My Inquiry
My Account
Analog Devices Inc. LT1173CS8#PBF
- Part No.:
- LT1173CS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1173CS8#PBF.pdf
- Description:
- IC REG BUCK BOOST ADJ 1.5A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:367
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT1173CS8#PBF from Analog Devices (formerly Linear Technology) is a micropower DC/DC converter IC capable of step-up, step-down, and inverting operation with internal 1A power switch. It delivers fixed or adjustable output voltages (e.g., 5V or 12V), operates from 2.0V to 30V input, consumes only 110µA quiescent current, and requires just three external components. It is used in battery-powered flash memory VPP generation and portable instrument power supplies.
For engineers reviewing the LT1173CS8#PBF datasheet, LT1173CS8#PBF pinout, LT1173CS8#PBF application, or LT1173CS8#PBF equivalent, key selection criteria include its gated-oscillator architecture for ultra-low IQ, programmable current limit via ILIM pin, on-chip low-battery comparator, auxiliary gain block for post-regulation or UVLO, and compatibility with SO-8 footprint for space-constrained designs.
Technical Context
The LT1173CS8#PBF implements a gated-oscillator switching architecture where the 23kHz oscillator activates only when feedback voltage falls below the 1.245V internal reference, minimizing idle current. Its adaptive base drive ensures switch saturation without overdrive, improving efficiency in both boost and buck topologies.
It integrates a dual-function auxiliary gain block (AO/SET pins) configurable as a low-battery detector or error amplifier, and a dedicated ILIM pin enabling precise external resistor programming of switch current limit-critical for stable operation across wide input voltage ranges and preventing inductor saturation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Quiescent Current | 110 µA at shutdown - enables multi-year battery life in always-on portable devices |
| Input Voltage Range | 2.0 V to 30 V - supports single-cell Li-ion (2.7–4.2 V), 9 V batteries, and industrial 24 V rails |
| Output Configurations | Adjustable (via FB pin) or fixed 5 V / 12 V - eliminates external feedback resistors for standard outputs |
| Switch Current Limit | Programmable up to 1.5 A via ILIM-to-VIN resistor - prevents MOSFET/inductor overload during input transients |
| Oscillator Frequency | 18–30 kHz (typ. 23 kHz) - balances EMI control and inductor size; no external timing component required |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded and portable equipment use |
| Package | 8-lead SOIC (SO-8) - surface-mount compatible with automated assembly and thermal performance θJA = 150°C/W |
Pinout & Package
LT1173CS8#PBF is housed in an 8-lead plastic SOIC (S8) package with standard SO-8 footprint (5.0 mm × 6.2 mm, 1.27 mm pitch). Thermal resistance is θJA = 150°C/W; maximum junction temperature is 90°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ILIM (Pin 1) | Current limit programming input | Connect resistor to VIN to set switch current threshold; open or tied to VIN for full 1.5 A capability |
| VIN (Pin 2) | Main power supply input | Accepts 2.0–30 V; powers internal circuitry and switch driver; must be bypassed with ≥1 µF ceramic capacitor |
| SW1 (Pin 3) | Power switch collector | In boost mode: connects to inductor/diode node; in buck mode: connects to VIN; rated to 50 V |
| SW2 (Pin 4) | Power switch emitter | In boost mode: grounded; in buck mode: drives inductor; must not fall below –0.5 V (Schottky clamp required) |
| GND (Pin 5) | Analog and power ground reference | Common return for feedback, gain block, and switch; requires low-impedance PCB connection |
| AO (Pin 6) | Auxiliary gain block open-collector output | Sinks up to 100 µA; used for low-battery flag, linear post-regulator drive, or UVLO signaling |
| SET (Pin 7) | Gain block non-inverting input | Connected to resistor divider from VIN for programmable trip point; bias current ≤100 nA |
| FB/SENSE (Pin 8) | Feedback input or fixed-output sense | On LT1173CS8#PBF (adjustable version): compares to 1.245 V reference; on -5/-12 variants: internal resistor divider sets VOUT |
Key Features
| Feature | Design Value |
|---|---|
| Gated oscillator architecture | Enables 110 µA quiescent current by disabling high-current circuitry between regulation cycles |
| Integrated 1 A NPN power switch | Eliminates external transistor; reduces BOM count and layout area in compact converters |
| User-adjustable current limit | Single external resistor sets peak switch current from ~400 mA to 1.5 A, protecting against inductor saturation |
| On-chip low-battery comparator | 1.20–1.30 V trip range with 5–10 mV hysteresis - provides reliable undervoltage detection without extra IC |
| Auxiliary gain block (AO/SET) | Configurable op-amp stage with 400–1000 V/V gain - supports linear post-regulation, UVLO, or battery monitoring |
Applications
| Flash Memory VPP Generation | Portable Instrument Power Supply |
|---|---|
Use Scenario: Generating +12 V programming voltage for NOR/NAND flash memory in handheld test equipment. IC Role / Device Role / Timing Role: Step-up DC/DC converter with fixed 12 V output and automatic load-disconnect during standby. Use Value: Delivers 50 mA at 12 V from 3 V battery with 81% efficiency and <110 µA sleep current - extends field calibration tool runtime. |
Use Scenario: Providing regulated 5 V rail for microcontroller, ADC, and display in battery-operated multimeter. IC Role / Device Role / Timing Role: Adjustable boost converter configured for 5 V output with integrated low-battery warning. Use Value: Maintains stable 5 V ±2.5% output across 2.0–3.6 V Li-ion discharge curve while signaling battery depletion via AO pin. |
| Laptop Peripheral Card Power | Battery Backup Supply |
Use Scenario: Powering USB-to-serial adapter card from 5 V host bus in ultraportable laptop docking station. IC Role / Device Role / Timing Role: Step-down regulator converting 5 V bus to 3.3 V logic rail with current limiting for short-circuit protection. Use Value: Supports 200 mA load at 3.3 V with <135 µA quiescent current in boost mode - minimizes parasitic drain on host system. |
Use Scenario: Maintaining real-time clock (RTC) and SRAM backup during main power failure in industrial controller. IC Role / Device Role / Timing Role: Low-IQ buck-boost converter accepting 2.0–5.5 V input to sustain 3.0 V backup rail. Use Value: Draws only 110 µA from coin cell while delivering 10 mA - enables >5-year RTC retention without recharge. |
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#PBF | Higher 1.3 MHz switching frequency; lower IQ (75 µA); no integrated current limit programming | Better suited for ultra-small inductor/capacitor designs; lacks ILIM pin for precise switch current control | Select when board space is critical and input range is narrow (2.7–6 V); avoid if wide VIN or programmable current limit is required |
| TPS61040DRVR | Fixed 28 V switch rating; 500 kHz oscillator; integrated soft-start; no auxiliary gain block | Optimized for LED backlighting; lacks comparator and gain block for system monitoring functions | Prefer for cost-sensitive consumer electronics needing fast transient response; not suitable for low-battery detection or post-regulation |
Compared with LT1173CS8#PBF, LT1307CS8#PBF offers higher frequency and lower IQ but omits the ILIM and AO/SET features essential for programmable protection and system supervision; TPS61040DRVR provides better integration for lighting loads but cannot replace the LT1173CS8#PBF's dual-role analog blocks in battery management systems.
Availability
LT1173CS8#PBF is available at Aetrix Electronics and suitable for flash memory VPP generation, portable instrument power supplies, and battery backup systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT1173CS8#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 power products.
The LT1173 product line was designed for ultra-low-power portable and battery-backed applications requiring flexible topology support (boost/buck/inverting), minimal external components, and integrated system supervision functions.
FAQ
What is the maximum output current capability of the LT1173CS8#PBF in step-up mode?
The LT1173CS8#PBF supports up to 80 mA at 5 V from a 3 V input in step-up mode, as specified in the datasheet under typical operating conditions. Peak switch current is limited to 1.5 A internally, but practical output current depends on inductor selection, diode drop, and thermal derating. For sustained 80 mA output, a 100 µH inductor and 1N5818 Schottky diode are recommended per application note TA01.
Can the LT1173CS8#PBF be used in step-down (buck) configuration?
Yes, the LT1173CS8#PBF operates in step-down mode with input voltages up to 30 V and delivers up to 200 mA at 5 V from a 12 V input. In buck mode, SW1 connects to VIN and SW2 drives the inductor; the ILIM pin must be used with a series resistor (e.g., 100 Ω) to limit peak switch current to ~650 mA and prevent saturation. Output voltage remains adjustable via the FB pin.
How does the ILIM pin function on the LT1173CS8#PBF?
The ILIM pin on the LT1173CS8#PBF allows external programming of the switch current limit using a resistor between ILIM and VIN. A 220 Ω resistor sets ~400 mA limit; lower resistance increases limit up to 1.5 A. This feature prevents inductor saturation and switch overstress during input voltage surges or light-load discontinuous conduction, making it essential for robust operation across variable input conditions.
Is the LT1173CS8#PBF pin-compatible with fixed-output variants like LT1173CS8-5#PBF?
No, the LT1173CS8#PBF (adjustable version) is not pin-compatible with fixed-output variants such as LT1173CS8-5#PBF. While all share the same SO-8 package and pinout numbering, the FB/SENSE pin (Pin 8) functions differently: on LT1173CS8#PBF it is a high-impedance comparator input, whereas on LT1173CS8-5#PBF it connects internally to a precision resistor divider for 5 V regulation - requiring different external feedback network design.
What is the role of the AO and SET pins on the LT1173CS8#PBF?
The AO (Pin 6) and SET (Pin 7) pins form an auxiliary gain block: SET is the non-inverting input referenced to the internal 1.245 V bandgap, and AO is an open-collector output sinking up to 100 µA. This block can be configured as a low-battery detector (using resistor divider on SET), linear post-regulator (AO driving pass transistor), or UVLO circuit - providing system-level supervision without adding discrete comparators or op-amps.
LT1173CS8#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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2V
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 1.245V
- Voltage - Output (Max):
- 50V (Switch)
- 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#PBF FAQ
1.How can I place an order for LT1173CS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1173CS8#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#PBF reliable?
The price and inventory of LT1173CS8#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#PBF is usually 5 days.
3.What payment methods are accepted for LT1173CS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1173CS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1173CS8#PBF?
LT1173CS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1173CS8#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#PBF?
For technical support, including LT1173CS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1173CS8#PBF requirements.
6.How does Aetrix verify that LT1173CS8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1173CS8#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#PBF meets industry standards.
7.What is the process for return or replacement of LT1173CS8#PBF?
All LT1173CS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1173CS8#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#PBF part is unused and in its original packaging.
Return procedure for LT1173CS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT1173CS8#PBF Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
