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Analog Devices Inc./Maxim Integrated MAX858ESA+
- Part No.:
- MAX858ESA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX858ESA+.pdf
- Description:
- IC REG BOOST PROG 125MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,849
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Product details
Overview
The MAX858ESA+ from Maxim Integrated is a high-efficiency, CMOS step-up DC-DC switching regulator optimized for low-input-voltage battery-powered systems. It accepts input voltages from 0.8V to VOUT, delivers a pin-selectable 3.3V or 5V output, features 125mA peak inductor current limiting, 25µA quiescent current, and operates in an 8-pin SO package rated for –40°C to +85°C. It is used in glucose meters and 2–3-cell portable medical instrumentation.
For engineers reviewing the MAX858ESA+ datasheet, MAX858ESA+ pinout, MAX858ESA+ application, or MAX858ESA+ equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative options, and supply-chain support for volume procurement and BOM continuity.
Technical Context
The MAX858ESA+ implements a minimum-off-time, current-limited pulse-frequency modulation (PFM) control scheme with no oscillator-switching frequency varies with load and input voltage up to 500kHz. Its internal N-channel sense-FET has ~4Ω on-resistance and starts reliably at 0.8V typical input.
It integrates a precision 1.25V reference (±1.5% over temperature), low-battery detection (LBI/LBO) with 25mV hysteresis, and bootstrap power derived from the OUT pin. The 3/5 pin selects fixed 3.3V (tied to OUT) or 5V (tied to GND) output without external resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 0.8V to VOUT; enables operation down to single-cell alkaline or NiMH depletion (≈0.9V under load). |
| Output Voltage | Pin-selectable 3.3V or 5V; eliminates need for external feedback resistors in fixed-output designs. |
| Peak Switch Current Limit | 125mA ±25mA; constrains inductor size and ESR requirements while limiting thermal stress. |
| Quiescent Supply Current | 25µA in active mode; extends runtime in intermittently active battery systems like glucose meters. |
| Shutdown Current | 1µA; reduces standby drain to negligible levels during system sleep or power-off states. |
| Reference Voltage Accuracy | ±1.5% over –40°C to +85°C; supports stable ADC biasing or comparator thresholds without calibration. |
| Start-Up Input Voltage | 0.8V typical; allows cold-start from deeply discharged batteries before regulation begins. |
Pinout & Package
MAX858ESA+ is housed in an 8-pin SO (Small Outline) package per JEDEC MS-012, with 1.27mm pitch, body dimensions 4.9 × 6.0 mm, and –40°C to +85°C operating range.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - LX | N-channel MOSFET drain | Switch node connecting to inductor; requires short, low-inductance PCB trace to minimize ringing and EMI. |
| 2 - GND | Power ground | Primary return path for switch current and IC bias; must connect directly to solid ground plane. |
| 3 - OUT | Regulator output / bootstrap supply | Delivers regulated 3.3V/5V; also powers internal circuitry-critical for start-up and stability. |
| 4 - LBI | Low-battery detector input | Analog input referenced to 1.25V; threshold set externally; <100nA bias enables high-impedance divider networks. |
| 5 - LBO | Low-battery open-drain output | Sinks current when LBI < 1.25V; requires external pull-up (e.g., to OUT) for CMOS-level signaling. |
| 6 - REF | 1.25V precision reference output | Stable voltage source for external circuits; supports ≤250µA source / ≤20µA sink; bypass with 0.22µF. |
| 7 - 3/5 | Output voltage select | Tie to GND for 5V output, to OUT for 3.3V output; internally diode-clamped-no external logic needed. |
| 8 - SHDN | Active-low shutdown control | Pulls entire IC into 1µA state; open-drain compatible up to 7V; must not float-tie high via resistor if unused. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low quiescent current | 25µA active / 1µA shutdown enables >1-year battery life in low-duty-cycle medical devices. |
| Fixed-output pin selection | 3/5 pin eliminates external feedback resistors-reduces BOM count and layout area in cost-sensitive designs. |
| Integrated low-battery monitor | LBI/LBO pair provides system-level battery health signaling without adding comparators or references. |
| Bootstrap-powered operation | Derives bias from OUT pin-permits input voltage to sag below VOUT after start-up (down to 0.8V). |
| 125mA peak-current limit | Enables use of compact, low-cost 47µH inductors (e.g., Sumida CDR74B-470) with minimal saturation risk. |
Applications
| Glucose Meters | Portable Data Collectors |
|---|---|
|
Use Scenario: Handheld point-of-care device measuring blood glucose with LCD display and microcontroller, powered by two AAA alkaline cells. IC Role / Device Role / Timing Role: Step-up regulator providing stable 3.3V rail for MCU, sensor interface, and display driver from decaying 1.8–3.0V battery input. Use Value: 0.8V start-up and 25µA quiescent current extend usable battery life by ≥30% versus higher-IQ alternatives. |
Use Scenario: Ruggedized barcode scanner used in warehouse logistics, operating on 2-cell NiMH batteries with intermittent wireless transmission. IC Role / Device Role / Timing Role: Generates 5V for RF transceiver and imaging sensor from 2.0–2.8V input; shutdown disables during idle periods. Use Value: 1µA shutdown current minimizes self-discharge during multi-hour standby-critical for daily-use field equipment. |
| Palmtop Computers | Medical Instrumentation |
|
Use Scenario: Legacy palmtop PDA with monochrome LCD, flash memory, and serial interface, powered by three AAA batteries. IC Role / Device Role / Timing Role: Supplies regulated 3.3V to CPU and peripherals while supporting dynamic load steps up to 100mA during screen refresh. Use Value: PFM architecture delivers >85% efficiency across 1–100mA loads-maintaining low thermal rise in sealed plastic enclosures. |
Use Scenario: Portable ECG monitor with analog front-end, ADC, and Bluetooth LE module, requiring precise 3.3V for signal integrity. IC Role / Device Role / Timing Role: Provides low-noise, well-regulated 3.3V rail; REF pin supplies clean 1.25V reference to ADC and comparator circuits. Use Value: ±1.5% reference tolerance over temperature ensures consistent ADC full-scale accuracy without recalibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up DC-DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61200DRCR | Adjustable output (1.8–5.5V); 1.2A switch current; 2.5µA IQ; requires external feedback resistors. | Better suited for higher-current, programmable-output systems; lacks integrated LBI/LBO. | Select when adjustable output and higher load capability (>100mA) are required; redesign needed for feedback and monitoring. |
| LT1944ES5#TRMPBF | Fixed 3.3V output only; 600mA switch current; 20µA IQ; 5-pin SOT-23 package; no LBI/LBO or REF pin. | Smaller footprint but no battery monitoring or reference output-requires external components for those functions. | Choose for space-constrained 3.3V-only applications where LBI/LBO and REF are handled elsewhere in the system. |
Compared with MAX858ESA+, TPS61200DRCR offers higher output current and lower quiescent current but requires external feedback and lacks integrated battery monitoring; LT1944ES5#TRMPBF saves board area but removes critical system-monitoring features and fixed dual-output flexibility.
Availability
MAX858ESA+ is available at Aetrix Electronics and suitable for glucose meters, portable data collectors, and medical instrumentation requiring stable component supply across extended production lifecycles.
Supply support for MAX858ESA+ 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, medical, and consumer applications.
The MAX856–MAX859 family was engineered specifically for ultra-low-power, small-footprint boost conversion in battery-critical portable medical and handheld devices-prioritizing start-up voltage, quiescent current, and integrated monitoring.
FAQ
What is the minimum input voltage required to start up the MAX858ESA+?
The MAX858ESA+ has a typical start-up input voltage of 0.8V, enabling reliable operation from deeply discharged single-cell alkaline or NiMH batteries. This value is confirmed in the Electrical Characteristics table under "Minimum Start-Up Supply Voltage" and validated in Figure MAX856-07. The MAX858ESA+ achieves this via a low-threshold N-channel sense-FET and bootstrap architecture that draws initial bias from the output capacitor.
How does the 3/5 pin select between 3.3V and 5V output on the MAX858ESA+?
On the MAX858ESA+, the 3/5 pin selects output voltage by logic level: tie to GND for 5V output, tie to OUT for 3.3V output. This is a hardwired configuration-not a dynamic control signal-and is implemented using internal diode clamping. The pin is not intended for toggling during operation; it sets the feedback ratio permanently at power-on. No external resistors are needed for either setting.
Does the MAX858ESA+ include a built-in low-battery detection function?
Yes, the MAX858ESA+ integrates a dedicated low-battery detector with LBI (input) and LBO (open-drain output) pins. When the voltage at LBI falls below the internal 1.25V reference, LBO sinks current to GND. The detection threshold is set externally using a resistor divider on LBI, and hysteresis is 25mV-both confirmed in the Electrical Characteristics table. LBI bias current is <100nA, enabling high-impedance dividers.
What is the purpose of the REF pin on the MAX858ESA+ and what load can it drive?
The REF pin on the MAX858ESA+ provides a precision 1.25V reference with ±1.5% tolerance over –40°C to +85°C. It can source up to 250µA or sink up to 20µA while maintaining accuracy, making it suitable for biasing ADCs, comparators, or sensor signal chains. The datasheet specifies a 0.22µF bypass capacitor to GND when loaded; if unloaded, ≥0.1µF suffices. This reference is internally trimmed and thermally compensated.
Can the MAX858ESA+ operate with an input voltage higher than its selected output voltage?
Yes-the MAX858ESA+ allows input voltage to exceed the selected output voltage (e.g., VIN = 4.2V with 3.3V output). In such cases, the output follows VIN minus the Schottky diode forward drop (VD), effectively acting as a pass-through. However, absolute maximum ratings restrict OUT-to-GND voltage to +7V, so VIN must never exceed 7V. This behavior is explicitly documented in the "Design Procedure" section under "Bootstrapping."
MAX858ESA+ 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-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Programmable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 0.8V
- Voltage - Input (Max):
- 6V
- Voltage - Output (Min/Fixed):
- 3.3V, 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 125mA (Switch)
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX858ESA+ FAQ
1.How can I place an order for MAX858ESA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX858ESA+ 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 MAX858ESA+ reliable?
The price and inventory of MAX858ESA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX858ESA+ is usually 5 days.
3.What payment methods are accepted for MAX858ESA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX858ESA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX858ESA+?
MAX858ESA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX858ESA+ 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 MAX858ESA+?
For technical support, including MAX858ESA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX858ESA+ requirements.
6.How does Aetrix verify that MAX858ESA+ is sourced from the original manufacturer or authorized distributors?
All MAX858ESA+ 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 MAX858ESA+ meets industry standards.
7.What is the process for return or replacement of MAX858ESA+?
All MAX858ESA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX858ESA+, 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 MAX858ESA+ part is unused and in its original packaging.
Return procedure for MAX858ESA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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