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Analog Devices Inc. LT1173CS8-5#PBF
- Part No.:
- LT1173CS8-5#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1173CS8-5#PBF.pdf
- Description:
- IC REG BUCK BOOST 5V 1.5A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:153
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Product details
Overview
LT1173CS8-5#PBF from Analog Devices (formerly Linear Technology) is a fixed-output 5V micropower DC/DC converter IC operating in step-up, step-down, or inverting topologies. It features 110µA quiescent current, internal 1A power switch, 23kHz oscillator, and operates from 2.0V to 30V input. It delivers 5V at 80mA from 3V input (boost) or 5V at 200mA from 12V input (buck), suited for battery-powered flash memory VPP generation.
For engineers reviewing the LT1173CS8-5#PBF datasheet, LT1173CS8-5#PBF pinout, LT1173CS8-5#PBF application, or LT1173CS8-5#PBF equivalent, key selection criteria include its fixed 5V output accuracy (±5%), programmable current limit via ILIM pin, integrated low-battery comparator, and SO-8 package compatibility with space-constrained portable designs.
Technical Context
The LT1173CS8-5#PBF uses a gated-oscillator architecture where the 23kHz switching cycle activates only when feedback voltage drops below the 1.245V internal reference, minimizing idle current. Its adaptive base drive ensures switch saturation without overdrive, improving efficiency across input ranges.
It integrates a dual-function auxiliary gain block (AO/SET pins) configurable as low-battery detector or error amplifier, and a dedicated current-limit circuit that terminates switch conduction based on external resistor value between ILIM and VIN - enabling robust operation under variable input conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.00V ±5% (guaranteed over full load and temperature range) |
| Input Voltage Range | 2.0V–12.6V (step-up), 3.0V–30V (step-down); supports single-cell Li-ion to 24V industrial rails |
| Quiescent Current | 110µA (switch off), 135µA (boost mode, no load); enables multi-year battery life in standby |
| Switch Current Limit | Programmable up to 1.5A peak; 400mA default with 220Ω resistor from ILIM to VIN |
| Oscillator Frequency | 18–30kHz (typ. 23kHz); low frequency reduces EMI and allows use of low-cost, high-saturation inductors |
| Efficiency | 81% measured at 12V→5V/100mA (step-down); optimized for light-to-moderate loads |
| Operating Temperature | 0°C to 70°C; suitable for commercial portable and peripheral applications |
Pinout & Package
LT1173CS8-5#PBF is housed in an 8-lead plastic SOIC (SO-8) package with standard JEDEC MS-012AC footprint, 1.27mm pitch, and thermal resistance θJA = 150°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ILIM (Pin 1) | Current limit programming input | Resistor from ILIM to VIN sets peak switch current; open or tied to VIN enables full 1.5A rating |
| VIN (Pin 2) | Main power supply input | Accepts 2.0V–30V; powers internal circuitry and switch driver; must be bypassed with ≥10µF capacitor |
| SW1 (Pin 3) | Power switch collector | In boost: connects to inductor/diode node; in buck: connects to VIN; withstands up to 50V |
| SW2 (Pin 4) | Power switch emitter | In boost: grounded; in buck: drives inductor; must not fall below –0.5V (Schottky clamp required) |
| GND (Pin 5) | Analog and power ground reference | Single-point ground connection; separates sensitive feedback path from high-current return |
| AO (Pin 6) | Auxiliary gain block open-collector output | Sinks 100µA max; used for low-battery flag, UVLO, or linear post-regulator control |
| SET (Pin 7) | Auxiliary gain block non-inverting input | Connected to resistor divider from VIN for trip-point setting; bias current ≤100nA |
| FB/SENSE (Pin 8) | Feedback input / fixed-output sense | Internally connected to 5V-setting resistors; must connect directly to regulated 5V output |
Key Features
| Feature | Design Value |
|---|---|
| Three-component topology | Only inductor, diode, and output capacitor required for full 5V regulation - reduces BOM count and board area |
| Integrated low-battery comparator | 1.245V reference with 5–10mV hysteresis enables accurate, self-contained battery monitoring without external ICs |
| Configurable operating mode | Same IC supports boost (2V→5V), buck (12V→5V), and inverting (5V→–5V) via pin-strapping - simplifies inventory and design reuse |
| Programmable current limit | Single resistor from ILIM to VIN adjusts peak switch current from ~400mA to 1.5A - prevents inductor saturation and switch overstress |
| SO-8 thermal performance | θJA = 150°C/W enables 500mW max power dissipation at ambient - sufficient for 5V/100mA continuous operation |
Applications
| Flash Memory VPP Generation | Portable Instrument Power |
|---|---|
|
Use Scenario: Generating +12V programming voltage for NOR/NAND flash memory in handheld data loggers. IC Role / Device Role / Timing Role: Fixed-output DC/DC converter providing regulated VPP during write/erase cycles; operates in step-up mode from 3.3V system rail. Use Value: Eliminates need for external charge pump or transformer-based solution; 110µA quiescent current preserves battery life between memory operations. |
Use Scenario: Supplying stable 5V rail to microcontroller, ADC, and sensor interface in battery-powered environmental monitors. IC Role / Device Role / Timing Role: Primary 5V regulator in buck configuration, accepting 9V–12V alkaline or NiMH input. Use Value: Delivers 200mA at 81% efficiency while maintaining <150µA total system standby current - extends field deployment to >12 months. |
| Laptop Peripheral Card Supply | Cellular Phone Baseband Bias |
|
Use Scenario: Powering USB-hosted add-on cards (e.g., GPS, RFID) from 5V PCIe slot with tight space constraints. IC Role / Device Role / Timing Role: Compact 5V regulator in SO-8 package; accepts 5V input, regulates to clean 5V output with low ripple. Use Value: Internal current limiting and thermal shutdown protect against short-circuit events on hot-plugged peripherals without external protection circuitry. |
Use Scenario: Providing isolated 5V bias for RF front-end ICs and analog baseband circuits in 2G/3G mobile handsets. IC Role / Device Role / Timing Role: Low-noise, low-EMI DC/DC source; operates in discontinuous conduction mode to minimize conducted emissions near sensitive receivers. Use Value: 23kHz switching frequency avoids GSM transmit bands (900/1800MHz); SO-8 layout minimizes parasitic inductance for clean analog supply. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar micropower DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1307CS8-5#PBF | 750kHz oscillator, higher efficiency (>85%) at light loads, but 350µA quiescent current | Better for noise-sensitive audio or RF sections; less suitable for ultra-low-power sleep modes | Choose LT1307CS8-5#PBF if efficiency above 10mA load is critical and 3× higher IQ is acceptable |
| TPS61200DRCR | Adjustable output (0.9–5.5V), 1.2MHz switching, 50µA IQ, but requires external feedback resistors | Supports dynamic voltage scaling; lacks integrated low-battery comparator and fixed 5V option | Choose TPS61200DRCR if system requires programmable output or lowest possible quiescent current, and can accommodate external resistors |
Compared with LT1173CS8-5#PBF, LT1307CS8-5#PBF trades lower quiescent current for higher switching frequency and efficiency, while TPS61200DRCR offers greater flexibility at the cost of added external components and absence of built-in monitoring functions.
Availability
LT1173CS8-5#PBF is available at Aetrix Electronics and suitable for portable instruments, cellular telephones, and flash memory VPP generators requiring stable component supply with long-term lifecycle support.
Supply support for LT1173CS8-5#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LT1173 product line was designed for ultra-low-power, multi-topology DC/DC conversion in battery-critical portable systems - emphasizing minimal quiescent current, minimal external components, and flexible configuration without sacrificing reliability.
FAQ
What is the output voltage tolerance of the LT1173CS8-5#PBF?
The LT1173CS8-5#PBF provides a fixed 5V output with guaranteed tolerance of ±5% (4.75V to 5.25V) across full load, line, and temperature ranges. This specification is ensured by factory-trimmed internal resistors and applies specifically to the -5 variant - not the adjustable LT1173 or -12 versions.
Can the LT1173CS8-5#PBF operate in step-down (buck) mode?
Yes, the LT1173CS8-5#PBF supports step-down operation from inputs up to 30V to deliver regulated 5V output. In buck mode, SW1 connects to VIN and SW2 drives the inductor; output current capability reaches 200mA at 12V input. The fixed 5V feedback network remains valid, requiring no external resistors.
How is current limiting configured on the LT1173CS8-5#PBF?
Current limiting on the LT1173CS8-5#PBF is set by connecting a resistor between ILIM (Pin 1) and VIN. A 220Ω resistor limits peak switch current to ~400mA; omitting the resistor or tying ILIM directly to VIN enables the full 1.5A rating. The relationship is monotonic and documented in the "Maximum Switch Current vs RLIM" curve.
Does the LT1173CS8-5#PBF include a low-battery detection function?
Yes, the LT1173CS8-5#PBF integrates a precision comparator referenced to 1.245V with 5–10mV hysteresis. Using the SET and AO pins, designers can configure a low-battery detector that asserts a logic-low flag when input voltage falls below a user-defined threshold - all without external comparators or references.
What package type does the LT1173CS8-5#PBF use, and is it RoHS-compliant?
The LT1173CS8-5#PBF uses an 8-lead plastic SOIC (SO-8) package per JEDEC MS-012AC, with 1.27mm lead pitch and exposed pad omitted. It is RoHS-compliant and lead-free, indicated by the #PBF suffix; the device meets IPC/JEDEC J-STD-020 moisture sensitivity level 3 and is rated for reflow soldering up to 260°C.
LT1173CS8-5#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
- 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#PBF FAQ
1.How can I place an order for LT1173CS8-5#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1173CS8-5#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 LT1173CS8-5#PBF reliable?
The price and inventory of LT1173CS8-5#PBF 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#PBF is usually 5 days.
3.What payment methods are accepted for LT1173CS8-5#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1173CS8-5#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1173CS8-5#PBF?
LT1173CS8-5#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1173CS8-5#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 LT1173CS8-5#PBF?
For technical support, including LT1173CS8-5#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1173CS8-5#PBF requirements.
6.How does Aetrix verify that LT1173CS8-5#PBF is sourced from the original manufacturer or authorized distributors?
All LT1173CS8-5#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 LT1173CS8-5#PBF meets industry standards.
7.What is the process for return or replacement of LT1173CS8-5#PBF?
All LT1173CS8-5#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1173CS8-5#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 LT1173CS8-5#PBF part is unused and in its original packaging.
Return procedure for LT1173CS8-5#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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