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Analog Devices Inc./Maxim Integrated MAX1928EUB18+T
- Part No.:
- MAX1928EUB18+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX1928EUB18+T.pdf
- Description:
- IC REG BUCK 1.8V 800MA 10UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:2,604
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Product details
Overview
MAX1928EUB18+T from Maxim Integrated is a 1.8V fixed-output, 800mA synchronous step-down DC-DC converter optimized for low-voltage microprocessor core power in space-constrained portable equipment. It operates from 2.6V to 5.5V input, delivers 1.8V ±1.5% output accuracy at up to 800mA, and achieves 1MHz fixed-frequency PWM switching with 140µA quiescent current in pulse-skipping mode. Its 10-pin µMAX package supports high-efficiency operation in WCDMA handsets and DSP core supplies.
For engineers reviewing the MAX1928EUB18+T datasheet, MAX1928EUB18+T pinout, MAX1928EUB18+T application, or MAX1928EUB18+T equivalent, key selection criteria include guaranteed 800mA output at 1.8V, 100% duty-cycle capability (340mV dropout at full load), integrated P/N-channel MOSFETs eliminating external diodes, POK output with 20ms delay, and selectable forced-PWM mode for RF-sensitive designs.
Technical Context
The MAX1928EUB18+T implements a current-mode, fixed-frequency (1MHz) PWM controller with pulse-frequency modulation (PFM) light-load optimization. Its internal architecture integrates a 1.25V reference, error amplifier with 250µS transconductance, and dual-MOSFET power stage (P-channel on-resistance ≤0.5Ω at 2.6V, N-channel ≤0.35Ω).
It features synchronous rectification, internal soft-start, undervoltage lockout (2.15–2.55V), and a dedicated open-drain POK output that asserts after VFB exceeds 90% of 1.8V for 20ms. The device supports both automatic PFM/PWM transition (at ~130mA load threshold) and forced-PWM mode via the PWM pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8V ±1.5% (1.764V to 1.836V) - ensures stable DSP/core rail without external feedback resistors. |
| Max Output Current | 800mA continuous - sufficient for low-power microprocessor cores and baseband ICs in handheld devices. |
| Input Voltage Range | 2.6V to 5.5V - compatible with single-cell Li-ion (3.0–4.2V), Li-polymer, and regulated 3.3V/5V rails. |
| Switching Frequency | 1MHz (±15%) - enables use of compact 4.7µH inductors and low-ESR ceramic capacitors. |
| Quiescent Current | 140µA (typ) in PFM mode - extends battery life in standby/sleep states of portable electronics. |
| Dropout Voltage | 340mV at 800mA - allows regulation down to VIN = 2.14V, critical for deep discharge battery operation. |
| POK Threshold | 1.566V to 1.674V (87–93% of 1.8V) - provides precise power-good assertion with 20ms delay after regulation. |
Pinout & Package
MAX1928EUB18+T is housed in a 10-pin µMAX package (3.0mm × 3.0mm × 0.8mm, 0.5mm pitch), thermally enhanced with exposed PGND pad. Pin 1 is PWM; Pin 10 is POK. The package supports reflow soldering per JEDEC J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWM (Pin 1) | Forced-PWM control input | Drive to BATT to enforce fixed-frequency PWM at all loads; drive to GND for automatic PFM/PWM transition. |
| GND (Pin 2) | Analog ground reference | Reference node for REF, FB, COMP; must be star-connected to PGND near device to minimize noise coupling. |
| REF (Pin 3) | Internal 1.25V reference output | Bypassed with 0.1µF capacitor to GND; supplies bias for error amplifier and POK comparator. |
| FB (Pin 4) | Feedback sense input | Internally referenced to 1.8V; connect directly to VOUT for fixed 1.8V operation (no external divider required). |
| COMP (Pin 5) | Compensation network connection | External RC network (e.g., 18kΩ + 1200pF) sets loop stability and transient response for 4.7µH inductor. |
| SHDN (Pin 6) | Shutdown enable input | Logic-high enables regulation; logic-low disables all circuitry, reducing supply current to 0.1µA (typ). |
| PGND (Pin 7) | Power ground return | High-current return path for LX switch and synchronous rectifier; must be low-impedance and tied to thermal pad. |
| LX (Pin 8) | Switch node connection | Connects to inductor; carries high dv/dt switching waveform - requires short, wide trace away from sensitive analog nodes. |
| BATT (Pin 9) | Main input supply | Accepts 2.6–5.5V; requires ≥10µF low-ESR bulk capacitor placed adjacent to pin for ripple suppression. |
| POK (Pin 10) | Open-drain power-good output | Asserts high-impedance when VFB > 1.566V for ≥20ms; pulled low during shutdown or undervoltage. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated N-channel MOSFET eliminates external Schottky diode, improving efficiency by ~5–8% at medium loads. |
| 100% duty-cycle operation | Enables dropout as low as 340mV at 800mA, extending usable battery range into deep discharge (<2.2V VIN). |
| Selectably forced PWM mode | Eliminates variable-frequency PFM noise, enabling use in RF sections (e.g., WCDMA transceivers) without spectral interference. |
| Internal soft-start | Prevents inrush current and output overshoot during startup; typical ramp time ~1ms with standard 10µF output cap. |
| Power-OK (POK) monitor | Provides system-level power sequencing and reset control with accurate 20ms delay after regulation is achieved. |
Applications
| WCDMA Handsets | DSP Core Power |
|---|---|
Use Scenario: Primary core voltage supply for baseband processors in 3G mobile handsets operating from single-cell Li-ion batteries. IC Role / Device Role / Timing Role: Step-down regulator delivering stable 1.8V at up to 800mA with fast transient response to burst-mode processing loads. Use Value: 140µA quiescent current extends standby time; 1MHz switching minimizes EMI near cellular RF bands; POK enables clean processor reset sequencing. |
Use Scenario: Dedicated power rail for low-voltage DSP cores requiring tight regulation and low noise in portable audio/video devices. IC Role / Device Role / Timing Role: Fixed 1.8V buck converter with forced-PWM capability to suppress switching noise during analog signal acquisition. Use Value: Synchronous rectification achieves >90% efficiency at 500mA; 1.8V ±1.5% accuracy maintains core timing margins; µMAX footprint saves PCB area. |
| PDA / Palmtop Systems | Battery-Powered Instrumentation |
Use Scenario: Main SoC core supply in handheld computing devices with dynamic load profiles and aggressive power management. IC Role / Device Role / Timing Role: High-efficiency DC-DC converter supporting both active (PWM) and sleep (PFM) modes to optimize energy per operation. Use Value: Automatic PFM/PWM transition reduces no-load current to 140µA; 10-pin µMAX package fits dense layouts; SHDN pin enables full system power gating. |
Use Scenario: Precision analog subsystem supply in portable test equipment where low-noise, stable voltage is critical for ADC/DAC performance. IC Role / Device Role / Timing Role: Low-ripple 1.8V source with selectable forced-PWM to avoid beat frequencies with sampling clocks. Use Value: 1MHz fixed frequency avoids interference with common 1–10MHz sampling rates; POK output validates rail stability before measurement cycles begin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down DC-DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | 1.8V fixed, 800mA, 3MHz switching, 17µA IQ (PFM), 2.05–6.5V input - higher frequency, lower IQ, but no POK output. | Lacks power-good signaling; better suited for ultra-low-IQ battery monitoring vs. processor core sequencing. | Choose TPS62231DRYR only if POK is unnecessary and 3MHz operation simplifies filtering in space-constrained designs. |
| RT8059NGSP | 1.8V fixed, 800mA, 1.5MHz, 22µA IQ (PFM), 2.5–5.5V input - includes POK, but no forced-PWM pin; uses external compensation. | Missing PWM control pin limits noise control in RF-sensitive layouts; requires additional compensation components. | Choose RT8059NGSP only if forced-PWM is not required and board space permits external RC network placement. |
Compared with TPS62231DRYR and RT8059NGSP, MAX1928EUB18+T uniquely combines POK output, selectable forced-PWM, and 100% duty-cycle operation in a single 10-pin µMAX package - making it optimal for battery-powered microprocessor core supplies requiring robust power sequencing and RF coexistence.
Availability
MAX1928EUB18+T is available at Aetrix Electronics and suitable for WCDMA handset design, DSP core power delivery, and portable instrumentation requiring stable component supply with full production traceability and long-term lifecycle support.
Supply support for MAX1928EUB18+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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.
The MAX1928EUB18+T belongs to Maxim's low-voltage, high-efficiency DC-DC converter product line, designed specifically for powering microprocessor cores and DSPs in battery-operated portable electronics with stringent size and efficiency requirements.
FAQ
What is the guaranteed output voltage accuracy of the MAX1928EUB18+T over temperature and line conditions?
The MAX1928EUB18+T guarantees output voltage accuracy of ±1.5% over the full operating temperature range (–40°C to +85°C) and input voltage range (2.6V to 5.5V). This corresponds to a 1.8V nominal output spanning 1.764V to 1.836V, verified by FB voltage accuracy specifications in the datasheet's Electrical Characteristics table under –40°C to +85°C conditions.
Does the MAX1928EUB18+T require external compensation components, and if so, what are the recommended values?
Yes, the MAX1928EUB18+T requires external compensation via a resistor (RC) and capacitor (CC) from COMP to GND. For the standard 1.8V application with a 4.7µH inductor, the recommended values are RC = 18kΩ and CC = 1200pF, as shown in Figure 3 of the MAX1928 datasheet. These values ensure stable operation with adequate phase margin across load and temperature variations.
Can the MAX1928EUB18+T operate with an input voltage below 2.6V, and what happens near the UVLO threshold?
No - the MAX1928EUB18+T has a guaranteed operating input range of 2.6V to 5.5V. Its undervoltage lockout (UVLO) activates with 35mV hysteresis between 2.15V (falling) and 2.55V (rising). Below 2.15V, the device shuts down completely; above 2.55V, it resumes normal operation after soft-start. Operation between 2.15V and 2.6V is undefined and not characterized.
How does the POK output of the MAX1928EUB18+T behave during startup and shutdown?
During startup, POK remains low-impedance until the soft-start completes and VFB exceeds 90% of 1.8V (i.e., >1.62V) for 20ms, then transitions to high-impedance. During shutdown (SHDN = GND), POK immediately goes low-impedance. In dropout or undervoltage conditions, POK also pulls low, providing reliable fault indication independent of regulator enable state.
Is the MAX1928EUB18+T pin-compatible with other variants in the MAX1927/MAX1928 family, such as the MAX1928EUB25+T?
Yes - all MAX1928 variants (including MAX1928EUB15+T, MAX1928EUB18+T, and MAX1928EUB25+T) share identical 10-pin µMAX packaging and pinout. They differ only in factory-trimmed FB reference voltage (1.5V, 1.8V, or 2.5V), allowing direct PCB substitution when output voltage requirements change - provided input/output capacitors and inductor are validated for the new voltage level.
MAX1928EUB18+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:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.6V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.8V
- Voltage - Output (Max):
- -
- Current - Output:
- 800mA
- Frequency - Switching:
- 800kHz ~ 1.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-uMAX/uSOP
MAX1928EUB18+T FAQ
1.How can I place an order for MAX1928EUB18+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1928EUB18+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 MAX1928EUB18+T reliable?
The price and inventory of MAX1928EUB18+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1928EUB18+T is usually 5 days.
3.What payment methods are accepted for MAX1928EUB18+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1928EUB18+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1928EUB18+T?
MAX1928EUB18+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1928EUB18+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 MAX1928EUB18+T?
For technical support, including MAX1928EUB18+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1928EUB18+T requirements.
6.How does Aetrix verify that MAX1928EUB18+T is sourced from the original manufacturer or authorized distributors?
All MAX1928EUB18+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 MAX1928EUB18+T meets industry standards.
7.What is the process for return or replacement of MAX1928EUB18+T?
All MAX1928EUB18+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1928EUB18+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 MAX1928EUB18+T part is unused and in its original packaging.
Return procedure for MAX1928EUB18+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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