150V Low IQ, Synchronous Step-Down DC/DC Controller
Features and Benefits
- Wide VIN Range: 4V to 60V (65V Abs Max)
- Low Operating IQ : 50μA
- Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 24V
- RSENSE or DCR Current Sensing
- Phase-Lockable Frequency (320kHz to 2.25MHz)
- Programmable Fixed Frequency (320kHz to 2.25MHz)
- Selectable Continuous, Pulse-Skipping or Low Ripple
- Burst Mode® Operation at Light Load
- Selectable Current Limit
- Very Low Dropout Operation: 98% Duty Cycle
- Adjustable Output Voltage Soft-Start or Tracking
- Power Good Output Voltage Monitor
- Output Overvoltage Protection
- Low Shutdown IQ : < 14μA
- Internal LDO Powers Gate Drive from VIN or EXTVCC
- No Current Foldback During Start-Up
- Small 20-Pin 3mm × 4mm QFN Package
The LTC7800 is a high performance step-down switching regulator DC/DC controller that drives an all N-channel synchronous power MOSFET stage. A constant frequency current mode architecture allows a phase-lockable frequency of up to 2.25MHz.
The 50μA no-load quiescent current extends operating run time 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 LTC7800 features a precision 0.8V reference and power good output indicator. A wide 4V to 60V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries. The output voltage of the LTC7800 can be programmed between 0.8V to 24V.
The TRACK/SS pin ramps the output voltages 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 conduction mode at light loads.
- Automotive Always-On Systems
- Battery Powered Digital Devices
- Distributed DC Power Systems
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit 2736A is a single output high voltage nonisolated synchronous step-down converter that drives all GaN transistor power stage. It features the LTC7800, a low quiescent current high frequency (programmable fixed frequency from 320kHz up to 2.25MHz) synchronous step-down DC/DC controller housed in a small 3mm × 4mm QFN package.
This DC2736A operates over an input voltage range from 30V to 55V, while the LTC7800 can operate up to 60V. This demo board produces a 12V output voltage with up to 20A output current, and is configured with a sense resistor for current sensing. A mode selector allows the DC2736A to operate in forced continuous operation, pulse-skipping or Burst Mode® operation during light loads.
The LTC7800 features two integrated 5V gate drivers with 20ns dead time which is good for GaN transistors or logiclevel MOSFETs to maximize efficiency. The EXTVCC pin permits the LTC7800 to be powered from the output of the switching regulator or other available source, reducing power dissipation and improving efficiency. Please refer to the LTC7800 data sheet for a complete description of the part operation and application information.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Models for the following parts are available in LTspice:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
Design tools for the following parts are available in LTpowerCAD:
LTC7800 Companion Parts
Recommended Related Parts
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.