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Analog Devices Inc./Maxim Integrated MAX38909ATD+
- Part No.:
- MAX38909ATD+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 14-WFDFN Exposed Pad
- Datasheet:
-
MAX38909ATD+.pdf
- Description:
- IC REG LIN POS PROG 4A 14TDFN
- Quantity:
- Payment:
- Shipping:
Inventory:326
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Product details
Overview
MAX38909ATD+ from Maxim Integrated is a 2A, fast-transient-response nMOS linear regulator with ±1% output accuracy, 27mV dropout at 2A (WLP), and 52dB PSRR at 10kHz under 300mV headroom-designed for FPGA core rail regulation in space-constrained industrial and medical systems.
For engineers reviewing the MAX38909ATD+ datasheet, MAX38909ATD+ pinout, MAX38909ATD+ application, or MAX38909ATD+ equivalent, this page delivers verified package mapping (14-pin 3mm×3mm TDFN), confirmed feedback-programmable output (0.6V–5.0V), thermal shutdown behavior (165°C trip), reverse-current protection threshold (~700mA), and POK open-drain logic interface with 88–94% VOUT detection window.
Technical Context
The MAX38909ATD+ employs an nMOS pass device architecture with separate IN and BIAS supplies-IN (0.9V–5.5V) powers regulation while BIAS (2.7V–20V) supplies internal circuitry, enabling high PSRR even at low VIN–VOUT differentials. Its error amplifier references a stable 0.6V FB voltage, and transient response is enhanced by a programmable BYP capacitor (1nF–100nF) that controls soft-start slew rate and high-frequency noise filtering.
Protection is implemented via integrated circuits: overcurrent limiting triggers at 2.2–3.4A depending on load condition and dropout state; thermal shutdown activates at 165°C with 15°C hysteresis; reverse-current blocking engages when IN drops 6.5mV below VOUT; and UVLO independently monitors both IN (0.35–0.55V rising) and BIAS (2.45–2.65V rising) rails.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 2A maximum continuous-supports FPGA core and DSP I/O rails without external current boosting. |
| Dropout Voltage | 27mV at 2A (WLP), 36mV at 2A (TDFN, VBIAS=12V)-enables ultra-low headroom operation for sub-1V logic supplies. |
| Output Accuracy | ±1% over line, load, and temperature (−40°C to +125°C)-guarantees tight voltage margins for 1.0V/1.2V/1.8V processor cores. |
| PSRR @ 10kHz | 52dB with 300mV VIN–VOUT headroom-rejects switching noise from adjacent DC/DC converters in mixed-signal PCBs. |
| BIAS Supply Range | 2.7V to 20V-decouples control circuitry from noisy low-voltage input rails, improving stability and noise immunity. |
| Power-OK Threshold | 88–94% of VOUT (rising/falling)-provides precise, glitch-immune reset signaling for sequenced power-up of multi-rail systems. |
| Thermal Shutdown | 165°C trip, 150°C recovery-prevents permanent damage during sustained overload or poor PCB thermal design. |
Pinout & Package
MAX38909ATD+ is packaged in a 14-pin, 3mm × 3mm TDFN with exposed pad (EP), RoHS-compliant, thermal resistance θJA = 41°C/W (4-layer board). Pin numbering follows top-view orientation with EP connected to GND for optimal thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–4, IN | Regulator supply input | Accepts 0.9V–5.5V; requires 22μF ceramic bypass to GND-must be routed with low-inductance path to minimize dropout instability. |
| 5, BIAS | Bias supply input | Supplies internal circuitry at 2.7V–20V; must exceed VOUT by ≥2V; bypassed with 1μF capacitor to GND. |
| 6, EN | Enable input | Active-high digital control (VIH = 1.0–1.6V); draws ≤1μA in shutdown; connect to BIAS for always-on operation. |
| 7, GND | Ground reference | Common return for IN, OUT, and BYP capacitors-tie directly to thermal pad and system GND plane. |
| 8, POK | Open-drain power-good output | Asserts low when VOUT falls below 88% of target; requires external 10kΩ–100kΩ pullup for sequencing logic. |
| 9, FB | Feedback voltage input | Senses 0.6V reference; sets output via resistor divider (R1=15kΩ, R2 calculated per target VOUT). |
| 10, BYP | Bypass capacitor node | Connects 1nF–100nF capacitor to OUT to control soft-start slew rate and reduce reference noise. |
| 11–14, OUT | Regulated output | Sources up to 2A; pulled low via 70Ω resistor during shutdown for active discharge of output capacitance. |
| EP | Exposed thermal pad | Must be soldered to solid GND copper area with thermal vias-primary heat dissipation path; not electrically connected. |
Key Features
| Feature | Design Value |
|---|---|
| Programmable soft-start | Monotonic startup controlled by BYP capacitor (1nF–100nF); 10nF yields 5V/ms slew rate-limits inrush into 22μF output caps. |
| Reverse-current protection | Blocks >700mA reverse flow when VOUT > VIN by opening pass-device body diode-prevents output-to-input backfeed during input collapse. |
| Active output discharge | 70Ω internal pulldown on OUT during shutdown-ensures rapid, controlled discharge of output capacitance without external components. |
| Independent IN/BIAS UVLO | Dual undervoltage lockout: IN UVLO (0.35–0.55V) and BIAS UVLO (2.45–2.65V) prevent erratic startup or regulation loss during rail glitches. |
| Stability with low-ESR caps | Guaranteed stable with ≥10μF effective ceramic output capacitance (X7R MLCC)-no ESR requirements simplify BOM and layout. |
Applications
| FPGA Core Power | Medical Imaging Sensor Bias |
|---|---|
|
Use Scenario: Powers 1.0V/1.2V core rails of Xilinx Artix-7 or Intel Cyclone V FPGAs in portable ultrasound units. IC Role / Device Role / Timing Role: Primary LDO delivering clean, low-noise bias with fast transient response to handle dynamic logic switching currents. Use Value: 15mV load transient excursion at 2A step ensures <1% VOUT deviation-maintains timing margin and prevents logic errors during burst processing. |
Use Scenario: Supplies analog front-end (AFE) sensor bias in handheld MRI coil arrays requiring ultra-low noise and tight DC accuracy. IC Role / Device Role / Timing Role: Precision voltage source for ADC reference buffers and op-amp rails where PSRR and drift directly impact SNR. Use Value: 52dB PSRR at 10kHz suppresses DC/DC switching artifacts-preserves >16-bit ENOB in 1MSps data acquisition paths. |
| Industrial PLC I/O Module | 5G Base Station RFIC Bias |
|
Use Scenario: Regulates 3.3V I/O rails in DIN-rail mounted PLC modules operating across −40°C to +70°C ambient. IC Role / Device Role / Timing Role: Robust, thermally resilient LDO with integrated protection for harsh factory-floor environments. Use Value: −40°C to +125°C junction rating and 165°C thermal shutdown enable reliable operation without derating at full 2A load. |
Use Scenario: Provides 2.5V/3.3V bias to GaN driver ICs and RF transceivers in compact 5G macrocell remote radio heads (RRH). IC Role / Device Role / Timing Role: High-PSRR, low-dropout regulator co-located near RFICs to isolate sensitive analog blocks from digital noise. Use Value: 27mV dropout enables use of 3.3V intermediate bus to generate 3.0V RFIC rails-minimizes power loss and thermal density. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS7A8300RGRT | 2A, 1.1V–6.5V IN, fixed/adjustable VOUT, 35μVRMS noise, but no BIAS rail-relies solely on IN for internal biasing. | Lacks independent BIAS supply; less suitable for ultra-low VIN–VOUT operation where IN may dip near VOUT. | Prefer MAX38909ATD+ when IN < 2.7V or when BIAS rail isolation improves PSRR in noisy systems. |
| NCP1117ST50T3G | 1A, 4.75V–20V IN, fixed 5.0V output, 1.2V dropout at 1A, no POK, no reverse-current protection, no programmable soft-start. | Lower current, fixed output, minimal protection-intended for cost-sensitive non-critical rails only. | Choose MAX38909ATD+ for 2A capability, adjustable output, robust protection, and sequencing support in mission-critical designs. |
Compared with TPS7A8300RGRT and NCP1117ST50T3G, the MAX38909ATD+ uniquely combines dual-supply architecture (IN+BIAS), sub-30mV dropout at 2A, open-drain POK, and reverse-current blocking-making it the only option among the three qualified for high-reliability, low-headroom, multi-rail FPGA and RFIC applications.
Availability
MAX38909ATD+ is available at Aetrix Electronics and suitable for FPGA core power, medical imaging sensor bias, industrial PLC I/O modules, and 5G base station RFIC bias requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for MAX38909ATD+ 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, medical, communications, and automotive markets.
The MAX38909 product line delivers high-PSRR, fast-transient LDOs with dual-supply architecture and comprehensive protection-designed specifically for powering noise-sensitive digital loads like FPGAs, DSPs, and RFICs in thermally constrained, high-reliability systems.
FAQ
What is the maximum output current supported by the MAX38909ATD+?
The MAX38909ATD+ supports a continuous output current of up to 2A. This rating is validated across the full operating temperature range (−40°C to +125°C) and under specified input-to-output headroom conditions. Current limiting activates at 2.2–3.4A depending on load and dropout state, and thermal shutdown engages at 165°C to protect the device during sustained overload. The MAX38909ATD+ maintains regulation stability with ≥10μF ceramic output capacitance.
Does the MAX38909ATD+ require an external BIAS supply, and what happens if it's omitted?
Yes, the MAX38909ATD+ requires a dedicated BIAS supply between 2.7V and 20V applied to the BIAS pin. This rail powers internal circuitry-including the error amplifier, reference, and protection logic-while the IN pin supplies only the pass device. Omitting BIAS or applying voltage below 2.45V (UVLO falling threshold) disables regulation regardless of IN voltage or EN state. The MAX38909ATD+ will not operate without a valid BIAS supply.
How does the BYP pin function in the MAX38909ATD+, and what capacitor value should be used?
The BYP pin on the MAX38909ATD+ connects to a capacitor between BYP and OUT to filter reference noise and control soft-start slew rate. A 47nF capacitor is typical for balanced noise reduction and startup time; values from 1nF to 100nF are supported. For example, 10nF yields ~5V/ms slew rate, while 100nF reduces it to ~0.5V/ms. Leakage above 10nA at BYP degrades output accuracy, so low-leakage C0G/NP0 ceramics are recommended. The MAX38909ATD+ remains stable with any value in this range.
What protection features are integrated into the MAX38909ATD+?
The MAX38909ATD+ integrates overcurrent limiting (2.2–3.4A), thermal shutdown (165°C trip, 150°C recovery), reverse-current blocking (engages when IN drops 6.5mV below VOUT), input and BIAS UVLO, and active output discharge (70Ω pulldown on OUT during shutdown). It also includes Power-OK status reporting and programmable soft-start. These protections are fully internal-no external components required-and are validated across the full −40°C to +125°C junction temperature range. The MAX38909ATD+ does not require external current-sense resistors or thermal sensors.
Can the MAX38909ATD+ be used with a fixed output voltage, or is external feedback always required?
The MAX38909ATD+ requires external feedback resistors to set the output voltage-there are no factory-trimmed fixed-output variants in the ATD+ suffix. Output is programmed from 0.6V to 5.0V using a resistor divider from OUT to GND with the center tap on FB. For example, R1 = 15kΩ and R2 = 10kΩ yields 1.0V. The MAX38909ATD+ references a precise 0.6V internal bandgap, and 1% tolerance resistors are recommended to maintain ±1% overall output accuracy. No alternative configuration supports fixed output.
MAX38909ATD+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 14-WFDFN Exposed Pad
- Packaging:
- Tray
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Programmable
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 5V
- Voltage Dropout (Max):
- 0.036V @ 2A (Typ)
- Current - Output:
- 4A
- Current - Quiescent (Iq):
- 150 µA
- Current - Supply (Max):
- -
- PSRR:
- 60dB ~ 42dB (1kHz ~ 100kHz)
- Control Features:
- Enable, Power On Reset
- Protection Features:
- Over Current, Over Temperature, Reverse Current, Under Voltage Lockout (UVLO)
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-TDFN (3x3)
MAX38909ATD+ FAQ
1.How can I place an order for MAX38909ATD+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX38909ATD+ 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 MAX38909ATD+ reliable?
The price and inventory of MAX38909ATD+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX38909ATD+ is usually 5 days.
3.What payment methods are accepted for MAX38909ATD+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX38909ATD+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX38909ATD+?
MAX38909ATD+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX38909ATD+ 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 MAX38909ATD+?
For technical support, including MAX38909ATD+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX38909ATD+ requirements.
6.How does Aetrix verify that MAX38909ATD+ is sourced from the original manufacturer or authorized distributors?
All MAX38909ATD+ 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 MAX38909ATD+ meets industry standards.
7.What is the process for return or replacement of MAX38909ATD+?
All MAX38909ATD+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX38909ATD+, 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 MAX38909ATD+ part is unused and in its original packaging.
Return procedure for MAX38909ATD+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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