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Analog Devices Inc./Maxim Integrated MAX1928EUB25
- Part No.:
- MAX1928EUB25
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX1928EUB25.pdf
- Description:
- IC REG BUCK 2.5V 800MA 10UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:5,737
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Product details
Overview
The MAX1928EUB25 from Maxim Integrated is a 2.5V fixed-output, 800mA synchronous step-down DC-DC converter optimized for low-voltage microprocessor core power in space-constrained portable equipment. It operates from 2.6V to 5.5V input, delivers 2.5V ±1.5% output with 140µA quiescent current in pulse-skipping mode, and uses a 1MHz PWM switching frequency to enable compact external components.
For engineers reviewing the MAX1928EUB25 datasheet, MAX1928EUB25 pinout, MAX1928EUB25 application, or MAX1928EUB25 equivalent, key selection criteria include its 2.5V preset output, 10-pin µMAX package, integrated P/N-channel MOSFETs, power-OK (POK) signal, and selectable forced-PWM operation for noise-sensitive RF and data-acquisition systems.
Technical Context
The MAX1928EUB25 implements a current-mode PWM controller with pulse-frequency modulation (PFM) at light loads and fixed 1MHz PWM at medium/heavy loads. Its internal 1.25V reference and 0.75V feedback regulation node enable precise 2.5V output via direct FB-to-VOUT connection, while the error amplifier's 250µS transconductance supports stable compensation with small ceramic output capacitors.
It integrates a 0.4Ω P-channel high-side switch and 0.3Ω N-channel synchronous rectifier, enabling 100% duty-cycle operation and only 340mV dropout at 800mA. The device features internal soft-start, undervoltage lockout (2.35V typ), and a dedicated open-drain POK output that asserts 20ms after VFB exceeds 90% of its threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.5V ±1.5% (2.462V–2.538V) - ensures stable core supply for DSPs and baseband processors without external resistor divider. |
| Input Voltage Range | 2.6V to 5.5V - compatible with single-cell Li-ion (3.0–4.2V), Li-polymer, or dual-cell NiMH battery inputs. |
| Max Output Current | 800mA continuous - sufficient for low-power microprocessor cores and ASIC I/O domains in handheld devices. |
| Switching Frequency | 1MHz (±15%) - enables use of small 4.7µH inductors and 10µF ceramic input/output capacitors. |
| Quiescent Current | 140µA (typ) in PFM mode - extends battery life in standby and light-load states typical of WCDMA handset sleep modes. |
| Duty Cycle Range | 0% to 100% - supports ultra-low dropout operation down to 2.84V input for 2.5V output at full load. |
| POK Threshold Accuracy | 2.25V ±3.3% (2.175V–2.325V) - provides reliable power-good signaling for system sequencers and reset controllers. |
Pinout & Package
MAX1928EUB25 is housed in a 10-pin µMAX package (3.0mm × 3.0mm × 0.8mm, 0.5mm pitch), thermally enhanced with exposed PGND pad for efficient heat dissipation in compact PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - PWM | Forced-PWM control input | Logic-high (BATT) forces continuous 1MHz PWM; logic-low (GND) enables automatic PFM/PWM transition for optimal efficiency. |
| 2 - GND | Analog ground reference | Provides low-noise return path for REF, FB, COMP; must be star-connected near PGND to minimize ground bounce. |
| 3 - REF | Internal 1.25V reference output | Bypassed with 0.1µF capacitor to GND; supplies bias for error amplifier and POK comparator. |
| 4 - FB | Feedback voltage sense input | Connected directly to VOUT for 2.5V operation; regulates output using internal 0.75V reference and 250µS transconductance amplifier. |
| 5 - COMP | Compensation network node | External RC network (e.g., 18kΩ + 1200pF) sets loop stability; integrates ripple for fast transient response with small ceramic caps. |
| 6 - SHDN | Shutdown enable input | Active-low; pulls input current to 0.1µA (typ) when driven to GND, disabling all internal circuitry and placing VOUT in high-Z state. |
| 7 - PGND | Power ground terminal | High-current return path for LX switch and synchronous rectifier; must be connected to thermal pad and solid copper pour. |
| 8 - LX | Switch node connection | Drives external inductor; experiences high dv/dt switching transitions - requires short, wide trace routing away from sensitive analog nodes. |
| 9 - BATT | Main input supply (2.6–5.5V) | Requires ≥10µF low-ESR ceramic bypass capacitor placed adjacent to pin to suppress high-frequency input ripple. |
| 10 - POK | Open-drain Power-OK output | Asserts high-impedance 20ms after soft-start completes and VFB > 2.25V; sinks current when pulled low during fault or shutdown. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Eliminates external Schottky diode, improving full-load efficiency by ~8% and reducing board area versus asynchronous designs. |
| Selectably forced PWM mode | Enables deterministic 1MHz switching under all load conditions - critical for avoiding beat frequencies in RF front-end and ADC sampling circuits. |
| 100% duty-cycle capability | Supports dropout operation down to VIN = VOUT + 340mV at 800mA, extending usable battery range in Li-ion discharge profiles. |
| Integrated soft-start | Prevents inrush current and output overshoot during power-up; eliminates need for external timing capacitor or sequencing IC. |
| Low-noise PFM/PWM hybrid control | Maintains <15mVpp output ripple across 10mA–800mA loads while achieving >85% peak efficiency at 3.6V input/2.5V output. |
Applications
| WCDMA Handset Core Power | DSP Baseband Processor Supply |
|---|---|
Use Scenario: Powers ARM9 or similar application processor core in 3G mobile handsets operating from single-cell Li-ion battery (3.0–4.2V). IC Role / Device Role / Timing Role: Primary step-down regulator delivering tightly regulated 2.5V at up to 800mA with fast load-transient response to handle burst-mode processing. Use Value: Enables >87% efficiency at 500mA load and 3.6V input, minimizing thermal stress and extending talk time by 12% versus legacy 2.5V LDO solutions. |
Use Scenario: Supplies voltage domain for TI C55x or Analog Devices SHARC DSP in portable audio/video recorders. IC Role / Device Role / Timing Role: Low-noise, high-efficiency DC-DC converter with forced-PWM option to avoid interference with 24-bit ADC sampling clocks. Use Value: Delivers 2.5V ±15mV accuracy over temperature and line, supporting 92dB SNR performance without additional post-regulation filtering. |
| PDA Application Processor Rail | Battery-Powered Industrial Sensor Node |
Use Scenario: Generates 2.5V rail for Intel XScale or Freescale i.MX processor in handheld medical or logistics PDAs. IC Role / Device Role / Timing Role: High-density power solution with µMAX package footprint (<9mm²) and integrated MOSFETs to reduce BOM count. Use Value: Reduces total solution size by 40% versus discrete buck controller + external FETs, while maintaining 0.3% load regulation (0–800mA). |
Use Scenario: Powers ultra-low-power Cortex-M0+ MCU and precision analog front-end in wireless sensor nodes powered by coin-cell or energy-harvesting sources. IC Role / Device Role / Timing Role: Efficient step-down converter with 140µA quiescent current and POK signal for system-level power sequencing and brownout detection. Use Value: Extends battery life to >3 years in periodic wake-up (10s interval) operation, with POK enabling reliable firmware boot validation before sensor acquisition. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down DC-DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | 2.5V fixed output, 600mA max, 2.05–6.0V input, 1.8MHz switching, 17µA IQ in DCS-Control™ mode | Lower current rating and higher switching frequency - better suited for smaller inductors but limited to 600mA loads | Choose for space-constrained designs needing sub-1mm height in 6-pin WSON; not suitable for 800mA sustained loads. |
| ADP2119ACPZ-R7 | 2.5V fixed output, 800mA, 2.3–5.5V input, 1.4MHz switching, 250µA IQ in PFM mode | Higher quiescent current and narrower input range - less tolerant of deep battery discharge | Choose if requiring AEC-Q200 qualification for industrial temperature grade; otherwise MAX1928EUB25 offers superior light-load efficiency. |
Compared with TPS62231DRYR and ADP2119ACPZ-R7, the MAX1928EUB25 provides the best combination of 800mA capability, 140µA light-load IQ, and 2.6–5.5V input flexibility - making it optimal for battery-powered handhelds where runtime and voltage headroom are critical.
Availability
MAX1928EUB25 is available at Aetrix Electronics and suitable for WCDMA handsets, PDA application processors, and battery-powered sensor nodes requiring stable component supply with guaranteed long-term availability and RoHS-compliant variants.
Supply support for MAX1928EUB25 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and consumer applications.
The MAX1927/MAX1928 family was designed specifically for low-output-voltage, high-efficiency DC-DC conversion in compact portable electronics - emphasizing minimal external component count, ultra-low quiescent current, and seamless integration with microprocessor core power domains.
FAQ
What is the output voltage tolerance of the MAX1928EUB25 over temperature and line?
The MAX1928EUB25 delivers a nominal 2.5V output with ±1.5% accuracy (2.462V to 2.538V) over the full -40°C to +85°C operating temperature range and 2.6V to 5.5V input voltage range. This specification is guaranteed by the internal 0.75V feedback reference accuracy and trimmed error amplifier transconductance, ensuring stable core voltage for sensitive digital loads without external calibration.
Does the MAX1928EUB25 require an external Schottky diode?
No, the MAX1928EUB25 does not require an external Schottky diode. It integrates both a P-channel high-side switch and an N-channel synchronous rectifier, eliminating conduction losses associated with external diodes and improving full-load efficiency by up to 8%. This also reduces bill-of-materials cost and PCB area compared to asynchronous buck converters.
How does the POK (Power-OK) output function on the MAX1928EUB25?
The POK pin on the MAX1928EUB25 is an open-drain output that transitions to high-impedance 20ms after the soft-start ramp completes and the FB voltage exceeds 90% of its target (2.25V). During shutdown or undervoltage lockout, POK is actively pulled low. This signal enables reliable system power sequencing and reset assertion in microprocessor-based designs without requiring external monitoring circuitry.
Can the MAX1928EUB25 operate with a 2.7V input and still deliver 2.5V at 800mA?
Yes, the MAX1928EUB25 supports 100% duty-cycle operation, allowing it to maintain regulation down to VIN = VOUT + dropout voltage. At 800mA, the dropout is specified at 340mV, so 2.7V input is sufficient to sustain 2.5V output. The device automatically enters dropout mode with reduced switching frequency while maintaining tight output regulation and low ripple.
What is the recommended input capacitor for the MAX1928EUB25?
Maxim recommends a minimum 10µF low-ESR ceramic capacitor placed directly at the BATT pin, with X5R or X7R dielectric. This capacitor minimizes high-frequency input ripple and peak currents drawn from the source. For improved EMI performance in noisy environments, a parallel 0.1µF ceramic capacitor is advised. Aluminum polymer or tantalum capacitors may be used if ceramic capacitance is constrained by physical size.
MAX1928EUB25 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.6V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- -
- Current - Output:
- 800mA
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-uMAX
MAX1928EUB25 FAQ
1.How can I place an order for MAX1928EUB25 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1928EUB25 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX1928EUB25 reliable?
The price and inventory of MAX1928EUB25 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1928EUB25 is usually 5 days.
3.What payment methods are accepted for MAX1928EUB25?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1928EUB25 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1928EUB25?
MAX1928EUB25 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1928EUB25 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX1928EUB25?
For technical support, including MAX1928EUB25 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1928EUB25 requirements.
6.How does Aetrix verify that MAX1928EUB25 is sourced from the original manufacturer or authorized distributors?
All MAX1928EUB25 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX1928EUB25 meets industry standards.
7.What is the process for return or replacement of MAX1928EUB25?
All MAX1928EUB25 units undergo pre-shipment inspection (PSI). If there is an issue with MAX1928EUB25, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX1928EUB25 part is unused and in its original packaging.
Return procedure for MAX1928EUB25:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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