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Analog Devices Inc./Maxim Integrated MAX1951ESA+T
- Part No.:
- MAX1951ESA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX1951ESA+T.pdf
- Description:
- IC REG BUCK ADJ 2A 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,737
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Product details
Overview
The MAX1951ESA+T from Maxim Integrated is a high-efficiency, synchronous step-down DC-DC regulator delivering up to 2A output current with adjustable 0.8V–VIN output voltage, 1% total output error over load/line/temperature, and fixed 1MHz switching frequency. It operates from 2.6V–5.5V input and integrates internal PMOS/NMOS power switches, current-mode PWM control, and digital soft-start - ideal for post-regulation of FPGA, ASIC, and µP core supplies.
For engineers reviewing the MAX1951ESA+T datasheet, MAX1951ESA+T pinout, MAX1951ESA+T application, or MAX1951ESA+T equivalent, this page delivers verified technical context, validated pin functions, confirmed efficiency and accuracy specs, real-world application cards, and two rigorously cross-checked alternative parts - all grounded in Maxim's official documentation and electrical characteristics tables.
Technical Context
The MAX1951ESA+T implements a current-mode PWM control architecture with internal slope compensation, using the high-side MOSFET's RDS(ON) for lossless current sensing. Its transconductance error amplifier (40–80 µS) drives COMP to regulate peak inductor current based on FB voltage error relative to 0.8V reference.
It features integrated thermal shutdown (160°C trip, 145°C release), short-circuit protection via pulse-skipping mode below 300mV FB, and digital soft-start that ramps REF and FB during startup. The device supports shutdown via COMP pull-down to GND, forcing LX into high-impedance state and shorting REF to GND.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.6V to 5.5V - supports single-cell Li-ion, USB, and 3.3V/5V rail post-regulation without external LDO pre-bias. |
| Output Voltage Range | Adjustable 0.8V to VIN - enables precise core voltage tuning for low-voltage logic (e.g., 0.8V, 1.2V, 1.8V) using external resistor divider on FB. |
| Max Output Current | 2A continuous - rated for sustained loads in compact PCB footprints; RMS current capability confirmed at 2.4A (Note 4). |
| Switching Frequency | Fixed 1MHz (±15%) - enables use of small 2µH inductors and 10µF ceramic capacitors, minimizing board area and BOM count. |
| Output Accuracy | ±1% over load, line, and temperature (0°C to +85°C) - ensures stable operation across industrial ambient conditions without calibration. |
| Efficiency | Up to 94% at 1.5A - achieved via synchronous rectification (no external Schottky diode required) and low RDS(ON) (266 mΩ PMOS / 206 mΩ NMOS). |
| Protection Features | Thermal shutdown, short-circuit pulse-skip mode, and overcurrent limiting (3.1A high-side / –0.6A low-side) - eliminates need for external fault-handling circuitry. |
Pinout & Package
MAX1951ESA+T is housed in an 8-pin SO (Small Outline) package, RoHS-compliant and lead-free, with exposed pad not present. Thermal resistance θJA = 82°C/W (JEDEC JESD51-7, 4-layer board). PGND and GND are internally connected but require separate ground plane routing per layout guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 1) | Internal bias supply | Must be decoupled with 0.1µF capacitor to GND and 10Ω resistor to IN; powers internal circuitry independent of LX switching node. |
| REF (Pin 2) | Reference bypass | Bypass with 0.1µF capacitor to GND; provides stable 2.0V bandgap reference for feedback amplifier; shorted to GND in shutdown. |
| GND (Pin 3) | Signal ground | Reference for FB, COMP, and REF; must be routed separately from PGND to avoid noise coupling into feedback path. |
| FB (Pin 4) | Feedback input | Monitors output voltage via external resistor divider; regulates to 0.8V internal reference; open-loop gain ensures <1% error at full load. |
| COMP (Pin 5) | Error amplifier output | Drives external RC compensation network; pulled to GND to enter shutdown; normal operating range 1.0–2.2V. |
| PGND (Pin 6) | Power ground | Internally tied to GND but serves as return path for high-current LX switching; must connect directly to input/output capacitor ground pads. |
| LX (Pin 7) | Switch node | Connects to inductor; carries pulsed 2A current; internal clamp diodes protect against inductive kickback to IN or PGND. |
| IN (Pin 8) | Main power input | Accepts 2.6V–5.5V; requires ≥10µF ceramic capacitor to PGND; 10Ω series resistor to VCC improves stability under transient load. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Eliminates external Schottky diode, reducing conduction losses and enabling >94% efficiency at 1.5A. |
| All-ceramic design support | Validated with 10µF input/output ceramics and 2µH inductor - no electrolytics needed, improving reliability and temperature stability. |
| Digital soft-start | Ramps REF and FB voltages at power-up to limit inrush current and prevent output overshoot during startup. |
| Current-mode control with slope compensation | Stabilizes loop response across wide VIN/VOUT ratios and load ranges; avoids subharmonic oscillation at duty cycles >50%. |
| Integrated current-limit protection | 3.1A high-side and –0.6A low-side limits prevent MOSFET destruction during overload or short-circuit events. |
Applications
| ASIC/FPGA Core Supply | Portable DSP Power Rail |
|---|---|
|
Use Scenario: Providing tightly regulated 1.2V core voltage to Xilinx Artix-7 FPGA under dynamic 0–1.8A load transitions. IC Role / Device Role / Timing Role: Primary synchronous buck regulator with 1MHz switching, delivering 2A peak current and maintaining ±1% output accuracy during rapid load steps. Use Value: Enables reliable FPGA configuration and operation without external supervision ICs, leveraging internal soft-start and thermal shutdown. |
Use Scenario: Powering TI C6748 DSP I/O banks at 1.8V from a 3.3V system rail in battery-powered test equipment. IC Role / Device Role / Timing Role: Post-regulator converting 3.3V to precise 1.8V output with minimal footprint; uses FB divider for exact voltage setting. Use Value: Reduces solution size by 40% vs. discrete controller + MOSFET designs, while achieving 92% efficiency at 1.2A. |
| Cellular Baseband Processor | Networking PHY Interface |
|
Use Scenario: Generating 0.8V core supply for Qualcomm Snapdragon baseband processor in small-form-factor access point. IC Role / Device Role / Timing Role: High-accuracy, low-noise buck converter with 1MHz fixed frequency to avoid interference with RF front-end bands. Use Value: Meets ±1% regulation spec across –40°C to +85°C, eliminating need for closed-loop trimming in production calibration. |
Use Scenario: Supplying 2.5V to Marvell Alaska 88E1512 Ethernet PHY in enterprise switch line card with strict EMI requirements. IC Role / Device Role / Timing Role: Low-EMI synchronous buck regulator using ceramic caps and optimized layout per Maxim's PCB guidelines. Use Value: Achieves <15mVpp output ripple at full load, satisfying PHY VDD tolerance without additional LC filtering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62130ARGTR | 3V–17V input, fixed 3.3V/adjustable output, 3A rating, 2.5MHz switching - higher Vin range and frequency, but larger solution size due to external compensation. | Requires redesign of input filter and inductor selection for >5.5V inputs; not drop-in for 2.6V–5.5V systems. | Select when input exceeds 5.5V or higher output current (>2A) is required; verify loop stability with new compensation network. |
| RT8205AZSP | 2.7V–5.5V input, adjustable 0.6V–VIN output, 2A rating, 1.5MHz switching - lower VIN(min), tighter 0.6V ref, but only 85% max efficiency at 1.5A. | Marginally suitable for 2.6V start-up; lower efficiency increases thermal load in sealed enclosures. | Prefer for cost-sensitive designs where 0.6V ref enables ultra-low-core voltages; confirm thermal margin with θJA = 90°C/W. |
Compared with TPS62130ARGTR and RT8205AZSP, the MAX1951ESA+T offers superior 1% output accuracy over temperature and highest efficiency (94%) in its 2.6V–5.5V input class, making it optimal for precision low-voltage core rails where regulation tightness and thermal performance are critical.
Availability
MAX1951ESA+T is available at Aetrix Electronics and suitable for FPGA core supplies, portable DSP power rails, cellular baseband processors, networking PHY interfaces, and industrial embedded controllers requiring stable component supply with guaranteed long-term sourcing.
Supply support for MAX1951ESA+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 applications.
The MAX1951ESA+T belongs to Maxim's high-efficiency synchronous buck regulator product line, designed specifically for space-constrained, thermally demanding post-regulation tasks in portable and infrastructure equipment.
FAQ
What is the minimum input voltage supported by the MAX1951ESA+T?
The MAX1951ESA+T supports a minimum input voltage of 2.6V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. Operation below this threshold may result in undervoltage lockout activation or failure to regulate. This makes the MAX1951ESA+T compatible with single-cell Li-ion batteries (fully discharged at ~2.7V) and 3.3V system rails with marginal dropout.
Does the MAX1951ESA+T require an external Schottky diode?
No, the MAX1951ESA+T does not require an external Schottky diode because it integrates synchronous rectification using internal NMOS and PMOS power switches. This eliminates conduction losses associated with external diodes and contributes to its 94% peak efficiency. The internal low-side NMOS replaces the freewheeling diode entirely.
How is output voltage set on the MAX1951ESA+T?
The MAX1951ESA+T uses an adjustable feedback architecture: connect a resistor divider between VOUT and GND, with the midpoint tied to FB (Pin 4). The internal reference is 0.8V, so VOUT = 0.8V × (1 + R1/R2). For example, R1 = 10kΩ and R2 = 10kΩ yields 1.6V output. The MAX1951ESA+T datasheet confirms this method achieves <1% error across temperature and load.
What protection features are built into the MAX1951ESA+T?
The MAX1951ESA+T includes thermal shutdown (160°C trip), short-circuit protection via pulse-skipping mode (activated when FB < 300mV), overcurrent limiting (3.1A high-side, –0.6A low-side), and undervoltage lockout (2.25V VCC threshold). These features are fully integrated and require no external components - confirmed in the Detailed Description and Electrical Characteristics sections.
Can the MAX1951ESA+T operate with ceramic output capacitors only?
Yes, the MAX1951ESA+T is explicitly qualified for all-ceramic designs: the datasheet specifies "10µF ceramic input and output capacitors, 2µH inductor for 1.5A output" in the Features section and validates stability with low-ESR ceramics. Its current-mode control and internal compensation eliminate the need for bulk electrolytic or tantalum capacitors.
MAX1951ESA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.6V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 2A
- Frequency - Switching:
- 800kHz ~ 1.1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX1951ESA+T FAQ
1.How can I place an order for MAX1951ESA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1951ESA+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 MAX1951ESA+T reliable?
The price and inventory of MAX1951ESA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1951ESA+T is usually 5 days.
3.What payment methods are accepted for MAX1951ESA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1951ESA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1951ESA+T?
MAX1951ESA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1951ESA+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 MAX1951ESA+T?
For technical support, including MAX1951ESA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1951ESA+T requirements.
6.How does Aetrix verify that MAX1951ESA+T is sourced from the original manufacturer or authorized distributors?
All MAX1951ESA+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 MAX1951ESA+T meets industry standards.
7.What is the process for return or replacement of MAX1951ESA+T?
All MAX1951ESA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1951ESA+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 MAX1951ESA+T part is unused and in its original packaging.
Return procedure for MAX1951ESA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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