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Analog Devices Inc./Maxim Integrated MAX1972EEE+
- Part No.:
- MAX1972EEE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
MAX1972EEE+.pdf
- Description:
- IC REG BUCK ADJ 750MA DL 16QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,668
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Product details
Overview
MAX1972EEE+ from Maxim Integrated is a dual-output, current-mode PWM buck regulator operating at a fixed 1.4MHz switching frequency, delivering up to 750mA per output from a 2.6V–5.5V input. It features 180° out-of-phase operation, ±1% output voltage accuracy over load/line/temperature, and integrated power-on reset (POR) with 175ms delay. It is used in USB-powered xDSL modems for compact, efficient dual-rail power conversion.
For engineers reviewing the MAX1972EEE+ datasheet, MAX1972EEE+ pinout, MAX1972EEE+ application, or MAX1972EEE+ equivalent, key selection considerations include its dual 750mA outputs, 1.4MHz fixed-frequency operation, PFO monitoring capability, 16-pin QSOP package, and compatibility with all-ceramic capacitor designs for space-constrained telecom and embedded systems.
Technical Context
The MAX1972EEE+ integrates two synchronous buck regulators sharing a single 1.4MHz oscillator and operating 180° out of phase to minimize input ripple. Its current-mode control uses internal MOSFET RDS(ON) for current sensing-eliminating external sense resistors-and includes slope compensation for loop stability across duty cycles.
It implements soft-start via REF pin charging (25µA current source), POR with 92% output threshold detection and 175ms delay, and an open-drain PFO that asserts high when VIN falls below 3.94V. The device supports three feedback modes per output: preset (1.8V/3.3V for OUT1; 1.5V/2.5V for OUT2), resistor-divider adjustable (1.2V to VIN), or sub-1V configuration when one output exceeds 1.2V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.6V to 5.5V - supports USB 5V, Li-ion battery, and industrial 3.3V/5V rails without external LDO pre-regulation. |
| Switching Frequency | 1.4MHz (fixed) - enables use of small 3.3–6.8µH inductors and low-ESR ceramic capacitors, reducing board area by >40% vs. 700kHz alternatives. |
| Output Current (each) | 750mA guaranteed - sufficient to replace dual LDOs in core logic + I/O rail applications (e.g., SFP modules, modem PHYs). |
| Output Voltage Accuracy | ±1% over load, line, and temperature - ensures stable microcontroller core voltage and analog subsystem bias under dynamic conditions. |
| POR Delay Time | 175ms - provides reliable system-level reset timing after power stabilization, compatible with FPGA and DSP boot sequences. |
| PFO Trip Threshold | 3.94V (falling edge) - detects USB bus collapse before downstream brownout, enabling graceful shutdown in portable xDSL devices. |
| Package | 16-pin QSOP (5.3mm × 10.2mm, 0.65mm pitch) - surface-mount compatible with standard reflow profiles and automated optical inspection. |
Pinout & Package
MAX1972EEE+ is housed in a 16-pin QSOP package with exposed pad (not electrically connected). Pin functions are validated per Maxim's official datasheet revision 1 (2/09) and match the MAX1970/MAX1972 shared pinout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LX1 | High-side switch node 1 | Connects to inductor for OUT1; carries pulsed high-current switching waveform; requires low-inductance layout to minimize EMI. |
| VCC | Analog supply | Bypassed with 0.1µF ceramic to GND; powers internal reference, comparators, and gate drivers; decoupled from IN via 10Ω resistor. |
| COMP1 | OUT1 compensation node | Connects RC network (e.g., 39kΩ + 680pF) to GND to stabilize feedback loop; pulled low during shutdown. |
| FB1 | OUT1 feedback input | Accepts voltage divider from OUT1 for adjustable regulation (1.2V–VIN) or connects directly for preset 1.8V/3.3V modes. |
| FB2 | OUT2 feedback input | Same function as FB1 for OUT2; supports 1.5V/2.5V presets or resistor-divider adjustment. |
| COMP2 | OUT2 compensation node | Independent compensation path for second regulator; identical design requirements as COMP1. |
| REF | Internal reference soft-start node | Charged at 25µA to initiate soft-start; bypassed with 0.01–1.0µF capacitor; pulled low during shutdown/UVLO. |
| GND | Analog ground | Reference for feedback, reference, and error amplifiers; separate from PGND in layout to avoid noise coupling. |
| POR | Open-drain power-on reset output | Asserts high 175ms after both outputs reach 92% regulation; drives external MCU reset with pullup. |
| EN | Enable input | Active-high logic control; pulling low reduces quiescent current to ~1µA and disables both outputs. |
| PFO | Open-drain power-fail output | Asserts high when VIN drops below 3.94V; used for USB power loss detection in modem applications. |
| FBSEL2 | OUT2 feedback select | Connect to GND → 1.5V; to VCC → 2.5V; floating → external resistor-divider mode. |
| FBSEL1 | OUT1 feedback select | Connect to GND → 1.8V; to VCC → 3.3V; floating → external resistor-divider mode. |
| IN | Main power input | 2.6V–5.5V supply; bypassed with 10µF ceramic to PGND; feeds internal regulators and high-side switches. |
| LX2 | High-side switch node 2 | Inductor connection for OUT2; 180° out-of-phase with LX1 to reduce input ripple RMS current by ~30%. |
| PGND | Power ground | Return path for high-current LX1/LX2 switching; must be low-impedance copper pour tied to IN capacitor ground. |
Key Features
| Feature | Design Value |
|---|---|
| 180° out-of-phase dual regulation | Reduces RMS input capacitor ripple current by ~30%, allowing smaller 10µF ceramic instead of larger tantalum or electrolytic. |
| All-ceramic capacitor support | Enables full ceramic BOM (IN, OUT1, OUT2, VCC, REF) - eliminates ESR-related instability and improves reliability in thermal cycling. |
| Sub-1V output capability | Permits generation of 1.0V core rails when paired with ≥1.2V auxiliary rail (e.g., 1.8V I/O), supporting modern low-voltage SoCs without external dividers. |
| Integrated PFO with 3.94V threshold | Provides deterministic USB power-loss detection without external comparator or resistor divider, simplifying compliance with USB 2.0 bus hold-up time. |
| Synchronous rectification | Eliminates external Schottky diodes - improves efficiency by 8–12% at 500mA and reduces thermal footprint in QSOP package. |
Applications
| xDSL Modems | USB-Powered Devices |
|---|---|
Use Scenario: Powering ADSL/VDSL PHY, controller, and line driver from single USB 5V port. IC Role / Device Role / Timing Role: Dual-buck regulator generating 3.3V (PHY interface) and 2.5V (analog front-end) with PFO-triggered graceful shutdown on USB disconnect. Use Value: Eliminates need for discrete DC-DC + LDO combinations; 1.4MHz operation avoids interference with DSL band (26–1104kHz). | Use Scenario: Compact portable test equipment powered solely via USB-C or legacy USB-A. IC Role / Device Role / Timing Role: Provides isolated 1.8V digital core and 1.5V analog sensor rail with coordinated soft-start and POR sequencing. Use Value: Meets USB power budget constraints (<900mA total) while maintaining ±1% regulation across variable load steps. |
| Copper Gigabit SFP Modules | Dual LDO Replacement |
Use Scenario: Powering SFP+ host interface (3.3V) and laser driver bias (2.5V) in enterprise switches. IC Role / Device Role / Timing Role: High-frequency buck regulator delivering clean, low-noise rails with minimal board area in 1×2 SFP footprint. Use Value: Replaces two 300mA LDOs with 750mA dual buck - improves efficiency from ~65% to >88% at full load, reducing module thermal density. | Use Scenario: Upgrading legacy designs using discrete 1.8V/2.5V LDOs to reduce heat and improve transient response. IC Role / Device Role / Timing Role: Drop-in replacement for dual-LDO solutions requiring same 16-pin QSOP footprint and enable/reset signaling. Use Value: Cuts quiescent current from ~100µA (two LDOs) to ~20mA (active), extends battery life in always-on IoT gateways. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1970EEE+ | Identical pinout and feature set, but POR delay = 16.6ms (vs. 175ms); no PFO functionality. | Suitable where faster system reset is required and USB power-fail detection is unnecessary. | Select MAX1970EEE+ only if POR timing must be <20ms and PFO is unused; otherwise MAX1972EEE+ offers broader system-monitoring capability. |
| TPS65270PWP | 2.5V–5.5V input; 1.2MHz switching; 1.2A per channel; no integrated PFO; requires external soft-start capacitor. | Higher current capability but lacks PFO and fixed 1.4MHz frequency; needs additional components for USB fault detection. | Choose TPS65270PWP for higher output current demand (>750mA) or TI ecosystem alignment; MAX1972EEE+ preferred for USB-aware designs with strict size constraints. |
Compared with MAX1970EEE+, MAX1972EEE+ adds PFO for USB power monitoring and extends POR delay to 175ms for robust FPGA boot sequencing; compared with TPS65270PWP, it delivers tighter output accuracy (±1% vs. ±2%), eliminates external soft-start components, and integrates PFO-reducing BOM count by 3–5 parts in USB-powered applications.
Availability
MAX1972EEE+ is available at Aetrix Electronics and suitable for xDSL modems, USB-powered devices, copper gigabit SFP modules, and dual LDO replacement applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for MAX1972EEE+ 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 demanding industrial, communications, and computing applications.
The MAX1970/MAX1971/MAX1972 family was engineered specifically for space-constrained, USB-powered broadband access equipment-emphasizing high-frequency operation, integrated monitoring (PFO/POR), and dual-rail flexibility without external current-sense resistors.
FAQ
What is the switching frequency of the MAX1972EEE+ and why is it significant?
The MAX1972EEE+ operates at a fixed 1.4MHz switching frequency. This high frequency allows the use of smaller inductors (3.3µH–6.8µH) and ceramic output capacitors, significantly reducing solution size and cost. It also places switching noise outside the xDSL frequency band (26kHz–1.1MHz), preventing interference with DSL signal integrity in modem applications.
Does the MAX1972EEE+ support sub-1V output voltages, and how is this achieved?
Yes, the MAX1972EEE+ supports sub-1V outputs (e.g., 1.0V) on one rail when the other output is configured above 1.2V. This is achieved using a two-resistor feedback network connecting FB1 to both OUT1 and OUT2, leveraging the internal 1.2V reference and error amplifier architecture-no external op-amps or dividers are needed.
How does the PFO (power-fail output) function in the MAX1972EEE+?
The PFO in the MAX1972EEE+ is an open-drain output that goes high when the input voltage (VIN) falls below 3.94V. It is designed for USB-powered systems to detect bus collapse early, enabling controlled shutdown before downstream brownout. A 10kΩ–100kΩ pullup to VIN or an output rail is required for proper logic-level assertion.
What is the purpose of the FBSEL1 and FBSEL2 pins on the MAX1972EEE+?
The FBSEL1 and FBSEL2 pins configure each output's regulation mode: connecting FBSEL1 to GND sets OUT1 to 1.8V, to VCC sets it to 3.3V; similarly, FBSEL2 selects 1.5V or 2.5V for OUT2. Leaving them unconnected enables external resistor-divider feedback for adjustable outputs from 1.2V to VIN.
Can the MAX1972EEE+ be used with all-ceramic capacitors, and what are the benefits?
Yes, the MAX1972EEE+ is fully compatible with all-ceramic capacitor designs on input, output, VCC, and REF nodes. Benefits include improved reliability (no electrolytic drying), smaller footprint, lower ESR (enhancing transient response), and elimination of ESR-dependent loop compensation-simplifying design and improving long-term stability in thermally cycled environments.
MAX1972EEE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable (Programmable)
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 2.6V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.2V (1.5V, 1.8V, 2.5V, 3.3V)
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 750mA
- Frequency - Switching:
- 1.4MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QSOP
MAX1972EEE+ FAQ
1.How can I place an order for MAX1972EEE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1972EEE+ 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 MAX1972EEE+ reliable?
The price and inventory of MAX1972EEE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1972EEE+ is usually 5 days.
3.What payment methods are accepted for MAX1972EEE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1972EEE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1972EEE+?
MAX1972EEE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1972EEE+ 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 MAX1972EEE+?
For technical support, including MAX1972EEE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1972EEE+ requirements.
6.How does Aetrix verify that MAX1972EEE+ is sourced from the original manufacturer or authorized distributors?
All MAX1972EEE+ 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 MAX1972EEE+ meets industry standards.
7.What is the process for return or replacement of MAX1972EEE+?
All MAX1972EEE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1972EEE+, 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 MAX1972EEE+ part is unused and in its original packaging.
Return procedure for MAX1972EEE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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