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Analog Devices Inc. LTC1503CS8-1.8#TRPBF
- Part No.:
- LTC1503CS8-1.8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1503CS8-1.8#TRPBF.pdf
- Description:
- IC REG CHARG PUMP 1.8V 100MA 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,307
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Product details
Overview
LTC1503CS8-1.8#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-output, inductorless switched-capacitor step-down DC/DC converter delivering 1.8 V ±4% at up to 100 mA from a 2.4 V–6 V input. It operates at 600 kHz, achieves 82.9% efficiency at 3.6 V input/100 mA load, and features shutdown disconnect, soft-start, and thermal/short-circuit protection - ideal for space-constrained Li-ion–powered handheld medical instruments.
For engineers reviewing the LTC1503CS8-1.8#TRPBF datasheet, LTC1503CS8-1.8#TRPBF pinout, LTC1503CS8-1.8#TRPBF application, or LTC1503CS8-1.8#TRPBF equivalent, key selection criteria include its no-inductor architecture, 25 µA no-load operating current, 5 µA shutdown current, 25 mVP-P output ripple with 10 µF ceramic output capacitor, and compatibility with 1 µF flying capacitors in 8-pin SO package.
Technical Context
The LTC1503CS8-1.8#TRPBF implements fractional switched-capacitor conversion using three selectable modes - 2:1, 3:2, and 1:1 - dynamically selected based on VIN/VOUT ratio and load to maximize efficiency across input and load variations. Internal comparators (COMP1 for regulation, COMP2 for mode skipping) enable seamless transitions between modes without external control.
Regulation is achieved by sensing a resistive divider of VOUT and enabling the charge pump network only as needed, enabling high light-load efficiency. The SHDN/SS pin integrates both shutdown control (threshold 0.2–0.5 V) and soft-start via external capacitor, with a 2 µA internal pull-up that ramps VREF to limit inrush current during turn-on.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 1.8 V ±4% (1.728–1.872 V), fixed and factory-trimmed - eliminates need for external feedback resistors. |
| Input Voltage Range | 2.4 V to 6 V - supports single-cell Li-ion (2.7–4.2 V), 3-cell NiMH (3.6–4.5 V), and regulated 3.3 V/5 V rails. |
| Max Output Current | 100 mA continuous - sufficient for low-power DSP cores, smart card controllers, and sensor interfaces. |
| Switching Frequency | 600 kHz fixed - enables use of small 1 µF ceramic flying capacitors and simplifies EMI filtering. |
| No-Load Operating Current | 25 µA typical - extends battery life in standby or intermittent-use portable devices. |
| Shutdown Current | 5 µA typical - ensures minimal drain during system sleep or power-off states. |
| Output Ripple | 25 mVP-P at 3.6 VIN/100 mA with 10 µF ceramic COUT - meets noise requirements for analog sensors and RF front-ends. |
| Protection Features | Indefinite short-circuit survival, overtemperature shutdown (≈150 °C), and automatic recovery - enhances system reliability without external circuitry. |
Pinout & Package
Package: 8-lead plastic SO (narrow, 0.150-inch width), RoHS-compliant, moisture sensitivity level 1, rated for –40°C to 85°C industrial temperature range.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT (Pin 1) | Regulated output voltage node | Delivers 1.8 V ±4%; must be bypassed to GND with ≥10 µF low-ESR capacitor; disconnected from VIN during shutdown. |
| C1– (Pin 2) | Flying capacitor C1 negative terminal | Connects to negative lead of first 1 µF external ceramic flying capacitor; part of charge transfer path in all conversion modes. |
| C1+ (Pin 3) | Flying capacitor C1 positive terminal | Connects to positive lead of first 1 µF flying capacitor; used in 2:1 and 3:2 modes for charge recycling. |
| VIN (Pin 4) | Main input supply connection | Accepts 2.4–6 V; requires ≥10 µF low-ESR bypass capacitor close to pin to stabilize input impedance and reduce noise. |
| SHDN/SS (Pin 5) | Combined shutdown and soft-start control | Drives into shutdown below 0.25 V; open-drain compatible; external capacitor sets VOUT ramp rate and limits inrush current. |
| C2+ (Pin 6) | Flying capacitor C2 positive terminal | Connects to positive lead of second 1 µF flying capacitor; essential for 3:2 mode operation and higher output current capability. |
| GND (Pin 7) | Analog and power ground reference | Must connect to low-impedance ground plane; serves as return path for flying caps, input/output bypass, and internal regulators. |
| C2– (Pin 8) | Flying capacitor C2 negative terminal | Connects to negative lead of second 1 µF flying capacitor; completes dual-capacitor topology required for 3:2 mode. |
Key Features
| Feature | Design Value |
|---|---|
| No-inductor architecture | Eliminates magnetic components, reduces board area by >40% vs buck converters, and avoids EMI from inductor switching. |
| Three-mode fractional conversion | Automatically selects 2:1, 3:2, or 1:1 charge-pump ratio to maintain >80% efficiency across full VIN (2.4–6 V) and IOUT (1–100 mA) range. |
| Integrated soft-start | External capacitor on SHDN/SS pin controls VOUT ramp time (e.g., 4.7 nF → ~4 ms), limiting peak inrush to ~5 mA with 10 µF COUT. |
| Low-quiescent-current shutdown | 5 µA shutdown current enables multi-year battery life in always-on monitoring devices with periodic wake-up cycles. |
| Robust protection suite | Withstands indefinite VOUT-to-GND short; limits output current to ~20 mA under short condition; shuts down at ~150 °C junction temp. |
| Industrial temperature rating | Specified and tested over –40°C to +85°C ambient - suitable for handheld medical, ruggedized industrial, and automotive accessory applications. |
Applications
| Handheld Medical Instruments | Smart Card Readers |
|---|---|
|
Use Scenario: Portable blood glucose meters and pulse oximeters powered by single-cell Li-ion batteries requiring stable 1.8 V supply for microcontroller and analog front-end. IC Role / Device Role / Timing Role: Primary step-down regulator converting 2.7–4.2 V battery voltage to tightly regulated 1.8 V for low-noise ADC reference and MCU core logic. Use Value: 25 µA no-load current extends battery runtime beyond 6 months in intermittent-use devices; 25 mVP-P ripple avoids ADC quantization errors. |
Use Scenario: Contactless smart card readers in point-of-sale terminals where compact PCB area and low standby power are critical. IC Role / Device Role / Timing Role: Power source for ISO/IEC 14443-A/B transceiver ICs and secure element, replacing LDOs to improve battery life. Use Value: 25% higher efficiency than LDOs at 50 mA load directly translates to 2× longer battery life; 8-pin SO footprint matches legacy LDO layouts. |
| Low-Power DSP Supplies | Cellular Phone Peripherals |
|
Use Scenario: Audio codec and voice processing DSPs in Bluetooth headsets operating from 3.6 V nominal Li-ion supply. IC Role / Device Role / Timing Role: Dedicated 1.8 V rail for DSP core and memory interface, isolated from noisy RF and digital domains. Use Value: 600 kHz switching frequency places ripple energy outside audio band (20 Hz–20 kHz); soft-start prevents pop noise during power-up. |
Use Scenario: Secondary power rail for camera modules or haptic drivers in feature phones where board space is constrained. IC Role / Device Role / Timing Role: Compact, low-BOM-count DC/DC solution replacing discrete charge-pump ICs and external pass FETs. Use Value: Only four external capacitors required (two 1 µF flying, two 10 µF bypass); MSOP/SO package options allow drop-in replacement in existing designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switched-capacitor step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1503CMS8-1.8#TRPBF | Same electrical specs, but in 8-lead MSOP (3 mm × 3 mm) instead of SO (4.9 mm × 3.9 mm); θJA = 150°C/W vs 200°C/W. | Better thermal performance and smaller footprint - preferred for ultra-compact designs with adequate airflow. | Select when PCB area is premium and thermal margin is tight; verify MSOP soldering process compatibility. |
| LTC1754-1.8 | Fixed 1.8 V output, SOT-23-5, 50 mA max, 13 µA IQ, no soft-start or mode skipping; simpler 1:1/2:1 only. | Limited to lighter loads and less demanding regulation - suitable for ASIC bias rails, not main processor supplies. | Choose only for <50 mA, cost-sensitive, space-limited applications where 100 mA capability and dynamic mode control are unnecessary. |
Compared with LTC1503CMS8-1.8#TRPBF and LTC1754-1.8, the LTC1503CS8-1.8#TRPBF offers the best balance of output current (100 mA), efficiency across wide input range, and integrated soft-start - making it the optimal choice for industrial and medical handhelds requiring robust, field-proven performance in SO package.
Availability
LTC1503CS8-1.8#TRPBF is available at Aetrix Electronics and suitable for handheld medical instruments, smart card readers, low-power DSP supplies, cellular phone peripherals, and portable electronic equipment requiring stable component supply with long-term manufacturability.
Supply support for LTC1503CS8-1.8#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 full product support, datasheets, and application engineering for legacy Linear parts including the LTC series.
The LTC1503CS8-1.8#TRPBF belongs to Linear's precision switched-capacitor DC/DC converter family, designed specifically for battery-powered portable systems needing high-efficiency, inductorless voltage reduction without sacrificing regulation accuracy or protection integrity.
FAQ
What is the maximum recommended output current for the LTC1503CS8-1.8#TRPBF?
The LTC1503CS8-1.8#TRPBF is specified to deliver up to 100 mA continuously under typical conditions (VIN = 3.6 V, TA = 25°C, with proper 10 µF input/output and 1 µF flying capacitors). At higher ambient temperatures or lower input voltages, derating applies - e.g., ~80 mA at 85°C ambient with VIN = 2.4 V. Exceeding 100 mA may trigger mode skipping or thermal shutdown.
Can the LTC1503CS8-1.8#TRPBF operate from a 2.4 V input?
Yes, the LTC1503CS8-1.8#TRPBF is fully specified down to 2.4 V input. At this minimum VIN, it operates in 1:1 gated-switch mode to maintain 1.8 V output, achieving ~65% efficiency at 100 mA. Input undervoltage lockout is not implemented, so operation remains functional across the entire 2.4 V–6 V range.
Does the LTC1503CS8-1.8#TRPBF require external feedback resistors?
No, the LTC1503CS8-1.8#TRPBF has a factory-trimmed, fixed 1.8 V output. Its internal reference and error amplifier are configured for direct 1.8 V regulation - eliminating external resistors, saving board space, and improving long-term stability versus resistor-based feedback networks.
How does the soft-start function work on the LTC1503CS8-1.8#TRPBF?
The SHDN/SS pin on the LTC1503CS8-1.8#TRPBF serves dual purpose: pulling it below 0.25 V enables shutdown, while connecting an external capacitor to GND enables soft-start. A 2 µA internal current source charges the capacitor, ramping the internal reference voltage linearly - thereby controlling VOUT slew rate and limiting inrush current to predictable levels (e.g., 4.7 nF → ~4 ms ramp, ~5 mA average).
Is the LTC1503CS8-1.8#TRPBF RoHS compliant and halogen-free?
Yes, the LTC1503CS8-1.8#TRPBF is RoHS compliant and halogen-free per Analog Devices' material declarations. The "#TRPBF" suffix explicitly denotes lead-free (Pb-free), RoHS-compliant, and tape-and-reel packaging - verified in the official ADI parametric database and product change notices.
LTC1503CS8-1.8#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:
- Charge Pump
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.4V
- Voltage - Input (Max):
- 6V
- Voltage - Output (Min/Fixed):
- 1.8V
- Voltage - Output (Max):
- -
- Current - Output:
- 100mA
- Frequency - Switching:
- 600kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LTC1503CS8-1.8#TRPBF FAQ
1.How can I place an order for LTC1503CS8-1.8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1503CS8-1.8#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 LTC1503CS8-1.8#TRPBF reliable?
The price and inventory of LTC1503CS8-1.8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1503CS8-1.8#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1503CS8-1.8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1503CS8-1.8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1503CS8-1.8#TRPBF?
LTC1503CS8-1.8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1503CS8-1.8#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 LTC1503CS8-1.8#TRPBF?
For technical support, including LTC1503CS8-1.8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1503CS8-1.8#TRPBF requirements.
6.How does Aetrix verify that LTC1503CS8-1.8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1503CS8-1.8#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 LTC1503CS8-1.8#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1503CS8-1.8#TRPBF?
All LTC1503CS8-1.8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1503CS8-1.8#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 LTC1503CS8-1.8#TRPBF part is unused and in its original packaging.
Return procedure for LTC1503CS8-1.8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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