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Analog Devices Inc. LTC1504AIS8-3.3#TRPBF
- Part No.:
- LTC1504AIS8-3.3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1504AIS8-3.3#TRPBF.pdf
- Description:
- IC REG BUCK 3.3V 500MA 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,809
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Product details
Overview
LTC1504AIS8-3.3#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-output 3.3V, 500mA synchronous step-down DC/DC regulator in SO-8 package, featuring internal 1.3Ω MOSFETs, 92% peak efficiency, 100% duty cycle operation, and integrated current limit control via IMAX pin. It delivers stable low-voltage power for portable digital systems requiring minimal external components.
For engineers reviewing the LTC1504AIS8-3.3#TRPBF datasheet, LTC1504AIS8-3.3#TRPBF pinout, LTC1504AIS8-3.3#TRPBF application, or LTC1504AIS8-3.3#TRPBF equivalent, key selection considerations include input voltage range (4V–10V), industrial temperature rating (–40°C to +85°C), SENSE-pin feedback architecture, soft-start programmability via SS pin, and compatibility with low-ESR output capacitors for fast transient response.
Technical Context
The LTC1504AIS8-3.3#TRPBF implements a synchronous buck topology with integrated P-channel high-side and N-channel low-side MOSFETs, enabling bidirectional output current (source/sink) for tight regulation under dynamic loads. Its internal 200kHz oscillator supports synchronization up to 500kHz, and the error amplifier features 48dB DC gain and 600µmho transconductance (industrial grade).
Current limiting is implemented via an ILIM amplifier comparing SW-node voltage during Q1 conduction against a reference set by an external resistor on IMAX; soft-start timing and current-limit loop compensation share the same external capacitor on SS pin. The SENSE pin is internally biased to 3.3V, eliminating external feedback resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±3% (SENSE pin regulated to 3.3V; no external divider required) |
| Max Output Current | 500mA continuous at 5V input → 3.3V output; limited by thermal dissipation in SO-8 package |
| Input Voltage Range | 4V to 10V - supports standard 5V and 9V rails; not rated for 2.7V without factory validation |
| Peak Efficiency | 92% at 500mA load - reduces thermal stress and extends battery life in portable systems |
| Switching Frequency | 200kHz typical (130–300kHz over industrial temp) - enables compact magnetics and predictable EMI profile |
| Internal Switch RDS(on) | 1.3Ω (typ) high-side, 1.3Ω (typ) low-side - defines conduction loss and thermal headroom at full load |
| Feedback Accuracy | ±1.8% SENSE voltage PSRR over 4V–10V VCC - ensures stable regulation despite input ripple |
Pinout & Package
Package: 8-lead plastic SO-8 (SOIC narrow), exposed pad not present; θJA = 90°C/W; JEDEC MS-012AC compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IMAX (1) | Current Limit Threshold Set | Internal 12µA sink sets voltage drop across external RIMAX; determines peak current limit (e.g., 47kΩ → ~250mA) |
| VCC (2) | Power Supply Input | 4V–10V input rail; requires local low-ESR ceramic bypass (≥1µF) adjacent to pin for stable reference operation |
| SW (3) | Switch Node | Drives external inductor; carries high di/dt square wave; must avoid parasitic coupling to sensitive analog nodes |
| GND (4) | Power & Signal Ground | Common return for VCC bypass, output capacitor, and feedback; serves as primary thermal path in SO-8 package |
| SENSE (5) | Fixed-Output Feedback | Internally referenced to 3.3V; connect directly to output node - no external resistors; loads external dividers if used |
| SHDN (6) | Active-Low Enable | Pull ≥2.4V to enable; ≤0.8V to shut down (<1µA quiescent); pulls SW low during shutdown to prevent backfeeding |
| SS (7) | Soft-Start & Current-Limit Control | External capacitor (e.g., 0.1µF) sets ramp time and compensates ILIM loop; shared node for both functions |
| COMP (8) | Error Amplifier Output | High-impedance node for external RC compensation network; directly drives PWM comparator; critical for loop stability |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous Buck Architecture | Enables output current sinking for active termination and fast load transient recovery without external diode |
| 100% Duty Cycle Operation | Minimizes dropout voltage - supports regulation down to VIN – VOUT ≈ 0.1V at light loads |
| Integrated 1.3Ω Power Switches | Eliminates need for external MOSFETs and gate drivers; reduces BOM count and layout complexity |
| Adjustable Current Limit | Single external resistor on IMAX pin sets threshold - protects IC and inductor during overload without sensing resistor |
| Industrial Temperature Range | Specified from –40°C to +85°C - suitable for embedded industrial and automotive auxiliary supply applications |
Applications
| Portable Digital Systems | Active Termination |
|---|---|
Use Scenario: Powering microcontroller cores, FPGAs, and memory interfaces in handheld test equipment and medical monitors. IC Role / Device Role / Timing Role: Primary 3.3V point-of-load regulator delivering tightly regulated, low-noise supply with fast transient response. Use Value: 500mA output and 92% efficiency extend battery runtime; SENSE feedback eliminates resistor tolerance errors in output voltage accuracy. | Use Scenario: Providing controlled 3.3V termination voltage for high-speed parallel buses (e.g., SCSI, PCI-X stubs) and DDR memory data lines. IC Role / Device Role / Timing Role: Active sink/source regulator maintaining precise bus voltage during signal transitions. Use Value: Bidirectional output current capability enables true active termination - avoids passive resistor power waste and improves signal integrity. |
| Auxiliary Voltage Supplies | Minimum Part Count Switchers |
Use Scenario: Generating isolated 3.3V bias for sensor signal conditioning, ADC references, or isolated communication interfaces (e.g., RS-485, CAN transceivers). IC Role / Device Role / Timing Role: Secondary regulated supply decoupled from main system rail; operates independently with SHDN control. Use Value: Shutdown current <1µA enables low-power sleep modes; SO-8 footprint simplifies integration into space-constrained modules. | Use Scenario: Replacing linear regulators (e.g., LM1117-3.3) in cost-sensitive consumer electronics where heat dissipation and efficiency matter. IC Role / Device Role / Timing Role: Drop-in upgrade offering >3× efficiency improvement over LDOs at 500mA load. Use Value: Requires only four external components (CIN, COUT, L, CSS) - reduces PCB area, assembly cost, and design validation effort. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | 3MHz switching frequency, 600mA output, smaller 6-pin WSON package; lacks 100% duty cycle and SENSE-pin architecture | Better suited for ultra-compact, high-frequency designs; not pin-compatible; requires external feedback resistors | Select when board space is critical and higher-frequency operation is acceptable; verify loop stability with ceramic output caps. |
| MAX17503GCU+T | 4.5V–60V input, 600mA, adjustable output; includes PMBus interface and extensive protection features; larger 16-pin TQFN | Targeted at industrial power supplies requiring wide VIN and telemetry; overkill for simple 5V→3.3V conversion | Choose when input voltage exceeds 10V or digital monitoring/control is required; not a drop-in replacement. |
Compared with TPS62231DRYR and MAX17503GCU+T, the LTC1504AIS8-3.3#TRPBF offers unique advantages in simplicity (no feedback resistors), 100% duty cycle for ultra-low dropout, and proven robustness in industrial temperature environments - making it optimal for cost-sensitive, thermally constrained 4V–10V input applications demanding minimal external parts.
Availability
LTC1504AIS8-3.3#TRPBF is available at Aetrix Electronics and suitable for portable digital systems, active termination circuits, and auxiliary voltage supplies requiring stable component supply, long-term industrial-grade reliability, and consistent parametric performance across temperature.
Supply support for LTC1504AIS8-3.3#TRPBF 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 its legacy of high-performance analog and power management ICs with rigorous characterization and long-lifecycle support.
The LTC1504A product line was designed specifically for compact, efficient, low-component-count DC/DC conversion in portable and industrial systems where thermal constraints and reliability under varying load conditions are critical.
FAQ
What is the operating temperature range for the LTC1504AIS8-3.3#TRPBF?
The LTC1504AIS8-3.3#TRPBF is specified for industrial temperature operation from –40°C to +85°C. This is confirmed in the Absolute Maximum Ratings table and Electrical Characteristics section, where parameters like fOSC, RSW, and ∆VSENSE are guaranteed across this full range. The "I" suffix in the part number explicitly denotes the industrial grade.
Does the LTC1504AIS8-3.3#TRPBF require external feedback resistors?
No, the LTC1504AIS8-3.3#TRPBF does not require external feedback resistors. Its SENSE pin is internally trimmed to 3.3V, and the device uses direct connection to the output node for regulation. This is clearly stated in the PIN FUNCTIONS section: "SENSE (LTC1504A-3.3) (Pin 5): Output Voltage Sense. Connect directly to the output voltage node."
How is current limiting configured on the LTC1504AIS8-3.3#TRPBF?
Current limiting on the LTC1504AIS8-3.3#TRPBF is set using a single external resistor between VCC and the IMAX pin. An internal 12µA current source pulls down IMAX, establishing a reference voltage. The ILIM amplifier compares this to the voltage drop across the internal high-side switch during conduction. Typical values: 47kΩ yields ~250mA limit; 22kΩ yields ~500mA.
Can the LTC1504AIS8-3.3#TRPBF operate with a 3.3V input voltage?
No, the LTC1504AIS8-3.3#TRPBF requires a minimum input voltage of 4V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. While the datasheet notes "Contact the LTC factory for guaranteed specifications at 2.7V supply," no validation is provided for operation below 4V, and 100% duty cycle cannot compensate for insufficient headroom in buck topology.
What is the purpose of the SS pin on the LTC1504AIS8-3.3#TRPBF?
The SS (Soft Start) pin on the LTC1504AIS8-3.3#TRPBF serves a dual function: it controls output voltage ramp rate during startup via an external capacitor, and it provides compensation for the current-limit loop. As described in Applications Information, the same capacitor (e.g., 0.1µF) sets both soft-start timing and ILIM loop stability - pulling current from SS during overloads to reduce COMP voltage and limit duty cycle.
LTC1504AIS8-3.3#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 10V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 500mA
- Frequency - Switching:
- 200kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LTC1504AIS8-3.3#TRPBF FAQ
1.How can I place an order for LTC1504AIS8-3.3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1504AIS8-3.3#TRPBF 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 LTC1504AIS8-3.3#TRPBF reliable?
The price and inventory of LTC1504AIS8-3.3#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1504AIS8-3.3#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1504AIS8-3.3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1504AIS8-3.3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1504AIS8-3.3#TRPBF?
LTC1504AIS8-3.3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1504AIS8-3.3#TRPBF 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 LTC1504AIS8-3.3#TRPBF?
For technical support, including LTC1504AIS8-3.3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1504AIS8-3.3#TRPBF requirements.
6.How does Aetrix verify that LTC1504AIS8-3.3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1504AIS8-3.3#TRPBF 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 LTC1504AIS8-3.3#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1504AIS8-3.3#TRPBF?
All LTC1504AIS8-3.3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1504AIS8-3.3#TRPBF, 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 LTC1504AIS8-3.3#TRPBF part is unused and in its original packaging.
Return procedure for LTC1504AIS8-3.3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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