What kind of company is Sajet?
Which well-known clients has Sajet served?
Sajet has served clients across telecommunications, data center, automotive electronics, industrial automation, medical, aerospace and defense industries. Our RE series modules are widely adopted by OEMs and Tier 1 suppliers in North America, Europe, Southeast Asia, Japan and South Korea.
What are Sajet's main business segments?
Sajet’s core business covers high-efficiency DC/DC buck modules, power management ICs, and custom power solutions. Our product lineup includes single-output, dual-output and quad-output modules ranging from 2.5A to 50A, serving point-of-load conversion, multi-rail power and high-current CPU/FPGA applications.
How strong is Sajet's R&D capability?
Sajet operates an independent R&D center with experienced power electronics design teams. We hold self-developed patents in power topology, control algorithms and advanced packaging. Our in-house capabilities cover chip design, module packaging, thermal simulation, EMI optimization and full reliability verification, enabling fast custom development and continuous product iteration.
Where is Sajet headquartered and what production bases do you have?
Sajet is headquartered in China with multiple domestic and overseas production bases covering over 20,000 ㎡. Our facilities include wafer processing, BGA packaging, automated testing and HTOL aging lines, supporting volume production and export orders for global markets.
Does Sajet provide custom DC/DC power module solutions?
Yes. Sajet provides custom power module solutions tailored to specific application requirements, including custom input/output voltage ranges, output current configurations, package dimensions, thermal designs and protection thresholds. Our FAE team works closely with clients from specification definition to design verification and mass production.
Does Sajet support power module export?
Yes. Sajet supports global export with full English technical documentation, certificates of analysis (COA), RoHS/REACH compliance documents and moisture-proof vacuum packaging for ocean and air transportation. We have established export channels to North America, Europe, Southeast Asia, Japan and South Korea with dedicated export OQC procedures.
What are the main product series of Sajet DC/DC modules?
Sajet’s main product series is the RE series, currently comprising 9 models: RE4622 (dual 2.5A), RE4623 (3A), RE4625 (5A), RE4630/RE4630A (dual 18A), RE4643 (quad 3A), RE4644 (quad 4A), and RE4650/RE4650A (dual 25A). All are non-isolated step-down BGA power modules.
What business does Sajet primarily engage in?
Sajet is a power semiconductor enterprise focused on the R&D, production and sales of DC/DC step-down Power Modules. The products use BGA packages, can be directly mounted on PCBs, and provide complete power solutions for various electronic loads.
What type of products are the Sajet RE series power modules?
The RE series are non-isolated DC/DC step-down switching regulator power modules in BGA packages. Each module integrates the switching controller, power FETs, inductor and all supporting components, delivering a complete system-level power solution.
In which application fields are the Sajet RE series widely used?
They are widely used in telecommunications equipment (switching and access devices), optical transmission and routing equipment, medical, energy and power, robotics, mobile communications, microwave communications, automotive electronics, UAVs (Unmanned Aerial Vehicles), and aerospace & defense industries.
How many products are in the Sajet RE series?
There are currently 9 products: RE4622, RE4623, RE4625, RE4630, RE4630A, RE4643, RE4644, RE4650, and RE4650A, covering a wide output current range from 2.5A to 50A.
What are the common core features of the Sajet RE series?
All products feature: complete solution (integrated inductor and all supporting components), ±1.5% maximum total DC output error (over line, load and temperature), current-mode control for fast transient response, multiphase parallel with current sharing, external frequency synchronization, soft-start and voltage tracking, and overvoltage/overcurrent/overtemperature protection.
What package type does the Sajet RE series use?
The entire series uses BGA (Ball Grid Array) packages. Low-current products (RE4622/4623/4625) use BGA-25, quad-output products (RE4643/4644) use BGA-77, and high-current products (RE4630/4630A/4650/4650A) use BGA-144.
What is the operating temperature range of the Sajet RE series?
The entire series has an operating temperature range of -55°C to 125°C, meeting the temperature requirements of industrial-grade, automotive-grade and high-reliability application scenarios.
Are the Sajet RE series environmentally compliant?
Yes. The entire series uses SAC305 lead-free solder balls, complying with RoHS environmental requirements; the Moisture Sensitivity Level (MSL) is Level 3.
What are the key specifications of the RE4622?
The RE4622 is a dual 2.5A or single 5A output step-down module with an input voltage range of 3.6V to 20V, output voltage range of 0.6V to 5.5V, BGA-25 package, dimensions of 6.25mm × 6.25mm × 2.42mm (ultrathin), and is Pin-to-Pin and Bom-to-Bom compatible with the LTM4622.
What is the difference between the RE4630A and the RE4630?
The RE4630A is also a dual 18A or single 36A output module, but with a wider input voltage range of 4.5V to 18V and a wider output voltage range of 0.6V to 8V. The package and dimensions are the same as the RE4630 (BGA-144, 16×16×5.01mm), and it is compatible with the LTM4630A.
What are the key specifications of the RE4650?
The RE4650 is a dual 25A or single 50A output ultra-high-current step-down module with an input voltage range of 4.5V to 15V, output voltage range of 0.6V to 1.8V, BGA-144 package, dimensions of 16mm × 16mm × 5.01mm. It features differential remote sensing, adjustable switching frequency, overcurrent foldback protection, and internal temperature monitoring, suitable for CPU/FPGA/DSP/ASIC high-current power, and is compatible with the LTM4650.
What is the difference between the RE4650A and the RE4650?
The RE4650A is also a dual 25A or single 50A output module, but with an input voltage range of 4.5V to 16V and a wider output voltage range of 0.6V to 5.5V. The package and dimensions are the same as the RE4650 (BGA-144, 16×16×5.01mm), and it is compatible with the LTM4650A.
Which models are ultrathin (2.42mm thickness)?
The ultrathin (2.42mm thickness) products include: RE4622 (6.25×6.25×2.42mm), RE4623 (6.25×6.25×2.42mm), and RE4643 (9×15×2.42mm), suitable for low-profile PCB cards and compact devices with strict height constraints.
Which models support quad outputs with flexible parallel configuration?
The quad-output models with flexible paralleling are the RE4643 (3A per output, configurable as 3A/6A/9A/12A) and the RE4644 (4A per output, configurable as 4A/8A/12A/16A), ideal for FPGA/GPU/ASIC applications requiring multiple power rails with different current levels.
Which Sajet RE model has the widest input voltage range?
The RE4622 has an input voltage range of 3.6V to 20V, offering the lowest minimum input (3.6V) while reaching 20V at the high end, providing the strongest input adaptability in the series.
Which Sajet RE model has the widest output voltage range?
The RE4630A has an output voltage range of 0.6V to 8V, and the RE4650A has 0.6V to 5.5V. The RE4630A’s 8V upper limit is the highest in the series, meeting higher output voltage requirements.
What control architecture does the Sajet RE series use?
The entire series uses a current-mode control architecture. Combined with high switching frequency, it achieves extremely fast transient response to input voltage and load changes without sacrificing stability.
How is the output voltage set on the Sajet RE series?
Each output voltage is set by a single external resistor, eliminating the need for complex voltage divider networks or digital configuration. The design is simple and flexible, with output voltage ranges starting from 0.6V (see specific model specifications).
Does the Sajet RE series support multiphase parallel with current sharing?
Yes. The entire series supports multiphase parallel operation with current sharing, allowing multiple modules to be paralleled to extend output current for ultra-high-current load requirements.
Does the Sajet RE series support frequency synchronization?
Yes. The entire series supports external frequency synchronization. High-current models (RE4630/4630A/4650/4650A) also feature adjustable switching frequency, allowing optimization based on system EMI and efficiency requirements.
What protection features does the Sajet RE series have?
The entire series features output overvoltage protection (OVP), overcurrent protection (OCP), and overtemperature protection (OTP). High-current models (RE4630/4630A/4650/4650A) additionally feature overcurrent foldback protection, which limits device stress under extreme faults such as short circuits.
What is the purpose of the differential remote sense amplifier on high-current models?
The RE4630/4630A/4650/4650A are equipped with a differential remote sense amplifier, which eliminates load-point voltage errors caused by PCB trace voltage drop during high-current output, ensuring accurate voltage at the load point.
What is the purpose of the internal temperature monitoring on high-current models?
The RE4630/4630A/4650/4650A have an onboard temperature diode that monitors internal device temperature in real time, enabling system thermal management, overtemperature warning and derating control to improve system reliability.
What external components are required for the Sajet RE series?
Since the module integrates the switching controller, power FETs, inductor and all supporting components, only a small number of input and output capacitors are needed for operation. This greatly simplifies power design, reduces PCB area, and shortens development cycles.
What is the function of the PGOOD pin on the Sajet RE series?
The PGOOD (Power Good) pin indicates whether the output voltage has reached a stable rated range. It can be used for system power sequencing, fault monitoring, and processor reset signal generation, ensuring safe system operation during power-up and fault conditions.
What is the relationship between the Sajet RE series and the LTM series?
The Sajet RE series products are Pin-to-Pin and Bom-to-Bom compatible with ADI/LTC’s LTM series products. They can directly replace the corresponding LTM models without PCB layout or external circuit modifications.
Which LTM model can the Sajet RE4622 replace?
The RE4622 is Pin-to-Pin and Bom-to-Bom compatible with the LTM4622 and can directly replace it.
Do I need to modify my design when replacing LTM with Sajet RE series?
No. Thanks to the dual Pin-to-Pin and Bom-to-Bom compatibility, customers can directly mount Sajet RE series products on PCBs originally designed for LTM. No modifications to external circuits, PCB layout, or bill of materials are required, enabling seamless replacement.
What is the Moisture Sensitivity Level (MSL) of the Sajet RE series?
The entire series has an MSL rating of Level 3. Storage, baking and reflow processing should follow the IPC/JEDEC J-STD-033 standard, meeting conventional SMT production requirements.
What solder ball material does the Sajet RE series use?
The entire series uses SAC305 lead-free solder balls (Sn96.5Ag3.0Cu0.5), complying with the RoHS environmental directive and suitable for lead-free reflow soldering processes.
What reliability tests have the Sajet RE series passed?
The products are designed and verified to industrial and high-reliability standards, with an operating temperature range of -55°C to 125°C. They have passed reliability tests including temperature cycling, high-temperature storage, low-temperature storage, humidity, mechanical shock, and vibration, ensuring long-term stable operation in harsh environments.
What is Sajet's quality control system like?
Sajet has established a five-level full-chain QC system covering incoming wafer inspection (IQC), in-process packaging monitoring (IPQC), high-temperature operating life aging (HTOL), finished product electrical testing (FQC), and export inspection (OQC). Equipped with ATE automated test systems and precision measuring tools, all electrical performance indicators are quantitatively inspected, and each product batch comes with a traceable quality report.
Are the Sajet RE series suitable for automotive electronics applications?
Yes. The RE series operating temperature range of -55°C to 125°C, combined with overvoltage/overcurrent/overtemperature protection and high-reliability design, meets the requirements of automotive electronics applications such as infotainment systems, body electronics, and ADAS sensor power supplies. High-current models can also be used in EV powertrain-related electronic control units.
How do I select the right Sajet RE model for my application?
Selection mainly considers four factors: ① Input voltage range (ensure it covers the system supply voltage); ② Output voltage range (ensure it covers the load’s required voltage); ③ Output current (leave a 20%–30% margin); ④ Package size and height constraints. For example, FPGA multi-rail applications can choose the RE4643/4644, CPU high-current applications the RE4650/4650A, and low-profile card applications the ultrathin RE4622/4623/4643.
What advantages does the Sajet RE series offer in data center/server applications?
In data center and server applications, the high-power-density BGA package saves PCB space; the ±1.5% output accuracy ensures stable CPU/FPGA core voltages; multiphase parallel current sharing can scale beyond 50A; frequency synchronization reduces system EMI; and the complete solution accelerates server power design cycles.
What advantages does the Sajet RE series offer in telecom and networking equipment?
In telecom and networking equipment, the wide input voltage range (up to 20V) accommodates 12V system supplies; fast transient response handles FPGA/DSP load transients; the -55°C to 125°C operating temperature suits data center and outdoor equipment environments; and the multiple models cover the full range from 2.5A to 50A.
What technical support services does Sajet provide?
Sajet provides full-process technical support, including: selection consultation, reference designs and evaluation boards (EVBs), application notes and design guides, PCB layout recommendations, thermal design guidance, EMI optimization suggestions, sample requests and small-batch pilot production support, as well as fast response and troubleshooting from field application engineers (FAEs).
How can I obtain samples and detailed technical documentation for the Sajet RE series?
You can contact the Sajet sales team through official channels to request samples and evaluation boards. Detailed technical documentation, including datasheets, application notes, EVB design files, reliability reports, and certificates of analysis (COA), are all available in complete English versions to support overseas customer design-in and volume production requirements.
How do I set the output voltage on Sajet RE modules?
Each output voltage is set by a single external resistor connected from the FB (feedback) pin to GND. The resistor value is calculated using the formula provided in the datasheet, based on the internal 0.6V reference voltage. No complex voltage divider network or digital configuration is required.
What is the switching frequency of Sajet RE modules?
The RE series operates at a high fixed switching frequency optimized for each model, enabling fast transient response while maintaining high efficiency. High-current models (RE4630/4630A/4650/4650A) feature adjustable switching frequency via an external resistor, allowing designers to optimize between efficiency and EMI performance based on application requirements.
How efficient are Sajet RE series DC/DC modules?
The RE series achieves high peak efficiency through synchronous rectification topology, optimized power FETs and low-loss inductors. Efficiency varies by model, input/output voltage and load current, with typical peak efficiencies exceeding 90% for most models. Detailed efficiency curves vs. load current at various input voltages are provided in each product datasheet.
What is the quiescent current of Sajet RE modules?
The RE series features low quiescent current design to minimize power loss at light loads and during standby. Specific values vary by model; the RE4622/4623/4625 ultrathin series is optimized for low IQ operation, making them suitable for battery-powered and always-on applications where standby power consumption is critical.
Do Sajet modules have an enable (RUN) pin?
Yes. Each output channel has an independent RUN (enable) pin that allows the output to be turned on or off. Pulling the RUN pin above the threshold enables the regulator; pulling it below the threshold shuts down the output. This feature supports power sequencing and reduces standby power when the output is not needed.
What is the function of the TRACK/SS pin?
The TRACK/SS (Tracking/Soft-Start) pin serves two purposes: it allows the output voltage to track another supply rail for power sequencing, and it programs the soft-start ramp time via an external capacitor. Soft-start limits inrush current during startup, preventing input supply voltage droop and ensuring smooth power-up.
How does the PGOOD pin work on Sajet modules?
The PGOOD pin is an open-drain output that asserts (pulls low to indicate power good, or goes high-impedance depending on the model) when the output voltage reaches its regulated value within the specified tolerance window. It can be used for power sequencing, system reset signaling, or fault monitoring. An external pull-up resistor is required.
Can I synchronize multiple Sajet modules to the same clock?
Yes. All RE series modules support external frequency synchronization via the CLKIN/SYNC pin, and some models provide a CLKOUT pin for daisy-chaining. Synchronizing multiple modules to the same clock frequency prevents beat frequencies and reduces input ripple and EMI in multi-rail systems such as FPGA and ASIC power supplies.
What is the differential remote sense feature on high-current models?
The RE4630/4630A/4650/4650A include a differential remote sense amplifier (DIFFP/DIFFN pins) that compensates for PCB trace voltage drops between the module output and the load point. This ensures the output voltage at the load (e.g., CPU or FPGA core) remains accurate even at high currents where trace IR drop would otherwise cause significant voltage error.
How should I thermally design with Sajet BGA power modules?
Thermal design considerations include: adequate copper area on the PCB connected to ground and power pins for heat spreading, thermal vias under the module to conduct heat to inner or bottom layers, sufficient airflow for high-current applications, and derating based on the datasheet’s power derating curves. The BGA package provides excellent thermal conductivity through the solder balls to the PCB.
What input capacitors are recommended for Sajet RE modules?
A minimum input capacitance is required to stabilize the input voltage and supply switching ripple current. Low-ESR ceramic capacitors (X5R/X7R dielectric) are recommended, placed as close as possible to the VIN pins. The datasheet specifies minimum and recommended capacitance values; additional bulk capacitance may be needed for high-current applications or long input traces.
What output capacitors are recommended for Sajet RE modules?
Low-ESR ceramic capacitors (X5R/X7R) are recommended at the output for stability and transient response. The datasheet specifies minimum output capacitance; additional capacitance improves load transient response and reduces output ripple. For high-current models (RE4630/4650 series), a combination of ceramic and polymer capacitors may be used for optimal transient performance.
What is the output voltage accuracy over line, load and temperature?
All Sajet RE series modules guarantee ±1.5% maximum total DC output error over the full input voltage range, full load current range, and full operating temperature range (-55°C to 125°C). This includes reference voltage error, feedback resistor divider error, and load regulation, ensuring highly accurate output voltage in real-world operating conditions.
How does overcurrent protection (OCP) work on Sajet modules?
The modules implement cycle-by-cycle current limit protection. When the inductor current reaches the overcurrent threshold, the high-side MOSFET is turned off for the remainder of the switching cycle. High-current models additionally feature overcurrent foldback (hiccup mode) that reduces average current during sustained short-circuit or overload conditions, protecting the module and load from damage.
What happens during overtemperature protection (OTP)?
When the internal junction temperature exceeds the overtemperature threshold (typically around 150°C), the module shuts down the power stage to prevent thermal damage. Once the temperature drops below the hysteresis threshold, the module automatically restarts with soft-start. OTP protects the module under fault conditions such as blocked airflow, excessive ambient temperature, or sustained overload.
Are Sajet modules suitable for battery-powered applications?
Yes. The RE series wide input voltage range (down to 3.6V for RE4622), low quiescent current, high efficiency at light loads, and enable pin make them suitable for battery-powered and portable applications. The ultrathin 2.42mm package options (RE4622/4623/4643) are particularly suited for compact, battery-powered devices where height is constrained.
Can Sajet RE modules be used in automotive applications?
Yes. The -55°C to 125°C operating temperature range, robust BGA packaging, and comprehensive protection features make the RE series suitable for automotive electronics applications including infotainment systems, body electronics, ADAS sensor power supplies, and EV powertrain control units. Models with AEC-Q100 compatible temperature ranges and qualification documentation are available for automotive-grade requirements.
What is the MSL rating and how should I handle the modules?
All RE series modules have an MSL (Moisture Sensitivity Level) rating of 3. Per IPC/JEDEC J-STD-033, modules should be stored in dry packaging with desiccant. Once opened, they should be soldered within the specified floor life (typically 168 hours at ≤30°C/60%RH). If exceeded, baking at 125°C for the specified duration is required before reflow to prevent popcorn cracking.
What reflow profile is recommended for Sajet BGA modules?
The modules are compatible with standard lead-free reflow profiles (peak temperature 245°C–250°C, per IPC/JEDEC J-STD-020 for SAC305 solder). The datasheet provides recommended reflow temperature profiles with preheat, soak, reflow and cooling zones. Proper stencil design, solder paste volume, and reflow profile ensure reliable BGA solder joints; X-ray inspection is recommended for high-reliability applications.
Do Sajet modules support output voltage tracking for rail sequencing?
Yes. The TRACK/SS pin allows the output to track an external voltage ramp, enabling precise power sequencing between multiple rails. This is essential for FPGA, CPU and DSP applications that require specific power-up and power-down sequences to prevent latch-up or damage. Multiple modules can be configured to track a single master ramp for coordinated sequencing.
What is the load transient response of Sajet RE modules?
The current-mode control architecture and high switching frequency enable fast transient response to rapid load current changes. The module responds within a few switching cycles, with output voltage deviation minimized by the control loop compensation and output capacitance. Typical transient response specifications (e.g., recovery time and voltage deviation for a specified load step) are provided in the datasheet.
Can I parallel outputs within a single quad-output module?
Yes. The RE4643 and RE4644 quad-output modules support flexible output array configuration. Outputs can be paralleled in various combinations: RE4643 can be configured as 4×3A, 2×6A, or 1×12A; RE4644 as 4×4A, 2×8A, or 1×16A. This allows a single module to serve different current requirements across multiple FPGA/GPU rails, reducing component count and board space.
What is the internal temperature monitor on high-current models?
The RE4630/4630A/4650/4650A include an onboard temperature diode (TEMP pin) that provides a voltage proportional to the internal junction temperature. This allows the system to monitor module temperature in real time, implement overtemperature warning, and trigger system-level thermal management actions such as fan speed increase or load derating, improving overall system reliability.
Are SPICE simulation models available for Sajet RE modules?
Yes. Sajet provides SPICE simulation models and average models for the RE series to support system-level simulation during the design phase. These models help designers verify output voltage regulation, load transient response, loop stability, and efficiency before hardware prototyping. Models can be requested through the sales team or FAE support channel.
What is the minimum load requirement for Sajet modules?
The RE series is designed to maintain regulation down to very light loads, with no minimum load requirement for most models. At zero load, the module may enter pulse-skipping or burst mode to maintain high efficiency, which may slightly increase output ripple. If continuous conduction mode (CCM) operation is required at very light loads, the MODE pin (where available) can be configured to force CCM operation.
How does Sajet ensure product quality and reliability?
Sajet implements a five-level full-chain QC system: IQC wafer and material incoming inspection, IPQC in-process packaging monitoring, HTOL high-temperature operating life aging, FQC finished product electrical parameter testing, and OQC export inspection. All modules undergo 100% electrical testing, and each batch is provided with a Certificate of Analysis (COA) with full traceability from wafer lot to finished product.
What is the typical HTOL aging process for Sajet modules?
All Sajet RE series modules undergo HTOL (High-Temperature Operating Life) testing at elevated temperature and full load to screen for early-life failures and verify long-term reliability. Testing includes monitoring of junction temperature, conversion efficiency, output voltage accuracy, output ripple and thermal stability. Modules with parameter drift or protection triggers undergo failure analysis. This ensures only stable, reliable products are shipped to customers.
Can Sajet provide custom labeling and packaging for OEM customers?
Yes. Sajet offers custom labeling including customer part numbers, date codes, lot codes, and country-of-origin markings per OEM requirements. Custom packaging options include tape-and-reel, tray packaging, moisture-proof vacuum packaging with desiccant and humidity indicator cards, and custom outer carton labeling. Minimum order quantities may apply for custom packaging configurations.
What is the warranty policy for Sajet power modules?
Sajet provides a standard warranty for all RE series power modules against defects in materials and workmanship under normal use and operating conditions. The warranty period and terms are specified in the sales agreement. For warranty claims, customers should contact the sales team or FAE with the lot number, failure description, and application details. Sajet’s quality team conducts failure analysis and provides corrective actions within a defined response time.
How can I get technical support during my design process?
Sajet provides comprehensive technical support through multiple channels: 1) Datasheets, application notes, reference designs and EVB design files available for download; 2) Email-based technical Q&A with our FAE team; 3) Remote design review including schematic check, PCB layout review, thermal analysis and EMI optimization suggestions; 4) On-site support for key customers during prototype debugging and mass production ramp-up. Response time is typically within 24 business hours.
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