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Analog Devices Inc./Maxim Integrated MAX1837EUT33+T
- Part No.:
- MAX1837EUT33+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- SOT-23-6
- Datasheet:
-
MAX1837EUT33+T.pdf
- Description:
- IC REG BUCK 3.3V 250MA SOT6
- Quantity:
- Payment:
- Shipping:
Inventory:2,553
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Product details
Overview
The MAX1837EUT33+T from Maxim Integrated is a high-efficiency, 6-pin SOT23 step-down DC-DC converter with a factory-preset 3.3V output, 4.5V–24V input range, 250mA max load current, and 12μA quiescent supply current. It integrates a 24V-rated internal P-channel MOSFET and operates up to 100% duty cycle for ultra-low dropout (120mV at 100mA), making it ideal for space-constrained, battery-powered industrial control and handheld devices.
For engineers reviewing the MAX1837EUT33+T datasheet, MAX1837EUT33+T pinout, MAX1837EUT33+T application, or MAX1837EUT33+T equivalent, key selection considerations include its preset 3.3V output accuracy (±3.6%), thermal shutdown at +160°C, shutdown current of 3μA, and compatibility with standard 47µH inductors and low-ESR output capacitors in compact SOT23 layouts.
Technical Context
The MAX1837EUT33+T employs a proprietary current-limited control architecture that dynamically adjusts switching frequency based on load-eliminating fixed-frequency PWM overhead and enabling 12μA no-load operation. Its 100% duty-cycle capability ensures regulation down to VIN − VDROPOUT, where dropout is determined by ILIM × (RLX + RINDUCTOR).
This device operates in discontinuous conduction mode (DCM) with programmable maximum on-time (7–13µs) and minimum off-time (0.2–0.6µs), using internal current sensing and zero-crossing detection to manage inductor discharge. The FB pin supports dual-mode operation: grounded for preset 3.3V output or configured with external resistors for adjustable 1.25V–VIN outputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 24V - supports wide-input industrial and battery systems including 9V, 12V, and 24V rails without external regulators. |
| Output Voltage | 3.3V ±3.6% (3.168V–3.432V) - factory-trimmed precision enables direct powering of 3.3V logic without feedback resistor network. |
| Max Output Current | 250mA - sufficient for microcontrollers, sensors, and interface ICs in portable instrumentation and distributed power nodes. |
| Quiescent Current | 12μA - minimizes standby power loss in always-on monitoring circuits and extends battery life in low-duty-cycle applications. |
| Dropout Voltage | 120mV at 100mA - enables usable operation down to VIN = 3.42V, critical for end-of-life battery voltage utilization. |
| Switching Frequency | Variable (≈1–2 MHz typical) - eliminates EMI peaks and allows use of small 47µH surface-mount inductors and ceramic capacitors. |
| Shutdown Current | 3μA - reduces system-level leakage during deep sleep modes while maintaining fast wake-up response. |
Pinout & Package
MAX1837EUT33+T is housed in a RoHS-compliant 6-pin SOT23 package (3.0mm × 1.7mm × 1.3mm), with exposed pad internally connected to GND for thermal and electrical integrity. Pin 1 is marked by a dot or beveled edge.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 FB | Dual-mode feedback input | Grounded for preset 3.3V output; connected to resistive divider for adjustable outputs - enables flexible design reuse across voltage variants. |
| 2 GND | Power and signal ground reference | Common return path for input capacitor, output capacitor, and inductor - must be star-connected to minimize noise coupling into FB node. |
| 3 IN | Main power input | Accepts 4.5V–24V; connects to source of internal P-MOSFET - requires local 10µF/25V ceramic or polymer input capacitor for stability. |
| 4 LX | Switch node | Drain of internal P-MOSFET - drives external inductor and freewheeling diode; high dV/dt node requiring tight layout and ground shielding. |
| 5 SHDN | Logic-controlled shutdown enable | Active-low input; pulls supply current to 3μA when ≤0.8V - must be tied to IN if unused or when output >5.5V to prevent malfunction. |
| 6 OUT | High-impedance output sense | Internally connected to feedback divider - tied to regulated output in preset mode; grounded in adjustable mode to disable internal divider. |
Key Features
| Feature | Design Value |
|---|---|
| 100% duty-cycle operation | Enables lowest possible dropout voltage (120mV @ 100mA), extending usable input range down to 3.42V for 3.3V output. |
| Current-limited control architecture | Eliminates fixed-frequency switching losses, reducing no-load current to 12μA and enabling variable-frequency DCM for efficiency optimization. |
| Integrated 24V P-channel MOSFET | Removes need for external high-voltage switch, simplifying BOM and PCB layout while supporting input rails up to 24V. |
| Thermal shutdown with 10°C hysteresis | Protects against sustained overload or poor heatsinking by cycling output until junction cools below +150°C. |
| Dual-mode FB pin | Supports both preset (GND) and adjustable (resistor divider) configurations - one footprint serves multiple output voltages across product families. |
Applications
| Industrial Sensor Node Power | Handheld Medical Instrument |
|---|---|
Use Scenario: Powering low-power MCU, analog front-end, and wireless transceiver in battery-operated environmental sensor node. IC Role / Device Role / Timing Role: Primary 3.3V step-down regulator delivering stable rail under dynamic load (10mA–250mA pulses) and extended shelf life. Use Value: 12μA quiescent current extends 2×AA battery life beyond 2 years in sleep-dominated operation; 100% duty cycle maintains regulation down to 3.4V battery voltage. |
Use Scenario: Supplying 3.3V to microcontroller, OLED display, and pulse oximeter analog circuitry in portable clinical device. IC Role / Device Role / Timing Role: Compact, low-noise DC-DC converter replacing linear regulator to improve efficiency and reduce thermal load in sealed enclosure. Use Value: 90%+ efficiency at 100mA eliminates heat buildup; SOT23 footprint fits tight mechanical constraints without compromising EMI performance. |
| 9V Battery-Powered Data Logger | Backup Power for Industrial PLC I/O Module |
Use Scenario: Converting 9V alkaline battery to regulated 3.3V for flash memory, RTC, and serial interface in field-deployed data recorder. IC Role / Device Role / Timing Role: High-input-voltage buck converter with undervoltage lockout (3.55V rising threshold) preventing brownout-induced firmware corruption. Use Value: Input UVLO ensures clean shutdown before battery sag compromises data integrity; 3μA shutdown current preserves residual charge for emergency logging. |
Use Scenario: Providing isolated 3.3V backup rail during main 24V supply interruption in programmable logic controller I/O module. IC Role / Device Role / Timing Role: Secondary regulated supply activated via SHDN pin during primary supply fault, sustaining communication and status registers. Use Value: Fast startup (<100µs) and 250mA drive capability maintain real-time I/O state during brief AC mains dips or fuse events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1776ETA+T | Higher output current (500mA), same 6-pin TDFN package, but requires external feedback for 3.3V output. | Used where higher drive capability is needed; lacks factory-preset 3.3V option - adds two resistors and layout complexity. | Select MAX1776ETA+T only when >250mA load or TDFN thermal performance is required; not drop-in for SOT23 footprint. |
| TPS62231DRYR | 3MHz fixed-frequency PWM, 300mA output, 2.05V–6.5V input - narrower VIN range and no 100% duty cycle. | Suitable for low-VIN applications (e.g., Li-ion single-cell); cannot replace MAX1837EUT33+T in 9V/12V/24V systems due to input limit. | Choose TPS62231DRYR only for sub-6.5V inputs where high-frequency operation and smaller inductors are prioritized over dropout performance. |
Compared with MAX1776ETA+T and TPS62231DRYR, the MAX1837EUT33+T uniquely combines factory-trimmed 3.3V output, 24V input support, 100% duty cycle, and SOT23 compactness - making it optimal for cost-sensitive, wide-input, battery-backed industrial modules where minimal BOM and layout simplicity are critical.
Availability
MAX1837EUT33+T is available at Aetrix Electronics and suitable for industrial sensor nodes, handheld medical instruments, 9V battery-powered data loggers, and backup power supplies requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for MAX1837EUT33+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 semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.
The MAX1836/MAX1837 family was designed specifically for low-power, wide-input-voltage DC-DC conversion in space-constrained battery-powered equipment - emphasizing ultra-low quiescent current, high efficiency across load range, and robust thermal protection.
FAQ
What is the guaranteed output voltage tolerance for MAX1837EUT33+T in preset mode?
The MAX1837EUT33+T guarantees a 3.3V output within ±3.6% (3.168V to 3.432V) across temperature (-40°C to +85°C) and load (0–250mA), as specified in the Electrical Characteristics table under "Output Voltage (Preset Mode)" with FB = GND. This tolerance reflects factory trimming and does not require external components.
Can MAX1837EUT33+T operate with input voltage below 4.5V?
No - the MAX1837EUT33+T has a hard input undervoltage lockout (UVLO) threshold of 3.55V (rising) and 3.45V (falling). Below 4.5V, operation is not guaranteed; attempting to power it below 3.45V will cause shutdown. For sub-4.5V inputs, consider alternatives like the TPS62231 series.
How does the shutdown function behave on MAX1837EUT33+T?
When SHDN is pulled ≤0.8V, the MAX1837EUT33+T enters shutdown mode, reducing supply current to 3μA and disabling the internal P-MOSFET. The LX node becomes high-impedance, isolating input from output. SHDN must never float - tie to IN if unused. Slew rate must exceed 10V/ms to avoid metastability.
What is the recommended inductor value for MAX1837EUT33+T in a standard 9V-to-3.3V application?
The typical application circuit specifies a 47µH inductor (e.g., Sumida CDRH5D28-470) for 9V input. Inductor selection balances size, ripple, and peak current - values from 10µH to 100µH are supported. Minimum inductance is calculated as L(MIN) = (VIN(MAX) − VOUT) × tON(MIN) / ILIM ≈ 1.2µH, so 47µH provides robust margin against saturation at 250mA load.
Does MAX1837EUT33+T support negative output voltage generation?
Yes - the MAX1837EUT33+T can be configured as an inverting buck-boost by floating the GND pin and referencing OUT to system ground, generating -3.3V (with MAX1837EUT33+T) or -5V (with MAX1837EUT50+T). Absolute ratings must be observed: |VIN − GND| ≤ 24V and |OUT − GND| ≤ 5.5V. Refer to Figure 7 in the datasheet for implementation details.
MAX1837EUT33+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):
- 4.5V
- Voltage - Input (Max):
- 24V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 250mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-6
MAX1837EUT33+T FAQ
1.How can I place an order for MAX1837EUT33+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1837EUT33+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 MAX1837EUT33+T reliable?
The price and inventory of MAX1837EUT33+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1837EUT33+T is usually 5 days.
3.What payment methods are accepted for MAX1837EUT33+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1837EUT33+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1837EUT33+T?
MAX1837EUT33+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1837EUT33+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 MAX1837EUT33+T?
For technical support, including MAX1837EUT33+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1837EUT33+T requirements.
6.How does Aetrix verify that MAX1837EUT33+T is sourced from the original manufacturer or authorized distributors?
All MAX1837EUT33+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 MAX1837EUT33+T meets industry standards.
7.What is the process for return or replacement of MAX1837EUT33+T?
All MAX1837EUT33+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1837EUT33+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 MAX1837EUT33+T part is unused and in its original packaging.
Return procedure for MAX1837EUT33+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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