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Analog Devices Inc./Maxim Integrated MAX1921EUT30+T
- Part No.:
- MAX1921EUT30+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- SOT-23-6
- Datasheet:
-
MAX1921EUT30+T.pdf
- Description:
- IC REG BUCK 3V 400MA SOT6
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MAX1921EUT30+T from Maxim Integrated is a fixed-output 3.0V, 400mA synchronous step-down DC-DC converter in a 6-pin SOT23 package, featuring 50μA quiescent current, 1.2MHz max switching frequency, and internal soft-start-designed for battery-powered wireless handsets and PDAs requiring compact, high-efficiency power conversion.
For engineers reviewing the MAX1921EUT30+T datasheet, MAX1921EUT30+T pinout, MAX1921EUT30+T application, or MAX1921EUT30+T equivalent, key selection criteria include guaranteed 400mA output at 3.0V, ±1.5% initial output accuracy, 2V–5.5V input range, shutdown current of 0.1μA, and compatibility with ceramic output capacitors in space-constrained portable designs.
Technical Context
The MAX1921EUT30+T employs a proprietary current-limited control scheme with 400ns minimum on-time and off-time, enabling fast transient response and stable operation across 0–400mA load range. Its internal synchronous rectifier eliminates external Schottky diodes and achieves >90% efficiency at medium loads.
This device integrates factory-trimmed 3.0V feedback reference (OUT pin), operates without external resistive divider, and uses voltage positioning architecture-leveraging inductor DCR for feed-forward load transient suppression-reducing peak-to-peak output excursions by ~50% versus conventional buck converters.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.0V ±1.5% (initial), ±3% over -40°C to +85°C - enables direct replacement of LDOs without feedback resistor network. |
| Max Output Current | 400mA continuous - supports core logic rails in handheld devices without thermal derating in SOT23 package. |
| Input Voltage Range | 2.0V to 5.5V - compatible with single Li+ (2.7–4.2V), 3×AA (3.0–4.5V), and 5V USB-supplied systems. |
| Quiescent Current | 50μA (no load, active) - extends battery life in always-on subsystems such as RTC or sensor monitoring. |
| Shutdown Current | 0.1μA - reduces system standby power to sub-microwatt levels when host asserts SHDN. |
| Switching Frequency | Up to 1.2MHz - permits use of ≤10μH inductors and ≤10μF ceramic output capacitors, minimizing board area. |
| UVLO Threshold | 1.85V (rising), 1.50V (falling) with 200mV hysteresis - prevents erratic startup/shutdown during brownout conditions. |
Pinout & Package
MAX1921EUT30+T is housed in a RoHS-compliant, lead-free 6-pin SOT23-6 package (JEDEC MO-178AA), with 0.95mm pitch and 2.9mm × 1.6mm footprint. Thermal pad is not present; power dissipation limited to 695mW at TA = +70°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - IN | Power input supply | Accepts 2.0–5.5V; requires local 2.2μF ceramic bypass capacitor to PGND/AGND. |
| 2 - AGND | Analog ground reference | Must be connected to PGND at single-point star ground; separates noise-sensitive control circuitry from power return path. |
| 3 - SHDN | Active-low enable control | Pulled high internally; drive low (≤0.4V) to enter 0.1μA shutdown; open or tied to IN for normal operation. |
| 4 - OUT | Fixed-output voltage sense | Internally connected to factory-trimmed resistive divider; no external components required for 3.0V regulation. |
| 5 - PGND | Power ground return | Carries high-frequency inductor current; must connect to AGND near device to minimize ground bounce. |
| 6 - LX | Switch node connection | Drives external inductor; requires short, low-inductance trace to minimize EMI and switching losses. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Eliminates external Schottky diode, improving efficiency >90% and reducing thermal stress in SOT23 package. |
| Digital soft-start | Gradually ramps current limit from 25% to 100% in steps, limiting inrush current and relaxing input capacitor sizing. |
| Voltage positioning architecture | Uses inductor DCR for feed-forward transient response, cutting output voltage overshoot/undershoot by ~50% vs. standard buck. |
| Ultra-low shutdown current | 0.1μA shutdown supply current enables multi-week battery shelf life in portable medical or IoT edge sensors. |
| High-frequency operation | 1.2MHz max switching allows 4.7–10μH inductors and 4.7–10μF X5R/X7R ceramics-reducing solution size by >40% vs. 500kHz converters. |
Applications
| Wireless Handset Power Management | PDA Core Logic Supply |
|---|---|
|
Use Scenario: Powers baseband processor I/O or RF front-end bias rails in CDMA/GSM handsets operating from single Li+ cell. IC Role / Device Role / Timing Role: Primary 3.0V step-down regulator delivering up to 400mA with fast load transient recovery (<40µs). Use Value: Replaces linear regulators to extend talk time by >35% while maintaining tight 3.0V ±3% regulation across temperature and load. |
Use Scenario: Supplies 3.0V rail to ARM9-based PDA application processors and SRAM during active and light-load states. IC Role / Device Role / Timing Role: High-efficiency buck converter with 50μA quiescent current and 0.1μA shutdown mode for dynamic power gating. Use Value: Enables 120-hour standby duration on two AA alkaline cells via ultra-low IQ and seamless transition between active/standby modes. |
| Battery-Powered Industrial Sensor Node | CDMA Power Amplifier Bias Supply |
|
Use Scenario: Powers ultra-low-power microcontroller, BLE radio, and analog sensor interface in sealed environmental monitors. IC Role / Device Role / Timing Role: Primary 3.0V system rail generator with integrated soft-start and UVLO hysteresis for reliable cold-start at -40°C. Use Value: Guarantees clean startup under weak battery conditions (2.0V VIN) and maintains regulation through full discharge curve to 2.2V. |
Use Scenario: Delivers stable 3.0V bias to CDMA PA driver stage in handset front-end modules with pulsed 300mA load profiles. IC Role / Device Role / Timing Role: Fast-transient buck regulator using voltage positioning to suppress 100mV output excursions during 200mA step loads. Use Value: Prevents PA gain droop and adjacent-channel leakage by limiting output deviation to <±15mV during 10–90% load transitions. |
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 | 3.0V fixed, 400mA, 2.05–6.0V input, 17μA IQ, 3.8MHz switching - smaller IQ but higher fSW demands tighter layout control. | Requires 1.0μH inductor and 4.7μF ceramic; better suited for ultra-thin wearables where board area is more constrained than thermal budget. | Select when lowest possible quiescent current (17μA) and smallest total solution size are prioritized over thermal margin in SOT23. |
| Analog Devices ADP2303ARMZ-3.0-R7 | 3.0V fixed, 3A rated, 3.0–20V input, 2.4MHz fSW, 3.5mA IQ - higher current capability and input range, but 70× higher IQ and larger 8-lead MSOP package. | Targets industrial 12V-input systems; incompatible with Li+-range inputs and space-constrained portable PCBs. | Select only if future-proofing for higher-current variants or 12V input compatibility is required; not a drop-in replacement for MAX1921EUT30+T. |
Compared with TPS62231DRYR, MAX1921EUT30+T offers superior thermal performance in SOT23 and proven robustness in CDMA PA bias applications; compared with ADP2303ARMZ-3.0-R7, it delivers identical 3.0V output with 70× lower IQ and 40% smaller footprint-but lacks high-voltage input support.
Availability
MAX1921EUT30+T is available at Aetrix Electronics and suitable for wireless handset power management, PDA core logic supply, and battery-powered industrial sensor nodes requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for MAX1921EUT30+T 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 MAX1920/MAX1921 product line was designed specifically for space-constrained, battery-operated portable electronics-delivering high-efficiency step-down conversion in the smallest possible SOT23 footprint without compromising transient response or thermal reliability.
FAQ
What is the exact output voltage tolerance of the MAX1921EUT30+T over temperature and load?
The MAX1921EUT30+T guarantees ±1.5% initial output voltage accuracy at +25°C with zero load. Over the full operating range of -40°C to +85°C and 0–400mA load, output voltage remains within ±3% of 3.0V. This specification is confirmed in the Electrical Characteristics table under "Output Voltage Accuracy (MAX1921)" with test conditions explicitly referencing IOUT = 0 to 400mA and TA = -40°C to +85°C.
Does the MAX1921EUT30+T require external feedback resistors to set the 3.0V output?
No, the MAX1921EUT30+T does not require external feedback resistors. It uses an internal factory-trimmed voltage divider connected to the OUT pin, which is preconfigured for 3.0V output. Unlike the adjustable MAX1920, this variant eliminates all external resistor networks-reducing BOM count, layout area, and calibration uncertainty. The OUT pin is dedicated solely to sensing and requires no external components.
What is the recommended input capacitor for the MAX1921EUT30+T, and why?
The recommended input capacitor for the MAX1921EUT30+T is a 2.2μF X5R or X7R ceramic capacitor placed as close as possible to the IN and AGND/PGND pins. This value is validated across 2.0–5.5V input range and 400mA load to suppress high-frequency switching noise and limit RMS input current ripple. Larger values (e.g., 4.7μF) improve hold-up during transients but offer diminishing returns beyond 2.2μF due to the device's 1.2MHz switching frequency and internal current-limit architecture.
Can the MAX1921EUT30+T operate reliably at the minimum 2.0V input voltage?
Yes, the MAX1921EUT30+T is fully specified to operate down to 2.0V input for the 1.5V, 1.8V, and 3.0V output variants (including MAX1921EUT30+T), as confirmed in the Electrical Characteristics table under "Startup Voltage" and "Input Voltage Range". At 2.0V input, it delivers regulated 3.0V output up to ~200mA; full 400mA capability resumes at VIN ≥ 2.5V. UVLO ensures clean startup above 1.85V and prevents oscillation during brownout.
How does the voltage positioning architecture in the MAX1921EUT30+T improve load transient response?
The MAX1921EUT30+T implements voltage positioning by feeding inductor current information directly into the control loop via the LX node and R1/CFF network. This creates intentional, controlled load regulation (~15mV/A) that counteracts output voltage deviations during rapid load steps-reducing peak-to-peak excursion by approximately 50% compared to conventional buck regulators. Measured data in the Typical Operating Characteristics (e.g., LOAD-TRANSIENT RESPONSE figure) confirms <±15mV deviation for 20mA→320mA steps at 3.0V output.
MAX1921EUT30+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-6
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 3V
- Voltage - Output (Max):
- -
- Current - Output:
- 400mA
- Frequency - Switching:
- Up to 1.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-6
MAX1921EUT30+T FAQ
1.How can I place an order for MAX1921EUT30+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1921EUT30+T 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 MAX1921EUT30+T reliable?
The price and inventory of MAX1921EUT30+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1921EUT30+T is usually 5 days.
3.What payment methods are accepted for MAX1921EUT30+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1921EUT30+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1921EUT30+T?
MAX1921EUT30+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1921EUT30+T 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 MAX1921EUT30+T?
For technical support, including MAX1921EUT30+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1921EUT30+T requirements.
6.How does Aetrix verify that MAX1921EUT30+T is sourced from the original manufacturer or authorized distributors?
All MAX1921EUT30+T 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 MAX1921EUT30+T meets industry standards.
7.What is the process for return or replacement of MAX1921EUT30+T?
All MAX1921EUT30+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1921EUT30+T, 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 MAX1921EUT30+T part is unused and in its original packaging.
Return procedure for MAX1921EUT30+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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