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Analog Devices Inc. LT1170IQ#PBF
- Part No.:
- LT1170IQ#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LT1170IQ#PBF.pdf
- Description:
- IC REG BUCK BOOST ADJ 5A DDPAK-5
- Quantity:
- Payment:
- Shipping:
Inventory:401
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Product details
Overview
LT1170IQ#PBF from Analog Devices (formerly Linear Technology) is a monolithic 5A, 100kHz current-mode switching regulator IC in a 5-lead DD (Dual Drain) plastic package, operating from 3V to 40V input, delivering up to 100W output power without external switches, and featuring internal 5A switch with 0.24Ω typical RDS(on), 6mA quiescent current, and shutdown mode drawing only 50µA - used in industrial DC-DC conversion, battery upconverters, and isolated flyback supplies.
For engineers reviewing the LT1170IQ#PBF datasheet, LT1170IQ#PBF pinout, LT1170IQ#PBF application, or LT1170IQ#PBF equivalent, this page delivers verified technical context, exact pin functions for Q-package layout, real-world application cards for buck/boost/flyback topologies, and two validated alternative parts with documented functional trade-offs.
Technical Context
The LT1170IQ#PBF implements current-mode control with adaptive anti-saturation drive for wide load-current efficiency stability, using an internal 100kHz oscillator and a transconductance error amplifier (3000–7000 µmho) referenced to a 1.224–1.274V bandgap. It supports all standard topologies - buck, boost, flyback, forward, inverting, and Cuk - via external component configuration.
Its feedback pin enables dual-mode operation: normal regulation at 1.24V reference or flyback-regulated mode (15.0–18.0V reference) when pulled low; the VC pin serves simultaneously as compensation node, current-limit adjust, soft-start input, and shutdown control (≤0.15V triggers 50µA standby).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Current Rating | 5A continuous - enables high-power DC-DC conversion without external MOSFETs in buck/boost designs. |
| Input Voltage Range | 3V to 40V - supports wide-range industrial, automotive, and battery-powered inputs. |
| Quiescent Current | 6mA - minimizes no-load power loss in always-on systems. |
| Shutdown Current | 50µA - allows ultra-low-power standby in portable or energy-sensitive applications. |
| Switch RDS(on) | 0.24Ω typical - limits conduction loss to ≤0.6W at 5A, enabling >90% efficiency in optimized layouts. |
| Reference Voltage | 1.224–1.274V (±2%) - provides stable feedback threshold for precise output voltage regulation. |
| Switching Frequency | 88–115kHz - balances EMI control, inductor size, and efficiency for medium-power designs. |
| Operating Temp Range | –40°C to +100°C - qualified for extended industrial ambient conditions without derating. |
Pinout & Package
The LT1170IQ#PBF uses a 5-lead DD (Dual Drain) plastic package with exposed tab connected internally to GND. Thermal resistance θJA varies with PCB copper area (≈25–45°C/W), enabling flexible thermal design without mandatory heatsink.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power Input | Primary supply input (3–40V); connects to input capacitor and inductor feed point. |
| VSW | Switch Output | Drain of internal 5A N-channel power switch; connects directly to inductor or transformer primary. |
| GND | Ground Reference | Power and signal ground; tab is electrically tied to this pin - must be soldered to large copper pour. |
| FB | Feedback Input | High-impedance input sensing output voltage divider; sets regulation point at 1.24V (or 15–18V in flyback mode). |
| VC | Error Amplifier Output / Control | Transconductance amplifier output; used for loop compensation, current limit adjustment, soft-start, and shutdown control. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 5A Power Switch | Eliminates need for external high-current MOSFETs, reducing BOM count and layout complexity in ≤100W converters. |
| Current-Mode Control Architecture | Provides inherent cycle-by-cycle current limiting, fast line transient response, and simplified loop compensation across variable input/load conditions. |
| Flyback-Regulated Mode Support | Enables fully floating, transformer-isolated outputs with no optocoupler required - ideal for medical or safety-isolated supplies. |
| Adaptive Anti-Saturation Drive | Maintains high efficiency across 0.1A–5A load range by dynamically optimizing gate drive to prevent switch saturation losses. |
| External Synchronization Capability | Accepts 120–160kHz sync pulses on VC pin for EMI reduction or multi-phase interleaving in system-level designs. |
Applications
| Industrial DC-DC Conversion | Battery Upconverter |
|---|---|
Use Scenario: Converting 12V vehicle battery or 24V PLC rail to regulated 5V/3.3V for embedded controllers and sensors. IC Role / Device Role / Timing Role: Primary switching regulator controlling inductor current and output voltage via current-mode PWM. Use Value: Delivers 5A peak output with 6mA quiescent current, enabling reliable operation during engine cranking (low-battery dips) and extended idle periods. | Use Scenario: Boosting single-cell Li-ion (3.0–4.2V) or lead-acid (6–12V) to 12V/15V for powering legacy peripherals or op-amp rails. IC Role / Device Role / Timing Role: High-efficiency boost controller with integrated switch, minimizing external components and board space. Use Value: Achieves >88% efficiency at 2A load with no external power transistor - critical for portable equipment runtime and thermal management. |
| Flyback Isolated Supply | Logic-to-Analog Rail Converter |
Use Scenario: Generating ±15V analog supply from 5V logic rail in data acquisition systems requiring galvanic isolation. IC Role / Device Role / Timing Role: Flyback-regulated controller using FB pin in low-threshold mode to regulate secondary-side voltage without optocoupler feedback. Use Value: Fully floating outputs up to transformer breakdown rating; eliminates isolation components while maintaining ±1% output accuracy. | Use Scenario: Converting 5V microcontroller logic supply into ±15V op-amp rails for precision instrumentation amplifiers. IC Role / Device Role / Timing Role: Inverting topology regulator generating negative output while sourcing positive current from same input. Use Value: Supports simultaneous +12V and –12V outputs with shared inductor and single IC - reduces cost and footprint vs. dual-controller solutions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-current switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3891EMSE#PBF | 40V input, 10A external switch, requires external MOSFETs; synchronous rectification support; 150kHz–750kHz programmable frequency. | Higher power scalability (≥200W), but adds layout complexity and gate-drive design effort. | Select when >100W output or programmable frequency/EMI shaping is required; not drop-in compatible. |
| LM5116MH/NOPB | 65V input, 5A external switch, current-mode control, 50–750kHz frequency range; no integrated power switch. | Broader input range and higher max voltage, but mandates external high-side MOSFET and driver. | Choose for 40–65V industrial inputs or where thermal separation of switch and controller is preferred. |
Compared with LTC3891EMSE#PBF and LM5116MH/NOPB, the LT1170IQ#PBF offers lowest component count and simplest layout for ≤100W applications due to its monolithic 5A switch, while trading off frequency flexibility and maximum input voltage for ease-of-use and proven ruggedness in legacy industrial designs.
Availability
LT1170IQ#PBF is available at Aetrix Electronics and suitable for industrial DC-DC conversion, battery-powered upconversion, and isolated flyback power supplies requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LT1170IQ#PBF 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
Analog Devices acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LT1170 family.
The LT1170 series belongs to Linear's legacy high-power monolithic switching regulator product line, designed specifically for robust, low-component-count DC-DC conversion in harsh industrial and transportation environments.
FAQ
What is the maximum input voltage rating for LT1170IQ#PBF?
The LT1170IQ#PBF has an absolute maximum supply voltage of 40V. Its recommended operating input range is 3V to 40V. Exceeding 40V risks permanent damage per Absolute Maximum Ratings. For designs requiring >40V input, the LT1170HV variant (60V rating) or alternatives like LM5116MH/NOPB should be considered instead of the LT1170IQ#PBF.
Does LT1170IQ#PBF support flyback topology without an optocoupler?
Yes, the LT1170IQ#PBF supports optocoupler-free flyback regulation via its dedicated flyback mode: pulling the FB pin below 0.45V switches the internal reference from 1.24V to 15.0–18.0V, allowing direct regulation of reflected flyback pulse amplitude. This enables fully floating, isolated outputs - confirmed in the LT1170/LT1171/LT1172 datasheet Figure TA03 and Operation section - without needing external feedback components for the LT1170IQ#PBF.
What package type and thermal characteristics apply to LT1170IQ#PBF?
The LT1170IQ#PBF uses a 5-lead DD (Dual Drain) plastic package with GND-connected metal tab. Its thermal performance depends on PCB copper area: θJA ranges from ~25°C/W (2.8 sq. in. 1oz Cu) to ~45°C/W (0.2 sq. in. 1oz Cu). Unlike TO-220 or TO-3 variants, the DD package relies entirely on PCB conduction - no separate heatsink is defined, and thermal design must prioritize tab soldering and copper spreading for the LT1170IQ#PBF.
Can LT1170IQ#PBF be synchronized to an external clock?
Yes, the LT1170IQ#PBF supports external synchronization between 120kHz and 160kHz by applying narrow (<0.3µs) pulses to the VC pin via an external transistor. This feature is explicitly documented in the "LT1170/LT1171/LT1172 Synchronizing" section of the datasheet, enabling EMI reduction and multi-phase interleaving - a capability retained across all LT1170 variants including the LT1170IQ#PBF.
What is the function of the VC pin on LT1170IQ#PBF beyond compensation?
The VC pin on the LT1170IQ#PBF serves four distinct functions: (1) error amplifier output for loop compensation, (2) current limit adjustment via external clamping, (3) soft-start initiation using a capacitor, and (4) total shutdown trigger when pulled ≤0.15V (reducing supply current to 50µA). All are confirmed in the Operation section and Electrical Characteristics table - making VC a multifunction control node unique to the LT1170IQ#PBF among monolithic regulators of its era.
LT1170IQ#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost, Cuk, Flyback, Forward Converter
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.244V
- Voltage - Output (Max):
- 65V (Switch)
- Current - Output:
- 5A (Switch)
- Frequency - Switching:
- 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 100°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DDPAK-5
LT1170IQ#PBF FAQ
1.How can I place an order for LT1170IQ#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1170IQ#PBF 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 LT1170IQ#PBF reliable?
The price and inventory of LT1170IQ#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1170IQ#PBF is usually 5 days.
3.What payment methods are accepted for LT1170IQ#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1170IQ#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1170IQ#PBF?
LT1170IQ#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1170IQ#PBF 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 LT1170IQ#PBF?
For technical support, including LT1170IQ#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1170IQ#PBF requirements.
6.How does Aetrix verify that LT1170IQ#PBF is sourced from the original manufacturer or authorized distributors?
All LT1170IQ#PBF 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 LT1170IQ#PBF meets industry standards.
7.What is the process for return or replacement of LT1170IQ#PBF?
All LT1170IQ#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1170IQ#PBF, 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 LT1170IQ#PBF part is unused and in its original packaging.
Return procedure for LT1170IQ#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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