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Analog Devices Inc./Maxim Integrated MAX1921EUT18+TG104
- Part No.:
- MAX1921EUT18+TG104
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- SOT-23-6
- Datasheet:
-
MAX1921EUT18+TG104.pdf
- Description:
- IC REG BUCK 1.8V 400MA SOT6
- Quantity:
- Payment:
- Shipping:
Inventory:3,752
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Product details
Overview
The MAX1921EUT18+TG104 from Maxim Integrated is a fixed-output 1.8V, 400mA synchronous step-down DC-DC converter in a 6-pin SOT23 package, featuring 50μA quiescent current, 1.2MHz max switching frequency, ±1.5% initial output accuracy, and internal soft-start - designed for battery-powered wireless handsets and PDAs requiring compact, high-efficiency power conversion.
For engineers reviewing the MAX1921EUT18+TG104 datasheet, MAX1921EUT18+TG104 pinout, MAX1921EUT18+TG104 application, or MAX1921EUT18+TG104 equivalent, key selection criteria include guaranteed 400mA output at 1.8V, 2V–5.5V input range, shutdown current of 0.1μA, SOT23-6 footprint compatibility, and voltage positioning for transient load stability in space-constrained portable systems.
Technical Context
The MAX1921EUT18+TG104 employs a proprietary current-limited control scheme with 400ns minimum on/off times, enabling fast transient response and near-constant frequency operation across 0–400mA loads. Its internal synchronous rectifier eliminates external Schottky diodes while delivering >90% efficiency at medium loads.
It integrates digital soft-start (25% incremental current limit ramp), UVLO with 1.9V rising threshold and 200mV hysteresis, and logic-controlled shutdown that places LX in high-impedance state. The device uses voltage positioning feedback via the OUT pin to reduce output voltage excursions during load transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8V ±1.5% (initial), supports stable core supply for low-voltage ASICs and RF ICs |
| Max Output Current | 400mA continuous - sufficient for baseband processors and CDMA power amplifiers |
| Input Voltage Range | 2V to 5.5V - compatible with single Li+ cells (2.7–4.2V) and 3.3V/5V rails |
| Quiescent Current | 50μA - enables >1000-hour standby in always-on portable devices |
| Shutdown Current | 0.1μA - minimizes battery drain during system sleep modes |
| Switching Frequency | Up to 1.2MHz - allows use of 4.7μH inductors and 4.7μF ceramic output capacitors |
| UVLO Threshold | 1.9V (rising), 1.6V (falling) - prevents erratic startup below safe battery voltage |
Pinout & Package
Package: 6-pin SOT23-6, RoHS-compliant lead-free (indicated by '+' suffix), 2.9mm × 1.6mm footprint, 1.1mm height.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - IN | Power input | Accepts 2V–5.5V; requires local 2.2μF ceramic bypass capacitor to PGND |
| 2 - AGND | Analog ground reference | Must be connected to PGND at single-point star ground to minimize noise coupling into feedback path |
| 3 - SHDN | Active-low enable control | Pull to GND for 0.1μA shutdown; tie to IN for normal operation; VIH ≥1.6V, VIL ≤0.4V |
| 4 - LX | Switch node | Connects to inductor; high dv/dt node - must be routed short and away from FB/OUT traces |
| 5 - PGND | Power ground return | Carries high pulsed currents; connect directly to AGND and input/output capacitor grounds |
| 6 - OUT | Fixed-output voltage sense | Internally connected to factory-trimmed resistor divider; no external components required for 1.8V regulation |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Eliminates external Schottky diode, improves efficiency >90%, reduces thermal stress in SOT23 |
| Voltage positioning architecture | Uses inductor DCR sensing to provide intentional load regulation, halving peak-to-peak output excursions during 20mA→320mA transients |
| Digital soft-start | Ramps current limit in 25% steps to limit inrush, reducing required input capacitance and avoiding brownout on weak batteries |
| High-frequency operation | 1.2MHz max switching enables compact 4.7μH/4.7μF output filter - saves >40% board area vs. 500kHz solutions |
| Low-noise shutdown mode | 0.1μA supply current with LX high-impedance - preserves battery life without leakage paths through inductor |
Applications
| CDMA Power Amplifier Supply | Wireless Handset Baseband Core |
|---|---|
Use Scenario: Powers CDMA PA stage requiring stable 1.8V at up to 350mA during transmission bursts. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 1.8V with fast line/load transient response to maintain PA linearity. Use Value: Voltage positioning reduces output undershoot/overshoot by 50%, preventing PA gain compression and spectral regrowth. | Use Scenario: Supplies 1.8V core voltage to baseband processor in next-generation GSM/UMTS handsets. IC Role / Device Role / Timing Role: High-efficiency point-of-load converter operating from single-cell Li+ battery (2.7–4.2V). Use Value: 50μA quiescent current extends standby time beyond 40 days; SOT23-6 footprint fits tight PCB real estate. |
| PDA Application Processor Rail | Handheld Terminal LCD Backlight Driver Bias |
Use Scenario: Provides 1.8V rail for ARM9-based application processor in palmtop PDA with 8-hour active runtime. IC Role / Device Role / Timing Role: Main system buck converter with shutdown control synchronized to OS suspend/resume cycles. Use Value: 0.1μA shutdown current enables multi-week shelf life; 1.2MHz switching avoids audible noise in audio-sensitive environments. | Use Scenario: Generates clean 1.8V bias for white LED driver IC in industrial handheld terminal with OLED display. IC Role / Device Role / Timing Role: Low-noise auxiliary supply decoupled from noisy display switching circuitry. Use Value: Internal soft-start prevents backlight flicker at power-on; ±1.5% output accuracy ensures consistent LED brightness across temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | 1.8V fixed, 400mA, 2.05–6.5V input, 3.6MHz switching, 22μA IQ | Higher frequency enables smaller inductors but increases EMI sensitivity; lacks voltage positioning | Preferred where ultra-low IQ and minimal BOM count outweigh transient performance requirements |
| RT8059GJ6 | 1.8V fixed, 500mA, 2.5–5.5V input, 1.5MHz switching, 60μA IQ | Higher current rating and wider VIN range; no integrated soft-start; different pinout (IN/EN/LX/PGND/FB/VOUT) | Used when higher output current headroom or alternate package (TSOT23-6) is needed; requires external soft-start RC network |
Compared with TPS62231DRYR and RT8059GJ6, the MAX1921EUT18+TG104 delivers superior transient suppression via voltage positioning and lower shutdown current (0.1μA), making it optimal for battery-critical portable designs where output stability under dynamic load dominates over raw efficiency or size minimization.
Availability
MAX1921EUT18+TG104 is available at Aetrix Electronics and suitable for wireless handset power management, PDA application processor rails, and CDMA power amplifier supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX1921EUT18+TG104 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 engineered specifically for space-constrained, battery-powered portable electronics - delivering high-efficiency step-down conversion with minimal external components and robust transient behavior under dynamic loads.
FAQ
What is the exact output voltage tolerance of the MAX1921EUT18+TG104 over temperature and load?
The MAX1921EUT18+TG104 guarantees ±3% output voltage accuracy over the full -40°C to +85°C operating temperature range and 0–400mA load current. At +25°C and zero load, initial accuracy is tighter at ±1.5%. This specification ensures reliable operation for 1.8V I/O and core rails in portable devices across environmental extremes.
Does the MAX1921EUT18+TG104 require external feedback resistors to set its 1.8V output?
No, the MAX1921EUT18+TG104 does not require external feedback resistors. Its 1.8V output is factory-preset using an internal trimmed resistor divider connected to the OUT pin. Unlike the adjustable MAX1920, this device operates as a true fixed-output converter with no external components needed on the OUT pin.
What is the recommended inductor value for the MAX1921EUT18+TG104 in a typical 3.3V-input to 1.8V-output application?
For a 3.3V input to 1.8V output application, the recommended inductor is 4.7μH with ≥550mA saturation current and low DC resistance (e.g., Coilcraft LPO1704 or Sumida CDRH2D18). This value balances efficiency, transient response, and physical size while supporting the full 400mA output capability of the MAX1921EUT18+TG104.
Can the MAX1921EUT18+TG104 operate from a 2.0V input source?
Yes, the MAX1921EUT18+TG104 supports input voltages as low as 2.0V - confirmed in its Electrical Characteristics table for the MAX1921EUT18 variant. This enables direct operation from partially discharged Li+ cells or dual-AA alkaline sources, maintaining regulation until the UVLO threshold (1.6V falling) is reached.
How does the voltage positioning feature of the MAX1921EUT18+TG104 improve load transient performance?
The MAX1921EUT18+TG104 implements voltage positioning by sensing inductor DCR to intentionally introduce controlled load regulation. This causes the no-load output to be slightly higher (~10–15mV), so that under sudden load steps (e.g., 20mA → 320mA), the output droop is reduced by ~50% compared to conventional buck regulators - critical for powering noise-sensitive RF and digital circuits.
MAX1921EUT18+TG104 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-6
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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):
- 1.8V
- 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
MAX1921EUT18+TG104 FAQ
1.How can I place an order for MAX1921EUT18+TG104 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1921EUT18+TG104 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 MAX1921EUT18+TG104 reliable?
The price and inventory of MAX1921EUT18+TG104 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1921EUT18+TG104 is usually 5 days.
3.What payment methods are accepted for MAX1921EUT18+TG104?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1921EUT18+TG104 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1921EUT18+TG104?
MAX1921EUT18+TG104 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1921EUT18+TG104 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 MAX1921EUT18+TG104?
For technical support, including MAX1921EUT18+TG104 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1921EUT18+TG104 requirements.
6.How does Aetrix verify that MAX1921EUT18+TG104 is sourced from the original manufacturer or authorized distributors?
All MAX1921EUT18+TG104 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 MAX1921EUT18+TG104 meets industry standards.
7.What is the process for return or replacement of MAX1921EUT18+TG104?
All MAX1921EUT18+TG104 units undergo pre-shipment inspection (PSI). If there is an issue with MAX1921EUT18+TG104, 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 MAX1921EUT18+TG104 part is unused and in its original packaging.
Return procedure for MAX1921EUT18+TG104:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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