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Analog Devices Inc./Maxim Integrated MAX1928EUB18
- Part No.:
- MAX1928EUB18
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX1928EUB18.pdf
- Description:
- IC REG BUCK 1.8V 800MA 10UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:30,575
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Product details
Overview
MAX1928EUB18 from Maxim Integrated is a 1.8V 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–5.5V input, delivers 1.8V ±1.5% output accuracy at up to 800mA, and achieves >90% peak efficiency at 3.6VIN/1.8VOUT. Its 1MHz PWM switching, 140µA quiescent current in pulse-skipping mode, and 100% duty-cycle operation enable high efficiency across load range in WCDMA handsets and PDAs.
For engineers reviewing the MAX1928EUB18 datasheet, MAX1928EUB18 pinout, MAX1928EUB18 application, or MAX1928EUB18 equivalent, key selection criteria include guaranteed 800mA output current at 1.8V, internal P/N-channel MOSFETs eliminating external diode, POK output with 20ms delay, selectable forced-PWM mode for RF-sensitive designs, and µMAX-10 package compatibility with tight PCB layouts.
Technical Context
The MAX1928EUB18 implements a current-mode, fixed-frequency (1MHz) PWM controller with pulse-frequency modulation (PFM) light-load optimization. Its dual-mode operation-PWM above ~130mA and PFM below-minimizes quiescent current to 140µA while maintaining regulation. The internal 1.25V reference and 0.75V FB regulation voltage set the 1.8V output via direct FB-to-VOUT connection.
It integrates a 0.25Ω (typ) P-channel high-side switch and 0.17Ω (typ) N-channel synchronous rectifier, enabling 340mV dropout at 800mA and eliminating external Schottky diodes. The device supports 100% duty cycle, soft-start, and open-drain POK output that asserts after VFB exceeds 90% of target for 20ms-critical for system power sequencing in battery-powered DSP cores.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8V ±1.5% (1.773V–1.827V), set internally-no external resistor divider required. |
| Max Output Current | 800mA continuous, supported by integrated 0.25Ω P-MOS and 0.17Ω N-MOS switches. |
| Input Voltage Range | 2.6V to 5.5V-compatible with single-cell Li-ion (3.0–4.2V) and 3.3V/5V rails. |
| Switching Frequency | 1MHz ±15% (0.85–1.15MHz), enabling compact 4.7µH inductors and 10µF ceramic input/output caps. |
| Quiescent Current | 140µA (typ) in PFM mode; rises to 2mA (typ) in forced-PWM mode for noise-sensitive applications. |
| POK Threshold Accuracy | 1.566V–1.674V (±3% of 1.8V), with 20ms delay after VFB crosses 90%-ensures stable power-good assertion. |
| Duty Cycle Range | 0% to 100%-supports dropout operation down to VIN = VOUT + 340mV at full load. |
Pinout & Package
MAX1928EUB18 is housed in a 10-pin µMAX package (3.0mm × 3.0mm × 0.8mm, 0.5mm pitch), thermally enhanced with exposed PGND pad. Pin 1 is PWM; pin 10 is POK. Package meets JEDEC MO-187AC standard and supports reflow soldering per J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWM (Pin 1) | Forced-PWM control input | Drive to GND enables automatic PFM/PWM transition; drive to BATT forces continuous 1MHz PWM-essential for EMI control in RF sections. |
| GND (Pin 2) | Analog ground reference | Separate from PGND; connects to quiet analog ground plane to minimize feedback path noise and ensure 0.3% load regulation. |
| REF (Pin 3) | Internal 1.25V reference output | Bypassed with 0.1µF capacitor to GND; supplies bias for error amplifier and sets FB regulation point at 0.75V. |
| FB (Pin 4) | Feedback sense input | Connected directly to VOUT for 1.8V operation; senses 0.75V reference-enables precise output regulation without external resistors. |
| COMP (Pin 5) | Compensation node | External RC network (e.g., 18kΩ + 1200pF) sets loop stability; allows use of small ceramic output capacitors (10µF) with fast transient response. |
| SHDN (Pin 6) | Shutdown enable input | Logic-low (<0.6V) disables converter, reducing supply current to 0.1µA (typ); logic-high (>1.6V) enables normal operation. |
| PGND (Pin 7) | Power ground return | High-current return path for LX switch and synchronous rectifier; must be star-connected to minimize ground bounce and ripple. |
| LX (Pin 8) | Switch node | Connects to inductor; carries high dv/dt switching waveform-requires short, wide trace away from sensitive analog nodes (FB, REF). |
| BATT (Pin 9) | Main power input | 2.6V–5.5V supply; requires ≥10µF low-ESR ceramic capacitor placed adjacent to pin to suppress input ripple and EMI. |
| POK (Pin 10) | Open-drain Power-OK output | Asserts high-impedance 20ms after VFB > 1.62V; pulled up externally to enable processor reset or system power sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated N-channel MOSFET eliminates external Schottky diode-reducing BOM count and improving efficiency by ~5% at light loads. |
| Selectable forced-PWM mode | PWM pin controls noise profile: PFM for battery life (140µA IQ), forced-PWM for predictable 1MHz spectrum in RF/data-acquisition systems. |
| 100% duty-cycle operation | Enables dropout as low as 340mV at 800mA-critical for maintaining 1.8V core voltage during Li-ion discharge from 3.4V to 2.8V. |
| Internal soft-start | Gradually ramps output over ~1ms-prevents inrush current into large output capacitors and avoids false POK assertion. |
| Power-OK (POK) output | Open-drain comparator with 20ms delay ensures system only releases reset after output stabilizes within ±3%-prevents premature processor boot. |
Applications
| WCDMA Handset Core Power | DSP Processor Supply |
|---|---|
Use Scenario: Powers ARM9 or similar baseband processor core requiring stable 1.8V at up to 800mA during burst transmission. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated core voltage; POK synchronizes with baseband ASIC reset timing. Use Value: 1MHz switching minimizes inductor size for thin handset profiles; PFM mode extends talk time by reducing no-load IQ to 140µA. |
Use Scenario: Supplies TI C55x or Analog Devices SHARC DSP core in portable audio analyzers. IC Role / Device Role / Timing Role: Low-noise, high-PSRR DC-DC source; forced-PWM mode prevents switching harmonics from aliasing into 96kHz audio sampling band. Use Value: Internal 0.25Ω/0.17Ω MOSFETs achieve >92% efficiency at 600mA, reducing thermal load on densely packed DSP PCBs. |
| PDA Application Processor Rail | Battery-Powered Industrial Sensor Node |
Use Scenario: Generates 1.8V for Intel XScale or Marvell PXA application processor in handheld terminals. IC Role / Device Role / Timing Role: Main system rail regulator; soft-start prevents brown-out during cold boot; POK enables orderly OS initialization. Use Value: 10-pin µMAX footprint (3×3mm) fits tight layout constraints; 2.6V min input supports operation down to single-cell Li-ion 2.8V. |
Use Scenario: Powers ultra-low-power Cortex-M0+ MCU and precision ADC in wireless sensor node with 10-year battery life target. IC Role / Device Role / Timing Role: High-efficiency intermediate rail generator; PFM mode dominates 99% of operating time (µA-level sleep currents). Use Value: 140µA quiescent current in PFM mode enables >10-year runtime on two AA cells; shutdown current <1µA extends shelf life. |
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 |
|---|---|---|---|
| Texas Instruments TPS62231DRYR | 1.8V fixed, 600mA output; 2.05–6.5V input; 1.8MHz switching; 17µA IQ in DCS-Control™ mode. | Lower max current (600mA vs. 800mA); higher switching frequency reduces inductor size but increases EMI filtering complexity. | Preferred when board space is more constrained than current demand, and lower IQ in deep-sleep modes is critical. |
| Analog Devices ADP2119ACPZ-R7 | 1.8V fixed, 800mA; 2.3–5.5V input; 1.2MHz switching; 300µA IQ in PFM; includes I2C programmability. | Wider input range starts at 2.3V; higher IQ (300µA vs. 140µA); adds digital interface for dynamic voltage scaling. | Chosen when system requires adaptive voltage scaling or operation below 2.6V (e.g., aging Li-ion cells), accepting higher light-load IQ. |
Compared with TPS62231DRYR and ADP2119ACPZ-R7, MAX1928EUB18 offers the highest guaranteed output current (800mA) at 1.8V within its 2.6–5.5V input window, lowest PFM quiescent current (140µA), and proven µMAX layout compatibility for high-density portable designs-making it optimal for WCDMA handset core rails where peak current and battery life are co-critical.
Availability
MAX1928EUB18 is available at Aetrix Electronics and suitable for WCDMA handsets, PDA application processors, and DSP core power applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX1928EUB18 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 product line was designed specifically for ultra-compact, high-efficiency core voltage regulation in battery-powered portable electronics-emphasizing low IQ, small external components, and robust light-load performance.
FAQ
What is the guaranteed output voltage accuracy of the MAX1928EUB18?
The MAX1928EUB18 guarantees output voltage accuracy of ±1.5% over temperature (–40°C to +85°C) and line/load conditions, corresponding to 1.773V to 1.827V at 1.8V nominal. This is specified in the Electrical Characteristics table under "FB Voltage Accuracy" for MAX1928-18, and confirmed by the typical operating curve showing <0.3% load regulation from 0–800mA.
Does the MAX1928EUB18 require an external feedback resistor divider?
No, the MAX1928EUB18 does not require an external feedback resistor divider. As a preset-output variant, it regulates to 1.8V by connecting the FB pin directly to the output. The internal 0.75V reference and factory-trimmed feedback network eliminate external components-unlike the adjustable MAX1927R which requires R1/R2.
How does the POK output of the MAX1928EUB18 behave during startup and shutdown?
During startup, the MAX1928EUB18's POK output remains low-impedance until the soft-start completes and VFB exceeds 90% of 1.8V (i.e., >1.62V) for 20ms, then transitions to high-impedance. During shutdown (SHDN = GND), POK immediately goes low-impedance-providing unambiguous power-fail signaling for system reset controllers.
What is the maximum junction temperature and thermal shutdown threshold for the MAX1928EUB18?
The MAX1928EUB18 has a maximum junction temperature of +150°C and incorporates thermal shutdown that activates at +160°C with 15°C hysteresis. This protects the device during overload or poor PCB thermal design, and recovery occurs automatically once die temperature falls below +145°C.
Can the MAX1928EUB18 operate with a 2.5V input supply?
No-the MAX1928EUB18 has a minimum input voltage of 2.6V per Absolute Maximum Ratings and Electrical Characteristics tables. At 2.5V input, undervoltage lockout (UVLO) engages (threshold 2.15–2.55V with 35mV hysteresis), disabling switching and forcing the device into shutdown-so 2.5V is outside functional specification.
MAX1928EUB18 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):
- 1.8V
- 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
MAX1928EUB18 FAQ
1.How can I place an order for MAX1928EUB18 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1928EUB18 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 MAX1928EUB18 reliable?
The price and inventory of MAX1928EUB18 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1928EUB18 is usually 5 days.
3.What payment methods are accepted for MAX1928EUB18?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1928EUB18 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1928EUB18?
MAX1928EUB18 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1928EUB18 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 MAX1928EUB18?
For technical support, including MAX1928EUB18 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1928EUB18 requirements.
6.How does Aetrix verify that MAX1928EUB18 is sourced from the original manufacturer or authorized distributors?
All MAX1928EUB18 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 MAX1928EUB18 meets industry standards.
7.What is the process for return or replacement of MAX1928EUB18?
All MAX1928EUB18 units undergo pre-shipment inspection (PSI). If there is an issue with MAX1928EUB18, 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 MAX1928EUB18 part is unused and in its original packaging.
Return procedure for MAX1928EUB18:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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