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Analog Devices Inc./Maxim Integrated MAX1974EUB+T
- Part No.:
- MAX1974EUB+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX1974EUB+T.pdf
- Description:
- IC REG BUCK ADJ 1A 10UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:2,980
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Product details
Overview
The MAX1974EUB+T from Maxim Integrated is a constant-frequency 1.4MHz PWM current-mode step-down regulator delivering up to 1A output current with ±1% output voltage accuracy over load, line, and temperature. It supports preset 1V or 1.5V outputs (via FBSEL pin), or adjustable output down to 0.75V using external resistors. Designed for space-constrained telecom and networking power rails, it operates from 2.6V–5.5V input and features 100% duty-cycle dropout capability.
For engineers reviewing the MAX1974EUB+T datasheet, MAX1974EUB+T pinout, MAX1974EUB+T application, or MAX1974EUB+T equivalent, this page delivers verified technical context, validated pin functions, confirmed operating parameters, and real-world application implementation details - all specific to the MAX1974EUB+T variant in 10-pin µMAX package.
Technical Context
The MAX1974EUB+T implements fixed-frequency current-mode PWM control with internal synchronous rectification, eliminating external freewheeling diodes. Its 1.4MHz switching frequency enables use of small 4.7µF ceramic input/output capacitors and compact 2.2–4.7µH inductors while operating outside DSL bands.
It integrates a POK (Power-OK) open-drain output that asserts low when VOUT falls below 90% of nominal regulation voltage, with hysteresis between 88–92% falling and 90–95% rising thresholds. The device uses on-resistance-based current sensing and includes thermal shutdown at +170°C with 20°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.6V to 5.5V - supports single-cell Li-ion, 3.3V/5V system rails without external LDO pre-regulation. |
| Output Voltage Options | Preset 1.0V or 1.5V (FBSEL = GND or IN); adjustable down to 0.75V - enables direct core/IO supply for low-voltage ASICs and FPGAs. |
| Switching Frequency | 1.2MHz to 1.6MHz (typ 1.4MHz) - ensures stable operation outside DSL band (25–1104kHz) and enables fast transient response. |
| Output Accuracy | ±1% over load, line, and -40°C to +85°C - guarantees tight regulation for DSP/ASIC core supplies requiring stable reference. |
| Max Output Current | 1A continuous - sufficient for powering baseband processors, optical transceivers, and modem PHY layers. |
| POK Threshold | 90% nominal VOUT rising edge, 88% falling edge - provides reliable power-good signaling for sequenced startup in multi-rail systems. |
| Soft-Start Time | 3.75ms (with 0.1µF SS capacitor) - limits inrush current during hot-plug or reset events in network equipment. |
Pinout & Package
Package: 10-pin µMAX (3mm × 3mm × 0.8mm, exposed pad), RoHS-compliant, rated for -40°C to +85°C ambient operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 FBSEL | Feedback Mode Selector | Selects preset output: GND → 1.0V, IN → 1.5V, unconnected → adjustable mode (0.75V–VIN). |
| 2 COMP | Compensation Node | Connects RC network to GND for loop stability; internally pulled to GND during shutdown/UVLO. |
| 3 FB | Feedback Input | Connected to output (preset) or resistor divider (adjustable); sets regulation point via 0.75V internal reference. |
| 4 SS | Soft-Start / Reference | Charged by 20µA current source; 0.75V reference for MAX1974; determines ramp time (tSS = 0.75V / 20µA × CSS). |
| 5 GND | Analog Ground | Reference for FB, COMP, SS; separate from PGND to minimize noise coupling into feedback path. |
| 6 POK | Power-OK Output | Open-drain signal active-low when VOUT < 90% nominal; requires external pullup (10kΩ–100kΩ) to logic supply. |
| 7 PGND | Power Ground | High-current return path for LX switch node; must be connected to exposed pad for thermal performance. |
| 8 LX | Switch Node | Connects to inductor; internal P-channel high-side and N-channel low-side MOSFETs enable synchronous operation. |
| 9 IN | Input Supply | 2.6V–5.5V input; bypassed with 4.7µF ceramic capacitor to PGND for EMI suppression and ripple reduction. |
| 10 ON | Enable Input | Logic-high (>1.6V) enables regulation; logic-low (<0.6V) forces shutdown with <10µA quiescent current. |
Key Features
| Feature | Design Value |
|---|---|
| 100% Duty-Cycle Operation | Enables dropout operation when VIN ≈ VOUT; eliminates need for linear post-regulators in low-VIN scenarios. |
| Synchronous Rectification | Integrated N-channel low-side MOSFET replaces Schottky diode - improves efficiency by ~5–8% at 1A vs. asynchronous designs. |
| Ultra-Small Footprint | 0.19in² total circuit area - achieved with 10-pin µMAX package and only two 4.7µF ceramic caps (no electrolytics required). |
| Internal Current Sensing | Uses MOSFET RDS(ON) instead of sense resistor - reduces BOM count, PCB area, and power loss in current path. |
| Thermal Shutdown Protection | Triggers at +170°C junction temperature with 20°C hysteresis - prevents permanent damage during overload or poor heatsinking. |
Applications
| DSL Modem Power Rail | Optical Transceiver Bias |
|---|---|
Use Scenario: Powers ADSL/VDSL line card PHY ICs requiring stable 1.5V or 1.0V at up to 1A with minimal board area. IC Role / Device Role / Timing Role: Primary DC/DC step-down regulator supplying core logic and analog front-end circuits. Use Value: 1.4MHz switching avoids interference with DSL upstream/downstream bands; POK enables safe sequencing with FPGA configuration. | Use Scenario: Supplies bias voltage to SFP/SFP+ laser drivers and limiting amplifiers in fiber-optic modules. IC Role / Device Role / Timing Role: High-accuracy, low-noise point-of-load regulator with fast transient response to handle burst-mode data traffic. Use Value: ±1% output accuracy maintains laser bias stability; 4.7µF ceramic output cap minimizes ESR-induced ripple affecting signal integrity. |
| Cellular Base Station RFIC | Central Office Telecom Shelf |
Use Scenario: Delivers clean 1.0V supply to RF transceivers and ADC/DAC blocks in macrocell BTS units. IC Role / Device Role / Timing Role: Secondary regulated rail derived from 3.3V or 5V backplane, supporting low-noise analog sections. Use Value: Synchronous topology achieves >90% efficiency at 1A; thermal shutdown protects against airflow failure in sealed enclosures. | Use Scenario: Powers line interface cards (LICs) and digital signal processors in carrier-grade DSLAM chassis. IC Role / Device Role / Timing Role: Compact, high-reliability buck converter for distributed 1.5V/1.0V rails across multiple daughterboards. Use Value: 10-pin µMAX package fits dense backplane layouts; POK output interfaces directly with shelf management controllers for fault reporting. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62130ARGTR | 3.0V–17V input range; 3.0MHz switching; no POK output; 1.2V–6.0V adjustable only | Lacks POK and preset 1.0V/1.5V modes; better suited for wide-input industrial apps, not telecom-specific timing | Select if input exceeds 5.5V or higher frequency is needed; verify absence of POK does not impact system sequencing. |
| RT8059GJ6F | 2.5V–5.5V input; 1.5MHz switching; 1.0V/1.2V/1.5V/1.8V presets; no POK; 0.6V–5.5V adjustable | Offers more preset voltages but no POK; soft-start time not specified; lower max current (0.6A) | Consider only for non-critical 1A loads; confirm 0.6A rating meets peak demand before substitution. |
Compared with TPS62130ARGTR and RT8059GJ6F, the MAX1974EUB+T uniquely combines telecom-optimized 1.4MHz operation, integrated POK signaling, and factory-preset 1.0V/1.5V outputs - making it the only option among the three qualified for DSL/central-office power sequencing requirements.
Availability
MAX1974EUB+T is available at Aetrix Electronics and suitable for DSL modems, optical transceivers, cellular base station RFICs, and central-office telecom equipment requiring stable component supply, long-term lifecycle support, and guaranteed RoHS compliance.
Supply support for MAX1974EUB+T 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, communications, and computing markets.
The MAX1973/MAX1974 product line was designed specifically for space-constrained, high-frequency point-of-load applications in telecom infrastructure - emphasizing ultra-small footprint, DSL-band immunity, and integrated power-good signaling.
FAQ
What is the function of the POK pin on the MAX1974EUB+T?
The POK (Power-OK) pin on the MAX1974EUB+T is an open-drain output that signals when the output voltage has reached and remains within regulation. It goes low when VOUT drops below 90% of its nominal value and returns to high-impedance when VOUT rises above 92.5%. The MAX1974EUB+T POK remains functional during shutdown and undervoltage lockout, provided VIN ≥ 1V.
Can the MAX1974EUB+T operate with input voltage below 2.6V?
No - the MAX1974EUB+T has a specified minimum input voltage of 2.6V. Below this, undervoltage lockout (UVLO) activates at ~2.35V (typ), disabling switching and forcing the device into shutdown. The MAX1974EUB+T will not regulate or deliver output current when VIN is less than 2.6V, and operation below the absolute minimum rating risks functional failure.
How do I configure the MAX1974EUB+T for a 1.5V preset output?
To configure the MAX1974EUB+T for 1.5V preset output, connect the FBSEL pin to the IN pin and tie the FB pin directly to the output. Do not use external resistors. This configuration leverages the internal 0.75V reference and feedback divider ratio to set VOUT = 1.5V. Confirm with oscilloscope measurement at FB (should read 0.75V) and output (should be 1.5V ±1%).
What is the maximum recommended output capacitance for the MAX1974EUB+T?
The MAX1974EUB+T is optimized for 4.7µF ceramic output capacitors (X5R/X7R dielectric), and the datasheet does not specify an upper limit. However, excessive capacitance (>22µF) may destabilize the control loop due to phase margin reduction. For best stability and transient response, keep total output capacitance ≤10µF unless compensated per the manufacturer's Type 1 compensation guidelines using COMP pin components.
Does the MAX1974EUB+T support 100% duty-cycle operation, and what is its dropout behavior?
Yes - the MAX1974EUB+T supports true 100% duty-cycle operation, enabling regulation even when VIN approaches VOUT. In dropout, VDROP = IOUT × (RDS(ON)P + RL), where RDS(ON)P is the high-side P-MOSFET on-resistance (0.23–0.46Ω typ) and RL is inductor DCR. This allows seamless transition from switching to linear-like operation without output collapse.
MAX1974EUB+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable (Programmable)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.6V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.75V (1V, 1.5V)
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 1A
- Frequency - Switching:
- 1.4MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-uMAX/uSOP
MAX1974EUB+T FAQ
1.How can I place an order for MAX1974EUB+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1974EUB+T 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 MAX1974EUB+T reliable?
The price and inventory of MAX1974EUB+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1974EUB+T is usually 5 days.
3.What payment methods are accepted for MAX1974EUB+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1974EUB+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1974EUB+T?
MAX1974EUB+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1974EUB+T 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 MAX1974EUB+T?
For technical support, including MAX1974EUB+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1974EUB+T requirements.
6.How does Aetrix verify that MAX1974EUB+T is sourced from the original manufacturer or authorized distributors?
All MAX1974EUB+T 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 MAX1974EUB+T meets industry standards.
7.What is the process for return or replacement of MAX1974EUB+T?
All MAX1974EUB+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1974EUB+T, 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 MAX1974EUB+T part is unused and in its original packaging.
Return procedure for MAX1974EUB+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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