My Inquiry
My Account
Analog Devices Inc. LT1172HVIQ#PBF
- Part No.:
- LT1172HVIQ#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LT1172HVIQ#PBF.pdf
- Description:
- IC REG BCK BST ADJ 1.25A DDPAK-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,215
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT1172HVIQ#PBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode switching regulator IC with integrated 1.25A power switch, operating from 3V to 60V input and delivering up to 25W in buck/boost/flyback topologies. It features 100kHz fixed-frequency operation, 50µA shutdown current, and internal 1.24V reference voltage. Used in isolated flyback converters for industrial power supplies.
For engineers reviewing the LT1172HVIQ#PBF datasheet, LT1172HVIQ#PBF pinout, LT1172HVIQ#PBF application, or LT1172HVIQ#PBF equivalent, key selection criteria include HV-grade 60V input rating, –40°C to 100°C operating temperature, 8-pin DIP/SO package compatibility, and flyback-regulated floating output capability.
Technical Context
The LT1172HVIQ#PBF implements current-mode control with adaptive anti-saturation drive for stable operation across wide load ranges. Its dual error amplifier architecture supports both normal (1.24V) and flyback (15V) regulation modes via feedback pin threshold detection.
It integrates a 75V-rated 1.25A switch, 2.3V internal LDO for biasing, and a 100kHz oscillator. Pin 4 (NC) is unconnected per datasheet; E1 and E2 emitter terminals enable ground-path optimization in 8-pin packages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 60V - supports wide industrial input rails including 24V, 48V, and battery-backed systems. |
| Switch Current Limit | 1.25A (TJ ≥ 25°C) - sets maximum continuous output power in buck/boost; derates at higher junction temperatures. |
| Reference Voltage | 1.24V ±2% - precision feedback threshold enabling accurate output voltage regulation with standard resistor dividers. |
| Shutdown Current | 50µA typical - enables ultra-low-power standby in battery-powered or energy-sensitive applications. |
| Switch Breakdown Voltage | 75V - allows safe operation with 60V input plus transient margin in flyback or boost configurations. |
| Operating Temperature | –40°C to 100°C - qualified for extended industrial environments without derating. |
| Switching Frequency | 100kHz nominal - balances efficiency, EMI, and magnetics size; externally synchronizable to 120–160kHz. |
Pinout & Package
LT1172HVIQ#PBF is supplied in an 8-lead plastic DIP (N8) or plastic SO (S8) package with exposed thermal pad (not electrically connected). Pin 4 is NC and must remain unconnected per datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Power and signal ground reference | Primary return path for internal regulators and feedback circuitry; connects to E1 emitter internally in TO-220/TO-3 variants. |
| VC (Pin 2) | Error amplifier output / control node | Used for frequency compensation, soft-start, current limit adjustment, and shutdown activation below 0.15V. |
| FB (Pin 3) | Feedback input | Accepts 1.24V reference for standard regulation or switches to 15V flyback mode when pulled low via external resistor. |
| NC (Pin 4) | No connection | Unbonded; must not be connected to any external circuit per datasheet advisory. |
| E2 (Pin 5) | Secondary emitter terminal | Optional connection to reduce ground-path error; leaving open doubles RDS(on) and halves current limit. |
| VSW (Pin 6) | Switch collector output | High-side switch node driving external inductor/diode; rated for 75V breakdown and 1.25A peak current. |
| E1 (Pin 7) | Primary emitter terminal | Mandatory ground connection point; tied internally to GND in TO-220/TO-3 packages. |
| VIN (Pin 8) | Main supply input | Accepts 3–60V DC; powers internal 2.3V LDO and oscillator; bypass capacitor required near pin. |
Key Features
| Feature | Design Value |
|---|---|
| Flyback-regulated floating outputs | Enables fully isolated multiple-output designs without optocouplers by regulating flyback pulse amplitude referenced to VIN. |
| Adaptive anti-saturation drive | Minimizes switch turn-off delay and driver dissipation across full load range, improving efficiency at light and heavy loads. |
| External synchronization support | Accepts 120–160kHz sync pulses on VC pin for EMI reduction and multi-regulator phase alignment. |
| Dual emitter terminals (E1/E2) | Allows precise ground sensing and programmable current limiting in 8-pin packages-E2 disconnection reduces max current by 2×. |
| Self-protected overload handling | Includes cycle-by-cycle current limiting, thermal foldback, and automatic shutdown under sustained overloads. |
Applications
| Industrial Isolated Power Supply | Battery-Powered Upconverter |
|---|---|
Use Scenario: Generating ±15V analog rails from a 24V industrial bus with galvanic isolation for PLC I/O modules. IC Role / Device Role / Timing Role: Primary-side controller in flyback topology regulating secondary output via reflected primary pulse amplitude. Use Value: Eliminates need for optocoupler or TL431 feedback network, reducing BOM count and improving long-term stability. | Use Scenario: Boosting 3.7V Li-ion battery voltage to 12V for portable instrumentation sensors. IC Role / Device Role / Timing Role: High-efficiency boost converter with 100kHz fixed-frequency operation minimizing inductor size. Use Value: Delivers >85% efficiency at 500mA load while maintaining regulation down to 3V input during battery discharge. |
| LCD Contrast Voltage Generator | DC-DC Inverter (+ to –) |
Use Scenario: Generating –10V to –26V negative bias for LCD segment drivers in handheld medical devices. IC Role / Device Role / Timing Role: Inverting buck-boost regulator using single inductor and diode, configured via FB pin threshold. Use Value: Achieves precise negative output with <±2% line/load regulation and no external op-amp or charge pump IC. | Use Scenario: Converting +5V logic rail to –5V for RS-232 interface level shifting in embedded gateways. IC Role / Device Role / Timing Role: Inverting regulator with fast transient response and low quiescent current (6mA). Use Value: Supports clean negative rail generation without transformer or discrete transistor stage, simplifying layout and cost. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1172CN8#PBF | Same die, 0°C to 100°C temp grade, non-HV input rating (max 40V VIN) | Not suitable for 48V or 60V input systems requiring HV tolerance | Select LT1172HVIQ#PBF when operating above 40V or in –40°C ambient environments. |
| LT1172IS8#PBF | Same HV rating and temperature range, but in 8-lead SO package instead of DIP | SO package offers smaller footprint and better thermal performance on PCBs with copper pour | Choose LT1172IS8#PBF for surface-mount production; LT1172HVIQ#PBF preferred for through-hole prototyping or legacy DIP layouts. |
Compared with LT1172CN8#PBF and LT1172IS8#PBF, the LT1172HVIQ#PBF uniquely combines –40°C start-up capability, 60V input rating, and DIP packaging-making it optimal for ruggedized industrial prototypes where thermal cycling and high-voltage transients coexist.
Availability
LT1172HVIQ#PBF is available at Aetrix Electronics and suitable for industrial power supplies, battery-powered upconverters, isolated flyback converters, and negative voltage generators requiring stable component supply across extended temperature and input voltage ranges.
Supply support for LT1172HVIQ#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 LT117x family.
The LT117x series was designed as monolithic high-power switching regulators targeting cost-sensitive, high-reliability industrial and instrumentation applications where minimal external components and robust fault protection are critical.
FAQ
What is the maximum input voltage rating for LT1172HVIQ#PBF?
The LT1172HVIQ#PBF has an absolute maximum supply voltage of 60V and a switch breakdown voltage of 75V. Its HV grade designation confirms operation up to 60V continuous input, unlike standard LT1172 variants rated for 40V max. This makes LT1172HVIQ#PBF suitable for 48V telecom and industrial bus applications with headroom for transients.
Can LT1172HVIQ#PBF be used in flyback topology with fully floating outputs?
Yes, the LT1172HVIQ#PBF supports flyback-regulated mode by pulling the FB pin below 0.45V, activating its internal flyback error amplifier with 15V reference. This enables regulation of secondary output voltage via reflected primary pulse amplitude-no optocoupler or auxiliary winding needed. The LT1172HVIQ#PBF's 75V switch rating ensures safe operation with typical flyback clamp voltages.
What is the purpose of Pin 4 (NC) on LT1172HVIQ#PBF?
Pin 4 on the LT1172HVIQ#PBF is designated NC (No Connection) and must remain unconnected. The datasheet explicitly states this pin may be active in future revisions but is unused in current silicon. Connecting Pin 4 risks undefined behavior or latch-up; LT1172HVIQ#PBF functionality relies solely on Pins 1–3 and 5–8 as defined in the N8/S8 pinout.
How does the dual-emitter configuration (E1/E2) affect LT1172HVIQ#PBF performance?
The LT1172HVIQ#PBF's E1 and E2 pins provide separate emitter connections for the internal power switch. E1 must always connect to system ground; E2 is optional. Leaving E2 open doubles the effective switch "on" resistance (to ~1Ω), halving current limit to ~0.625A and reducing I²R loss during overload-but increasing conduction loss at full load. This trade-off is documented for thermal management in miniDIP packages.
Does LT1172HVIQ#PBF support external frequency synchronization?
Yes, the LT1172HVIQ#PBF supports external synchronization between 120kHz and 160kHz via the VC pin. A narrow (<0.3µs) ground pulse applied to VC resets the internal oscillator. This feature enables EMI reduction through spread-spectrum alignment and avoids beat frequencies in multi-rail systems-critical for noise-sensitive analog or communication circuits using LT1172HVIQ#PBF.
LT1172HVIQ#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):
- 60V
- Voltage - Output (Min/Fixed):
- 1.244V
- Voltage - Output (Max):
- 75V (Switch)
- Current - Output:
- 1.25A (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
LT1172HVIQ#PBF FAQ
1.How can I place an order for LT1172HVIQ#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1172HVIQ#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 LT1172HVIQ#PBF reliable?
The price and inventory of LT1172HVIQ#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1172HVIQ#PBF is usually 5 days.
3.What payment methods are accepted for LT1172HVIQ#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1172HVIQ#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1172HVIQ#PBF?
LT1172HVIQ#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1172HVIQ#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 LT1172HVIQ#PBF?
For technical support, including LT1172HVIQ#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1172HVIQ#PBF requirements.
6.How does Aetrix verify that LT1172HVIQ#PBF is sourced from the original manufacturer or authorized distributors?
All LT1172HVIQ#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 LT1172HVIQ#PBF meets industry standards.
7.What is the process for return or replacement of LT1172HVIQ#PBF?
All LT1172HVIQ#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1172HVIQ#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 LT1172HVIQ#PBF part is unused and in its original packaging.
Return procedure for LT1172HVIQ#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT1172HVIQ#PBF Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
