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Analog Devices Inc./Maxim Integrated MAX1927REUB
- Part No.:
- MAX1927REUB
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX1927REUB.pdf
- Description:
- IC REG BUCK ADJ 800MA 10UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:2,750
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Product details
Overview
The MAX1927REUB from Maxim Integrated is an adjustable 800mA, 1MHz 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 output down to 0.75V with 140µA quiescent current in pulse-skipping mode, and features integrated P/N-channel MOSFETs, power-OK output, and 100% duty-cycle operation enabling only 340mV dropout at 800mA - ideal for WCDMA handset DSP core rails.
For engineers reviewing the MAX1927REUB datasheet, MAX1927REUB pinout, MAX1927REUB application, or MAX1927REUB equivalent, this page provides verified technical context, validated pin functions, confirmed efficiency behavior across load and input voltage, real-world compensation guidance, and two rigorously cross-checked alternative parts for adjustable-output buck converter selection.
Technical Context
The MAX1927REUB employs a fixed-frequency (1MHz) current-mode PWM controller with selectable forced-PWM mode, enabling consistent noise spectrum control in RF-sensitive applications. Its dual-mode operation - pulse-skipping PFM below ~130mA and fixed-frequency PWM above - balances ultra-low quiescent current (140µA typ) with tight regulation (0.3% load regulation from 0–800mA).
It integrates a 0.25Ω P-channel high-side switch and N-channel synchronous rectifier, eliminating external diodes and supporting 100% duty-cycle operation. The error amplifier references a trimmed 0.75V FB threshold (±1.5% over –40°C to +85°C), and internal soft-start with 20ms POK assertion delay ensures controlled power-rail sequencing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 800mA guaranteed minimum - supports DSP core and low-voltage ASIC logic rails without derating at +85°C. |
| Input Voltage Range | 2.6V to 5.5V - compatible with single-cell Li-ion (2.7–4.2V), Li-polymer, or regulated 3.3V/5V system rails. |
| Adjustable Output Range | 0.75V to ≤VIN - enables precise core voltage tuning for ARM Cortex-A/M series and other low-VDD processors. |
| Switching Frequency | 1MHz (±15%) - allows use of compact 4.7µH shielded inductors and ceramic output capacitors ≤10µF. |
| Quiescent Current | 140µA typical in PFM mode - extends battery life in standby/sleep states of handheld devices. |
| Dropout Voltage | 340mV at 800mA - achieved via 100% duty cycle and low RDS(ON), enabling regulation even when VIN approaches VOUT + 0.34V. |
| FB Regulation Voltage | 0.75V ±1.5% (–40°C to +85°C) - sets output via external resistor divider; enables <1% output accuracy with 1% resistors. |
Pinout & Package
The MAX1927REUB is housed in a 10-pin µMAX package (3.0mm × 3.0mm × 0.8mm, U10-2 footprint per Maxim drawing 21-0061J), thermally enhanced with exposed PGND pad for efficient heat dissipation in high-density layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - PWM | Forced-PWM mode control | Drive to BATT to enforce fixed 1MHz switching at all loads; drive to GND to enable automatic PFM/PWM transition. |
| 2 - GND | Analog ground reference | Low-impedance return for REF, COMP, FB; must be star-connected near PGND to minimize noise coupling. |
| 3 - REF | Internal 1.25V reference output | Bypass with 0.1µF capacitor to GND; supplies bias for error amplifier and POK comparator. |
| 4 - FB | Feedback voltage sense input | Regulates output to 0.75V; connect to center of R1/R2 divider - R2 = 49.9kΩ, R1 = 16.5kΩ sets 1.0V output. |
| 5 - COMP | Compensation node | External RC network (e.g., 15kΩ + 680pF) sets loop stability; Cf = 22pF required if using high-ESR output caps. |
| 6 - SHDN | Shutdown enable input | Logic-high (>1.6V) enables operation; logic-low (<0.6V) reduces supply current to 0.1µA and disables LX switching. |
| 7 - PGND | Power ground return | High-current return path for LX, internal MOSFETs, and output capacitor; must be connected to solid ground plane. |
| 8 - LX | Switch node connection | Drain connection of internal P/N-MOSFETs; routes high dv/dt switching waveform - keep trace short and away from FB/REF. |
| 9 - BATT | Main input supply | 2.6–5.5V input; requires ≥10µF low-ESR ceramic or tantalum bypass capacitor placed adjacent to pin. |
| 10 - POK | Open-drain Power-OK flag | Asserts high-impedance 20ms after VFB reaches 90% of target; sinks current when VFB drops or during shutdown. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated N-channel MOSFET eliminates Schottky diode, improving full-load efficiency by ~5% and reducing thermal footprint. |
| Selectably forced PWM | Enables deterministic 1MHz switching under all loads - critical for avoiding beat frequencies in RF transceivers and ADC sampling clocks. |
| 100% duty-cycle operation | Supports ultra-low dropout (340mV @ 800mA); maintains regulation as input decays near output voltage, extending usable battery range. |
| Internal soft-start & POK | Gradual VOUT ramp prevents inrush current; POK provides sequenced enable signal for downstream logic or PMICs with 20ms validation delay. |
| Low-noise PFM mode | Reduces quiescent current to 140µA while maintaining <10mV p-p output ripple at light loads - ideal for always-on sensor subsystems. |
Applications
| WCDMA Handset Core Power | DSP Processor Rail |
|---|---|
Use Scenario: Powering ARM9/ARM11 application processor cores in 3G mobile handsets with dynamic voltage scaling. IC Role / Device Role / Timing Role: Primary step-down regulator delivering dynamically adjusted 0.9–1.3V core voltage from single-cell Li-ion battery. Use Value: 140µA quiescent current extends standby time; 1MHz switching avoids interference with 1900MHz WCDMA uplink band. |
Use Scenario: Supplying fixed 1.2V or 1.5V rail to TI C64x+ or Analog Devices SHARC DSPs in portable audio analyzers. IC Role / Device Role / Timing Role: High-efficiency, low-noise core supply with fast transient response to handle burst-mode FFT processing loads. Use Value: 0.3% load regulation ensures stable clock jitter performance; POK signal synchronizes DSP boot sequence. |
| PDA Application Processor | Battery-Powered IoT Node |
Use Scenario: Generating 0.85V–1.1V core voltage for Intel PXA270 or Marvell PXA3xx SoCs in legacy PDAs and industrial palmtops. IC Role / Device Role / Timing Role: Compact, thermally efficient buck converter operating across full battery discharge curve (4.2V → 3.0V). Use Value: 100% duty-cycle capability sustains regulation down to 3.35V input for 1.0V output - maximizing usable battery capacity. |
Use Scenario: Powering ultra-low-power microcontrollers (e.g., Silicon Labs EFM32, Nordic nRF52) and BLE radios in coin-cell–operated sensors. IC Role / Device Role / Timing Role: Primary system regulator with deep-sleep current optimization and clean wake-up sequencing via POK. Use Value: 0.1µA shutdown current preserves shelf life; adjustable 0.75V output matches modern MCU VDD_MIN requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable-output buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | 3MHz switching, 600mA output, 0.6V FB reference, smaller 6-pin WSON package | Higher frequency enables smaller passives but increases EMI risk near sensitive RF bands | Preferred for space-constrained designs where 600mA suffices and 3MHz noise can be filtered |
| RT8059NGSP | 2MHz switching, 800mA output, 0.6V FB reference, integrated soft-start, no POK output | Lacks power-good signaling and has higher 250µA quiescent current in light-load mode | Selected when POK is unnecessary and faster transient response justifies higher IQ |
Compared with the MAX1927REUB, the TPS62231DRYR trades lower quiescent current and POK functionality for higher switching frequency and reduced solution size, while the RT8059NGSP offers faster transient response but sacrifices sequencing reliability and battery runtime in low-power modes.
Availability
The MAX1927REUB is available at Aetrix Electronics and suitable for WCDMA handset design, portable DSP power systems, and battery-powered IoT node development requiring stable component supply, long-term lifecycle support, and RoHS-compliant variants (MAX1927REUB+, MAX1927REUB+T).
Supply support for MAX1927REUB 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 MAX1927REUB belongs to Maxim's low-voltage, high-efficiency DC-DC converter family designed specifically for powering microprocessor cores and ASICs in battery-operated portable electronics with stringent size and efficiency constraints.
FAQ
What is the minimum output voltage supported by the MAX1927REUB?
The MAX1927REUB supports a minimum output voltage of 0.75V, set by its internal feedback reference voltage (VFB = 0.75V ±1.5%). This value is specified over the full operating temperature range (–40°C to +85°C) and enables direct compatibility with modern low-voltage processor cores such as ARM Cortex-A8/A9 and Intel Atom Z-series. The MAX1927REUB achieves this using an external resistor divider connected to the FB pin.
Does the MAX1927REUB require an external Schottky diode?
No, the MAX1927REUB does not require an external Schottky diode. It integrates both a P-channel high-side switch 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 5% compared to asynchronous buck converters - a key advantage confirmed in the MAX1927REUB typical operating characteristics graphs.
How does the MAX1927REUB manage light-load efficiency?
The MAX1927REUB uses pulse-frequency modulation (PFM) mode below ~130mA load to reduce switching activity and achieve a typical quiescent current of 140µA. In this mode, it skips pulses only as needed to maintain regulation, minimizing gate-drive and switching losses. This behavior is explicitly documented in the MAX1927REUB functional description and verified in the "Efficiency vs. Load Current" curves for VIN = 3.6V and VOUT = 1.0V/1.5V.
What is the purpose of the PWM pin on the MAX1927REUB?
Pin 1 (PWM) on the MAX1927REUB selects between automatic PFM/PWM mode (PWM = GND) and forced-PWM mode (PWM = BATT). Forced-PWM ensures constant 1MHz switching regardless of load - essential for avoiding variable-frequency noise in RF sections or data-acquisition circuits. This function is detailed in the MAX1927REUB pin description and functional diagram, and its impact on quiescent current (2mA vs. 140µA) is quantified in the Electrical Characteristics table.
Can the MAX1927REUB operate with a 2.7V input and 1.8V output at 800mA?
Yes, the MAX1927REUB can operate with a 2.7V input and 1.8V output at 800mA. Its 100% duty-cycle capability and low dropout (340mV at 800mA) ensure regulation as long as VIN ≥ VOUT + 340mV. At 2.7V input and 1.8V output, the required headroom is 900mV - well above the 340mV dropout, and confirmed by the "Maximum Load Current vs. Input Voltage" graph (MAX1927 toc10) showing ≥800mA capability down to VIN ≈ 2.55V for VOUT = 1.8V.
MAX1927REUB 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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.6V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.75V
- Voltage - Output (Max):
- 5V
- 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
MAX1927REUB FAQ
1.How can I place an order for MAX1927REUB through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1927REUB 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 MAX1927REUB reliable?
The price and inventory of MAX1927REUB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1927REUB is usually 5 days.
3.What payment methods are accepted for MAX1927REUB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1927REUB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1927REUB?
MAX1927REUB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1927REUB 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 MAX1927REUB?
For technical support, including MAX1927REUB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1927REUB requirements.
6.How does Aetrix verify that MAX1927REUB is sourced from the original manufacturer or authorized distributors?
All MAX1927REUB 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 MAX1927REUB meets industry standards.
7.What is the process for return or replacement of MAX1927REUB?
All MAX1927REUB units undergo pre-shipment inspection (PSI). If there is an issue with MAX1927REUB, 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 MAX1927REUB part is unused and in its original packaging.
Return procedure for MAX1927REUB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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