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Analog Devices Inc./Maxim Integrated MAX1951ESA+
- Part No.:
- MAX1951ESA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX1951ESA+.pdf
- Description:
- IC REG BUCK ADJ 2A 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:794
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Product details
Overview
MAX1951ESA+ from Maxim Integrated is a high-efficiency, synchronous PWM 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 for on-board postregulation in FPGA core supplies.
For engineers reviewing the MAX1951ESA+ datasheet, MAX1951ESA+ pinout, MAX1951ESA+ application, or MAX1951ESA+ equivalent, key selection criteria include its adjustable output range, guaranteed 2A continuous output, internal soft-start, thermal-overload protection, and SO-8 package compatibility with all-ceramic external components.
Technical Context
The MAX1951ESA+ uses current-mode PWM control with internal slope compensation and digital soft-start. Its transconductance error amplifier (40–80 µS) drives COMP to regulate peak inductor current, while internal high-side PMOS (266 mΩ max) and low-side NMOS (206 mΩ max) enable synchronous rectification without external diodes.
It features integrated current sensing via high-side RDS(ON), 1.25V internal reference (1.96–2.03V), and dual current limits: +2.4–4.5A high-side and –0.6A low-side. Thermal shutdown activates at 160°C with 15°C hysteresis, and UVLO disables switching below VCC = 1.95V.
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 rails without pre-regulation. |
| Output Current | Guaranteed 2A continuous - sufficient for FPGA I/O banks or DSP cores with margin. |
| Output Voltage Range | Adjustable 0.8V to VIN - enables precise core voltage setting down to sub-1V logic domains. |
| Switching Frequency | 0.8–1.1 MHz - allows compact 2µH inductors and 10µF ceramic input/output capacitors. |
| Total Output Error | <1% over load, line, and temperature (–40°C to +85°C) - ensures stable regulation across industrial operating conditions. |
| Efficiency | Up to 94% - minimizes thermal load in space-constrained embedded systems. |
| Package | 8-pin SO (SOIC) - standard footprint with 1.27mm pitch, compatible with automated assembly. |
Pinout & Package
MAX1951ESA+ is housed in an 8-pin SO (Small Outline) package with exposed pad not present; thermal resistance θJA = 82°C/W (JEDEC 4-layer board). Pin functions are validated per Maxim's official pin description table and functional diagram.
| 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 independently of LX switching noise. |
| REF (Pin 2) | Reference bypass node | Bypassed with 0.1µF capacitor to GND; stabilizes 2V internal bandgap reference used by error amplifier. |
| GND (Pin 3) | Signal ground reference | Separate from PGND; connects only to signal-side capacitors and feedback network to avoid noise coupling. |
| FB (Pin 4) | Feedback input | Connects to output via external resistor divider to set 0.8V–VIN output; internal 0.783–0.807V regulation threshold enables ±1% accuracy. |
| COMP (Pin 5) | Error amplifier output | Drives external RC compensation network; pulled below 0.17V to enter shutdown mode with high-impedance LX. |
| PGND (Pin 6) | Power ground return | Internally connected to GND but must be routed separately on PCB; carries high-frequency inductor return current to minimize EMI. |
| LX (Pin 7) | Switch node | Connects directly to inductor; contains internal PMOS high-side and NMOS low-side switches with 266mΩ/206mΩ RDS(ON). |
| IN (Pin 8) | Main power input | Accepts 2.6–5.5V; requires ≥10µF ceramic capacitor to PGND and 10Ω series resistor to VCC for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Eliminates external Schottky diode, improving efficiency by ~5% and reducing BOM count and board area. |
| Digital soft-start | Prevents inrush current during startup by ramping REF and FB voltages, enabling reliable cold-boot in battery-powered systems. |
| Thermal-overload protection | Shuts down at 160°C junction temperature and auto-restarts after 15°C cooldown, preventing permanent damage during sustained overload. |
| Current-limit protection | High-side limit (2.4–4.5A) prevents MOSFET failure; low-side limit (–0.6A) blocks reverse current into LX during light-load discontinuous conduction. |
| All-ceramic design support | Enables full use of low-ESR/low-ESL ceramic capacitors on input and output, eliminating electrolytic parts and extending lifetime. |
Applications
| ASIC/DSP Core Supply | Set-Top Box Power |
|---|---|
Use Scenario: Providing tightly regulated 1.2V core voltage to a multi-core DSP in a consumer media processor. IC Role / Device Role / Timing Role: Primary step-down regulator generating clean, low-noise core rail with fast transient response to dynamic CPU load changes. Use Value: 1% output accuracy and 1MHz switching ensure stable operation under 0–2A load steps, minimizing voltage droop during burst processing. | Use Scenario: Generating 3.3V I/O supply for HDMI interface and memory subsystem in a cable set-top box. IC Role / Device Role / Timing Role: Post-regulator converting 5V main rail to precise 3.3V, synchronized to system clock domain for noise-sensitive video paths. Use Value: Synchronous architecture and ceramic-capacitor compatibility reduce output ripple to <15mVpp, meeting HDMI compliance requirements. |
| Cellular Base Station RFIC | Industrial Networking PHY |
Use Scenario: Delivering 1.8V bias to RF transceiver ICs in small-cell LTE base station radio modules. IC Role / Device Role / Timing Role: High-efficiency point-of-load regulator placed near RFIC to minimize IR drop and EMI coupling into analog front-end. Use Value: 94% peak efficiency and SO-8 thermal profile allow operation at 70°C ambient without heatsink, saving board space in dense RF layouts. | Use Scenario: Powering 2.5V PHY layer in Gigabit Ethernet switch ASIC within industrial temperature-rated networking equipment. IC Role / Device Role / Timing Role: Robust DC-DC converter with thermal shutdown and UVLO ensuring uninterrupted link operation during brownouts or thermal stress. Use Value: –40°C to +85°C guaranteed operation and 1% regulation tolerance maintain IEEE 802.3 compliance across extended environmental conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | Fixed 1.8V output; 3MHz switching; 1.8A rated; 2.05–6.0V input; DSBGA-6 package | Not adjustable; higher frequency reduces inductor size but increases EMI filtering complexity | Select when fixed 1.8V output suffices and ultra-compact layout is prioritized over adjustability. |
| RT8059GJ6 | Adjustable 0.6–5.5V output; 1.5A rated; 2.5–5.5V input; SOT-23-6 package; no internal compensation | Lower current rating; requires external compensation components; smaller package limits thermal performance | Select for cost-sensitive, lower-current designs where board space is constrained and thermal load is minimal. |
Compared with TPS62231DRYR and RT8059GJ6, the MAX1951ESA+ uniquely combines 2A output capability, 0.8V–VIN adjustability, integrated compensation, and SO-8 thermal robustness-making it optimal for industrial and telecom applications demanding reliability and flexibility.
Availability
MAX1951ESA+ is available at Aetrix Electronics and suitable for FPGA core supplies, cellular base station RFIC biasing, industrial Ethernet PHY powering, and set-top box I/O regulation requiring stable component supply across extended temperature ranges.
Supply support for MAX1951ESA+ 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, communications, and computing markets.
The MAX1951ESA+ belongs to Maxim's high-efficiency synchronous buck regulator product line, engineered specifically for space-constrained, thermally demanding post-regulation tasks in portable and infrastructure equipment.
FAQ
What is the maximum guaranteed output current for MAX1951ESA+ across its full operating temperature range?
The MAX1951ESA+ guarantees 2A continuous output current over its full –40°C to +85°C operating temperature range, as confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables. This rating accounts for thermal derating in the SO-8 package and is validated under worst-case input voltage (2.6V) and output voltage (0.8V) conditions with proper PCB copper area and airflow.
Does MAX1951ESA+ require external compensation components, and if so, what are the recommended values for a 1.5V/1.5A application?
Yes, MAX1951ESA+ requires external RC compensation on the COMP pin. For a 1.5V/1.5A application with 10µF output capacitance, Maxim recommends R1 = 51.1kΩ (1%) and C2 = 220pF (10%), calculated using current-mode loop stability criteria and verified in the Design Procedure section. These values ensure phase margin >45° and unity-gain frequency at 200kHz.
Can MAX1951ESA+ operate with ceramic capacitors only on both input and output, and what are the minimum values?
Yes, MAX1951ESA+ is explicitly designed for all-ceramic operation. The datasheet specifies a minimum 10µF ceramic input capacitor and 10µF ceramic output capacitor for stable 1.5A operation. Lower values may be used with careful loop compensation, but 10µF is the validated baseline for ripple suppression and transient response across the full load range.
What protection features are integrated into MAX1951ESA+, and how do they behave during fault conditions?
MAX1951ESA+ integrates short-circuit protection via pulse-skip mode (limiting current to ~3A typ during output shorts), thermal shutdown at 160°C with 15°C hysteresis, input undervoltage lockout (UVLO) below 1.95V, and dual current limits (+2.4–4.5A high-side, –0.6A low-side). During faults, it enters safe high-impedance state with LX floating and REF shorted to GND.
Is MAX1951ESA+ pin-compatible with MAX1952ESA+, and what design changes are needed when substituting between them?
No, MAX1951ESA+ and MAX1952ESA+ are not pin-compatible replacements. While both use the same 8-pin SO package and share identical pinout, the MAX1952ESA+ has internal 1.8V feedback resistors connecting FB to REF, whereas the MAX1951ESA+ requires external resistors for adjustable output. Substituting requires removing external FB resistors and verifying output voltage accuracy and loop stability.
MAX1951ESA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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+ FAQ
1.How can I place an order for MAX1951ESA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1951ESA+ 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+ reliable?
The price and inventory of MAX1951ESA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1951ESA+ is usually 5 days.
3.What payment methods are accepted for MAX1951ESA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1951ESA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1951ESA+?
MAX1951ESA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1951ESA+ 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+?
For technical support, including MAX1951ESA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1951ESA+ requirements.
6.How does Aetrix verify that MAX1951ESA+ is sourced from the original manufacturer or authorized distributors?
All MAX1951ESA+ 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+ meets industry standards.
7.What is the process for return or replacement of MAX1951ESA+?
All MAX1951ESA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1951ESA+, 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+ part is unused and in its original packaging.
Return procedure for MAX1951ESA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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