LTC3736-2 - Dual 2-Phase, No RSENSE Synchronous Controller with Output Tracking
Features
- No Current Sense Resistors Required
- Out-of-Phase Controllers Reduce Required Input Capacitance
- Tracking Function
- Wide VIN Range: 2.75V to 9.8V
- 0.6V ±1% Voltage Reference
- High Current Limit
- Constant Frequency Current Mode Operation
- Low Dropout Operation: 100% Duty Cycle
- True PLL for Frequency Locking or Adjustment
- Selectable Pulse Skipping/Forced Continuous Operation
- Auxiliary Winding Regulation
- Internal Soft-Start Circuitry
- Power Good Output Voltage Monitor
- Output Overvoltage Protection
- Micropower Shutdown: IQ = 9μA
- Tiny Low Profile (4mm × 4mm) QFN and narrow SSOP packages.
Typical Application
Description
The LTC®3736-2 is a 2-phase dual synchronous step-down switching regulator controller with tracking that drives external complementary power MOSFETs using few external components. The constant frequency current mode architecture with MOSFET VDS sensing eliminates the need for sense resistors and improves efficiency. Power loss and noise due to the ESR of the input capacitance are minimized by operating the two controllers out of phase.
Pulse skipping operation provides high efficiency at light loads. 100% duty cycle capability provides low dropout operation, extending operating time in battery-powered systems.
The switching frequency can be programmed up to 750kHz, allowing the use of small surface mount inductors and capacitors. For noise sensitive applications, the LTC3736-2 switching frequency can be externally synchronized from 250kHz to 850kHz. An internal soft-start, which can be lengthened externally, smoothly ramps the output voltage during start-up.
The LTC3736-2 is available in the tiny thermally enhanced (4mm × 4mm) QFN and 24-lead narrow SSOP packages.
| Max Current Sense Voltage | Burst Mode |
Soft Start | Spread Spectrum | |
| LTC3736 | 204mV | Yes | No | No |
| LTC3736-1 | 204mV | No | No | Yes |
| LTC3736-2 | 345mV | No | Yes | No |
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LTC3736EGN-2#PBF | SSOP-24 | GN | E | 05-08-1641 (GN24) | Yes |
| LTC3736EGN-2#TRPBF | SSOP-24 | GN | E | 05-08-1641 (GN24) | Yes |
| LTC3736EUF-2#PBF | 4x4 QFN-24 | UF | E | 05-08-1697 | Yes |
| LTC3736EUF-2#TRPBF | 4x4 QFN-24 | UF | E | 05-08-1697 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC3736EGN-2#PBF | SSOP-24 | E | $5.45 | $3.80 | Yes | |
| LTC3736EGN-2#TRPBF | SSOP-24 | E | $3.86 | Yes | ||
| LTC3736EUF-2#PBF | 4x4 QFN-24 | E | $5.63 | $3.90 | Yes | |
| LTC3736EUF-2#TRPBF | 4x4 QFN-24 | E | $4.00 | Yes | ||
| Buy Now • Request Samples | ||||||
Demo Boards
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC922A | LTC3736EUF-2 Demo Board | 2-Phase, 2.7V ≤ VIN ≤ 8V, Vout1 = 2.5V @ 5A, Vout2 = 1.8V @ 5A | Contact Factory | |
| Buy Now | |||
Applications
- One or Two Lithium-Ion Powered Devices
- Notebook and Palmtop Computers, PDAs
- Portable Instruments
- Distributed DC Power Systems
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Design Tools
LTspice
LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice
To launch a ready to run LTspice demonstration circuit for this part:
- Step 1: If you have not installed LTspice on this computer, download and install LTspice
- Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
- Step 3: If LTspice does not automatically open after clicking the link above, 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
To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.
Models for the following parts are available in LTspice:
LTC3736
LTC3736-1
LTC3736-2
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
