Features and Benefits
- Sub-Milliohm DCR Sensing or DrMOS with Current Sense Improves Efficiency
- Operates with Power Blocks, DrMOS or External Gate Drivers and MOSFETs
- ±0.5% Total Output Voltage Accuracy
- Flexible Phase Configuration
- Dual Output Current Monitoring
- tON(MIN) = 40ns, Capable of Very Low Duty Cycles at High Frequency
- Dual Differential Remote Sensing Amplifiers
- Programmable Frequency Range of 250kHz to 1.2MHz
- VIN Range Is Not Limited by IC
- VCC Range: 4.5V to 5.5V
- VOUT Range: 0.5V to 2.0V
- 48 Lead (5mm × 6mm) GQFN for LTC7852
- 36 Lead (4mm × 5mm) QFN for LTC7852-1
The LTC7852/LTC7852-1 is a six-phase, dual output current mode synchronous step-down switching regulator controller that works in conjunction with external power train devices such as DrMOS, power blocks or discrete N-channel MOSFETs and associated gate drivers. Its flexible design enables 1-, 2-, 3-, 4-, 5-, and 6-phase configurations. The LTC7852 offers a unique feature that enhances the signal-to-noise ratio of the current sense signal, allowing the use of inductors with very low DC winding resistances for maximum efficiency. The controller achieves a minimum on-time of just 40ns, permitting the use of high switching frequency at high step-down ratios. 8-, 10- or 12 phases with two ICs can be paralleled for very high current requirements up to 400A.
The remote sense differential amplifiers and a precise reference provide accurate output voltages between 0.5V and 2.0V. The input voltage is not limited by the controller. Hiccup mode protection from output shorts or overcurrent minimizes the thermal dissipation.
The LTC7852-1 is designed specifically for DrMOS with an internal current sense signal.
- Computer Systems
- Telecom and Datacom Systems
- DC Power Distribution 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 2631A features the LTC7852 in two high output current, high efficiency step down converters each with its own assembly type. The converter for the –A assembly provides two 3-phase outputs of 1.0V / 100A & 1.5V/100A. The –B assembly provides a single 6-phase 1.0V/200A output. Block diagrams are shown in Figure 3. Both converters operate over a 7V to 14V input voltage range at a switching frequency of 400kHz.
The power stage for each phase consists of a 5mm × 5mm DrMOS and 11.3mm × 11.0mm 0.25µH ferrite inductor with a DCR of 0.32mΩ typical. The LTC7852 employs a peak current mode architecture which allows accurate DCR sensing and sharing with sub-mOhm DCR inductors. The LTC7852 provides a three-state compatible PWM output for each DrMOS.
Additional features of the DC2631A include:
- Differential sensing for the output voltages of VOUT1 and VOUT2
- IMON pins to monitor the inductor current of each rail.
- Optional resistors and jumpers to change the phase arrangement for VOUT1 & VOUT2:
- VOUT1: 4ph, VOUT2: 2ph
- VOUT1: 5ph, VOUT2: 1ph
- Note, the default arrangement is: VOUT1: 3ph, VOUT2: 3ph
- Optional resistors and jumpers to parallel VOUT1 & VOUT2.
- RUN, PGOOD, PLLIN and CLKOUT pins
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:
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.