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Analog Devices Inc. LT1432CN8
- Part No.:
- LT1432CN8
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LT1432CN8.pdf
- Description:
- IC REG CTRLR BUCK 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,035
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Product details
Overview
LT1432CN8 from Analog Devices (formerly Linear Technology) is a dedicated 5V step-down switching regulator controller IC designed to drive external current-mode switchers (e.g., LT1170/LT1270 family) in high-efficiency buck converters. It delivers regulated +5V output with up to 90% efficiency, features 60mV ultra-low-loss current sensing, logic-controlled burst mode for light loads (5–100mA), and shutdown current of 15µA. It is used in portable digital systems requiring stable 5V rail generation from 6V–30V inputs.
For engineers reviewing the LT1432CN8 datasheet, LT1432CN8 pinout, LT1432CN8 application, or LT1432CN8 equivalent, key selection considerations include its fixed +5V output regulation, compatibility with LT1070-family switchers, burst-mode quiescent input current (1.3mA), 8-pin DIP package, and precise 60mV current limit sense voltage with copper-trace temperature tracking.
Technical Context
The LT1432CN8 implements a transconductance error amplifier with internal 5.0V reference and open-collector NPN level-shifting output to drive the VC pin of external switchers. Its control loop uses feedback from the VOUT pin (bypassed via capacitor) rather than the switcher's FB pin, enabling operation with floating ground topologies.
Burst mode is implemented by converting the error amplifier into a hysteretic comparator-forcing the external switcher into alternating full-on pulses and full micropower shutdown. This reduces average input supply current from ~6mA (normal mode) to ~1.3mA while increasing output ripple to 100mVp-p.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Regulated Output Voltage | +5.0V ±1%, enabling direct powering of TTL/CMOS logic without post-regulation. |
| Current Limit Sense Voltage | 60mV ±4%, matched to copper PCB trace resistance with +0.33%/°C TC for accurate, low-loss current sensing. |
| Input Voltage Range | 6V to 30V, supporting wide-range battery and industrial DC bus inputs. |
| Burst Mode Quiescent Input Current | 1.3mA typical, extending battery life in memory-keep-alive and sleep-mode applications. |
| Shutdown Current | 15µA typical, lower than typical battery self-discharge rates. |
| Efficiency (Normal Mode) | 91% at 0.5A load, optimized for mid-load power conversion with minimal conduction losses. |
| Transconductance (VOUT → VC) | 2000µmho typical, simplifying loop compensation when used with LT1070-family switchers. |
Pinout & Package
LT1432CN8 is housed in an 8-lead plastic DIP (N8) package with through-hole mounting and 0.3" width. Pin spacing is 0.1" (2.54mm), compatible with standard prototyping and production PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VLIM | Current limit sense input | Accepts 60mV sense voltage from external resistor or PCB trace; current out of pin during limiting. |
| VOUT | Output voltage feedback node | Connected directly to regulated 5V output; bypassed with capacitor to GND for stable loop operation. |
| VIN | Main input supply | Accepts 6V–30V unregulated input; powers internal circuitry and supplies V+ via internal path during startup. |
| V+ | Floating supply for external switcher | Provides isolated 5V-derived bias to LT1070-family switcher; generated via D2/C3 peak-detect circuit. |
| MODE | Operating mode control | GND = normal mode; open = burst mode; >2.5V = shutdown (15µA draw). |
| GND | Analog ground reference | Common return for internal amplifier and reference; must be connected to switcher's floating ground node. |
| VC | Switcher control output | Open-collector NPN output driving external switcher's VC pin; sinks up to 1.5mA, sources 40–100µA. |
| DIODE | Catch diode anode connection | Connects to anode of external Schottky catch diode (e.g., MBR330P); rated to 30V. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed +5V output regulation | Internal 5.0V reference ensures stable output without external resistors-reducing BOM count and layout sensitivity. |
| Ultra-low-loss current sensing | 60mV sense threshold minimizes I²R loss and enables use of low-cost, low-value PCB copper traces as current-sense elements. |
| Logic-selectable burst mode | Zero external components needed to enable burst mode-simply leave MODE pin floating to reduce light-load quiescent current by >75%. |
| Startup assist circuitry | Internal current path from VIN to V+ enables reliable cold-start without auxiliary supply, critical for battery-powered systems. |
| Temperature-compensated sense voltage | +0.33%/°C TC matches copper resistance drift, maintaining accurate current limit across –40°C to +85°C operating range. |
Applications
| Laptop Power Management | Portable Data Logger |
|---|---|
Use Scenario: Maintaining 5V supply to SRAM and real-time clock during system sleep mode with <100mA load. IC Role / Device Role / Timing Role: LT1432CN8 acts as burst-mode controller, dynamically cycling external LT1271 switcher to minimize battery drain while preserving data integrity. Use Value: Achieves 1.3mA quiescent input current and 15µA shutdown-enabling >30-day battery hold-up for 12V/1.2Ah packs. | Use Scenario: Converting 12V vehicle battery or solar-charged pack to regulated 5V for microcontroller and sensor interface in field-deployed instrumentation. IC Role / Device Role / Timing Role: LT1432CN8 serves as primary buck controller, coordinating LT1170 switcher and external components to deliver stable 5V under variable input (6–30V) and load (0–3A). Use Value: Delivers >90% efficiency at 500mA and supports wide input range-reducing need for upstream pre-regulation or redundant power paths. |
| DC Bus Distribution System | Battery-Powered Digital Widget |
Use Scenario: Providing clean, efficient 5V rail from 24V industrial DC bus to multiple embedded controllers and I/O modules. IC Role / Device Role / Timing Role: LT1432CN8 functions as centralized 5V controller, driving high-current LT1270A switcher with integrated current limiting and thermal robustness. Use Value: Enables single-point 5V generation with 60mV current sense accuracy and 30V absolute max input-eliminating risk of overvoltage damage in noisy bus environments. | Use Scenario: Powering handheld consumer electronics (e.g., barcode scanners, medical testers) from two or three AA/AAA cells (3–4.5V) boosted to 5V via external switcher. IC Role / Device Role / Timing Role: LT1432CN8 operates as precision 5V regulator controller, managing LT1072 switcher in buck-boost configuration with tight line/load regulation. Use Value: Provides 10mV line regulation and 25mV load regulation-ensuring consistent logic-level margins across battery discharge curve. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 5V buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1701AIS8 | Monolithic synchronous buck controller with integrated gate drivers; requires external MOSFETs; no burst mode; 5V output adjustable via resistor divider. | Designed for higher-current (>5A), higher-efficiency designs where board space permits discrete FETs and layout complexity is acceptable. | Select LTC1701AIS8 only if synchronous rectification is required and design can accommodate external high-side/low-side FETs and tighter layout constraints. |
| MAX5033ASA+ | Fixed 5V monolithic buck regulator (not controller); integrates switch, diode, and compensation; 600mA max output; no external switcher interface. | Suitable for low-power (<600mA), space-constrained applications where integration outweighs flexibility and efficiency at light loads. | Choose MAX5033ASA+ only for simple, low-current point-of-load regulation where external switcher coordination and burst-mode optimization are unnecessary. |
Compared with LTC1701AIS8 and MAX5033ASA+, the LT1432CN8 uniquely combines external switcher flexibility, ultra-low 60mV current sensing, and hardware-selectable burst mode-making it optimal for medium-power, battery-sensitive 5V buck systems requiring long sleep duration and wide input range.
Availability
LT1432CN8 is available at Aetrix Electronics and suitable for laptop power management, portable data loggers, DC bus distribution systems, and battery-powered digital widgets requiring stable component supply and long-term lifecycle support.
Supply support for LT1432CN8 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 products including the LT1432 series.
The LT1432 belongs to Linear Technology's high-efficiency switching controller product line, engineered specifically for 5V buck converter applications requiring precision regulation, ultra-low quiescent current, and seamless interoperability with the LT1070/LT1170/LT1270 families.
FAQ
What is the function of the MODE pin on the LT1432CN8?
The MODE pin on the LT1432CN8 selects operating mode: grounded for normal continuous switching, open-circuit for burst mode (reducing quiescent current to 1.3mA), or pulled above 2.5V for shutdown (15µA). The LT1432CN8 uses this pin to configure dynamic power states without external logic-critical for battery longevity in portable devices.
Can the LT1432CN8 be used with switching regulators other than the LT1070 family?
The LT1432CN8 is explicitly designed for use with LT1070/LT1170/LT1270-family current-mode switchers, whose VC pin interface, timing, and current-sink capability match LT1432CN8's transconductance output. While possible with careful adaptation, using LT1432CN8 with non-LT switchers risks instability, inaccurate current limiting, or startup failure due to mismatched drive strength and loop dynamics.
What is the significance of the 60mV current limit sense voltage in the LT1432CN8?
The 60mV current limit sense voltage in the LT1432CN8 minimizes power loss in the sense element and allows direct use of low-resistance PCB copper traces instead of discrete shunt resistors. Its +0.33%/°C temperature coefficient matches copper's resistance drift-ensuring consistent current-limit accuracy from –40°C to +85°C without calibration, a key advantage in automotive and industrial environments.
How does burst mode improve efficiency at light loads in the LT1432CN8?
Burst mode improves efficiency at light loads (5–100mA) by converting the LT1432CN8's error amplifier into a hysteretic comparator-causing the external switcher to operate in short, high-duty bursts followed by full micropower shutdown. This reduces average input supply current from ~6mA (normal mode) to ~1.3mA, cutting standby power loss from 60mW to ~15mW while maintaining 5V regulation.
What package type is used for the LT1432CN8, and is it RoHS-compliant?
The LT1432CN8 uses an 8-lead plastic DIP (N8) package with through-hole mounting. As a legacy Linear Technology part manufactured prior to full RoHS transition, the standard LT1432CN8 is not RoHS-compliant; however, Analog Devices offers lead-free (RoHS-compliant) versions under alternate order codes (e.g., LT1432CDD#PBF in SO-8), and Aetrix Electronics can provide compliance documentation upon request for qualified replacements.
LT1432CN8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Type:
- -
- Function:
- -
- Output Configuration:
- -
- Topology:
- -
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- -
- Frequency - Switching:
- -
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- -
- Clock Sync:
- -
- Serial Interfaces:
- -
- Control Features:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LT1432CN8 FAQ
1.How can I place an order for LT1432CN8 through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1432CN8 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 LT1432CN8 reliable?
The price and inventory of LT1432CN8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1432CN8 is usually 5 days.
3.What payment methods are accepted for LT1432CN8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1432CN8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1432CN8?
LT1432CN8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1432CN8 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 LT1432CN8?
For technical support, including LT1432CN8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1432CN8 requirements.
6.How does Aetrix verify that LT1432CN8 is sourced from the original manufacturer or authorized distributors?
All LT1432CN8 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 LT1432CN8 meets industry standards.
7.What is the process for return or replacement of LT1432CN8?
All LT1432CN8 units undergo pre-shipment inspection (PSI). If there is an issue with LT1432CN8, 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 LT1432CN8 part is unused and in its original packaging.
Return procedure for LT1432CN8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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