Datasheet LTC3890 (Analog Devices)
| Fabricante | Analog Devices |
| Descripción | 60V Low IQ, Dual, 2-Phase Synchronous Step-Down DC/DC Controller |
| Páginas / Página | 40 / 1 — FEATURES. DESCRIPTION. Wide VIN Range: 4V to 60V (65V Abs Max). Low … |
| Formato / tamaño de archivo | PDF / 935 Kb |
| Idioma del documento | Inglés |
FEATURES. DESCRIPTION. Wide VIN Range: 4V to 60V (65V Abs Max). Low Operating IQ: 50µA (One Channel On)
Versión de texto del documento
LTC3890 60V Low IQ, Dual, 2-Phase Synchronous Step-Down DC/DC Controller
FEATURES DESCRIPTION
n
Wide VIN Range: 4V to 60V (65V Abs Max)
The LTC®3890 is a high performance dual step-down n
Low Operating IQ: 50µA (One Channel On)
switching regulator DC/DC controller that drives all n
Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 24V
N-channel synchronous power MOSFET stages. A constant n
RSENSE or DCR Current Sensing
frequency current mode architecture allows a phase- n Out-of-Phase Controllers Reduce Required Input lockable frequency of up to 850kHz. Power loss and noise Capacitance and Power Supply Induced Noise due to the ESR of the input capacitor are minimized by n Phase-Lockable Frequency (75kHz to 850kHz) operating the two controller output stages out-of-phase. n Programmable Fixed Frequency (50kHz to 900kHz) The 50μA no-load quiescent current extends operating run n Selectable Continuous, Pulse-Skipping or Low Ripple time in battery-powered systems. OPTI-LOOP® compensa- Burst Mode® Operation at Light Loads tion allows the transient response to be optimized over n Selectable Current Limit a wide range of output capacitance and ESR values. The n Very Low Dropout Operation: 99% Duty Cycle LTC3890 features a precision 0.8V reference and power n Adjustable Output Voltage Soft-Start or Tracking good output indicators. A wide 4V to 60V input supply n Power Good Output Voltage Monitors range encompasses a wide range of intermediate bus n Output Overvoltage Protection voltages and battery chemistries. n Low Shutdown IQ : < 14µA n Internal LDO Powers Gate Drive from VIN or EXTVCC Independent TRACK/SS pins for each controller ramp the n No Current Foldback During Start-Up output voltages during start-up. Current foldback limits n Small Low Profile (0.75mm) 5mm × 5mm QFN Package MOSFET heat dissipation during short-circuit conditions. The PLLIN/MODE pin selects among Burst Mode operation,
APPLICATIONS
pulse-skipping mode, or continuous conduction mode at light loads. For a leaded package version (28-lead Narrow n Automotive Always-On Systems SSOP), see the LTC3890-1 data sheet. n Battery Operated Digital Devices L, LT, LTC, LTM, Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. n Distributed DC Power Systems Patents, including 5481178, 5705919, 5929620, 6100678, 6144194, 6177787, 6304066, 6580258, 7230497.
TYPICAL APPLICATION High Efficiency Dual 8.5V/3.3V Output Step-Down Converter Efficiency and Power Loss
VIN
vs Output Current
9V TO 60V 22µF 4.7µF 100 10000 VIN = 12V VIN INTVCC 90 VOUT = 3.3V TG1 TG2 0.1µF 0.1µF 80 1000 4.7µH BOOST1 BOOST2 8µH POWER LOSS (mW) 70 SW1 SW2 60 100 BG1 BG2 50 LTC3890 PGND 40 10 EFFICIENCY (%) SENSE1+ SENSE2+ 30 0.008Ω 0.01Ω 20 1 V SENSE1– SENSE2– V OUT1 OUT2 10 3.3V 8.5V VFB1 VFB2 0 0.1 5A 100k ITH1 ITH2 100k 3A 0.0001 0.001 0.01 0.1 1 10 470µF 1000pF 1000pF TRACK/SS1 SGND TRACK/SS2 330µF OUTPUT CURRENT (A) 10.5k 3890 TA01b 31.6k 34.8k 34.8k 0.1µF 0.1µF 3890 TA01a 3890fc 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
FEATURES DESCRIPTION
n
Wide VIN Range: 4V to 60V (65V Abs Max)
The LTC®3890 is a high performance dual step-down n
Low Operating IQ: 50µA (One Channel On)
switching regulator DC/DC controller that drives all n
Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 24V
N-channel synchronous power MOSFET stages. A constant n
RSENSE or DCR Current Sensing
frequency current mode architecture allows a phase- n Out-of-Phase Controllers Reduce Required Input lockable frequency of up to 850kHz. Power loss and noise Capacitance and Power Supply Induced Noise due to the ESR of the input capacitor are minimized by n Phase-Lockable Frequency (75kHz to 850kHz) operating the two controller output stages out-of-phase. n Programmable Fixed Frequency (50kHz to 900kHz) The 50μA no-load quiescent current extends operating run n Selectable Continuous, Pulse-Skipping or Low Ripple time in battery-powered systems. OPTI-LOOP® compensa- Burst Mode® Operation at Light Loads tion allows the transient response to be optimized over n Selectable Current Limit a wide range of output capacitance and ESR values. The n Very Low Dropout Operation: 99% Duty Cycle LTC3890 features a precision 0.8V reference and power n Adjustable Output Voltage Soft-Start or Tracking good output indicators. A wide 4V to 60V input supply n Power Good Output Voltage Monitors range encompasses a wide range of intermediate bus n Output Overvoltage Protection voltages and battery chemistries. n Low Shutdown IQ : < 14µA n Internal LDO Powers Gate Drive from VIN or EXTVCC Independent TRACK/SS pins for each controller ramp the n No Current Foldback During Start-Up output voltages during start-up. Current foldback limits n Small Low Profile (0.75mm) 5mm × 5mm QFN Package MOSFET heat dissipation during short-circuit conditions. The PLLIN/MODE pin selects among Burst Mode operation,
APPLICATIONS
pulse-skipping mode, or continuous conduction mode at light loads. For a leaded package version (28-lead Narrow n Automotive Always-On Systems SSOP), see the LTC3890-1 data sheet. n Battery Operated Digital Devices L, LT, LTC, LTM, Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. n Distributed DC Power Systems Patents, including 5481178, 5705919, 5929620, 6100678, 6144194, 6177787, 6304066, 6580258, 7230497.
TYPICAL APPLICATION High Efficiency Dual 8.5V/3.3V Output Step-Down Converter Efficiency and Power Loss
VIN
vs Output Current
9V TO 60V 22µF 4.7µF 100 10000 VIN = 12V VIN INTVCC 90 VOUT = 3.3V TG1 TG2 0.1µF 0.1µF 80 1000 4.7µH BOOST1 BOOST2 8µH POWER LOSS (mW) 70 SW1 SW2 60 100 BG1 BG2 50 LTC3890 PGND 40 10 EFFICIENCY (%) SENSE1+ SENSE2+ 30 0.008Ω 0.01Ω 20 1 V SENSE1– SENSE2– V OUT1 OUT2 10 3.3V 8.5V VFB1 VFB2 0 0.1 5A 100k ITH1 ITH2 100k 3A 0.0001 0.001 0.01 0.1 1 10 470µF 1000pF 1000pF TRACK/SS1 SGND TRACK/SS2 330µF OUTPUT CURRENT (A) 10.5k 3890 TA01b 31.6k 34.8k 34.8k 0.1µF 0.1µF 3890 TA01a 3890fc 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts