Features: Wide Output Voltage Range: 0.8V VOUT 10V
Low Operating IQ: 80µA (One Channel On)
Out-of-Phase Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
OPTI-LOOP® Compensation Minimizes COUT
±1% Output Voltage Accuracy
Wide VIN Range: 4V to 36V Operation
Phase-Lockable Fixed Frequency 140kHz to 650kHz
Selectable Continuous, Pulse Skipping or Low Ripple Burst Mode® Operation at Light Loads
Dual N-Channel MOSFET Synchronous Drive
Very Low Dropout Operation: 99% Duty Cycle
Adjustable Output Voltage Soft-Start or Tracking
Output Current Foldback Limiting
Power Good Output Voltage Monitor
Output Overvoltage Protection
Low Shutdown IQ: 8µA
Internal LDO Powers Gate Drive from VIN or VOUT
Small 5mm * 5mm QFN PackageApplication Automotive Systems
Battery-Operated Digital Devices
Distributed DC Power SystemsPinout
SpecificationsInput Supply Voltage (VIN)...................................36V to 0.3V
Top Side Driver Voltages
(BOOST1, BOOST2)..............................................42V to 0.3V
Switch Voltage (SW1, SW2) ...................................36V to 5V
(BOOST1-SW1), (BOOST2-SW2) .........................8.5V to 0.3V
RUN1, RUN2 ......................................................... 7V to 0.3V
SENSE1+, SENSE2+, SENSE1,
SENSE2 Voltages .............................................11V to 0.3V
PLLIN/MODE, PLLLPF, Voltages .................... INTVCC to 0.3V
PHASMD, FOLDDIS, TRACK/SS1, TRACK/SS2
Voltages ....................................................... INTVCC to 0.3V
EXTVCC ...............................................................10V to 0.3V
ITH1, ITH2, VFB1, VFB2 Voltages .......................2.7V to 0.3V
PGOOD1, PGOOD2 Voltages.............................. 8.5V to 0.3V
Peak Output Current <10µs (TG1, TG2, BG1, BG2) .............. 3A
INTVCC Peak Output Current .......................................... 50mA
Operating Temperature Range (Note 2) ....... 40°C to 85°C
Junction Temperature (Note 3) ..................................... 125°C
Storage Temperature Range ....................... 65°C to 125°C
DescriptionThe LTC®3827 is a high performance dual step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phase-lockable frequency of up to 650kHz. Power loss and noise due to the ESR of the input capacitor ESR are minimized by operating the two controller output stages out of phase.
The 80µA no-load quiescent current extends operating life in battery powered systems. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3827 features a precision 0.8V reference and a power good output indicator. A wide 4V to 36V input supply range encompasses all battery chemistries.
Independent TRACK/SS pins for each controller ramp the output voltage during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions.
The PLLIN/MODE pin selects among Burst Mode operation, pulse skipping mode, or continuous inductor current mode at light loads. For a leaded package version (28-lead SSOP), see the LTC3827-1 datasheet.
LTC3827 Data Sheet
