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Renesas ISL85412FRTZ
- Part No.:
- ISL85412FRTZ
- Manufacturer:
- Renesas
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
ISL85412FRTZ.pdf
- Description:
- IC REG BUCK ADJ 150MA 8TDFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,218
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Product details
Overview
ISL85412FRTZ from Renesas (formerly Intersil) is a wide-input synchronous buck DC-DC regulator delivering up to 150mA output current with 3.5V–40V input range, integrated high-side/low-side NMOS FETs, and 700kHz fixed switching frequency. It operates in selectable PFM or forced PWM mode and features internal soft-start, power-good flag, and -40°C to +125°C junction temperature rating-used in industrial control power rails and battery-powered instrumentation.
For engineers reviewing the ISL85412FRTZ datasheet, ISL85412FRTZ pinout, ISL85412FRTZ application, or ISL85412FRTZ equivalent, key selection criteria include its wide VIN capability, integrated MOSFETs eliminating external gate drivers, no-compensation design, light-load efficiency optimization via MODE pin control, and TDFN-8 package thermal performance for space-constrained high-voltage systems.
Technical Context
The ISL85412FRTZ implements peak current-mode PWM control with internal slope compensation (450mV/T), 930mV/A current sense transresistance, and a 600mV reference voltage for feedback regulation. Its error amplifier uses internal 150kΩ/54pF compensation, eliminating external components.
Light-load operation switches automatically to PFM when eight consecutive zero-current crossings are detected-enabling >85% efficiency at 10mA load with 12VIN/3.3VOUT. Overcurrent protection triggers at 0.4A peak current, while thermal shutdown activates at 150°C with 20°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 40V - supports direct connection to 24V industrial buses or 36V battery stacks without pre-regulation. |
| Output Current | 150mA continuous - sufficient for powering microcontrollers, sensors, and interface ICs in distributed systems. |
| Switching Frequency | 700kHz nominal - enables compact 10–47µH inductors and reduces output ripple without requiring large LC filters. |
| FET On-Resistance | High-side: 1300mΩ max; low-side: 800mΩ max - defines conduction loss budget and thermal rise under full load. |
| Feedback Reference | 0.599V ±10mV - sets output voltage accuracy via external resistor divider; enables 1.0V to 12V programmable outputs. |
| Soft-Start Time | 2.3ms typical - prevents inrush current into downstream capacitors during power-up sequencing. |
| Power-Good Threshold | ±6% window around regulation - provides reliable system reset signaling with hysteresis to avoid chatter near regulation limits. |
Pinout & Package
ISL85412FRTZ is housed in an 8-lead 3mm×3mm TDFN package with exposed thermal pad (EPAD), optimized for high-power-density PCB layouts and thermal dissipation in industrial environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 MODE | Mode selection logic input | Configures PFM (grounded) or forced PWM (tied to VCC); internal 5MΩ pull-down prevents floating state. |
| 2 BOOT | Bootstrap supply node | Drives high-side NMOS gate; requires 100nF capacitor to PHASE for charge replenishment each cycle. |
| 3 VIN | Main power input | Supplies both power stage and internal LDO; requires ≥10µF ceramic decoupling close to pin. |
| 4 PHASE | Switch node | Connects internal FETs to external inductor; high dv/dt node demanding tight layout and ground vias. |
| 5 EN | Enable control input | Active-high enable with 1.45V threshold; tied to VIN for automatic startup; not compatible with VCC connection. |
| 6 PG | Open-drain power-good output | Pulled low during soft-start, undervoltage, or overtemperature; internal 5MΩ pull-up enables direct MCU monitoring. |
| 7 VCC | Bias LDO output | 5V ±0.5V regulated supply for internal circuitry; decoupled with 1µF ceramic to PGND. |
| 8 FB | Feedback input | Inverting input of error amplifier; connected to resistor divider from VOUT to set output voltage with 0.599V reference. |
| EPAD | Thermal and signal ground | Must be soldered to PCB GND plane with ≥5 vias for thermal conduction and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Wide 3.5V–40V input range | Eliminates need for upstream pre-regulators in 12V/24V/36V industrial and automotive auxiliary power domains. |
| Integrated high-side and low-side NMOS | Reduces BOM count by two discrete MOSFETs and associated gate drivers; simplifies layout and improves reliability. |
| No external compensation required | Internal 150kΩ/54pF RC network enables stable loop response across all output voltages and loads without tuning. |
| Selectable PFM/PWM operation | Enables >90% efficiency at light loads (e.g., 1mA sensor bias) while maintaining tight regulation and low noise in PWM mode. |
| Internal soft-start and power-good | Provides controlled ramp-up and deterministic system reset signaling-critical for FPGA, MCU, and analog subsystem sequencing. |
| Robust protection suite | Includes overcurrent (0.4A), overtemperature (150°C), boot UVLO, and negative current limiting (-0.3A) for field-reliable operation. |
Applications
| Industrial Control Power | Portable Medical Instrumentation |
|---|---|
|
Use Scenario: Powering isolated ADCs, digital I/O modules, and PLC fieldbus interfaces in 24V rail systems. IC Role / Device Role / Timing Role: Primary point-of-load regulator converting unregulated 24V bus to 3.3V/5V for logic and analog subsystems. Use Value: Wide VIN tolerance accommodates brownouts and surges common in factory floor wiring; integrated FETs reduce footprint on dense backplane cards. |
Use Scenario: Supplying low-noise 1.8V/2.5V rails for biosensor front-ends and Bluetooth LE radios in handheld diagnostic devices. IC Role / Device Role / Timing Role: Efficient battery-life-extending regulator operating from single-cell Li-ion (3.0–4.2V) or dual-cell alkaline (1.8–3.2V). Use Value: PFM mode delivers >88% efficiency at 100µA load, extending runtime; small TDFN package fits within compact handheld enclosures. |
| Distributed Cloud Infrastructure | High-Voltage Sensor Signal Conditioning |
|
Use Scenario: Providing auxiliary 12V-to-3.3V conversion for fan controllers, LED indicators, and SMBus interface ICs in server PSUs. IC Role / Device Role / Timing Role: Secondary regulator fed from intermediate 12V distribution rail, supporting hot-swap and telemetry functions. Use Value: 40V absolute max rating ensures survival during 12V rail transients; PG output enables firmware-controlled fault reporting. |
Use Scenario: Biasing precision op-amps and reference buffers in 36V industrial current-loop transmitters (4–20mA). IC Role / Device Role / Timing Role: Isolated auxiliary supply generating clean 5V rail from raw 36V loop supply, rejecting common-mode noise. Use Value: Integrated MOSFETs and internal compensation eliminate noise-generating external components near sensitive analog circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2451DT-LF-Z | 3.3V–36V input, 0.6A output, 2MHz switching, no PFM mode, requires external compensation. | Better suited for higher-current loads but lacks light-load efficiency optimization and integrated compensation. | Choose MP2451DT-LF-Z only if >150mA output and faster transient response are required; ISL85412FRTZ preferred for ultra-low quiescent current and simplicity. |
| TPS560200DBVR | 4.5V–17V input, 600mA output, 500kHz, integrated compensation, no PFM, smaller 2.9mm×1.6mm SOT-563 package. | Limited to lower input voltages; unsuitable for 24V+ industrial or battery-stack applications. | TPS560200DBVR fits tighter board spaces but cannot replace ISL85412FRTZ in 36V or wide-VIN designs-verify VIN compliance first. |
Compared with MP2451DT-LF-Z and TPS560200DBVR, the ISL85412FRTZ uniquely combines 40V max input, integrated PFM/PWM selection, no-compensation design, and robust thermal performance in a 3×3mm footprint-making it optimal for space-constrained, high-voltage, low-power embedded systems where design simplicity and reliability are prioritized over raw current capability.
Availability
ISL85412FRTZ is available at Aetrix Electronics and suitable for industrial control, portable medical instrumentation, and distributed cloud infrastructure requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for ISL85412FRTZ 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
Renesas Electronics Corporation acquired Intersil in 2017 and continues to develop and support its high-performance analog and power management portfolio.
The ISL85412FRTZ belongs to Renesas' wide-input synchronous buck regulator family, designed specifically for rugged, low-power point-of-load conversion in industrial, medical, and infrastructure equipment where input voltage variability and board space are critical constraints.
FAQ
What is the maximum input voltage rating for the ISL85412FRTZ?
The ISL85412FRTZ has an absolute maximum input voltage rating of +43V, with recommended operation from 3.5V to 40V. Exceeding 40V continuously may trigger overvoltage protection or degrade long-term reliability. The device's internal protection circuits-including boot UVLO and overtemperature shutdown-help maintain safe operation even during transient overvoltage events on the VIN pin.
Does the ISL85412FRTZ require external compensation components?
No, the ISL85412FRTZ features internal compensation with a fixed 150kΩ resistor and 54pF capacitor, eliminating the need for external loop compensation. This simplifies design, reduces BOM count, and ensures stable regulation across all supported output voltages (1.0V to 12V) and load conditions without tuning.
How does the MODE pin affect ISL85412FRTZ operation?
The MODE pin selects between PFM (light-load efficiency mode) and forced PWM (constant-frequency regulation). Grounding MODE enables automatic PFM entry below ~10mA load; tying MODE to VCC forces continuous PWM operation regardless of load. An internal 5MΩ pull-down ensures defined state if left unconnected.
What thermal performance can be expected from the ISL85412FRTZ in a standard PCB layout?
In a typical 4-layer PCB with the EPAD soldered to a 1cm² internal GND plane using ≥5 thermal vias, the ISL85412FRTZ achieves θJA ≈ 47°C/W. At 150mA output with 12VIN/3.3VOUT, junction temperature rise remains under 35°C-well within the -40°C to +125°C operating range, even in sealed enclosures.
Can the ISL85412FRTZ be used to generate a 12V output?
Yes, the ISL85412FRTZ supports output voltages up to 12V using the FB pin and an external resistor divider. For 12V output with 0.599V reference, use R1 = 90.9kΩ and R2 = 4.75kΩ (per Table 1 in FN8378). Ensure input voltage exceeds 12.5V to maintain regulation margin and verify inductor saturation current rating for the selected duty cycle.
ISL85412FRTZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- Packaging:
- Tray
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 34V
- Current - Output:
- 150mA
- Frequency - Switching:
- 700kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TDFN (3x3)
ISL85412FRTZ FAQ
1.How can I place an order for ISL85412FRTZ through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL85412FRTZ 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 ISL85412FRTZ reliable?
The price and inventory of ISL85412FRTZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL85412FRTZ is usually 5 days.
3.What payment methods are accepted for ISL85412FRTZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL85412FRTZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL85412FRTZ?
ISL85412FRTZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL85412FRTZ 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 ISL85412FRTZ?
For technical support, including ISL85412FRTZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL85412FRTZ requirements.
6.How does Aetrix verify that ISL85412FRTZ is sourced from the original manufacturer or authorized distributors?
All ISL85412FRTZ 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 ISL85412FRTZ meets industry standards.
7.What is the process for return or replacement of ISL85412FRTZ?
All ISL85412FRTZ units undergo pre-shipment inspection (PSI). If there is an issue with ISL85412FRTZ, 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 ISL85412FRTZ part is unused and in its original packaging.
Return procedure for ISL85412FRTZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ISL85412FRTZ Tags
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