LTM4644/LTM4644-1 ELECTRICAL CHARACTERISTICSNote 1: Stresses beyond those listed under Absolute Maximum Ratings and guaranteed over full –55°C to 125°C internal operating temperature may cause permanent damage to the device. Exposure to any Absolute range. Note that the maximum ambient temperature consistent with Maximum Rating condition for extended periods may affect device these specifications is determined by specific operating conditions in reliability and lifetime. conjunction with board layout, the rated package thermal resistance and Note 2: The LTM4644E/LTM4644E-1 is tested under pulsed load other environmental factors. conditions such that TJ ≈ TA. The LTM4644E/LTM4644-1 is guaranteed to Note 3: 100% tested at wafer level. meet performance specifications over the 0°C to 125°C internal operating Note 4: See output current derating curves for different VIN, VOUT and TA. temperature range. Specifications over the full –40°C to 125°C internal Note 5: This IC includes overtemperature protection that is intended operating temperature range are assured by design, characterization and to protect the device during momentary overload conditions. Junction correlation with statistical process controls. The LTM4644I/LTM4644I-1 temperature will exceed 125°C when overtemperature protection is active. is guaranteed to meet specifications over the full –40°C to 125°C internal Continuous operation above the specified maximum operating junction operating temperature range. The LTM4644MP/LTM4644MP-1 is tested temperature may impair device reliability. TYPICAL PERFORMANCE CHARACTERISTICS (Per Channel)Efficiency vs Load Current fromEfficiency vs Load Current fromDCM Mode Efficiency from5VIN (One Channel Operating)12VIN (One Channel Operating)1.5VOUT 100 95 100 90 95 90 80 70 90 85 60 85 80 50 40 EFFICIENCY (%) 5V 80 EFFICIENCY (%) OUT EFFICIENCY (%) 3.3V 75 OUT 3.3VOUT 30 2.5VOUT 2.5VOUT 20 75 1.8VOUT 70 1.8VOUT 1.5VOUT 1.5VOUT 10 5VIN 1.2VOUT 1.2VOUT 12VIN 70 65 0 0 1 2 3 4 0 1 2 3 4 0.001 0.01 0.1 1 10 LOAD CURRENT (A) LOAD CURRENT (A) LOAD CURRENT (A) 4644 G01 4644 G02 4644 G03 1.0V Output Transient Response1.5V Output Transient Response2.5V Output Transient Response VOUT VOUT VOUT 50mV/DIV 50mV/DIV 50mV/DIV AC-COUPLED AC-COUPLED AC-COUPLED LOAD STEP LOAD STEP LOAD STEP 1A/DIV 1A/DIV 1A/DIV 20µs/DIV 4644 G04 20µs/DIV 4644 G05 20µs/DIV 4644 G06 VIN = 12V, VOUT = 1V, IOUT = 3A TO 4A, 1A/µs VIN = 12V, VOUT = 1.5V, IOUT = 3A TO 4A, 1A/µs VIN = 12V, VOUT = 2.5V, IOUT = 3A TO 4A, 1A/µs CFF = 10pF CFF = 10pF CFF = 10pF OUTPUT CAPACITOR = 1 • 47µF CERAMIC OUTPUT CAPACITOR = 1 • 47µF CERAMIC OUTPUT CAPACITOR = 1 • 47µF CERAMIC Rev. G 4 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Block Diagram Decoupling Requirements Operation Applications Information Typical Applications Package Description Revision History Package Photo Design Resources Related Parts