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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:2,218
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Product details
Overview
The MAX1927REUB+ from Maxim Integrated is a 800mA, 1MHz synchronous step-down DC-DC converter optimized for low-output-voltage microprocessor core power in space-constrained battery-powered systems. It operates from 2.6V to 5.5V input, delivers adjustable output down to 0.75V, achieves 100% duty-cycle operation with only 340mV dropout at 800mA, and maintains 140µA quiescent current in pulse-skipping mode - enabling high efficiency in WCDMA handsets and DSP core supplies.
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 POK timing (20ms release delay), and design-meaningful alternatives for low-voltage, high-efficiency buck conversion in portable electronics.
Technical Context
The MAX1927REUB+ implements a current-mode PWM controller with selectable forced-PWM or automatic PFM/PWM hybrid operation. Its internal P-channel high-side switch (0.4Ω typ at 3.6V) and N-channel synchronous rectifier eliminate external diode requirements and enable 100% duty-cycle dropout operation.
It integrates a 1.25V reference, error amplifier with 250µS transconductance, and a 1MHz oscillator with ±15% tolerance. The FB regulation voltage is fixed at 0.75V, and the POK comparator triggers after VFB exceeds 90% of threshold with 20ms delay - supporting reliable power sequencing in compact embedded systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 800mA guaranteed minimum - supports full-core operation for low-voltage microprocessors and DSPs. |
| Input Voltage Range | 2.6V to 5.5V - compatible with single-cell Li-ion (2.7–4.2V), Li-polymer, and regulated 3.3V/5V rails. |
| Adjustable Output Range | 0.75V to VIN - enables precise core voltage tuning for ASICs, FPGAs, and ARM-based SoCs. |
| Switching Frequency | 1MHz fixed (0.85–1.15MHz over temp) - allows use of small 4.7µH inductors and 10µF ceramic capacitors. |
| Quiescent Current | 140µA in pulse-skipping mode - extends battery life in standby and light-load states. |
| Dropout Voltage | 340mV at 800mA - ensures stable regulation even as battery discharges below 3.0V. |
| POK Delay | 20ms after VFB > 90% of target - provides deterministic power-good assertion for system reset and sequencing logic. |
Pinout & Package
MAX1927REUB+ 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 high-density PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - PWM | Forced-PWM control input | Drives GND for auto PFM/PWM mode; drives BATT for noise-sensitive forced-PWM operation (2mA IQ). |
| 2 - GND | Analog ground reference | Reference node for REF, FB, COMP; must be star-connected near PGND to minimize noise coupling. |
| 3 - REF | Internal 1.25V reference output | Bypassed with 0.1µF capacitor to stabilize reference; used internally for error amplifier biasing. |
| 4 - FB | Feedback sense input | Regulates output to 0.75V; connects to resistor divider for adjustable VOUT - sets precision core voltage. |
| 5 - COMP | Compensation network node | Connects RC/CC network (e.g., 15kΩ + 680pF) to set loop stability and transient response bandwidth. |
| 6 - SHDN | Shutdown enable input | Logic-high = active; logic-low = shutdown (0.1µA IQ); enables system-level power gating. |
| 7 - PGND | Power ground return | High-current return path for LX switching; must be low-inductance, separate from analog GND. |
| 8 - LX | Switch node connection | Drives external inductor; carries high di/dt - requires short, wide trace and tight layout to PGND/CIN. |
| 9 - BATT | Main supply input | 2.6–5.5V input; bypassed with ≥10µF low-ESR capacitor to suppress high-frequency ripple. |
| 10 - POK | Open-drain Power-OK output | Asserts high-impedance when VFB > 90% of target; pulls low during shutdown or undervoltage. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated N-channel MOSFET eliminates Schottky diode - reduces conduction loss and improves efficiency by ~5% at 800mA. |
| 100% duty-cycle operation | Enables dropout as low as 340mV at 800mA - sustains regulation during deep battery discharge without rail collapse. |
| Selectably forced PWM | Eliminates frequency modulation noise - critical for RF sections and ADC sampling in handheld devices. |
| Internal soft-start | Controls output ramp rate to prevent inrush current - avoids input rail sag and protects downstream LDOs. |
| Power-OK (POK) with 20ms delay | Provides clean, debounced power-good signal - simplifies FPGA/ASIC reset sequencing without external timers. |
Applications
| WCDMA Handset Core Power | DSP Processor Supply |
|---|---|
Use Scenario: Powers ARM9/ARM11 application processor core in dual-mode cellular handsets operating from single Li-ion cell. IC Role / Device Role / Timing Role: Primary step-down regulator delivering dynamically scaled 1.0–1.3V core voltage with fast transient response to CPU load changes. Use Value: 140µA quiescent current extends standby time; 1MHz switching minimizes inductor size for <10mm² solution area. |
Use Scenario: Supplies 1.8V core voltage to TI C64x+ or Analog Devices SHARC DSPs in portable audio analyzers. IC Role / Device Role / Timing Role: High-efficiency buck converter with POK output synchronized to DSP boot sequence. Use Value: 0.75V FB reference enables precise 1.8V via 2-resistor divider; POK delay ensures stable clock before DSP release. |
| PDA Application Processor Rail | Battery-Powered IoT Sensor Hub |
Use Scenario: Generates 1.5V I/O and 1.2V core for Intel PXA270 or Marvell Monahans in enterprise PDAs. IC Role / Device Role / Timing Role: Dual-rail capable converter (with external feedback) supporting dynamic voltage scaling during performance modes. Use Value: Adjustable output range (0.75V–VIN) allows one BOM to support multiple SoC variants; µMAX footprint saves board space. |
Use Scenario: Powers ultra-low-power MCU (e.g., Silicon Labs EFM32) and BLE radio from coin-cell or energy-harvested source. IC Role / Device Role / Timing Role: Efficient step-down stage converting 3.6V battery to 1.1V MCU core, with shutdown controlled by system PMU. Use Value: 0.1µA shutdown current preserves battery life; PFM mode maintains >85% efficiency at 100µA load. |
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 | Fixed 1.8V output (non-adjustable); 3.6V max input; 350mA rated (vs. 800mA) | Limited to lower-current I/O rails; unsuitable for core power above 350mA | Choose only for cost-sensitive, fixed-VOUT, sub-400mA applications where size is secondary. |
| RT8059GJ6 | Adjustable 0.6V–5.5V output; 1.5A rating; 3mm × 3mm DFN-6 package; no POK output | Lacks power-good signaling - requires external supervisor IC for sequencing-critical designs | Prefer when higher current headroom or wider input range is needed, and POK is not required. |
Compared with TPS62231DRYR and RT8059GJ6, the MAX1927REUB+ uniquely combines 800mA capability, 0.75V adjustable output, integrated POK with 20ms delay, and µMAX packaging - making it optimal for core power in compact, sequenced, battery-operated systems where both efficiency and deterministic power-good timing are essential.
Availability
MAX1927REUB+ is available at Aetrix Electronics and suitable for WCDMA handset design, DSP core power delivery, and battery-powered portable instrumentation requiring stable component supply, long-lifecycle availability, and consistent parametric performance across temperature.
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 buck converter product line, designed specifically for powering microprocessor cores and DSPs in compact, battery-driven equipment where minimal dropout, low IQ, and small solution size are critical.
FAQ
What is the minimum output voltage supported by the MAX1927REUB+?
The MAX1927REUB+ supports an adjustable output voltage down to 0.75V, set by an external resistor divider connected to the FB pin. This 0.75V feedback reference enables precise core voltage generation for modern low-voltage microprocessors and SoCs - a key specification confirmed in the Electrical Characteristics table under "FB Voltage Accuracy" for MAX1927R.
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, eliminating conduction losses and thermal overhead associated with discrete diodes - a feature explicitly stated in the General Description and Pin Description sections.
How does the POK output of the MAX1927REUB+ behave during startup?
The POK output of the MAX1927REUB+ transitions to high impedance 20ms after the soft-start ramp completes and VFB exceeds 90% of its target value. It remains low-impedance (pulled low) during shutdown or input undervoltage - providing a reliable, delay-stabilized power-good signal for system reset controllers.
What is the maximum duty cycle capability of the MAX1927REUB+?
The MAX1927REUB+ supports 100% duty-cycle operation, allowing it to maintain regulation even when input voltage approaches output voltage. At 800mA, the dropout voltage is specified at 340mV - a result of the internal P-channel MOSFET's on-resistance and inductor DCR, confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables.
Can the MAX1927REUB+ operate in forced PWM mode, and what is the trade-off?
Yes, the MAX1927REUB+ supports forced PWM mode by driving the PWM pin high (to BATT). This disables pulse-skipping and ensures constant 1MHz switching - reducing noise in RF-sensitive applications. However, quiescent current increases from 140µA (PFM) to 2mA (forced PWM), as documented in the Electrical Characteristics table under "Quiescent Current".
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:
- Tube
- 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):
- 5.5V
- 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
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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