The CXSD62686 is a synchronous step-down DC/DC converter based on COT control mode. Two N-channel MOSFETs on the high side and the low side are integrated to provide a continuous output current of 3A. The input voltage range is wide from 4V to 18V, and the output voltage can be flexibly set from 0.6V to 6V via an external resistor divider. The chip is packaged in a compact TSOT23-6 with an operating temperature range of -40°C to 85°C for harsh application environments.
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[ CXSD62686 ]"
In modern digital electronic systems, such as digital TV, home network terminals, set-top boxes and other highly integrated devices, the transient response, efficiency and reliability of power management chips are highly demanded. JTM-IC (jtm-ic.com) launchedCXSD62686, is a tailor-made for such applications.High Performance Synchronous Buck Converter. It uses advancedFixed on-time control technology, setUltra-fast transient response, high integration, wide input voltage rangeAll in one, it provides engineers with a stable, efficient and easy-to-design power solution.
1. CXSD62686 Product Core Overview
CXSD62686 is based onCOT control modeThe synchronous step-down DC/DC converter, internally integrated high-side and low-side two N-channel MOSFETs, can provide continuous3A output current. Its wide input voltage range4V to 18V, the output voltage can be used through an external resistor divider0.6V to 6VFlexible settings. The chip uses a compactTSOT23-6 package, the operating temperature range is-40 ℃ to 85 ℃Suitable for harsh application environments.
2. Highlight Performance and Key Benefits
2.1. COT control and ultra-fast transient response.: Unlike traditional voltage mode or current mode PWM, COT mode directly controls the on-time of the switch according to the output voltage ripple, realizingSubmicrosecond load transient response, Greatly reduce the output voltage overshoot and undershoot, especially suitable for high-speed digital core (such as FPGA, ASIC, DDR) power supply.
2.2. Simplify design without external compensation: COT control architecture is naturally stable and allows direct useLow ESR ceramic output capacitor, andNo need for complex external loop compensation networks, significantly simplifies the design process, reducing the number of components and PCB area.
2.3. High efficiency and intelligent power management: The internal synchronous rectification architecture eliminates Schottky diode losses and combines optimized gate drive to achieve efficient conversion over the full load range. The chip has the function of automatic switching in light load mode, which can maintain high efficiency and reduce the standby power consumption of the system.
2.4. Comprehensive integrated protection function: Chip built-inSoft-start, cycle-by-cycle valley current limit, input undervoltage lockout, and thermal shutdownMultiple protection mechanisms. Its unique "hiccup" mode short-circuit protection can restart periodically when the output is continuously short-circuited, effectively protecting the chip and load safety.
2.5. Fixed frequency advantage and low ripple.Operating at a pseudo-fixed frequency (typically 750KHz) helps predict and optimize EMI performance. Combined with COT control and low ESR capacitance, it is possibleVery low output voltage ripple.
3. target application areas
With its wide input range, high output capability and excellent dynamic performance, CXSD62686 are ideal for the following applications:
• Consumer digital products: Digital TV (DTV), digital set-top box (STB), home media center, Blu-ray player core board power supply.
· Network and communication equipmentDSL modem, optical network terminal (ONT), wireless router, switch processor and interface power supply.
Industrial and Embedded Systems: Industrial control motherboard, single board computer, test and measurement equipment need to be efficient, stable buck occasions.
· General purpose high pressure to low pressure system: Generate low-voltage, high-current power rails from the 12V or 5V bus, such as DDR voltage, chipset core voltage, etc.
4. in-depth design guidelines and selection recommendations
For optimal CXSD62686 performance, JTM-IC provide the following proven design points:
4.1. Output voltage setting: The output voltage is set by a resistor divider (R1, R2) connected between VOUT and GND, and fed back to the FB pin. The calculation formula is:
To ensure accuracy, it is recommended to use1% accuracyof resistance. Recommended values for standard resistors from 1.0V to 5.0V output are provided in the data sheet.
4.2. Inductance and capacitance selection：
4.3. Power inductance: According to the output voltage and current, it is recommended to use1.0 μH to 3.3 μHThe inductance value (refer to Table 1 of the manual for details). The rated current of the inductor shall be greater than the sum of the maximum load current and the ripple current, and the saturation current shall be higher than the peak current.
4.4. Input capacitance: Place a near the VIN pin10 μF to 22 μFThe ceramic capacitor is used to filter out input noise and provide transient current.
4.5. Output capacitance: Recommended Use22 μF to 68 μFLow ESR multilayer ceramic capacitors. The COT architecture has specific requirements for ESR, and MLCC with recommended values ensures optimal performance and stability.
4.6. bootstrap capacitor: A must be connected between the BS and SW pins0.1μFThe ceramic capacitor is used to drive the internal high-side MOSFET.
4.7. The golden rule of PCB layout：
· Minimize the power loop: The loop area formed by the input capacitor (CIN), the VIN/SW pin of the chip, and the output capacitor (COUT) should beAs small as possible. Use short and wide traces to reduce parasitic inductance and resistance, and reduce switching noise and voltage spikes.
· Single point grounding and heat dissipation: Pass the GND pin of the chip and the ground terminal of the input and output capacitors through oneSolid ground planeConnect. Use PCB copper foil to dissipate heat at the bottom of the chip to improve thermal performance.
Protection of sensitive signals: FB Feedback Route Yeshigh impedance node, mustaway fromnoise sources such as inductors and SW switch nodes. Place the feedback resistors R1, R2 as close to the FB pin as possible.
· Control area of SW node: SW node has high frequency voltage swing, its PCB copper area should beappropriate controlIt should not be too large to reduce the antenna effect and reduce the radiated EMI.
5. packaging and reliability
CXSD62686 with a smallTSOT23-6 package, While providing powerful power handling capabilities, it saves valuable PCB space to the maximum extent. JTM-IC follow strict quality control standards to ensure that each chip has high reliability and consistency to meet the stringent requirements of consumer to industrial applications.
6. epilogue
CXSD62686 represents JTM-IC's technical strength in the field of high efficiency, high dynamic response buck converters. It willUltra-fast transient advantages of COT control, efficiency advantages of synchronous rectification, comprehensive protection functions and minimal peripheral requirementsThe perfect combination provides engineers with powerful tools to meet the power challenges of modern digital systems. Whether it is the pursuit of the ultimate performance of consumer electronics, or the requirements of stable and reliable network communication equipment, CXSD62686 is your trusted power core.
Visit the official JTM-IC website immediately (jtm-ic.com）Get the CXSD62686's complete data sheet, detailed application notes, reference design schematics, and PCB layout files. Our team of technical experts is ready to provide you with professional support, from sample application to mass production import, to help your project success. Choose JTM-IC and choose efficient and reliable power solutions.
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