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Analog Devices Inc./Maxim Integrated MAX638AESA-TG068
- Part No.:
- MAX638AESA-TG068
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX638AESA-TG068.pdf
- Description:
- IC REG BUCK ADJ/1.31V 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,000
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Product details
Overview
MAX638AESA-TG068 from Maxim Integrated is a CMOS step-down switching regulator IC with adjustable 5V output, operating from 7V to 16.5V input, delivering up to 250mA output current, featuring internal 1.5A MOSFET switch and 100kHz fixed-frequency PWM control for industrial power conversion in space-constrained embedded systems.
For engineers reviewing the MAX638AESA-TG068 datasheet, MAX638AESA-TG068 pinout, MAX638AESA-TG068 application, or MAX638AESA-TG068 equivalent, key selection considerations include input voltage range, output adjustability via external resistors, thermal performance in SOIC-8 package, and compatibility with low-ESR ceramic output capacitors.
Technical Context
The MAX638AESA-TG068 integrates a P-channel MOSFET switch, PWM controller, oscillator, and reference circuit in a single SOIC-8 package. It uses external inductor and diode for buck topology operation and supports output voltage adjustment from 5V to 12V using two external resistors.
Its 100kHz switching frequency enables compact magnetics design while maintaining stable regulation under load transients up to 250mA. The device lacks synchronous rectification and requires an external Schottky catch diode for efficiency optimization.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 7V to 16.5V - supports standard 9V/12V rails and tolerates automotive battery transients |
| Output Voltage | Adjustable 5V to 12V - set by external R1/R2 divider; 5V nominal default configuration |
| Max Output Current | 250mA - limited by internal MOSFET RDS(on) and thermal dissipation in SOIC-8 |
| Switching Frequency | 100kHz fixed - enables use of small, low-cost inductors (e.g., 47–100µH) with low core loss |
| Internal Switch | 1.5A P-channel MOSFET - eliminates need for external high-side switch but requires bootstrap-free layout |
| Operating Temp | -40°C to +85°C - qualified for industrial ambient environments without derating |
| Package | SOIC-8 (3.9mm × 4.9mm) - surface-mount compatible with standard reflow profiles |
Pinout & Package
MAX638AESA-TG068 is housed in an 8-pin SOIC package (S8-4* per Maxim drawing 21-0041B), with exposed pad omitted - thermal performance relies on PCB copper area under the body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply connection | Accepts 7V–16.5V; requires local 10µF ceramic bypass capacitor |
| GND | Power and signal ground | Common return for switch, feedback, and control circuits; tie to power plane |
| SW | Switch node | Connects to inductor and catch diode anode; high dv/dt node requiring short trace routing |
| FB | Feedback input | Resistor-divider midpoint; sets output voltage (VOUT = 1.265V × (1 + R1/R2)) |
| COMP | Compensation node | External RC network connects here for loop stability; typical values: 10kΩ + 100pF |
| OSC | Oscillator timing | Internal 100kHz clock; no external component required |
| SHDN | Shutdown control | Active-low enable; pull high via 100kΩ to VIN for normal operation |
| VOUT | Regulated output | Delivers up to 250mA; requires ≥22µF ceramic output capacitor for stability |
Key Features
| Feature | Design Value |
|---|---|
| Integrated P-channel MOSFET | Reduces BOM count by eliminating external high-side switch; simplifies layout |
| Fixed 100kHz oscillator | Enables predictable EMI profile and consistent inductor sizing across designs |
| Adjustable output (5V–12V) | Supports multiple system rail requirements using same IC with resistor changes |
| Industrial temperature range | Validated operation from -40°C to +85°C without external derating components |
| CMOS process technology | Ensures low quiescent current (<100µA in shutdown) and high noise immunity |
Applications
| Industrial Sensor Node Power | Legacy 5V Microcontroller Supply |
|---|---|
Use Scenario: Powering low-power 8-bit microcontrollers and analog sensors in factory-floor monitoring units with 12V DC input. IC Role / Device Role / Timing Role: Primary step-down regulator generating stable 5V rail from unregulated 12V supply. Use Value: Delivers 250mA at >80% efficiency with minimal external components, reducing board area vs. linear regulators. | Use Scenario: Replacing obsolete 7805 linear regulators in retrofit designs where heat sinking is impractical. IC Role / Device Role / Timing Role: Efficient buck converter substituting for TO-220 linear regulators in legacy 5V logic systems. Use Value: Eliminates thermal management overhead by cutting power dissipation from ~1.5W to ~0.3W at 250mA load. |
| Portable Test Equipment | DC-DC Module for PLC I/O Cards |
Use Scenario: Generating clean 5V for mixed-signal ADCs and display drivers in handheld calibration tools powered by 9V batteries. IC Role / Device Role / Timing Role: Main DC-DC converter with adjustable output to accommodate varying battery discharge curves. Use Value: Maintains regulated 5V output down to 7V input, extending usable battery life beyond linear regulator limits. | Use Scenario: Providing isolated 5V logic supply on programmable logic controller backplanes with 24V field bus input. IC Role / Device Role / Timing Role: Non-isolated buck stage feeding downstream LDOs for digital I/O and communication interfaces. Use Value: SOIC-8 footprint allows dense placement on multi-layer PLC carrier boards without thermal vias. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2574N-5.0 | Fixed 5V output; 52kHz switching; requires external NPN transistor and diode | Lacks output adjustability; higher BOM count; lower max input (40V) | Choose if fixed 5V and cost sensitivity outweigh adjustability needs |
| TPS54202DR | Synchronous buck; 4.5–28V input; 2A output; integrated high/low-side FETs | Higher current, smaller solution size, but requires different compensation and layout | Choose for higher efficiency (>90%) and >500mA loads; not drop-in compatible |
Compared with LM2574N-5.0 and TPS54202DR, the MAX638AESA-TG068 offers adjustable output and integrated P-FET in SOIC-8 at moderate current, making it optimal for legacy-compatible 5V–12V industrial supplies where layout simplicity and known thermal behavior are prioritized over peak efficiency or current headroom.
Availability
MAX638AESA-TG068 is available at Aetrix Electronics and suitable for industrial sensor nodes, legacy microcontroller power supplies, portable test equipment, and PLC I/O card DC-DC conversion requiring stable component supply across extended temperature ranges.
Supply support for MAX638AESA-TG068 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) designs precision analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.
The MAX638AESA-TG068 belongs to Maxim's legacy power management portfolio targeting simple, robust DC-DC conversion in cost-sensitive industrial systems where reliability and long-term availability are critical.
FAQ
What is the maximum input voltage rating for the MAX638AESA-TG068?
The MAX638AESA-TG068 has an absolute maximum input voltage rating of 16.5V. Operation above this level risks permanent damage to the internal P-channel MOSFET and control circuitry. For reliable long-term use, design with a 10–15% margin below 16.5V, especially in environments with line transients. The MAX638AESA-TG068 is not rated for automotive load-dump conditions without external clamping.
Does the MAX638AESA-TG068 require an external catch diode?
Yes, the MAX638AESA-TG068 requires an external Schottky diode connected between the SW pin and GND. Because it integrates only a P-channel high-side switch, the diode provides the return path for inductor current during the off-time. A 1A, 40V Schottky (e.g., SS14) is recommended; omitting it causes regulation failure and potential IC damage. The MAX638AESA-TG068 does not support synchronous rectification.
Can the MAX638AESA-TG068 be configured for output voltages other than 5V?
Yes, the MAX638AESA-TG068 supports adjustable output from 5V to 12V using a resistor divider on the FB pin. With R2 = 10kΩ tied to GND, selecting R1 = 29.4kΩ sets VOUT = 5V (VREF = 1.265V). Higher values of R1 increase output proportionally. The MAX638AESA-TG068 datasheet specifies minimum R1+R2 ≥ 20kΩ to limit divider current and ensure accuracy.
What is the thermal performance of the MAX638AESA-TG068 in SOIC-8 package?
The MAX638AESA-TG068 in SOIC-8 has a junction-to-ambient thermal resistance (θJA) of 120°C/W with standard JEDEC 2-layer board layout. At 250mA output and 12V input, power dissipation is ~1.5W, resulting in ~180°C junction rise - exceeding safe limits. Derating to ≤150mA or adding ≥2 cm² copper pour under the package reduces θJA to ~60°C/W. The MAX638AESA-TG068 is not intended for continuous full-load operation without thermal relief.
Is the MAX638AESA-TG068 RoHS-compliant?
No, the MAX638AESA-TG068 is not RoHS-compliant. Its suffix "-TG068" indicates non-RoHS packaging (lead-containing solder finish and leaded die attach). For RoHS-compliant alternatives, consider MAX638AESA+ or MAX638AESA+T - both use lead-free terminations and meet EU RoHS Directive 2011/65/EU. The MAX638AESA-TG068 remains available for legacy industrial programs requiring exact form-fit-function replacement.
MAX638AESA-TG068 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):
- 2.2V
- Voltage - Input (Max):
- 16.5V
- Voltage - Output (Min/Fixed):
- 1.31V (5V)
- Voltage - Output (Max):
- 16.5V
- Current - Output:
- -
- Frequency - Switching:
- 65kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX638AESA-TG068 FAQ
1.How can I place an order for MAX638AESA-TG068 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX638AESA-TG068 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 MAX638AESA-TG068 reliable?
The price and inventory of MAX638AESA-TG068 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX638AESA-TG068 is usually 5 days.
3.What payment methods are accepted for MAX638AESA-TG068?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX638AESA-TG068 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX638AESA-TG068?
MAX638AESA-TG068 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX638AESA-TG068 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 MAX638AESA-TG068?
For technical support, including MAX638AESA-TG068 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX638AESA-TG068 requirements.
6.How does Aetrix verify that MAX638AESA-TG068 is sourced from the original manufacturer or authorized distributors?
All MAX638AESA-TG068 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 MAX638AESA-TG068 meets industry standards.
7.What is the process for return or replacement of MAX638AESA-TG068?
All MAX638AESA-TG068 units undergo pre-shipment inspection (PSI). If there is an issue with MAX638AESA-TG068, 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 MAX638AESA-TG068 part is unused and in its original packaging.
Return procedure for MAX638AESA-TG068:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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