65V, 2A Synchronous Step-Down Regulator with 2.5μA Quiescent Current
Features and Benefits
- Wide Input Range: 3.3V to 60V
- 1.5A Peak Switch Current (LT1976)
- 100µA Quiescent Current (LT1976)**
- 1.6mA Quiescent Current (LT1976B)
- Low Shutdown Current: IQ < 1µA
- Power Good Flag with Programmable Threshold
- Load Dump Protection to 60V
- 200kHz Switching Frequency
- Saturating Switch Design: 0.2Ω On-Resistance
- Peak Switch Current Maintained Over Full Duty Cycle Range*
- 1.25V Feedback Reference Voltage
- Easily Synchronizable
- Soft-Start Capability
- Small 16-Pin Thermally Enhanced TSSOP Package
The LT1976/LT1976B are 200kHz monolithic step-down switching regulators that accept input voltages up to 60V. A high efficiency 1.5A, 0.2Ω switch is included on the die along with all the necessary oscillator, control and logic circuitry. Current mode topology is used for fast transient response and good loop stability.
Innovative design techniques along with a new high voltage process achieve high efficiency over a wide input range. Efficiency is maintained over a wide output current range by employing Burst Mode operation at low currents, utilizing the output to bias the internal circuitry, and by using a supply boost capacitor to fully saturate the power switch. The LT1976B does not shift into Burst Mode operation at low currents, eliminating low frequency output ripple at the expense of efficiency. Patented circuitry maintains peak switch current over the full duty cycle range.* Shutdown reduces input supply current to less than 1µA. External synchronization can be implemented by driving the SYNC pin with logic-level inputs. A single capacitor from the CSS pin to the output provides a controlled output voltage ramp (soft-start). The devices also have a power good flag with a programmable threshold and time-out and thermal shutdown protection.
The LT1976/LT1976B are available in a 16-pin TSSOP package with Exposed Pad leadframe for low thermal resistance.
- High Voltage Power Conversion
- 14V and 42V Automotive Systems
- Industrial Power Systems
- Distributed Power Systems
- Battery-Powered 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 (2)
Demonstration circuit 977 is a monolithic step-down DC/DC switching converter featuring the LT1976B. The LT1976B is the non-burst mode version of the LT1976 IC. The LT1976B operates down to zero load without burst mode resulting in the lowest ripple output over the full load current range. The board is optimized for 3.3V output at up to 1A load current for an input voltage range of 4V to 60V. Minimum on-time restrictions and 3.3V output may limit the steady state maximum input voltage (above which pulse-skipping occurs) to 42V.
Demonstration circuit 481 is a monolithic step-down DC/DC switching converter featuring the LT1976. The board is optimized for 3.3V output at up to 1A load current for an input voltage range of 4V to 60V. Minimum on-time restrictions and 3.3V output may limit the steady state maximum input voltage to 42V (up to 47V for some boards) before pulse skipping occurs.
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.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
Models for the following parts are available in LTspice:
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Sample & Buy
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