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Analog Devices Inc. LT1072CS8#PBF
- Part No.:
- LT1072CS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1072CS8#PBF.pdf
- Description:
- IC REG BUCK BOOST ADJ 1.25A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:135
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Product details
Overview
LT1072CS8#PBF from Analog Devices (formerly Linear Technology) is a monolithic 1.25A current-mode switching regulator IC in an 8-lead plastic SOIC package. It supports buck, boost, flyback, forward, inverting, and Cuk topologies; operates from 3V to 60V input; delivers up to 20W output power; features internal 1.25A switch with 0.6Ω typical RDS(on); and enables fully floating isolated outputs via built-in flyback regulation mode - used in offline converters, battery upconverters, and dual-polarity op-amp supplies.
For engineers reviewing the LT1072CS8#PBF datasheet, LT1072CS8#PBF pinout, LT1072CS8#PBF application, or LT1072CS8#PBF equivalent, key selection criteria include its 40kHz fixed-frequency operation, shutdown current of 50µA, feedback reference voltage of 1.244V, flyback reference voltage of 16.3V, and compatibility with external synchronization up to 70kHz - all critical for isolated DC/DC design, industrial power rails, and low-quiescent-power standby systems.
Technical Context
The LT1072CS8#PBF implements current-mode control with adaptive anti-saturation switch drive, enabling stable operation across wide load ranges without efficiency loss. Its oscillator runs at 40kHz (±5kHz), and the internal 1.25A NPN switch has a maximum breakdown voltage of 60V - validated for the S8 package variant per Absolute Maximum Ratings.
It integrates a 1.244V bandgap reference, transconductance error amplifier (4400 µmho typ), flyback amplifier (300 µmho typ), and dual-mode feedback threshold (0.45V normal / 0.54V flyback). The VC pin serves as error amplifier output, current limit adjust, soft-start node, and shutdown control - pulled below 0.15V to enter 50µA shutdown mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 60V - supports wide-input industrial, automotive, and battery-derived supplies without external pre-regulation. |
| Switch Current Limit | 1.25A (typ) at ≥25°C - defines maximum continuous output current capability in buck/boost configurations. |
| Feedback Reference Voltage | 1.244V (typ) - sets output voltage accuracy in non-isolated topologies using resistor divider on FB pin. |
| Flyback Reference Voltage | 16.3V (typ) - enables optocoupler-free isolated regulation by sensing reflected flyback pulse amplitude. |
| Quiescent Supply Current | 6mA (typ) - determines no-load power loss in always-on applications like sensor nodes or backup rails. |
| Shutdown Supply Current | 50µA (typ) - enables ultra-low-power standby in energy-sensitive systems such as portable medical devices. |
| Switching Frequency | 40kHz (typ) - balances EMI, inductor size, and efficiency for medium-power DC/DC stages. |
Pinout & Package
LT1072CS8#PBF is housed in an 8-lead plastic SOIC (narrow, 0.150-inch width) package with θJA = 130°C/W. Pin 1 is marked with a notch or dot; leads are gull-wing surface-mount.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (E2) | Second Emitter Terminal | Optional emitter connection; leaving open reduces switch current limit by 2× and doubles RDS(on) - used for derating under overload conditions. |
| 2 (VSW) | Switch Collector Output | High-current NPN collector node; connects to inductor/diode in all topologies - must handle 60V transient spikes. |
| 3 (E1) | Primary Emitter Terminal | Internally tied to GND pin; must be externally connected to ground plane to maintain accurate current sensing and thermal path. |
| 4 (VIN) | Power Input | Supplies internal LDO (2.3V) and switch driver; accepts 3–60V with <1% line regulation effect on VREF. |
| 5 (GND) | Ground Reference | Common return for internal circuitry, error amplifier, and E1 emitter - requires low-impedance PCB plane for stability. |
| 6 (VC) | Error Amplifier Output / Control | Current-output node (gm = 4400 µmho); used for compensation, current limit adjustment, soft-start, and shutdown activation. |
| 7 (FB) | Feedback Input | High-impedance input (750 nA max bias) referenced to 1.244V; dual-threshold (0.45V/0.54V) selects normal or flyback regulation mode. |
| 8 (NC) | No Connect | Unbonded pad; must remain unconnected and un-routed to avoid parasitic coupling or mechanical stress. |
Key Features
| Feature | Design Value |
|---|---|
| Flyback-regulated mode | Enables fully floating, transformer-coupled outputs without optocouplers - reduces BOM count and improves reliability in isolated supplies. |
| Adaptive anti-saturation drive | Maintains high efficiency across 0.1A–1.25A load range by dynamically adjusting base drive - eliminates need for external current-sense resistors. |
| External synchronization support | Accepts 48–70kHz sync pulses via VC pin - allows EMI reduction through frequency dithering or alignment with system clocks. |
| Self-protected overload handling | Integrates cycle-by-cycle current limiting, thermal foldback, and shutdown - prevents damage during short-circuit or startup faults. |
| Minimal external components | Requires only inductor, diode, capacitor, and two resistors for basic operation - accelerates prototyping and reduces layout sensitivity. |
Applications
| Offline AC/DC Converter | Battery-Powered Upconverter |
|---|---|
|
Use Scenario: Converting rectified 100–370V DC (from universal AC input) to regulated 12V/1A for industrial controllers. IC Role / Device Role / Timing Role: Primary-side controller implementing flyback topology with primary-side regulation - replaces optocoupler and TL431. Use Value: Achieves ±5% output regulation over line/load/temperature with <20W output and <50µA standby consumption. |
Use Scenario: Boosting 3.6V Li-ion battery to 12V for portable instrumentation or wireless gateways. IC Role / Device Role / Timing Role: High-efficiency boost converter operating in discontinuous conduction mode (DCM) at 40kHz. Use Value: Delivers >85% peak efficiency at 0.5A load while maintaining 6mA quiescent draw to extend battery runtime. |
| Dual-Polarity Op-Amp Supply | Isolated Sensor Interface Power |
|
Use Scenario: Generating ±15V rails from single 5V logic supply for precision analog front-ends in data acquisition systems. IC Role / Device Role / Timing Role: Inverting buck-boost controller with split-winding inductor - provides symmetrical, low-noise outputs. Use Value: Enables rail-to-rail op-amp operation with <10mV p-p ripple and <0.1% cross-regulation between ±15V outputs. |
Use Scenario: Powering isolated current/voltage sensors in motor drives where primary and secondary sides require galvanic separation. IC Role / Device Role / Timing Role: Flyback controller regulating secondary-side output via primary-side sensing - meets IEC 61800-5-1 reinforced insulation requirements. Use Value: Eliminates optocoupler aging drift and achieves <2kV RMS isolation with <1% output tolerance over temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1072CT#PBF | TO-220-5 package; higher θJA (50°C/W); 40V max input; same electrical specs. | Better thermal performance at >10W; requires heatsink for continuous 1.25A operation. | Select when board space allows TO-220 mounting and >15W output power is needed. |
| LT1072CN8#PBF | 8-lead PDIP package; θJA = 130°C/W; identical S8 pinout except NC pin replaced by E2; same 60V input rating. | Through-hole assembly compatible; slightly lower creepage/clearance than SOIC; same flyback functionality. | Select for legacy through-hole production or when SOIC reflow is unavailable. |
Compared with LT1072CT#PBF and LT1072CN8#PBF, the LT1072CS8#PBF offers identical regulation architecture and flyback capability in a compact, RoHS-compliant surface-mount package optimized for automated assembly and moderate-power density - making it ideal for space-constrained industrial modules where thermal management is handled via PCB copper area rather than discrete heatsinks.
Availability
LT1072CS8#PBF is available at Aetrix Electronics and suitable for offline AC/DC converters, battery-powered upconverters, dual-polarity op-amp supplies, and isolated sensor interface power requiring stable component supply across extended product lifecycles.
Supply support for LT1072CS8#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 technical and manufacturing continuity for legacy Linear products including the LT1072 family.
The LT1072 product line was designed as a monolithic, high-current switching regulator IC to simplify isolated and non-isolated DC/DC conversion - targeting industrial, medical, and test equipment where reliability, minimal external parts, and flyback regulation without optocouplers are critical.
FAQ
What is the maximum input voltage rating for the LT1072CS8#PBF?
The LT1072CS8#PBF has a maximum switch breakdown voltage of 60V, and its Absolute Maximum Rating for input voltage is 60V. This is explicitly specified for the S8 package variant in the datasheet's "Absolute Maximum Ratings" table - distinct from the 40V rating of the standard LT1072 or 75V of the LT1072HV variants.
Does the LT1072CS8#PBF support flyback topology without an optocoupler?
Yes, the LT1072CS8#PBF supports optocoupler-free flyback regulation via its dedicated flyback amplifier and 16.3V flyback reference voltage. When the FB pin is pulled below 0.54V, the IC enters flyback mode and regulates output by sensing the amplitude of the reflected flyback pulse - eliminating the need for secondary-side feedback components.
How does the E2 pin function on the LT1072CS8#PBF?
The E2 pin on the LT1072CS8#PBF is the second emitter terminal of the internal NPN switch. Leaving E2 unconnected reduces the switch current limit by 2× (to ~0.625A) and doubles RDS(on), providing a simple hardware method to derate the device under overload conditions - though efficiency drops above 100mA due to increased conduction loss.
What is the purpose of the VC pin on the LT1072CS8#PBF?
The VC pin on the LT1072CS8#PBF serves four integrated functions: (1) error amplifier output for loop compensation, (2) current limit adjustment via external clamping, (3) soft-start control using a capacitor, and (4) shutdown activation when pulled below 0.15V - reducing supply current to 50µA. Its gm = 4400 µmho enables precise external control of regulation behavior.
Can the LT1072CS8#PBF be synchronized to an external clock?
Yes, the LT1072CS8#PBF supports external synchronization from 48kHz to 70kHz by pulling the VC pin to ground with a narrow (<1µs) transistor pulse. This feature allows EMI reduction through frequency alignment or dithering - confirmed in the "LT1072 Synchronizing" section of the datasheet, with timing diagrams and offset voltage calculations provided.
LT1072CS8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- 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):
- 1.25V
- Voltage - Output (Max):
- 60V (Switch)
- Current - Output:
- 1.25A (Switch)
- Frequency - Switching:
- 40kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 100°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1072CS8#PBF FAQ
1.How can I place an order for LT1072CS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1072CS8#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 LT1072CS8#PBF reliable?
The price and inventory of LT1072CS8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1072CS8#PBF is usually 5 days.
3.What payment methods are accepted for LT1072CS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1072CS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1072CS8#PBF?
LT1072CS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1072CS8#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 LT1072CS8#PBF?
For technical support, including LT1072CS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1072CS8#PBF requirements.
6.How does Aetrix verify that LT1072CS8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1072CS8#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 LT1072CS8#PBF meets industry standards.
7.What is the process for return or replacement of LT1072CS8#PBF?
All LT1072CS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1072CS8#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 LT1072CS8#PBF part is unused and in its original packaging.
Return procedure for LT1072CS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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