Datasheet LTC3826-1 (Analog Devices)

LTC3826-1 30µA IQ, Dual, 2-Phase Synchronous Step-Down Controller
FEATURES DESCRIPTION
n
Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 10V
The LTC®3826-1 is a high performance dual step-down n
Low Operating IQ: 30μA (One Channel On)
switching regulator controller that drives all N-channel n
Out-of-Phase Controllers Reduce Required Input
synchronous power MOSFET stages. A constant frequency
Capacitance and Power Supply Induced Noise
current mode architecture allows a phase-lockable fre- n
OPTI-LOOP® Compensation Minimizes COUT
quency of up to 650kHz. Power loss and noise due to the n
±1% Output Voltage Accuracy
ESR of the input capacitor ESR are minimized by operating n
Wide V
the two controller output stages out of phase.
IN Range: 4V to 36V Operation
n
Phase-Lockable Fixed Frequency 140kHz to 650kHz
The 30μA no-load quiescent current extends operating n Selectable Continuous, Pulse Skipping or
Low Ripple
life in battery powered systems. OPTI-LOOP compensa- Burst Mode® Operation at Light Loads tion allows the transient response to be optimized over n Dual N-Channel MOSFET Synchronous Drive a wide range of output capacitance and ESR values. The n Very Low Dropout Operation: 99% Duty Cycle LTC3826-1 features a precision 0.8V reference and a power n Adjustable Output Voltage Soft-Start or Tracking good output indicator. A wide 4V to 36V input supply range n Output Current Foldback Limiting encompasses all battery chemistries. n Power Good Output Voltage Monitor n Independent TRACK/SS pins for each controller ramp the Output Overvoltage Protection output voltage during start-up. Current foldback limits n Low Shutdown IQ: 4μA MOSFET heat dissipation during short-circuit conditions. n Internal LDO Powers Gate Drive from VIN or VOUT n Small 28-Lead SSOP Package The PLLIN/MODE pin selects among Burst Mode opera- tion, pulse skipping mode, or continuous inductor cur-
APPLICATIONS
rent mode at light loads. For a leadless package version (5mm × 5mm QFN) with additional features, see the n Automotive Systems LTC3826 data sheet. n Battery-Operated Digital Devices L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. n Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation. Distributed DC Power Systems All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 5929620, 6177787, 6144194, 5408150, 6580258, 6304066, 5705919.
TYPICAL APPLICATION High Effi ciency Dual 8.5V/3.3V Step-Down Converter
VIN
Effi ciency and Power Loss
4V TO 36V 22μF
vs Load Current
4.7μF 50V VIN INTVCC 100 10000 TG1 TG2 90 0.1μF BOOST1 BOOST2 80 1000 3.3μH 0.1μF 7.2μH POWER LOSS (mW) SW1 SW2 70 BG1 BG2 60 100 LTC3826-1 PGND 50 SENSE1+ 40 SENSE2+ 10 EFFICIENCY (%) 30 0.015Ω 0.015Ω 20 1 V SENSE1– SENSE2– OUT1 VOUT2 10 3.3V VFB1 VFB2 8.5V FIGURE 13 CIRCUIT 5A 62.5k 192.5k 3.5A I 0 0.1 TH1 ITH2 0.00001 0.0001 0.001 0.01 0.1 1 10 220pF 150μF 220pF TRACK/SS1 TRACK/SS2 150μF SGND 20k 20k OUTPUT CURRENT (A) 15k 15k 0.1μF 0.1μF 38261 TA01b 38261 TA01 38261fb 1