Datasheet LTC3838 (Analog Devices) - 4
| Hersteller | Analog Devices |
| Beschreibung | Dual, Fast, Accurate Step- Down DC/DC Controller with Differential Output Sensing |
| Seiten / Seite | 54 / 4 — elecTrical characTerisTics. The. denotes the specifications which apply … |
| Dateiformat / Größe | PDF / 746 Kb |
| Dokumentensprache | Englisch |
elecTrical characTerisTics. The. denotes the specifications which apply over the specified operating
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LTC3838
elecTrical characTerisTics The
l
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 Current Sensing
V – SENSE(MAX)1,2 Maximum Valley Current Sense Threshold VRNG = 2V, VFB = 0.57V, VSENSE = 2.5V l 80 100 120 mV (V + – – SENSE1,2 – VSENSE1,2 ) VRNG = 0V, VFB = 0.57V, VSENSE = 2.5V l 21 30 40 mV V – RNG = INTVCC, VFB = 0.57V, VSENSE = 2.5V l 39 50 61 mV V – SENSE(MIN)1,2 Minimum Valley Current Sense Threshold VRNG = 2V, VFB = 0.63V, VSENSE = 2.5V –50 mV (V + – – SENSE1,2 – VSENSE1,2 ) VRNG = 0V, VFB = 0.63V, VSENSE = 2.5V –15 mV (Forced Continuous Mode) V – RNG = INTVCC, VFB = 0.63V, VSENSE = 2.5V –25 mV 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 VSENSE = 0.6V 1.2 µA (Internal 500k Resistor to SGND) V – SENSE = 5V 10 µA
Start-Up and Shutdown
VRUN1,2 RUN Pin On Threshold VRUN1,2 Rising l 1.1 1.2 1.3 V RUN Pin On Hysteresis VRUN1,2 Falling from On Threshold 100 mV IRUN1,2 RUN Pin Pull-Up Current when Off RUN1,2 = SGND 1.2 µA RUN Pin Pull-Up Current Hysteresis IRUN1,2(HYS) = IRUN1,2(ON) – IRUN1,2(OFF) 5 µA UVLO INTVCC Undervoltage Lockout INTVCC Falling l 3.3 3.7 V INTVCC Rising l 4.2 4.5 V ITRACK/SS1,2 Soft-Start Pull-Up Current 0V < TRACK/SS1,2 < 0.6V 1 µA
Frequency and Clock Synchronization
f Clock Output Frequency RT = 205k 200 kHz (Steady-State Switching Frequency) RT = 80.6k 450 500 550 kHz RT = 18.2k 2000 kHz Channel 2 Phase (Relative to Channel 1) PHASMD = SGND 180 Deg PHASMD = Floating 180 Deg PHASMD = INTVCC 240 Deg CLKOUT Phase (Relative to Channel 1) PHASMD = SGND 60 Deg PHASMD = Floating 90 Deg PHASMD = INTVCC 120 Deg VPLLIN(H) Clock Input High Level Into MODE/PLLIN 2 V VPLLIN(L) Clock Input Low Level Into MODE/PLLIN 0.5 V RMODE/PLLIN MODE/PLLIN Input DC Resistance With Respect to SGND 600 kΩ
Gate Drivers
RTG(UP)1,2 TG Driver Pull-Up On Resistance TG High 2.5 Ω RTG(DOWN)1,2 TG Driver Pull-Down On Resistance TG Low 1.2 Ω RBG(UP)1,2 BG Driver Pull-Up On Resistance BG High 2.5 Ω RBG(DOWN)1,2 BG Driver Pull-Down On Resistance BG Low 0.8 Ω tD(TG/BG)1,2 Top Gate Off to Bottom Gate On Delay Time (Note 6) 20 ns tD(BG/TG)1,2 Bottom Gate Off to Top Gate On Delay Time (Note 6) 15 ns 3838fb 4 For more information www.linear.com/LTC3838 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Typical Applications Package Description Revision History Typical Application Related Parts
elecTrical characTerisTics The
l
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 Current Sensing
V – SENSE(MAX)1,2 Maximum Valley Current Sense Threshold VRNG = 2V, VFB = 0.57V, VSENSE = 2.5V l 80 100 120 mV (V + – – SENSE1,2 – VSENSE1,2 ) VRNG = 0V, VFB = 0.57V, VSENSE = 2.5V l 21 30 40 mV V – RNG = INTVCC, VFB = 0.57V, VSENSE = 2.5V l 39 50 61 mV V – SENSE(MIN)1,2 Minimum Valley Current Sense Threshold VRNG = 2V, VFB = 0.63V, VSENSE = 2.5V –50 mV (V + – – SENSE1,2 – VSENSE1,2 ) VRNG = 0V, VFB = 0.63V, VSENSE = 2.5V –15 mV (Forced Continuous Mode) V – RNG = INTVCC, VFB = 0.63V, VSENSE = 2.5V –25 mV 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 VSENSE = 0.6V 1.2 µA (Internal 500k Resistor to SGND) V – SENSE = 5V 10 µA
Start-Up and Shutdown
VRUN1,2 RUN Pin On Threshold VRUN1,2 Rising l 1.1 1.2 1.3 V RUN Pin On Hysteresis VRUN1,2 Falling from On Threshold 100 mV IRUN1,2 RUN Pin Pull-Up Current when Off RUN1,2 = SGND 1.2 µA RUN Pin Pull-Up Current Hysteresis IRUN1,2(HYS) = IRUN1,2(ON) – IRUN1,2(OFF) 5 µA UVLO INTVCC Undervoltage Lockout INTVCC Falling l 3.3 3.7 V INTVCC Rising l 4.2 4.5 V ITRACK/SS1,2 Soft-Start Pull-Up Current 0V < TRACK/SS1,2 < 0.6V 1 µA
Frequency and Clock Synchronization
f Clock Output Frequency RT = 205k 200 kHz (Steady-State Switching Frequency) RT = 80.6k 450 500 550 kHz RT = 18.2k 2000 kHz Channel 2 Phase (Relative to Channel 1) PHASMD = SGND 180 Deg PHASMD = Floating 180 Deg PHASMD = INTVCC 240 Deg CLKOUT Phase (Relative to Channel 1) PHASMD = SGND 60 Deg PHASMD = Floating 90 Deg PHASMD = INTVCC 120 Deg VPLLIN(H) Clock Input High Level Into MODE/PLLIN 2 V VPLLIN(L) Clock Input Low Level Into MODE/PLLIN 0.5 V RMODE/PLLIN MODE/PLLIN Input DC Resistance With Respect to SGND 600 kΩ
Gate Drivers
RTG(UP)1,2 TG Driver Pull-Up On Resistance TG High 2.5 Ω RTG(DOWN)1,2 TG Driver Pull-Down On Resistance TG Low 1.2 Ω RBG(UP)1,2 BG Driver Pull-Up On Resistance BG High 2.5 Ω RBG(DOWN)1,2 BG Driver Pull-Down On Resistance BG Low 0.8 Ω tD(TG/BG)1,2 Top Gate Off to Bottom Gate On Delay Time (Note 6) 20 ns tD(BG/TG)1,2 Bottom Gate Off to Top Gate On Delay Time (Note 6) 15 ns 3838fb 4 For more information www.linear.com/LTC3838 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Typical Applications Package Description Revision History Typical Application Related Parts