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Analog Devices Inc. LT1170CQ#PBF
- Part No.:
- LT1170CQ#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LT1170CQ#PBF.pdf
- Description:
- IC REG BUCK BOOST ADJ 5A DDPAK-5
- Quantity:
- Payment:
- Shipping:
Inventory:234
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Product details
Overview
LT1170CQ#PBF from Analog Devices (formerly Linear Technology) is a monolithic 5A, 100kHz current-mode switching regulator IC in a 5-lead DD (Dual In-line Derivative) package. It integrates a high-current power switch, oscillator, error amplifier, and protection circuitry, enabling buck, boost, flyback, forward, inverting, and Cuk topologies. It operates from 3V to 40V input, delivers up to 100W output power, and supports isolated flyback regulation with floating outputs - used in industrial DC-DC conversion and battery-powered systems.
For engineers reviewing the LT1170CQ#PBF datasheet, LT1170CQ#PBF pinout, LT1170CQ#PBF application, or LT1170CQ#PBF equivalent, key selection criteria include its 5A internal switch, 100kHz fixed-frequency operation, 6mA quiescent current, shutdown mode drawing only 50µA, and compatibility with standard 5-pin TO-220/TO-3 footprints despite its DD package form factor.
Technical Context
The LT1170CQ#PBF uses current-mode control architecture where switch duty cycle is directly set by sensed switch current rather than output voltage feedback alone. Its adaptive anti-saturation drive dynamically adjusts gate drive to minimize conduction loss across wide load ranges, while the integrated 1.24V bandgap reference and transconductance error amplifier (3000–7000 µmho) enable precise regulation in both normal and flyback modes.
It supports dual regulation modes: standard feedback (VFB = 1.24V) for non-isolated topologies and flyback-regulated mode (VFB threshold ≈ 0.45V, VFB_REF = 15.0–18.0V) for transformer-coupled designs. The VC pin serves as a multifunction node for compensation, soft-start, current limit adjustment, and shutdown - pulled below 0.15V to enter 50µA standby state.
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/flyback designs. |
| Switching Frequency | 100kHz typical - balances efficiency, EMI, and magnetics size; externally synchronizable to 120–160kHz. |
| Input Voltage Range | 3V to 40V - supports wide-range industrial, automotive, and battery inputs including 12V/24V systems. |
| Quiescent Supply Current | 6mA - minimizes no-load power loss in always-on applications like remote sensors or backup supplies. |
| Shutdown Current | 50µA typical - enables ultra-low-power standby in portable or energy-harvesting systems. |
| Reference Voltage | 1.244V ±20mV - stable bandgap reference for accurate output voltage setting via resistive divider. |
| Switch Breakdown Voltage | 65V - allows safe operation with 40V max input and transient margin in industrial environments. |
| Error Amp Transconductance | 3000–7000 µmho - provides high loop gain for tight line/load regulation and stable compensation. |
Pinout & Package
The LT1170CQ#PBF is housed in a 5-lead DD (Dual In-line Derivative) package with exposed tab connected to GND. This thermally enhanced plastic package shares mechanical footprint compatibility with standard 5-lead TO-220 but features a smaller outline and surface-mount–friendly leadform.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power Input | Primary supply input (3V–40V); connects to input capacitor and high-side of inductor in buck/boost. |
| VSW | Switch Output | Drains internal 5A N-channel switch; connects to inductor/diode node in all topologies. |
| GND | Ground Reference | Power and signal ground; tab is electrically tied to this pin for thermal and EMI performance. |
| FB | Feedback Input | Senses output voltage divider; <0.45V selects flyback mode; 1.24V sets regulation point in standard mode. |
| VC | Error Amplifier Output / Control | Multi-function pin: compensation node, soft-start capacitor connection, current limit clamp, and shutdown trigger (<0.15V). |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 5A, 65V Power Switch | Eliminates need for external high-current MOSFETs, reducing BOM count and layout complexity in 100W-class converters. |
| Current-Mode Control Architecture | Provides inherent cycle-by-cycle current limiting, fast line transient response, and simplified loop compensation across varying loads. |
| 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, allowing noise-sensitive systems to avoid EMI bands or synchronize multiple regulators. |
| Self-Protected Operation | Includes thermal foldback, current limiting, and overvoltage protection - operates "bust-proof" like linear regulators with minimal external components. |
Applications
| Industrial DC-DC Conversion | Battery-Powered Upconversion |
|---|---|
Use Scenario: Converting 12V or 24V rail to 5V/3.3V for PLC I/O modules, motor drives, or sensor interfaces in harsh factory environments. IC Role / Device Role / Timing Role: Primary switching controller implementing buck topology with integrated 5A switch and 100kHz fixed-frequency timing. Use Value: Delivers up to 100W with no external power devices, simplifies thermal design via GND-tab thermal path, and withstands 40V transients per spec. | Use Scenario: Boosting single-cell Li-ion (3.0–4.2V) or lead-acid (6–15V) battery to 12V for portable instrumentation or emergency lighting. IC Role / Device Role / Timing Role: High-efficiency boost controller using current-mode regulation and adaptive anti-sat drive to maintain >88% efficiency down to 10% load. Use Value: 6mA quiescent current extends battery runtime; 50µA shutdown mode enables long-term storage without drain. |
| Flyback Isolated Power Supply | Logic-Level Dual-Rail Generation |
Use Scenario: Generating isolated ±15V op-amp supplies or 5V microcontroller rails from unregulated 24V industrial input with reinforced insulation. IC Role / Device Role / Timing Role: Flyback controller regulating secondary output via primary-side sensing - uses FB pin low-threshold mode and internal 15V flyback reference. Use Value: Fully floating outputs up to transformer breakdown rating; eliminates optocoupler and TL431, reducing cost and component count. | Use Scenario: Generating ±12V rails from 5V logic supply for analog front-ends, data acquisition, or audio amplifiers in test equipment. IC Role / Device Role / Timing Role: Inverting topology controller with integrated switch, using VC pin for soft-start and current limit tuning during rail startup. Use Value: Single-chip solution replaces discrete charge-pump or transformer-based designs; 5A switch handles peak inrush into bulk capacitance. |
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 |
|---|---|---|---|
| LTC3703-5 | External MOSFET driver (no internal switch), 5V–36V input, supports up to 10A with external FETs. | Requires external high-side/lower FETs and gate drivers; better suited for >100W or higher efficiency needs. | Select when higher power, adjustable frequency, or synchronous rectification is required - not a drop-in replacement. |
| LM2596T-5.0 | 3A internal switch, 40V max input, 150kHz fixed frequency, lower integration (no flyback mode, no VC pin control). | Limited to non-isolated buck only; lacks multi-topology support and flyback regulation capability. | Choose for cost-sensitive, lower-power (≤60W) buck-only applications where isolation and topology flexibility are unnecessary. |
Compared with LTC3703-5 and LM2596T-5.0, the LT1170CQ#PBF uniquely combines 5A integration, flyback-mode capability, and VC pin programmability - making it optimal for compact, isolated, or multi-topology designs under 100W where minimizing external components is critical.
Availability
LT1170CQ#PBF is available at Aetrix Electronics and suitable for industrial DC-DC conversion, battery-powered upconversion, and flyback isolated power supply applications requiring stable component supply, long-lifecycle support, and consistent parametric performance across temperature.
Supply support for LT1170CQ#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, datasheets, and application notes for legacy Linear parts including the LT1170 family.
The LT1170 series was designed as a rugged, monolithic switching regulator platform targeting high-reliability industrial, telecom, and military-grade power conversion where simplicity, integration, and multi-topology flexibility are essential.
FAQ
What is the maximum input voltage rating for the LT1170CQ#PBF?
The LT1170CQ#PBF has an absolute maximum supply voltage of 40V, with recommended operating range from 3V to 40V. Exceeding 40V risks permanent damage per Absolute Maximum Ratings. For higher-input applications, the LT1170HVCQ#PBF variant supports up to 60V input and 75V switch breakdown voltage.
Does the LT1170CQ#PBF support flyback topology with primary-side regulation?
Yes, the LT1170CQ#PBF supports flyback-regulated mode via its FB pin: pulling FB below ~0.45V disconnects the main error amplifier and activates the flyback amplifier, which regulates based on a 15.0–18.0V internal reference. This enables fully floating, optocoupler-free isolated outputs - confirmed in the datasheet's Block Diagram and Electrical Characteristics tables.
What is the function of the VC pin on the LT1170CQ#PBF?
The VC pin on the LT1170CQ#PBF serves four key functions: (1) error amplifier output for compensation network connection, (2) current limit adjustment via external clamp voltage, (3) soft-start initiation using a capacitor, and (4) shutdown activation when pulled below 0.15V - reducing supply current to 50µA. Its behavior is explicitly defined in the Operation section and Electrical Characteristics table.
Can the LT1170CQ#PBF be synchronized to an external clock?
Yes, the LT1170CQ#PBF can be externally synchronized to frequencies between 120kHz and 160kHz by applying narrow (<0.3µs) pulses to the VC pin using an external transistor. This is documented in the "LT1170/LT1171/LT1172 Synchronizing" section, including circuit examples with bipolar and MOSFET drivers and offset calculation formulas.
What package type is used by the LT1170CQ#PBF, and how does it differ from TO-220?
The LT1170CQ#PBF uses a 5-lead DD (Dual In-line Derivative) package - a surface-mount–compatible variant with the same pinout and thermal tab (GND-connected) as standard 5-lead TO-220, but with shorter leads and smaller body. It is not a through-hole TO-220; the "CQ" suffix specifically denotes the DD package per Linear's Order Information table.
LT1170CQ#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:
- 0°C ~ 100°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DDPAK-5
LT1170CQ#PBF FAQ
1.How can I place an order for LT1170CQ#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1170CQ#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 LT1170CQ#PBF reliable?
The price and inventory of LT1170CQ#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1170CQ#PBF is usually 5 days.
3.What payment methods are accepted for LT1170CQ#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1170CQ#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1170CQ#PBF?
LT1170CQ#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1170CQ#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 LT1170CQ#PBF?
For technical support, including LT1170CQ#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1170CQ#PBF requirements.
6.How does Aetrix verify that LT1170CQ#PBF is sourced from the original manufacturer or authorized distributors?
All LT1170CQ#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 LT1170CQ#PBF meets industry standards.
7.What is the process for return or replacement of LT1170CQ#PBF?
All LT1170CQ#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1170CQ#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 LT1170CQ#PBF part is unused and in its original packaging.
Return procedure for LT1170CQ#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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