Analog Devices Inc. LTC4151CDD-1#PBF

Overview

LTC4151CDD-1#PBF from Analog Devices (formerly Linear Technology) is a high-side power monitor IC with integrated 12-bit ΔΣ ADC, operating from 7V to 80V input supply. It continuously or on-demand measures high-side current (via 81.92mV full-scale differential sense), input voltage (102.4V full-scale), and external ADIN voltage (2.048V full-scale), all reported via I²C. It is used in telecom power systems for real-time rail monitoring and fault detection.

For engineers reviewing the LTC4151CDD-1#PBF datasheet, LTC4151CDD-1#PBF pinout, LTC4151CDD-1#PBF application, or LTC4151CDD-1#PBF equivalent, key selection considerations include its split I²C data path (SDAI/SDAO), 0°C to 70°C temperature grade, 10-lead 3mm × 3mm DFN package, and inverted SDAO output optimized for opto-isolated bus interfaces.

Technical Context

The LTC4151CDD-1#PBF implements a ΔΣ ADC architecture that inherently averages noise during conversion, supporting continuous scan mode at 7.5Hz or single-shot snapshot mode. Its dedicated SDAI (data input) and inverted SDAO (data output) pins decouple signal directionality to simplify opto-isolation without level-shifting circuitry.

It features internal 6V clamping on SCL, SDAI, and SDAO pins, allowing direct pull-up to VIN (up to 80V), eliminating need for auxiliary low-voltage supplies. The SHDN pin is absent-shutdown control is implemented exclusively via I²C register G7 (snapshot mode disable) and register G4 (test mode), distinguishing it from the base LTC4151 variant.

Key Specifications

Pinout & Package

Package: 10-lead (3mm × 3mm) plastic DFN (DD package), exposed pad (Pin 11) optional GND connection. Thermal resistance θ_JA = 45°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-side current and voltage monitoring applications.

Compared with INA226AIDGST, LTC4151CDD-1#PBF integrates rail voltage and auxiliary analog monitoring without external components; compared with LTC4151CMS-1#PBF, it offers superior thermal performance and smaller PCB area in the same commercial temperature grade.

Availability

LTC4151CDD-1#PBF is available at Aetrix Electronics and suitable for telecom infrastructure, industrial 48V DC distribution, and automotive onboard charger designs requiring stable component supply, long-lifecycle support, and guaranteed lead-free compliance.

Supply support for LTC4151CDD-1#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 LTC4151 product line was designed specifically for high-voltage, isolated power monitoring in telecom, industrial, and automotive systems - emphasizing integration, noise immunity, and simplified opto-isolation.

FAQ

What is the function of the SDAO pin on the LTC4151CDD-1#PBF?

The SDAO pin on the LTC4151CDD-1#PBF is an inverted open-drain I²C data output, designed to drive the anode of an opto-coupler directly. Unlike standard I²C SDA, its logic is inverted so that a high-to-low transition on the master's SDA line appears as a low-to-high transition at the opto-coupler input - matching typical opto-isolator input polarity and eliminating external inverters. This feature is exclusive to the LTC4151-1 variants, including LTC4151CDD-1#PBF.

Does the LTC4151CDD-1#PBF have a shutdown pin like the base LTC4151?

No, the LTC4151CDD-1#PBF does not include a physical SHDN pin. Shutdown functionality is implemented entirely through software control of the I²C CONTROL register (address 06h). Setting bit G7 disables continuous scanning, and clearing bit G4 exits test mode - effectively reducing dynamic power consumption. This differs from the base LTC4151 (e.g., LTC4151CDD#PBF), which uses a dedicated hardware SHDN pin to reduce quiescent current to 120µA.

Can the LTC4151CDD-1#PBF measure negative voltages or bidirectional current?

No, the LTC4151CDD-1#PBF is designed for unidirectional high-side current sensing only. Its SENSE+ and SENSE– inputs accept differential voltages from 0mV to +81.92mV - corresponding to positive current flow from VIN through the external sense resistor to load. It cannot resolve polarity reversal or negative differential inputs. For bidirectional current monitoring, a dedicated bidirectional current sense amplifier (e.g., INA240) paired with a separate ADC is required.

What is the maximum I²C clock frequency supported by the LTC4151CDD-1#PBF?

The LTC4151CDD-1#PBF supports standard-mode I²C operation up to 400kHz maximum SCL clock frequency. Its timing parameters - including minimum tLOW (0.65µs), tHIGH (50ns), and tBUF (0.12µs) - are fully compliant with the I²C specification for standard mode. It does not support fast-mode (1MHz) or high-speed mode; attempting to exceed 400kHz may result in communication errors or missed ACKs.

How is the I²C device address configured on the LTC4151CDD-1#PBF?

The I²C device address of the LTC4151CDD-1#PBF is configured using two three-state pins: ADR1 (Pin 7) and ADR0 (Pin 8). Each pin can be tied to VIN (logic high), GND (logic low), or left open (high-impedance), enabling nine unique 7-bit addresses (0xC0–0xCE, excluding 0xC6). The base address is 0b1100110 (0xC6), and ADR1/ADR0 select bits a1/a0 to form the final address. Address configuration is documented in Table 1 of the datasheet and applies identically across all LTC4151 variants, including LTC4151CDD-1#PBF.