Datasheet ADP2138, ADP2139 (Analog Devices) - 4

ADP2138/ADP2139 Data Sheet ABSOLUTE MAXIMUM RATINGS
Junction-to-ambient thermal resistance (θJA) of the package is
Table 3.
based on modeling and calculation using a 4-layer board. The
Parameter Rating
junction-to-ambient thermal resistance is highly dependent on VIN, EN, MODE −0.4 V to +6.5 V the application and board layout. In applications where high VOUT, SW to GND −1.0 V to (VIN + 0.2 V) maximum power dissipation exists, close attention to thermal Temperature Range board design is required. The value of θJA may vary, depending on Operating Ambient −40°C to +85°C PCB material, layout, and environmental conditions. The specified Operating Junction −40°C to +125°C values of θJA are based on a 4-layer, 4 in. × 3 in., circuit board. Refer Storage Temperature −65°C to +150°C to JEDEC JESD 51-9 for detailed information pertaining to board Lead Temperature Range −65°C to +150°C construction. For additional information, see AN-617 Application Soldering (10 sec) 300°C Note, MicroCSPTM Wafer Level Chip Scale Package. Vapor Phase (60 sec) 215°C ΨJB is the junction-to-board thermal characterization parameter Infrared (15 sec) 220°C measured in units of °C/W. ΨJB of the package is based on modeling ESD Model and calculation using a 4-layer board. The JESD51-12, Guidelines Human Body ±1500 V for Reporting and Using Package Thermal Information, states that Charged Device ±500 V thermal characterization parameters are not the same as thermal Machine ±100 V resistances. ΨJB measures the component power flowing through multiple thermal paths rather than through a single path, which Stresses above those listed under Absolute Maximum Ratings is the procedure for measuring thermal resistance, θJB. There- may cause permanent damage to the device. This is a stress fore, ΨJB thermal paths include convection from the top of the rating only; functional operation of the device at these or any package as wel as radiation from the package; factors that make other conditions above those indicated in the operational ΨJB more useful in real-world applications than θJB. Maximum section of this specification is not implied. Exposure to absolute junction temperature (TJ) is calculated from the board temperature maximum rating conditions for extended periods may affect (TB) and power dissipation (PD) using the formula device reliability. TJ = TB + (PD × ΨJB)
THERMAL DATA
Refer to JEDEC JESD51-8 and JESD51-12 for more detailed Absolute maximum ratings apply individually only, not in information about ΨJB. combination.
THERMAL RESISTANCE
ADP2138/ADP2139 can be damaged when the junction tempera- θJA and ΨJB are specified for the worst-case conditions, that is, a ture limits are exceeded. Monitoring ambient temperature does device soldered in a circuit board for surface-mount packages. not guarantee that the junction temperature (TJ) is within the specified temperature limits. In applications with high power
Table 4. Thermal Resistance
dissipation and poor thermal resistance, the maximum ambient
Package Type θJA ΨJB Unit
temperature may need to be derated. In applications with mod- 6-Ball WLCSP 170 80 °C/W erate power dissipation and low printed circuit board (PCB) thermal resistance, the maximum ambient temperature can exceed the maximum limit for as long as the junction temperature
ESD CAUTION
is within specification limits. The junction temperature (TJ) of the device is dependent on the ambient temperature (TA), the power dissipation of the device (PD), and the junction-to-ambient thermal resistance of the package (θJA). Maximum junction temperature (T J) is calculated from the ambient temperature (T A) and power dissipation (PD) using the formula T J = TA + (PD × θJA) Rev. C | Page 4 of 20 Document Outline Features Applications General Description Typical Applications Circuit Revision History Table of Contents Specifications Input and Output Capacitor, Recommended Specifications Absolute Maximum Ratings Thermal Resistance ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Theory of Operation Control Scheme PWM Mode Power Save Mode Power Save Mode Current Threshold Enable/Shutdown Short-Circuit Protection Undervoltage Lockout Thermal Protection Soft Start Current Limit 100% Duty Operation Discharge Switch Applications Information ADIsimPower Design Tool External Component Selection Inductor Thermal Considerations PCB Layout Guidelines Evaluation Board Evaluation Board Layout Outline Dimensions Ordering Guide