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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:1,901
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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 to 5.5V input, delivers 1.8V ±1.5% output accuracy at up to 800mA, achieves 1MHz fixed-frequency PWM switching, and maintains 140µA quiescent current in pulse-skipping mode - enabling high efficiency in WCDMA handsets and battery-powered DSP systems.
For engineers reviewing the MAX1928EUB18+ datasheet, MAX1928EUB18+ pinout, MAX1928EUB18+ application, or MAX1928EUB18+ equivalent, key selection criteria include its 1.8V preset output, 10-pin µMAX package footprint, POK (power-ok) open-drain signal, selectable forced-PWM mode for RF-sensitive designs, and 100% duty-cycle capability supporting ultra-low dropout operation.
Technical Context
The MAX1928EUB18+ employs a current-mode, fixed-frequency 1MHz PWM controller with integrated P-channel high-side and N-channel synchronous rectifier MOSFETs - eliminating external diode requirements. Its control architecture dynamically switches between pulse-frequency modulation (PFM) at light loads (<130mA) and PWM at medium/heavy loads, minimizing ripple while sustaining 140µA quiescent current.
It features internal 1.25V reference, 0.75V feedback regulation threshold, and a dedicated compensation pin (COMP) supporting external RC network tuning for stability with ceramic output capacitors. The device integrates soft-start, undervoltage lockout (2.35V typ), thermal shutdown (160°C), and a power-OK comparator with 20ms delay after VFB exceeds 90% of target.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8V ±1.5% (1.773V–1.827V) - ensures stable core supply for 1.8V logic and DSP processors without external feedback resistors. |
| Max Output Current | 800mA continuous - sufficient for low-power microprocessor cores and baseband ICs in handheld devices. |
| Input Voltage Range | 2.6V to 5.5V - compatible with single-cell Li-ion (3.0–4.2V), Li-polymer, and regulated 3.3V/5V rails. |
| Switching Frequency | 1MHz (±15%) - enables use of compact 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 mobile UI and sensor subsystems. |
| Dropout Voltage | 340mV at 800mA - achieved via 100% duty cycle and low RDS(ON) (0.25Ω P-MOSFET) for operation near battery minimum voltage. |
| POK Threshold Accuracy | 1.566V–1.674V (90% of 1.8V) - provides precise power-good assertion timing for system sequencing and reset management. |
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 for efficient heat dissipation in compact PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - PWM | Forced-PWM mode control | Logic-high (BATT) forces continuous 1MHz PWM; logic-low (GND) enables automatic PFM/PWM transition - critical for noise-sensitive RF sections. |
| 2 - GND | Analog ground reference | Separate from PGND; must be connected to quiet analog ground plane to avoid error amplifier noise coupling. |
| 3 - REF | Internal 1.25V reference output | Bypassed with 0.1µF capacitor to GND; supplies bias for internal error amplifier and POK comparator. |
| 4 - FB | Feedback sense input | Internally referenced to 0.75V; tied directly to VOUT for 1.8V operation - eliminates external resistor divider and associated tolerance errors. |
| 5 - COMP | Compensation node | Connects external RC network (e.g., 18kΩ + 1200pF) to set loop bandwidth and phase margin for stability with low-ESR ceramic output caps. |
| 6 - SHDN | Shutdown enable input | Active-low; pulls <0.6V to disable regulator and reduce supply current to 0.1µA - enables system-level power gating. |
| 7 - PGND | Power ground return | High-current return path for LX switch and synchronous rectifier; must be star-connected to minimize ground bounce and EMI. |
| 8 - LX | Switch node | Connects to inductor; carries high di/dt switching current - requires short, wide trace routing away from sensitive analog nodes. |
| 9 - BATT | Main input supply | 2.6–5.5V input; requires ≥10µF low-ESR ceramic capacitor placed adjacent to pin to suppress high-frequency ripple. |
| 10 - POK | Open-drain power-good indicator | Asserts high-impedance 20ms after VFB reaches 90% of 1.8V; used for processor reset hold-off and system power sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated N-channel MOSFET replaces Schottky diode - improves full-load efficiency by ~8% and eliminates diode forward drop losses. |
| 100% duty-cycle operation | Enables dropout voltage as low as 340mV at 800mA - sustains regulation down to 2.14V input when VOUT = 1.8V. |
| Selectably forced PWM mode | Eliminates variable-frequency PFM noise - essential for coexistence with GSM/WCDMA transceivers and ADC sampling clocks. |
| Internal soft-start | Controls output ramp rate to prevent inrush current - limits peak input current during startup and avoids brownout on weak batteries. |
| Power-OK (POK) output | Provides system-level power validation with 20ms delay - enables reliable processor boot sequencing and fault detection before firmware execution. |
Applications
| WCDMA Handset Core Power | DSP Baseband 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 1.8V at up to 800mA with fast transient response to CPU burst loads. Use Value: 140µA quiescent current extends standby time; POK signal synchronizes application processor reset with stable rail establishment. |
Use Scenario: Supplies 1.8V core voltage to digital signal processors in portable audio/video encoders and modems. IC Role / Device Role / Timing Role: High-efficiency synchronous buck converter with forced-PWM mode enabled to avoid interference with IF sampling clocks. Use Value: 1MHz switching allows small 4.7µH inductor; 100% duty cycle maintains regulation during battery discharge to 2.14V. |
| PDA Application Processor Rail | Battery-Powered Industrial Sensor Node |
Use Scenario: Generates 1.8V supply for application SoC in palm-sized PDAs with tight board area constraints. IC Role / Device Role / Timing Role: Compact µMAX-packaged DC-DC converter providing low-noise, high-PSRR core power with integrated soft-start. Use Value: 10-pin µMAX footprint (3.0×3.0mm) saves >40% board area vs. comparable SO-8 solutions; no external diode reduces BOM count. |
Use Scenario: Powers 1.8V microcontroller and wireless transceiver (e.g., BLE SoC) in long-life battery-operated environmental sensors. IC Role / Device Role / Timing Role: Ultra-low-quiescent-current buck regulator supporting intermittent wake-up cycles with sub-100µA sleep current. Use Value: 140µA PFM quiescent current minimizes battery drain during 99%+ sleep time; SHDN pin enables full system shutdown. |
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 | 1.8V fixed, 800mA, 3MHz switching, 17µA quiescent current - higher frequency enables smaller passives but lower max output current at 3.3V input. | Optimized for ultra-thin wearables requiring minimal inductor height; lacks POK output and forced-PWM control. | Choose TPS62231DRYR only if board space is constrained to <2.0mm height and POK signaling is not required. |
| RT8059ZSP | 1.8V fixed, 1A, 1.5MHz, 25µA quiescent current - higher current rating and lower IQ, but no POK output and no forced-PWM option. | Targeted at cost-sensitive consumer electronics; uses SOT-23-6 package with fewer pins and no compensation flexibility. | Choose RT8059ZSP when 1A headroom is needed and system-level power sequencing is handled externally. |
Compared with TPS62231DRYR and RT8059ZSP, the MAX1928EUB18+ uniquely combines POK signaling, selectable forced-PWM, and 100% duty-cycle dropout performance - making it the preferred choice for RF-coexistent, battery-critical, and sequenced-power applications where reliability and noise control outweigh raw efficiency metrics.
Availability
MAX1928EUB18+ is available at Aetrix Electronics and suitable for WCDMA handset design, DSP baseband power, PDA application processor rails, and battery-powered industrial sensor nodes requiring stable component supply across extended production lifecycles.
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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.
The MAX1928EUB18+ belongs to Maxim's low-voltage, high-efficiency DC-DC converter product line - engineered specifically for powering microprocessor cores and DSPs in compact, battery-operated portable electronics with stringent noise and efficiency requirements.
FAQ
What is the guaranteed minimum output current for MAX1928EUB18+?
The MAX1928EUB18+ guarantees a minimum continuous output current of 800mA across the full operating temperature range (-40°C to +85°C) and input voltage range (2.6V to 5.5V), as confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables. This rating holds under thermal conditions where junction temperature remains below 150°C and PCB layout follows recommended thermal guidelines including proper PGND copper pour.
Does MAX1928EUB18+ require an external Schottky diode?
No, the MAX1928EUB18+ does not require an external Schottky diode. It integrates both a P-channel high-side MOSFET and an N-channel synchronous rectifier, enabling full synchronous rectification. This eliminates conduction losses associated with external diodes and improves full-load efficiency by approximately 8% compared to asynchronous buck converters.
How is the output voltage set on MAX1928EUB18+?
The MAX1928EUB18+ has a factory-trimmed fixed 1.8V output. The FB pin is internally configured to regulate at 0.75V, and the device achieves 1.8V output by internal resistor scaling - requiring only a direct connection from FB to VOUT. No external feedback resistors are needed, ensuring ±1.5% output accuracy over temperature and line without calibration.
What is the function of the PWM pin on MAX1928EUB18+?
The PWM pin on MAX1928EUB18+ selects the operating mode: tying it to GND enables automatic PFM/PWM transition based on load current, while tying it to BATT forces continuous 1MHz PWM operation regardless of load. Forced PWM eliminates variable-frequency switching noise - critical for RF sections and precision data acquisition circuits where spectral purity matters.
Can MAX1928EUB18+ operate with input voltage below 2.6V?
No, MAX1928EUB18+ cannot operate reliably below 2.6V. Its absolute minimum input voltage is specified as 2.6V in the Electrical Characteristics table, and undervoltage lockout activates at 2.15V (rising) to 2.55V (falling). Operation below 2.6V risks failure to start, regulation loss, or undefined behavior - especially near dropout where 100% duty cycle depends on sufficient gate drive from the input rail.
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:
- Obsolete
- 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:
- 800kHz ~ 1.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-uMAX/uSOP
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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