Datasheet LTC3838-2 (Analog Devices) - 3

LTC3838-2
e lecTrical characTerisTics The
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denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C. VIN = 15V unless otherwise noted (Note 3). SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loops
VIN Input Voltage Operating Range 4.5 38 V VOUT1,2 Regulated Output Voltage Operating Range VOUT1 Regulated Differentially with Respect to 0.6 5.5 V V – OUTSENSE1 , VOUT2 Regulated Differentially with Respect to V – DFB2 IQ Input DC Supply Current Both Channels Enabled MODE/PLLIN = 0V, No Load 3 mA Only One Channel Enabled RUN1 or RUN2 (But Not Both) = 0V 2 mA Shutdown Supply Current RUN1 = RUN2 = 0V 15 µA V – FB1 Regulated Feedback Voltage on Channel 1 ITH1 = 1.2V, VOUTSENSE1 = 0V (Note 5) (V + – OUTSENSE1 – VOUTSENSE1 ) TA = 25°C 0.5985 0.6 0.6015 V TA = 0°C to 85°C l 0.596 0.6 0.604 V TA = –40°C to 125°C l 0.594 0.6 0.606 V Regulated Feedback Voltage on Channel 1 VIN = 4.5V to 38V, ITH1 = 0.5V to 1.9V, Over Line, Load and Common Mode –0.5V < V – OUTSENSE1 < 0.5V (Note 5) TA = 0°C to 85°C l 0.594 0.6 0.606 V TA = –40°C to 125°C l 0.591 0.6 0.609 V –0.2V < V – OUTSENSE1 < 0.2V TA = 0°C to 85°C l 0.5955 0.6 0.6045 V TA = –40°C to 125°C l 0.594 0.6 0.606 V V – FB2 Regulated Feedback Voltage on Channel 2 VDFB2 = 0V, ITH2 = 1.2V (Note 5) (2 • V + – DFB2 – VDFB2 ) EXTVREF2 = 0.6V, TA = 25°C 0.598 0.6 0.602 V Regulated Feedback Voltage on Channel 2 ITH2 = 0.5V to 1.9V, –0.2V < V – DFB2 < 0.2V, Over Line, Load and Common Mode TA = –40°C to 125°C (Note 5) EXTVREF2 = 0.6V, VIN = 4.5V to 38V l 0.596 0.6 0.604 V EXTVREF2 = 1.5V, VIN = 4.5V to 38V l 1.494 1.5 1.506 V EXTVREF2 = 2.5V, VIN = 5.5V to 38V l 2.493 2.5 2.507 V I + + + – VOUTSENSE1 VOUTSENSE1 Input Bias Current VOUTSENSE1 = 0.6V, VOUTSENSE1 = 0V 0 ±25 nA I – – + – VOUTSENSE1 VOUTSENSE1 Input Bias Current VOUTSENSE1 = 0.6V, VOUTSENSE1 = 0V –25 –50 µA IEXTVREF2 EXTVREF2 Input Bias Current EXTVREF2 = 0.6V –5 ±50 nA VEXTVREF2 Maximum EXTVREF2 Input Operating Voltage VIN ≥ INTVCC ≥ 5V, TRACK/SS2 > 2.5V l 2.5 V VIN ≥ INTVCC ≥ 4V, TRACK/SS2 > 1.5V l 1.5 V Minimum EXTVREF2 Input Operating Voltage l 0.4 V I + + + – VDFB2 VDFB2 Input Bias Current VDFB2 = 0.3V, VDFB2 = 0V 0 ±25 nA I – – + – VDFB2 VDFB2 Input Bias Current VDFB2 = 0.3V, VDFB2 = 0V –6 –12 µA gm(EA)1,2 Error Amplifier Transconductance ITH = 1.2V (Note 5) 1.7 mS (∆ITH1,2/∆VFB1,2) tON(MIN)1,2 Minimum Top Gate On-Time VIN = 38V, VOUT = 0.6V, RT = 20k (Note 6) 30 ns tOFF(MIN)1,2 Minimum Top Gate Off-Time (Note 6) 90 ns
Current Sensing
V + – SENSE(MAX)1,2 Maximum Valley Current Sense Threshold VOUTSENSE1 = 0.57V, VOUTSENSE1 = 0V, l 24 30 36 mV (V + – + – SENSE1,2 – VSENSE1,2 ) EXTVREF2 = 0.6V, VDFB2 = 0.285V, VDFB2 = 0V, V – SENSE1,2 = 2.5V V + – SENSE(MIN)1,2 Minimum Valley Current Sense Threshold VOUTSENSE1 = 0.63V, VOUTSENSE1 = 0V, –15 mV (V + – + – SENSE1,2 – VSENSE1,2 ) EXTVREF2 = 0.6V, VDFB2 = 0.315V, VDFB2 = 0V, (Forced Continuous Mode) V – SENSE1,2 = 2.5V I + + SENSE1,2 SENSE1,2+ Pins Input Bias Current VSENSE = 0.6V ±5 ±50 nA V + SENSE = 5V 1 ±2 µA I – – SENSE1,2 SENSE1,2– Pins Input Bias Current (Internal VSENSE = 0.6V 1.2 µA 500k Resistor to SGND) V – SENSE = 5V 10 µA 38382fa For more information www.linear.com/3838-2 3 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts