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Analog Devices Inc./Maxim Integrated MAX738ACWE+
- Part No.:
- MAX738ACWE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MAX738ACWE+.pdf
- Description:
- IC REG BUCK 5V 750MA 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,288
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Product details
Overview
MAX738ACWE+ from Maxim Integrated is a 5V-output, current-mode PWM step-down DC-DC converter optimized for 6V–16V input operation and delivering up to 750mA load current. It features fixed-frequency switching (160kHz typical), ±5% output voltage accuracy over line/load/temperature, 85–96% efficiency, and integrated protections including cycle-by-cycle current limiting, undervoltage lockout, and programmable soft-start. It is used in portable radios, cellular handsets, and distributed power systems requiring compact, high-efficiency regulation.
For engineers reviewing the MAX738ACWE+ datasheet, MAX738ACWE+ pinout, MAX738ACWE+ application, or MAX738ACWE+ equivalent, key selection criteria include guaranteed 750mA output at 5V across 6–16V input, 16-pin wide SO package thermal performance, shutdown current of 6µA, oscillator frequency stability (159–212.5kHz for MAX744A variant), and compatibility with single 33µH inductor designs without custom magnetics.
Technical Context
The MAX738ACWE+ implements a current-mode PWM control architecture with dual feedback loops: an inner current-sense loop enabling cycle-by-cycle current limiting and fast transient response, and an outer voltage loop using a 1.23V bandgap reference and error amplifier for precise 5V regulation. Its internal P-channel MOSFET switch drives the LX pin with on-resistance specified at 2.0Ω.
It operates in continuous or discontinuous conduction mode depending on input voltage, load, and inductor value; supports programmable soft-start via external capacitor/resistor on SS pin; and includes undervoltage lockout (enable threshold 5.7V, hysteresis ~0.25V) and shutdown control via active-low SHDN pin. The device requires no inductor design-guaranteed performance with standard 33µH inductors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.00V ±5% - tightly regulated across full line, load, and temperature range without external resistor divider. |
| Input Voltage Range | 6.0V to 16.0V - supports wide-input battery and adapter-powered systems including 9V and 12V rails. |
| Max Output Current | 750mA - guaranteed continuous output at 5V with VIN ≥ 6V and proper thermal management. |
| Efficiency | 85% to 96% - enables minimal power loss and thermal rise in space-constrained portable applications. |
| Quiescent Current | 1.7mA - low operating supply current preserves battery life during active regulation. |
| Shutdown Current | 6µA - ultra-low standby draw extends system sleep time in battery-backed devices. |
| Oscillator Frequency | 160kHz typical (MAX738A), 159–212.5kHz guaranteed (MAX744A) - fixed-frequency operation simplifies EMI filtering and component selection. |
| Reference Voltage | 1.23V ±8% - internal bandgap reference supplies up to 100µA and enables accurate feedback sensing at OUT pin. |
Pinout & Package
MAX738ACWE+ is housed in a 16-pin wide SO (small-outline) package with 0.300" body width, 0.050" lead pitch, and exposed thermal pad (not electrically connected). Pin 1 is located at bottom-left corner when notch faces upward; pins 1–8 occupy bottom row left-to-right, pins 9–16 top row right-to-left.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SHDN) | Active-low shutdown control | Pulling low disables internal FET, drops output to 0V, and reduces supply current to 6µA; tie to V+ for normal operation. |
| 2 (REF) | Bandgap reference output | Provides stable 1.23V reference; bypass with ≤0.047µF capacitor to GND for noise immunity and stability. |
| 3 (SS) | Soft-start timing and current limit control | Capacitor to GND sets startup ramp time and peak current limit; 510kΩ resistor to SHDN enables >1A short-circuit protection. |
| 4 (CC) | Compensation node | Connects 330pF capacitor between CC and OUT to stabilize outer voltage loop and optimize transient response. |
| 5 (OUT) | Feedback sense input | Connected directly to +5V output; forms resistive divider with internal 1.23V reference to regulate output voltage. |
| 6 (GND) | Power and signal ground | Internally tied to all ground nodes; must be connected to low-impedance PCB ground plane for stability and EMI control. |
| 7 (LX) | Switch node | Drain of internal P-channel MOSFET; connects to inductor and catch diode; handles high dv/dt and peak currents up to 2A. |
| 8 (V+) | Main power input | Accepts 6–16V unregulated input; requires local 1µF ceramic + bulk electrolytic bypassing close to pin. |
| 9–10, 12–15 (N.C.) | No connect | No internal connection; leave floating or ground per layout best practices; not usable as thermal pads. |
| 11 (GND) | Secondary ground terminal | Internally connected to pin 6; provides additional low-inductance path to ground for improved thermal and noise performance. |
| 16 (V+) | Redundant power input | Electrically identical to pin 8; used to distribute input current and reduce trace resistance/inductance in high-current layouts. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode PWM control | Enables precise cycle-by-cycle current limiting, superior load-transient response, and simplified compensation versus voltage-mode controllers. |
| Single-inductor design | Guarantees full 750mA output using only one standard 33µH inductor-no custom magnetics or iterative design required. |
| Programmable soft-start | External RC network on SS pin controls startup slew rate and prevents inrush current, while also setting short-circuit current limit threshold. |
| Integrated protection suite | Includes undervoltage lockout (5.7V enable), overcurrent detection (~1.5A), and automatic soft-start recovery after fault conditions. |
| Low-noise fixed-frequency operation | 160kHz typical switching frequency allows predictable EMI filtering and use of small, cost-effective passive components. |
Applications
| Portable Radios | Cellular Handsets |
|---|---|
Use Scenario: Battery-powered FM/AM transceivers requiring clean 5V rail for RF front-end and baseband ICs. IC Role / Device Role / Timing Role: Primary 5V buck regulator supplying power to analog RF sections and digital signal processors. Use Value: 85–96% efficiency extends talk time; ±5% output accuracy ensures stable PLL and ADC operation; low 6µA shutdown current preserves standby battery life. | Use Scenario: Compact GSM/CDMA handsets needing efficient 5V conversion from single-cell Li-ion (3.0–4.2V) with boost stage or dual-cell (6–8.4V) input. IC Role / Device Role / Timing Role: Main system power regulator for baseband processor, display driver, and audio codec. Use Value: 750mA output supports burst transmit loads; programmable soft-start prevents brownout during power-up; 16-pin SO package enables dense PCB layout. |
| Distributed Power Systems | Computer Peripherals |
Use Scenario: Industrial or telecom equipment with centralized 12V/24V backplane distributing power to multiple 5V subsystems. IC Role / Device Role / Timing Role: Local point-of-load (POL) regulator converting intermediate bus voltage to stable 5V for FPGA I/O banks or microcontroller peripherals. Use Value: Wide 6–16V input accommodates bus variations; cycle-by-cycle current limiting protects against shorted daughterboards; thermal robustness supports convection-cooled enclosures. | Use Scenario: USB-powered hubs, external SSD enclosures, or docking stations drawing from 5V USB upstream but requiring isolated or boosted 5V rails. IC Role / Device Role / Timing Role: Secondary 5V regulator providing noise-isolated power for high-speed USB PHY or SATA controller. Use Value: Fixed 160kHz frequency avoids USB 2.0 harmonics; low EMI due to current-mode control meets FCC Class B; 1.7mA quiescent current minimizes parasitic drain. |
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 |
|---|---|---|---|
| MAX744ACWE+ | Guaranteed oscillator frequency range 159–212.5kHz; tighter frequency tolerance for low-noise radio applications; same 750mA output and 16-pin wide SO package. | Better suited for RF-sensitive environments where oscillator jitter and EMI must be minimized; identical pinout and footprint. | Select MAX744ACWE+ when EMI compliance in portable communications systems is critical; otherwise MAX738ACWE+ offers identical power capability at lower cost. |
| LM2678-5.0/NOPB | 5V fixed-output buck controller with 5A capability, 260kHz switching, and external MOSFET drive; larger TO-220-5 package; requires external inductor and diode. | Targets higher-power applications (>1A); lacks integrated FET and soft-start programmability; less compact solution. | Choose LM2678-5.0/NOPB only when >1A output or higher thermal headroom is required; MAX738ACWE+ is superior for space-constrained 750mA designs with integrated simplicity. |
Compared with MAX744ACWE+, the MAX738ACWE+ offers identical 750mA output and package but with looser oscillator tolerance-making it suitable for general-purpose portable power where absolute EMI control is secondary. Versus LM2678-5.0/NOPB, MAX738ACWE+ delivers integrated-FET simplicity, smaller footprint, and lower BOM count at the expense of peak current headroom.
Availability
MAX738ACWE+ is available at Aetrix Electronics and suitable for portable instruments, cellular handsets, distributed power systems, and computer peripherals requiring stable component supply, consistent parametric performance, and long-term industrial availability.
Supply support for MAX738ACWE+ 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 consumer applications.
The MAX730A/MAX738A/MAX744A product line was designed as highly integrated, fixed-output current-mode buck regulators targeting battery-powered and intermediate-bus power conversion where simplicity, reliability, and minimal external component count are essential.
FAQ
What is the maximum input voltage rating for the MAX738ACWE+?
The MAX738ACWE+ has an absolute maximum input voltage rating of +18V at the V+ pin. Its recommended operating input voltage range is 6.0V to 16.0V. Operation above 16.0V may compromise reliability or violate safe operating area limits, even if within absolute max ratings. Always observe derating guidelines for extended temperature or high-duty-cycle conditions.
Does the MAX738ACWE+ require an external catch diode?
Yes, the MAX738ACWE+ requires an external Schottky or high-speed silicon rectifier diode (e.g., 1N5817) connected between LX and GND. The device integrates only the P-channel MOSFET switch-not the freewheeling path-so the diode is essential for continuous conduction mode operation and energy transfer during the switch-off phase.
Can the MAX738ACWE+ operate with a 33µH inductor across its full input and load range?
Yes, the MAX738ACWE+ is fully characterized and guaranteed to deliver 750mA at 5V using a single 33µH inductor (e.g., Sumida CD105-330N) across its entire 6–16V input range and 0–750mA load range. No inductor redesign is needed-the device's current-mode control and compensation scheme ensure stability and performance with this preselected value.
What is the function of the SS pin on the MAX738ACWE+ and how is it configured?
The SS (soft-start) pin on the MAX738ACWE+ controls startup ramp time and peak current limit via an external capacitor to GND. A typical 0.1µF capacitor yields ~11ms soft-start; adding a 510kΩ resistor from SS to SHDN enables >1A short-circuit protection. The SS pin clamps the error amplifier output during startup, preventing inrush and ensuring orderly power-up.
Is the MAX738ACWE+ pin-compatible with the MAX744ACWE+?
Yes, the MAX738ACWE+ and MAX744ACWE+ share identical 16-pin wide SO packaging, pinout, and electrical interface-including V+, LX, GND, OUT, CC, SS, REF, and SHDN assignments. They differ only in oscillator frequency specifications and guaranteed performance limits; both are drop-in replacements in hardware, though MAX744ACWE+ adds tighter frequency control for RF-sensitive applications.
MAX738ACWE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 6V
- Voltage - Input (Max):
- 16V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 750mA
- Frequency - Switching:
- 160kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
MAX738ACWE+ FAQ
1.How can I place an order for MAX738ACWE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX738ACWE+ 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 MAX738ACWE+ reliable?
The price and inventory of MAX738ACWE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX738ACWE+ is usually 5 days.
3.What payment methods are accepted for MAX738ACWE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX738ACWE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX738ACWE+?
MAX738ACWE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX738ACWE+ 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 MAX738ACWE+?
For technical support, including MAX738ACWE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX738ACWE+ requirements.
6.How does Aetrix verify that MAX738ACWE+ is sourced from the original manufacturer or authorized distributors?
All MAX738ACWE+ 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 MAX738ACWE+ meets industry standards.
7.What is the process for return or replacement of MAX738ACWE+?
All MAX738ACWE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX738ACWE+, 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 MAX738ACWE+ part is unused and in its original packaging.
Return procedure for MAX738ACWE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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