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Analog Devices Inc./Maxim Integrated MAX8505EEE+T
- Part No.:
- MAX8505EEE+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
MAX8505EEE+T.pdf
- Description:
- IC REG BUCK ADJ 3A 16QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,091
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Product details
Overview
MAX8505EEE+T from Maxim Integrated is a synchronous step-down DC-DC regulator with integrated high- and low-side N-channel MOSFETs, delivering up to 3A output current at 1MHz or 500kHz switching frequency, ±1% output voltage accuracy (0.8V to 0.85×VIN), and open-drain Power-OK monitoring - designed for powering microprocessor cores and I/O rails in space-constrained server and telecom systems.
For engineers reviewing the MAX8505EEE+T datasheet, MAX8505EEE+T pinout, MAX8505EEE+T application, or MAX8505EEE+T equivalent, key selection considerations include adjustable soft-start via external capacitor, dual-frequency selection (CTL pin), in-regulation startup behavior, thermal shutdown at +170°C, and compatibility with ceramic output capacitors down to 47µF.
Technical Context
The MAX8505EEE+T employs current-mode PWM control with slope compensation to stabilize the inner loop and prevent subharmonic oscillation at duty cycles >50%. Its transconductance error amplifier (60–160 µS) drives the COMP pin, where an external RC network sets loop bandwidth and phase margin.
It integrates dual current-limit protection: high-side peak limit (~6A typ) and low-side valley limit (~3.8A typ), plus thermal shutdown with 20°C hysteresis and UVLO on VCC (2.2V–2.55V thresholds). The POK output monitors FB within ±12% of 0.8V reference and asserts low after 25–100 µs fault delay.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3A continuous - supports ASIC/microprocessor core loads without external current boosting |
| Input Voltage Range | 2.25V to 5.5V - enables operation from single Li-ion or 3.3V/5V rails with bias supply |
| Output Voltage Range | 0.8V to 0.85×VIN - adjustable via resistive divider on FB pin; supports 1.2V core and 0.8V I/O rails |
| Switching Frequency | 500kHz or 1MHz - selected by CTL pin voltage; higher frequency reduces inductor size (1µH typical) |
| Output Accuracy | ±1% over line, load, and temperature - ensures stable voltage under dynamic CPU load transitions |
| Power-OK Threshold | FB = 0.8V ±12% - provides reliable system power-good signaling for sequenced enable logic |
| Thermal Shutdown | +170°C with 20°C hysteresis - protects against sustained overload or poor PCB thermal design |
Pinout & Package
MAX8505EEE+T is housed in a 16-pin QSOP package (4.9mm × 6mm footprint) with exposed thermal pad (not electrically connected). Pin assignments are validated per Maxim's official pin description and functional diagram.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1,3,14,16 LX | Inductor switch node | Connects all four pins together to external 1µH inductor; carries high di/dt switching current; requires local 3300pF ceramic to PGND |
| 2,4 IN | Main input power rail | Accepts 2.25–5.5V; must be bypassed with two 22µF ceramics to GND; pins tied externally |
| 5 BST | Bootstrap supply for high-side gate driver | Connected via 0.1µF ceramic to LX; charged through external Schottky diode from IN |
| 6 VCC | Low-side gate drive and internal circuit supply | Decoupled with 10Ω resistor + 0.1µF ceramic to GND; UVLO threshold 2.2–2.55V |
| 7 POK | Open-drain power-good indicator | Pulls low when FB deviates >±12% from 0.8V; requires external pull-up to ≤5.5V |
| 8 CTL | Frequency select / enable control | GND = shutdown; 0.55–0.7×VCC = 500kHz; >0.8×VCC = 1MHz |
| 9 COMP | Loop compensation node | Connects external RC network to GND; pulled to GND during shutdown/UVLO/thermal fault |
| 10 FB | Voltage feedback input | Regulates to 0.8V; sets output via resistive divider; input bias <0.1µA minimizes divider error |
| 11 REF | Soft-start timing reference | Capacitor here (0.01–1µF) sets ramp time (32ms/µF); pulled to 0V in shutdown |
| 12 GND | Analog ground reference | Reference for REF, FB, COMP; separate from PGND to reduce noise coupling |
| 13,15 PGND | Power ground return | High-current return path for LX and IN; connect to GND at single point near IC |
Key Features
| Feature | Design Value |
|---|---|
| Integrated dual MOSFETs | Eliminates need for external high- and low-side switches; reduces BOM count and layout area |
| In-regulation soft-start | Prevents output voltage dip during power-on when downstream devices draw sudden load current |
| Ceramic-capacitor compatible | Stable with 47µF ceramic output cap - avoids bulk electrolytics and improves transient response |
| Current-mode control | Simplifies loop compensation; enables fast transient response and inherent cycle-by-cycle current limiting |
| Adjustable switching frequency | Enables optimization between efficiency (500kHz) and component size (1MHz) without changing layout |
| Robust protection suite | Includes overcurrent (high/low side), thermal shutdown, UVLO, and short-circuit recovery - no external fault management needed |
Applications
| Microprocessor Core Supply | FPGA I/O Rail |
|---|---|
Use Scenario: Powers ARM Cortex-A series or Intel Atom processor cores requiring tightly regulated 1.0–1.2V at up to 3A with fast load-step response. IC Role / Device Role / Timing Role: Primary buck converter delivering core voltage; regulates via FB pin; POK signals host controller when voltage stabilizes. Use Value: ±1% accuracy and in-regulation soft-start prevent core reset during boot; 1MHz operation allows compact 1µH inductor placement near CPU die. |
Use Scenario: Supplies configurable FPGA I/O banks (e.g., Xilinx Artix-7) needing 0.8–1.8V with low noise and ±12% POK window. IC Role / Device Role / Timing Role: Secondary buck regulator; CTL pin set to 500kHz for higher light-load efficiency; FB divider sets precise I/O voltage. Use Value: Dual current-limit architecture handles FPGA configuration surge currents without latch-off; ceramic output cap ensures clean I/O signaling. |
| Server Memory DIMM Regulator | Telecom Line Card DC-DC Stage |
Use Scenario: Generates DDR4 memory VDDQ (1.2V) on enterprise server DIMMs with strict ripple (<30mV) and thermal constraints. IC Role / Device Role / Timing Role: Point-of-load regulator; uses 1MHz mode to minimize inductor size in dense DIMM layout; POK enables memory controller initialization handshake. Use Value: 3A rating supports dual-rank DDR4 modules; thermal shutdown at +170°C prevents failure in confined airflow environments. |
Use Scenario: Provides intermediate 3.3V rail from 48V backplane in telecom line cards, feeding downstream POL converters. IC Role / Device Role / Timing Role: Primary intermediate buck stage; operates at 500kHz for optimal efficiency across partial-load conditions; IN pins accept wide-input range with bias assist. Use Value: Input range down to 2.25V with bias enables brownout ride-through; robust ESD-rated QSOP package withstands board-level handling in telecom assembly. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54332DR | 3A, 3.5–28V input, fixed 500kHz, ±2% accuracy, no integrated POK | Lacks power-good output and in-regulation soft-start; requires external monitoring circuitry | Choose when input voltage exceeds 5.5V and POK is not required; verify loop stability with external compensation |
| RT8205AZSP | 3A, 4.5–24V input, 600kHz, ±1.5% accuracy, open-drain POK, no dual-frequency option | Fixed 600kHz only; wider input range but higher minimum VIN limits use in low-voltage systems | Prefer for cost-sensitive industrial designs where 1MHz flexibility is unnecessary and input ≥4.5V is guaranteed |
Compared with TPS54332DR and RT8205AZSP, the MAX8505EEE+T uniquely combines 2.25V minimum input, dual-frequency selection, ±1% accuracy, and integrated in-regulation soft-start - making it optimal for low-voltage, high-density computing and telecom POL applications where startup behavior and precision are critical.
Availability
MAX8505EEE+T is available at Aetrix Electronics and suitable for server power delivery, FPGA power management, and telecom line card designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX8505EEE+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 demanding industrial, computing, and communications applications.
The MAX8505 belongs to Maxim's high-efficiency synchronous buck regulator product line, engineered for compact, high-current point-of-load conversion in space-constrained digital systems with stringent accuracy and reliability requirements.
FAQ
What input voltage range does the MAX8505EEE+T support, and how does the bias supply affect it?
The MAX8505EEE+T operates from 2.6V to 5.5V on its main IN pins. With an active 2.6V–5.5V bias supply applied to VCC, the effective input voltage range extends down to 2.25V - enabling use with single-cell Li-ion or low-dropout pre-regulated rails. This extended range is confirmed in Absolute Maximum Ratings and Electrical Characteristics tables under "IN Voltage Range" with VCC present.
How is output voltage set on the MAX8505EEE+T, and what is the reference voltage tolerance?
The MAX8505EEE+T output voltage is set using an external resistive divider from VOUT to the FB pin, which regulates to a nominal 0.800V reference. Per Electrical Characteristics, VFB is guaranteed 0.791V to 0.808V over –40°C to +85°C, contributing directly to the overall ±1% output accuracy specification. The MAX8505EEE+T datasheet provides the exact formula R2 = R3 × (VOUT/VREF – 1) for divider design.
Does the MAX8505EEE+T require external MOSFETs, and what is its maximum output current capability?
No, the MAX8505EEE+T integrates both high-side and low-side N-channel MOSFETs - eliminating the need for external switches. It delivers up to 3A continuous output current, verified under conditions VIN = VCC = 3.3V, VOUT = 1.2V, L = 1µH/5.9mΩ, and TA = –40°C to +85°C. Peak current capability is limited by internal current-sense thresholds (6A high-side, 3.8A low-side).
What protection features does the MAX8505EEE+T include, and how do they behave during fault conditions?
The MAX8505EEE+T includes current-limit (high- and low-side), short-circuit, thermal-overload (trip at +170°C, restart at +150°C), and VCC undervoltage lockout (2.2V–2.55V). During overload, it enters hiccup mode: switching halts until thermal recovery, then reinitiates soft-start. Short-circuit current is limited to ~4.5A (typ) at VIN = 5V, preventing destructive current escalation.
Can the MAX8505EEE+T operate at both 500kHz and 1MHz, and how is frequency selected?
Yes, the MAX8505EEE+T supports both 500kHz and 1MHz switching frequencies. Frequency is selected via the CTL pin: grounding CTL disables the device; applying 0.55–0.7×VCC selects 500kHz; applying >0.8×VCC selects 1MHz. Electrical Characteristics confirm typical frequencies of 0.44–0.56MHz (500kHz mode) and 0.95–1.05MHz (1MHz mode) across input voltage and temperature.
MAX8505EEE+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SSOP (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):
- 4.68V
- Current - Output:
- 3A
- Frequency - Switching:
- 500kHz, 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QSOP
MAX8505EEE+T FAQ
1.How can I place an order for MAX8505EEE+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX8505EEE+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 MAX8505EEE+T reliable?
The price and inventory of MAX8505EEE+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX8505EEE+T is usually 5 days.
3.What payment methods are accepted for MAX8505EEE+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX8505EEE+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX8505EEE+T?
MAX8505EEE+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX8505EEE+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 MAX8505EEE+T?
For technical support, including MAX8505EEE+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX8505EEE+T requirements.
6.How does Aetrix verify that MAX8505EEE+T is sourced from the original manufacturer or authorized distributors?
All MAX8505EEE+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 MAX8505EEE+T meets industry standards.
7.What is the process for return or replacement of MAX8505EEE+T?
All MAX8505EEE+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX8505EEE+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 MAX8505EEE+T part is unused and in its original packaging.
Return procedure for MAX8505EEE+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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