link to page 7 link to page 7 Data SheetADA4938-1/ADA4938-2ABSOLUTE MAXIMUM RATINGS The power dissipated in the package (P Table 5. D) is the sum of the quiescent power dissipation and the power dissipated in the ParameterRating package due to the load drive. The quiescent power is the voltage Supply Voltage 12 V between the supply pins (VS) times the quiescent current (IS). Power Dissipation See Figure 4 The power dissipated due to the load drive depends upon the Storage Temperature Range −65°C to +125°C particular application. The power due to load drive is calculated Operating Temperature Range −40°C to +85°C by multiplying the load current by the associated voltage drop Lead Temperature (Soldering, 10 sec) 300°C across the device. RMS voltages and currents must be used in Junction Temperature 150°C these calculations. Stresses at or above those listed under Absolute Maximum Airflow increases heat dissipation, which effectively reduces θJA. Ratings may cause permanent damage to the product. This is a In addition, more metal directly in contact with the package stress rating only; functional operation of the product at these leads/exposed pad from metal traces, through-holes, ground, or any other conditions above those indicated in the operational and power planes reduces the θJA. section of this specification is not implied. Operation beyond Figure 4 shows the maximum safe power dissipation in the the maximum operating conditions for extended periods may package vs. the ambient temperature for the ADA4938-1, affect product reliability. 16-lead LFCSP (95°C/W) and the ADA4938-2, 24-lead LFCSP THERMAL RESISTANCE (65°C/W) on a JEDEC standard 4-layer board. θ 3.5 JA is specified for the device (including exposed pad) soldered to a high thermal conductivity 4-layer circuit board, as described in )3.0 EIA/JESD 51-7. The exposed pad is not electrical y connected to (W N the device. It is typical y soldered to a pad on the PCB that is IO2.5T thermal y and electrical y connected to an internal ground plane. PAADA4938-2ISSI2.0Table 6. Thermal ResistanceD ERPackage TypeθW1.5JAUnitADA4938-1 16-Lead LFCSP (Exposed Pad) 95 °C/W M PO1.0 24-Lead LFCSP (Exposed Pad) 65 °C/W MU XIMA0.5Maximum Power Dissipation0 The maximum safe power dissipation in the ADA4938-1/ –40 –30 –20 –100102030405060708090 103 ADA4938-2 packages is limited by the associated rise in AMBIENT TEMPERATURE (°C) 06592- junction temperature (TJ) on the die. At approximately 150°C, Figure 4. Maximum Power Dissipation vs. Temperature, 4-Layer Board which is the glass transition temperature, the plastic changes its properties. Even temporarily exceeding this temperature limit can change the stresses that the package exerts on the die, ESD CAUTION permanently shifting the parametric performance of the ADA4938-1/ADA4938-2. Exceeding a junction temperature of 150°C for an extended period can result in changes in the silicon devices, potentially causing failure. Rev. B | Page 7 of 26 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAMS REVISION HISTORY SPECIFICATIONS DUAL-SUPPLY OPERATION ±DIN to ±OUT Performance VOCM to ±OUT Performance SINGLE-SUPPLY OPERATION ±DIN to ±OUT Performance VOCM to ±OUT Performance ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE Maximum Power Dissipation ESD CAUTION PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TEST CIRCUTS TERMINOLOGY THEORY OF OPERATION ANALYZING AN APPLICATION CIRCUIT SETTING THE CLOSED-LOOP GAIN ESTIMATING THE OUTPUT NOISE VOLTAGE THE IMPACT OF MISMATCHES IN THE FEEDBACK NETWORKS CALCULATING THE INPUT IMPEDANCE OF AN APPLICATION CIRCUIT INPUT COMMON-MODE VOLTAGE RANGE IN SINGLE-SUPPLY APPLICATIONS TERMINATING A SINGLE-ENDED INPUT SETTING THE OUTPUT COMMON-MODE VOLTAGE LAYOUT, GROUNDING, AND BYPASSING HIGH PERFORMANCE ADC DRIVING OUTLINE DIMENSIONS ORDERING GUIDE