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Analog Devices Inc. LT1173CS8-5#TRPBF
- Part No.:
- LT1173CS8-5#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1173CS8-5#TRPBF.pdf
- Description:
- IC REG BUCK BOOST 5V 1.5A 8SO
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LT1173CS8-5#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-output 5V micropower DC/DC converter IC in SO-8 package, operating from 2.0V to 12.6V input in step-up mode or up to 30V in step-down mode, delivering up to 200mA at 5V from 12V input, with 110µA quiescent current and internal 1A power switch - used in battery-powered flash memory VPP generation and portable instrument power rails.
For engineers reviewing the LT1173CS8-5#TRPBF datasheet, LT1173CS8-5#TRPBF pinout, LT1173CS8-5#TRPBF application, or LT1173CS8-5#TRPBF equivalent, key selection criteria include its fixed 5V output, programmable current limit via ILIM pin, integrated low-battery comparator, 23kHz gated oscillator architecture, and compatibility with step-up, step-down, and inverting topologies without external feedback resistors.
Technical Context
The LT1173CS8-5#TRPBF implements a gated oscillator switching architecture where the internal 23kHz oscillator activates only when FB voltage falls below the 1.245V reference, minimizing quiescent current to 110µA. Its adaptive base drive ensures switch saturation without overdrive, improving efficiency in both step-up and step-down configurations.
Pin 8 (FB/SENSE) connects directly to output for fixed 5V regulation; internal resistor divider sets VOUT = 5.00V ±2.5% (4.75–5.25V). The ILIM pin enables user-adjustable current limiting (e.g., 400mA with 220Ω to VIN), and the AO/SET pins provide auxiliary gain block functionality for low-battery detection or post-regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.00V ±2.5% - eliminates need for external feedback resistors in 5V supply designs. |
| Input Voltage Range | 2.0V–12.6V (step-up), 30V max (step-down) - supports single-cell Li-ion, multi-cell alkaline, and industrial rail inputs. |
| Quiescent Current | 110µA (switch off), 135µA (boost no load) - enables >1-year battery life in intermittent-use portable instruments. |
| Switch Current Limit | Programmable up to 1.5A - protects against inductor saturation and switch overstress across input voltage variations. |
| Oscillator Frequency | 18–30kHz (typ. 23kHz) - balances EMI control and inductor size; gated operation reduces average switching loss. |
| Operating Temp | 0°C to 70°C - suitable for commercial-grade embedded systems and consumer electronics enclosures. |
| Package | SO-8 (S8) - surface-mount compatible with automated assembly; θJA = 150°C/W for thermal management. |
Pinout & Package
LT1173CS8-5#TRPBF uses an 8-pin plastic SOIC (S8) package with standard SO-8 footprint and 1.27mm pitch. Pin 1 (ILIM) sets current limit; Pin 2 (VIN) accepts 2–30V input; Pins 3 (SW1) and 4 (SW2) form the NPN power switch collector/emitter; Pin 5 (GND) is ground reference; Pin 6 (AO) is open-collector auxiliary output; Pin 7 (SET) is gain block non-inverting input; Pin 8 (FB/SENSE) connects directly to regulated 5V output.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ILIM (Pin 1) | Current limit programming node | Resistor from ILIM to VIN sets switch current trip point (e.g., 220Ω → ~400mA); tie directly to VIN for full 1.5A capability. |
| VIN (Pin 2) | Main power input | Supplies internal circuitry and switch; withstands up to 36V absolute max; powers oscillator, reference, and driver stages. |
| SW1 (Pin 3) | Power switch collector | In step-up: drives inductor/diode; in step-down: connects to VIN; rated for 50V max voltage swing. |
| SW2 (Pin 4) | Power switch emitter | In step-up: grounded; in step-down: drives inductor/diode; must not fall below –0.5V to avoid latch-up. |
| GND (Pin 5) | Analog/digital ground reference | Common return for reference, comparator, oscillator, and gain block; requires low-impedance PCB connection. |
| AO (Pin 6) | Auxiliary gain block output | Open-collector NPN output sinking up to 100µA - used for low-battery flag or error signal to MCU. |
| SET (Pin 7) | Gain block non-inverting input | Accepts voltage divider from VIN to set low-battery threshold; bias current <100nA minimizes divider loading. |
| FB/SENSE (Pin 8) | Feedback sense input | Internally connected to 5V-setting resistor divider; shorted to VOUT for regulation - no external resistors required. |
Key Features
| Feature | Design Value |
|---|---|
| Gated oscillator architecture | Enables 110µA quiescent current by disabling high-current circuitry between regulation cycles - critical for battery longevity. |
| Integrated 1A NPN power switch | Eliminates external transistor and base drive components; reduces BOM count and layout area in space-constrained designs. |
| Fixed 5V output with internal resistor network | Removes need for external feedback dividers - simplifies design, improves accuracy, and avoids resistor tolerance drift effects. |
| User-programmable current limit | Single resistor on ILIM pin allows precise switch current clamping - prevents inductor saturation and overcurrent failure during input transients. |
| On-chip low-battery comparator | 1.245V reference with 5–10mV hysteresis enables reliable undervoltage detection using only two external resistors on SET pin. |
Applications
| Flash Memory VPP Generation | Portable Instrument Power Supply |
|---|---|
Use Scenario: Generating +12V programming voltage for NOR/NAND flash memory in handheld test equipment with single 3.7V Li-ion cell. IC Role / Device Role / Timing Role: Step-up DC/DC converter providing regulated 12V output from 3V–4.2V battery input; LT1173CS8-5#TRPBF variant not used here - but LT1173CS8-12 is pin-compatible family member. Use Value: Enables in-system flash reprogramming without external boost modules; 81% efficiency at 50mA reduces thermal load in sealed enclosures. | Use Scenario: Powering 5V analog front-end and microcontroller in battery-operated multimeter with 2×AA alkaline cells (2.0–3.2V range). IC Role / Device Role / Timing Role: Fixed 5V step-up regulator delivering 80mA continuous output; LT1173CS8-5#TRPBF provides stable rail despite battery discharge curve. Use Value: 110µA quiescent current extends battery life beyond 18 months in sleep mode; SO-8 package fits compact 2-layer PCB. |
| Laptop Peripheral Card Power | Cellular Phone Backlight Driver |
Use Scenario: Providing isolated 5V rail for USB add-on card in legacy laptop docking station with variable 9–12V input. IC Role / Device Role / Timing Role: Step-down regulator converting 12V system rail to 5V logic supply; LT1173CS8-5#TRPBF operates in buck mode with SW1 tied to VIN and SW2 driving inductor. Use Value: Internal current limit (via ILIM resistor) prevents overcurrent during hot-plug events; 200mA output supports multiple USB peripherals. | Use Scenario: Driving white LED backlight in early GSM handset using 3.6V Li-ion battery with dynamic brightness control. IC Role / Device Role / Timing Role: Step-up converter generating ~5.5V from battery to forward-bias series LEDs; LT1173CS8-5#TRPBF not used - but adjustable LT1173 variant enables dimming via FB voltage modulation. Use Value: Gated oscillator minimizes standby current during display-off periods; Schottky diode interface supports fast PWM dimming without audible noise. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1173CN8-5 | DIP-8 package, 0°C–70°C commercial temp, higher θJA (130°C/W), leaded through-hole mounting | Suitable for prototyping, lab equipment, or legacy through-hole assemblies where SO-8 reflow is unavailable | Select LT1173CN8-5 for hand-soldered evaluation or repair; LT1173CS8-5#TRPBF preferred for volume SMT production. |
| LT1111CS8-5#TRPBF | 72kHz oscillator, smaller inductor/capacitor requirements, same SO-8 pinout, 100µA IQ, 5V fixed output | Better suited for space-constrained designs requiring <100µH inductors and lower output ripple at higher frequency | Choose LT1111CS8-5#TRPBF when board area is critical and EMI filtering can accommodate 72kHz; LT1173CS8-5#TRPBF retains advantage in ultra-low-noise analog sections. |
Compared with LT1173CN8-5, the LT1173CS8-5#TRPBF offers superior thermal performance in SMT layouts and smaller footprint; versus LT1111CS8-5#TRPBF, it provides lower EMI and relaxed component tolerances due to its 23kHz fundamental frequency - making it preferable in mixed-signal portable instruments.
Availability
LT1173CS8-5#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation, flash memory programming circuits, and battery-backed peripheral supplies requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
Supply support for LT1173CS8-5#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, Inc. (ADI) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and power management.
The LT1173 family was originally developed by Linear Technology (acquired by ADI in 2017) to address ultra-low-power DC/DC conversion needs in portable and battery-critical applications - emphasizing micropower operation, topology flexibility, and integrated protection features.
FAQ
What is the output voltage tolerance of the LT1173CS8-5#TRPBF?
The LT1173CS8-5#TRPBF delivers a fixed 5.00V output with a guaranteed tolerance of ±2.5% (4.75V to 5.25V) over temperature and line conditions. This specification is ensured by laser-trimmed internal resistor networks and a stable 1.245V bandgap reference, eliminating dependency on external component tolerances.
Can the LT1173CS8-5#TRPBF operate in step-down (buck) mode?
Yes, the LT1173CS8-5#TRPBF supports step-down operation with input voltages up to 30V and delivers 5V at up to 200mA from a 12V input. In buck mode, SW1 connects to VIN and SW2 drives the inductor-diode network; output voltage remains regulated at 5V via internal feedback, and current limiting via ILIM pin is recommended for reliability.
Does the LT1173CS8-5#TRPBF require external feedback resistors?
No, the LT1173CS8-5#TRPBF does not require external feedback resistors. It integrates precision resistors to set the 5V output, with Pin 8 (FB/SENSE) connected directly to the output node. This eliminates resistor matching errors, temperature drift, and layout sensitivity - simplifying design and improving long-term stability.
How is current limiting configured on the LT1173CS8-5#TRPBF?
Current limiting on the LT1173CS8-5#TRPBF is configured by connecting a resistor between Pin 1 (ILIM) and VIN. For example, a 220Ω resistor limits peak switch current to approximately 400mA. If no limiting is needed, ILIM is tied directly to VIN. The relationship between RLIM and current limit is monotonic and documented in the "Maximum Switch Current vs RLIM" curves.
What is the purpose of the AO and SET pins on the LT1173CS8-5#TRPBF?
The AO (Pin 6) and SET (Pin 7) pins implement an auxiliary gain block with the negative input tied internally to the 1.245V reference. SET accepts a voltage divider from VIN to set a low-battery threshold; AO provides an open-collector output that sinks up to 100µA when the threshold is crossed - enabling direct interface with microcontroller interrupt or reset lines without additional components.
LT1173CS8-5#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-Up, Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2V
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 1.5A (Switch)
- Frequency - Switching:
- 23kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1173CS8-5#TRPBF FAQ
1.How can I place an order for LT1173CS8-5#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1173CS8-5#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 LT1173CS8-5#TRPBF reliable?
The price and inventory of LT1173CS8-5#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1173CS8-5#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1173CS8-5#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1173CS8-5#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1173CS8-5#TRPBF?
LT1173CS8-5#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1173CS8-5#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 LT1173CS8-5#TRPBF?
For technical support, including LT1173CS8-5#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1173CS8-5#TRPBF requirements.
6.How does Aetrix verify that LT1173CS8-5#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1173CS8-5#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 LT1173CS8-5#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1173CS8-5#TRPBF?
All LT1173CS8-5#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1173CS8-5#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 LT1173CS8-5#TRPBF part is unused and in its original packaging.
Return procedure for LT1173CS8-5#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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