance, the maximum ambient temperature can
Table 4. Thermal Resistance
exceed the maximum limit as long as the junction temperature
Package Type θJA ΨJB Unit
is within specification limits. The junction temperature (T 5-Lead TSOT 170 43 °C/W J) of the device is dependent on the ambient temperature (T A), the power dissipation of the device (PD), and the junction-to-
ESD CAUTION
ambient thermal resistance of the package (θJA). Maximum junction temperature (TJ) is calculated from the ambient temperature (TA) and power dissipation (PD) using the following formula: TJ = TA + (PD × θJA) Junction-to-ambient thermal resistance (θJA) of the package is based on modeling and calculation using a 4-layer board. The junction-to-ambient thermal resistance is highly dependent on the application and board layout. In applications where high Rev. C | Page 5 of 20 Document Outline Features Applications Typical Application Circuits General Description Table of Contents Revision History Specifications Input and Output Capacitor, Recommended Specifications Absolute Maximum Ratings Thermal Data Thermal Resistance ESD Caution Pin Configurations and Function Descriptions Typical Performance Characteristics Theory of Operation Applications Information Capacitor Selection Output Capacitor Input Bypass Capacitor Input and Output Capacitor Properties Undervoltage Lockout Enable Feature Current Limit and Thermal Overload Protection Thermal Considerations Printed Circuit Board Layout Considerations Outline Dimensions Ordering Guide