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Analog Devices Inc./Maxim Integrated MAX1837ESA33
- Part No.:
- MAX1837ESA33
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX1837ESA33.pdf
- Description:
- IC REG BCK ADJ/1.25V 250MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:378
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Product details
Overview
MAX1837ESA33 from Maxim Integrated is a high-efficiency, 24V-rated step-down DC-DC converter with preset 3.3V output, internal P-channel MOSFET switch, 100% duty cycle capability, and 250mA load current support. It operates from 4.5V to 24V input, delivers 120mV dropout at 100mA, and draws only 12µA quiescent current-ideal for battery-powered handheld devices and industrial control supplies.
For engineers reviewing the MAX1837ESA33 datasheet, MAX1837ESA33 pinout, MAX1837ESA33 application, or MAX1837ESA33 equivalent, key selection criteria include its 24V input tolerance, 3.3V preset output accuracy (±3.6%), 100% duty cycle for ultra-low dropout, and SOT23-6 package compatibility with space-constrained PCB layouts.
Technical Context
The MAX1837ESA33 uses a proprietary current-limited control architecture that enables variable-frequency operation up to 100% duty cycle-eliminating fixed PWM switching losses and reducing light-load supply current to 12µA. Its internal 24V P-channel MOSFET (RDS(ON) = 2Ω typ) and integrated current sensing eliminate external sense resistors.
Dropout behavior is defined by RDS(ON) and inductor DCR, yielding 120mV at 100mA; thermal shutdown activates at +160°C with 10°C hysteresis. The FB pin supports dual-mode operation: grounded for 3.3V preset mode or connected to a resistor divider for adjustable outputs from 1.25V to VIN.
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. |
| Output Voltage | 3.3V ±3.6% (3.168V–3.432V) - factory-preset, no external feedback required for standard 3.3V logic rail. |
| Max Output Current | 250mA - sufficient for powering microcontrollers, sensors, and low-power peripherals without external boost. |
| Quiescent Current | 12µA - extends battery life in always-on or sleep-mode applications such as remote sensors. |
| Dropout Voltage | 120mV at 100mA - enables operation down to VIN = 3.42V while maintaining 3.3V regulation. |
| Shutdown Current | 3µA - ensures minimal leakage during system standby or deep-sleep states. |
| Switching Frequency | Variable (≈1–2MHz range) - adapts dynamically to load, optimizing efficiency across 0.1mA–250mA range. |
Pinout & Package
MAX1837ESA33 is housed in a 6-pin SOT23-6 package (JEDEC MO-178AA) with exposed pad (EP) internally connected to GND for thermal and electrical grounding. Pin 1 is FB, pin 2 is GND, pin 3 is IN, pin 4 is LX, pin 5 is SHDN, and pin 6 is OUT.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Dual-mode feedback input | Grounded for 3.3V preset mode; connects to resistor divider for adjustable output (1.25V–VIN). |
| GND (Pin 2) | Power and signal ground reference | Primary return path for internal circuitry and LX current; must be tied to EP pad for thermal stability. |
| IN (Pin 3) | Main power input | Connects to 4.5V–24V supply; source terminal of internal P-MOSFET; requires local 10µF/25V ceramic or low-ESR input capacitor. |
| LX (Pin 4) | Switch node | Drain of internal P-MOSFET; connects directly to inductor (L1) and catch diode anode; high dv/dt node requiring tight layout. |
| SHDN (Pin 5) | Logic-controlled enable/disable | Active-low shutdown: <0.8V disables regulator (3µA IQ); >2.4V enables operation; must not float. |
| OUT (Pin 6) | Output voltage sense | Internally connected to feedback divider; connect to regulated output in preset mode; tie to GND in adjustable mode. |
Key Features
| Feature | Design Value |
|---|---|
| 100% Duty Cycle Operation | Enables ultra-low dropout (120mV @100mA), extending usable battery voltage range down to ~3.42V for 3.3V output. |
| Current-Limited Control Architecture | Eliminates fixed-frequency switching losses; reduces light-load IQ to 12µA and enables variable-frequency response to load transients. |
| Integrated 24V P-Channel MOSFET | Removes need for external high-voltage switch; simplifies BOM and layout while supporting up to 24V input without level-shifting. |
| Dual-Mode Feedback (FB) | Supports both preset (GND) and adjustable (resistor divider) configurations-enabling reuse across 3.3V/5V designs with one footprint. |
| Thermal Shutdown with Hysteresis | Protects against sustained overload: shuts down at +160°C, re-enables at +150°C-prevents thermal runaway in enclosed or high-ambient environments. |
Applications
| Handheld Medical Sensors | Industrial 4–20mA Loop Supplies |
|---|---|
Use Scenario: Portable blood glucose meters and pulse oximeters powered by single 9V alkaline batteries. IC Role / Device Role / Timing Role: Primary 3.3V power rail generator for MCU, analog front-end, and display driver. Use Value: 12µA quiescent current extends battery life beyond 12 months in intermittent-use devices; 100% duty cycle maintains regulation until battery drops to 3.42V. | Use Scenario: Two-wire field transmitters converting sensor signals into 4–20mA loop current. IC Role / Device Role / Timing Role: Local 3.3V supply for precision ADC, DAC, and loop-control ICs operating from loop-derived 12–24V. Use Value: 24V input rating allows direct connection to loop supply without pre-regulation; 250mA output supports multiple ICs and transient loads during calibration. |
| Notebook Peripheral Modules | Backup Power Management |
Use Scenario: USB-C docking station add-on modules (e.g., HDMI, Ethernet) requiring isolated 3.3V from 5V/12V bus. IC Role / Device Role / Timing Role: Compact, efficient step-down stage delivering clean 3.3V to interface ICs with minimal board area. Use Value: SOT23-6 footprint and 2MHz typical switching frequency allow use of 22µH inductors and small ceramic capacitors-reducing solution size by >40% vs. legacy controllers. | Use Scenario: Real-time clock (RTC) and SRAM backup circuits in industrial PLCs using supercapacitor or coin-cell storage. IC Role / Device Role / Timing Role: Low-quiescent buck converter charging backup capacitor or regulating backup rail during main power loss. Use Value: 3µA shutdown current minimizes self-discharge of backup energy sources; 120mV dropout ensures full utilization of stored voltage down to 3.42V. |
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 | 3.3V fixed output, 300mA, 2.05–6.0V input, 17µA IQ, 2mm × 2mm WSON-6 | Lower input voltage ceiling (6V max); unsuitable for 9V/12V/24V battery or industrial rails. | Select when input is limited to ≤6V and ultra-small WSON package is prioritized over wide-VIN capability. |
| LT1930ES5#TRMPBF | 3.3V fixed output, 250mA, 3.6–25V input, 100µA IQ, SOT23-5 (no SHDN pin) | Higher quiescent current (100µA vs. 12µA); lacks dedicated shutdown pin-requires external enable circuitry. | Select when absolute minimum bill-of-materials is critical and 100µA IQ is acceptable for battery runtime. |
Compared with TPS62231DRYR and LT1930ES5#TRMPBF, MAX1837ESA33 uniquely combines 24V input tolerance, 12µA quiescent current, and integrated shutdown in a standard SOT23-6-making it optimal for wide-input, battery-sensitive, and space-constrained industrial and portable designs.
Availability
MAX1837ESA33 is available at Aetrix Electronics and suitable for handheld medical sensors, industrial 4–20mA loop supplies, and notebook peripheral modules requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for MAX1837ESA33 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, communications, and computing markets.
The MAX1836/MAX1837 product line was designed specifically for low-power, wide-input DC-DC conversion in battery-operated and distributed power systems-emphasizing ultra-low IQ, 100% duty cycle, and compact packaging.
FAQ
What is the maximum input voltage supported by the MAX1837ESA33?
The MAX1837ESA33 supports an absolute maximum input voltage of 24V, with operational specification from 4.5V to 24V. This enables direct use with 9V batteries, 12V industrial rails, and 24V backup systems without pre-regulation. Exceeding 24V risks permanent damage per Absolute Maximum Ratings.
Does the MAX1837ESA33 require external feedback components for 3.3V output?
No-the MAX1837ESA33 is factory-configured for 3.3V preset output. Simply connect FB (Pin 1) to GND and OUT (Pin 6) to the regulated output node. No external resistors are needed unless adjusting output voltage outside 3.3V.
What is the dropout voltage of the MAX1837ESA33 at 200mA load?
While the datasheet specifies 120mV dropout at 100mA, the dropout voltage scales linearly with load due to RDS(ON) and inductor DCR. At 200mA, expected dropout is approximately 240mV (based on 2Ω typical RDS(ON) and typical inductor DCR), enabling regulation down to ~3.54V input.
Can the MAX1837ESA33 be used in shutdown mode with output voltages above 5.5V?
No-shutdown functionality is disabled when output voltage exceeds 5.5V. For adjustable outputs >5.5V, SHDN must be permanently tied to IN. This restriction is explicitly stated in the datasheet Note 2 and applies to all MAX1836/MAX1837 variants, including MAX1837ESA33.
Which package type does the MAX1837ESA33 use, and is the exposed pad electrically connected?
The MAX1837ESA33 uses the SOT23-6 package (JEDEC MO-178AA) with an exposed metal pad (EP). The EP is internally connected to GND through a soft bond-requiring external solder connection to PCB ground plane for optimal thermal performance and electrical stability.
MAX1837ESA33 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable (Fixed)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 24V
- Voltage - Output (Min/Fixed):
- 1.25V (3.3V)
- Voltage - Output (Max):
- 24V
- Current - Output:
- 250mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX1837ESA33 FAQ
1.How can I place an order for MAX1837ESA33 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1837ESA33 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 MAX1837ESA33 reliable?
The price and inventory of MAX1837ESA33 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1837ESA33 is usually 5 days.
3.What payment methods are accepted for MAX1837ESA33?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1837ESA33 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1837ESA33?
MAX1837ESA33 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1837ESA33 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 MAX1837ESA33?
For technical support, including MAX1837ESA33 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1837ESA33 requirements.
6.How does Aetrix verify that MAX1837ESA33 is sourced from the original manufacturer or authorized distributors?
All MAX1837ESA33 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 MAX1837ESA33 meets industry standards.
7.What is the process for return or replacement of MAX1837ESA33?
All MAX1837ESA33 units undergo pre-shipment inspection (PSI). If there is an issue with MAX1837ESA33, 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 MAX1837ESA33 part is unused and in its original packaging.
Return procedure for MAX1837ESA33:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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