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Analog Devices Inc./Maxim Integrated MAX748AEPA+
- Part No.:
- MAX748AEPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX748AEPA+.pdf
- Description:
- IC REG BUCK 3.3V 500MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,371
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Product details
Overview
MAX748AEPA+ from Maxim Integrated is a -40°C to +85°C industrial-grade, 3.3V-output, step-down DC-DC switching regulator with current-mode PWM control. It accepts 3.3V–16V input, delivers up to 500mA, achieves 85%–90% efficiency, and features 0.2µA shutdown current - used in portable instrumentation and battery-powered 5V-to-3.3V conversion.
For engineers reviewing the MAX748AEPA+ datasheet, MAX748AEPA+ pinout, MAX748AEPA+ application, or MAX748AEPA+ equivalent, key selection criteria include input voltage range (3.3V–16V), guaranteed 300mA/500mA load capability across temperature, fixed-frequency PWM operation (159–212.5kHz), soft-start programmability, and integrated overcurrent/undervoltage protection.
Technical Context
The MAX748AEPA+ implements a current-mode PWM buck topology with dual feedback loops: an inner current-sense loop enabling cycle-by-cycle current limiting (1.2A peak) and an outer voltage loop using a 1.23V bandgap reference for ±5% output regulation. Its oscillator operates at 159–212.5kHz over temperature, supporting stable filtering and small external magnetics.
It integrates a P-channel power MOSFET switch (LX pin), programmable soft-start (SS pin with 0.047µF typical), compensation network interface (CC pin), and active-low shutdown (SHDN) with 0.2µA quiescent draw. Undervoltage lockout triggers at 2.7V (falling) and releases at 2.95V (rising), preventing partial FET turn-on and thermal stress.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±5% over line, load, and temperature - eliminates external resistor divider and ensures stable logic supply. |
| Input Voltage Range | 3.3V to 16.0V - supports wide-input battery and adapter-fed systems including 12V rails and multi-cell Li-ion stacks. |
| Max Output Current | 500mA at V+ ≥ 4.75V (guaranteed) - sufficient for powering microcontrollers, sensors, and low-power peripherals. |
| Switching Frequency | 159kHz to 212.5kHz (guaranteed) - enables predictable EMI filtering and use of standard 22µH inductors without custom magnetics design. |
| Shutdown Current | 0.2µA typical - extends battery life in always-on or sleep-mode portable devices. |
| Efficiency | 85%–90% typical at 100–300mA - reduces thermal load and improves power density in space-constrained designs. |
| Quiescent Supply Current | 1.7mA (typical) - balances light-load efficiency and fast transient response without excessive bias consumption. |
Pinout & Package
MAX748AEPA+ is housed in an 8-pin plastic DIP package (0.300" width), suitable for through-hole prototyping and industrial PCBs requiring mechanical robustness and thermal margin.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (V+) | Supply Input | Primary DC input (3.3V–16V); requires parallel 1µF ceramic + bulk electrolytic bypass to GND for stability. |
| 2 (LX) | Power Switch Drain | Drain of internal P-channel MOSFET; connects to inductor and catch diode anode - handles high dv/dt switching. |
| 3 (GND) | Ground Reference | Analog and power ground return; must be low-inductance connection to minimize noise coupling into REF/SS/OUT. |
| 4 (OUT) | Voltage Sense Input | Feedback node tied directly to regulated 3.3V output; sets regulation point via internal 1.23V reference amplifier. |
| 5 (CC) | Compensation Input | External compensation point for voltage-loop stability; typically connected to OUT via 330pF capacitor. |
| 6 (SS) | Soft-Start Control | Capacitor-based ramp generator; controls startup surge current and enables short-circuit protection (0.047µF typical). |
| 7 (REF) | Reference Output | Stable 1.23V bandgap source (≤100µA drive); requires 1000pF bypass to GND for noise immunity. |
| 8 (SHDN) | Shutdown Enable | Active-low logic input; pulls output to 0V and disables internal circuitry when grounded - enables system-level power sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode PWM control | Enables precise cycle-by-cycle current limiting (1.2A peak), faster load-transient response, and simplified loop compensation vs. voltage-mode. |
| Integrated P-channel MOSFET switch | Eliminates need for external high-side switch and gate driver - reduces BOM count and layout complexity. |
| Programmable soft-start | Capacitor-controlled ramp on SS pin prevents inrush current and ensures orderly power-up in multi-rail systems. |
| Undervoltage lockout (UVLO) | Prevents erratic operation below 2.7V (falling) and ensures clean startup above 2.95V - protects against brownout-induced latch-up. |
| Fixed 3.3V output with ±5% accuracy | Guaranteed regulation across -40°C to +85°C, 3.3V–16V input, and 0–500mA load - simplifies compliance testing for industrial applications. |
Applications
| Portable Instrumentation | Hand-Held Computers |
|---|---|
|
Use Scenario: Battery-powered multimeters and data loggers requiring stable 3.3V supply from variable 4.5–12V Li-ion or alkaline sources. IC Role / Device Role / Timing Role: Primary step-down regulator converting unregulated battery voltage to clean 3.3V for MCU, ADC, and display drivers. Use Value: 0.2µA shutdown current extends shelf life; 85%–90% efficiency minimizes heat in sealed enclosures. |
Use Scenario: Ruggedized handheld terminals operating in field environments with wide ambient temperature swings (-40°C to +85°C). IC Role / Device Role / Timing Role: Core power management IC delivering regulated 3.3V to ARM Cortex-M processors and wireless transceivers. Use Value: Guaranteed 500mA output at full temperature range enables reliable operation under worst-case load and thermal conditions. |
| Computer Peripherals | Cellular Phones (Legacy Baseband) |
|
Use Scenario: USB-powered docking stations and external storage adapters needing efficient 5V-to-3.3V conversion with minimal footprint. IC Role / Device Role / Timing Role: Compact, fixed-output buck converter replacing linear regulators to reduce thermal dissipation on dense PCBs. Use Value: Fixed 22µH inductor compatibility eliminates magnetics design effort and accelerates time-to-market. |
Use Scenario: Early GSM/GPRS handsets where baseband ICs required tightly regulated 3.3V from noisy 3.6–4.2V Li-ion batteries. IC Role / Device Role / Timing Role: Primary DC-DC converter supplying core logic voltage while rejecting battery ripple and load transients. Use Value: 159–212.5kHz fixed frequency enables predictable EMI filtering and avoids interference with RF front-end bands. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX763AEPA+ | Lower input range (3.3V–11V), same 3.3V output, 1.4mA quiescent current, identical 8-pin DIP package and pinout. | Optimized for ≤12V systems (e.g., USB-powered devices); not suitable for 12–16V industrial rails. | Select MAX763AEPA+ only if input never exceeds 11V - avoids overvoltage stress on internal switch. |
| TPS62231DRVR | 3MHz synchronous buck, 2.05–6.5V input, 3.3V output, 1.5µA shutdown, 0.65mm × 0.65mm WSON-6 package. | Targets ultra-compact, high-frequency designs; lacks UVLO hysteresis and soft-start programmability. | Choose TPS62231DRVR for space-constrained consumer electronics; avoid for industrial systems requiring robust fault protection. |
Compared with MAX763AEPA+, MAX748AEPA+ supports higher input voltages (up to 16V) and delivers greater peak current capability under wide-temperature conditions; compared with TPS62231DRVR, it offers superior thermal ruggedness, programmable soft-start, and integrated protection features - making it preferred for industrial and portable instrumentation.
Availability
MAX748AEPA+ is available at Aetrix Electronics and suitable for portable instrumentation, hand-held computers, and computer peripherals requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX748AEPA+ 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 MAX748A series was designed as a robust, fixed-output, current-mode buck regulator family targeting battery-powered and wide-input industrial equipment - emphasizing reliability, ease of use, and minimal external component count.
FAQ
What is the guaranteed output current for MAX748AEPA+ over its full -40°C to +85°C temperature range?
The MAX748AEPA+ guarantees 300mA output current for input voltages from 4.0V to 16V across its full -40°C to +85°C operating range. At input voltages ≥4.75V, it guarantees 500mA output - verified per Electrical Characteristics tables in the official Maxim datasheet Rev 0 (9/93). This rating accounts for thermal derating and internal MOSFET performance limits.
Does MAX748AEPA+ require an external MOSFET or diode in the buck circuit?
No, MAX748AEPA+ integrates a P-channel power MOSFET switch on-die (accessible via LX pin) and requires only an external Schottky catch diode (e.g., 1N5817) and 22µH inductor. The internal switch eliminates external high-side driver complexity, and the fixed 3.3V output removes need for feedback resistors - reducing total solution size and bill-of-materials cost.
Can MAX748AEPA+ operate with input voltage below 3.3V?
MAX748AEPA+ has an absolute minimum input voltage of 3.3V per datasheet specifications, and undervoltage lockout activates below 2.7V (falling). While the device may briefly conduct at ~3.0V input, regulation is not guaranteed, output voltage sags, and maximum load current drops significantly - so operation below 3.3V is not recommended or characterized for MAX748AEPA+.
What is the purpose of the REF pin on MAX748AEPA+, and how must it be used?
The REF pin on MAX748AEPA+ provides a stable 1.23V bandgap reference output capable of sourcing up to 100µA. It must be bypassed to GND with a 1000pF capacitor (as specified in Figure 1 and Pin Description) to suppress noise and ensure regulation accuracy. Leaving REF unconnected or improperly bypassed degrades output voltage stability and transient response.
How does the soft-start function work on MAX748AEPA+, and what capacitor value is recommended?
The soft-start function on MAX748AEPA+ uses an external capacitor (C1) connected between SS pin and GND to control startup slew rate and limit inrush current. A 0.047µF capacitor provides ~4ms soft-start time at V+ = 8V (per Table 1), enabling controlled output ramp-up and short-circuit protection. Values < 0.01µF disable overcurrent protection, so 0.047µF is the validated default for robust operation.
MAX748AEPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.3V
- Voltage - Input (Max):
- 16V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 500mA
- Frequency - Switching:
- 180kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX748AEPA+ FAQ
1.How can I place an order for MAX748AEPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX748AEPA+ 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 MAX748AEPA+ reliable?
The price and inventory of MAX748AEPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX748AEPA+ is usually 5 days.
3.What payment methods are accepted for MAX748AEPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX748AEPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX748AEPA+?
MAX748AEPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX748AEPA+ 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 MAX748AEPA+?
For technical support, including MAX748AEPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX748AEPA+ requirements.
6.How does Aetrix verify that MAX748AEPA+ is sourced from the original manufacturer or authorized distributors?
All MAX748AEPA+ 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 MAX748AEPA+ meets industry standards.
7.What is the process for return or replacement of MAX748AEPA+?
All MAX748AEPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX748AEPA+, 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 MAX748AEPA+ part is unused and in its original packaging.
Return procedure for MAX748AEPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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