Analog Devices Inc. LTC3265IDHC#TRPBF

Overview

LTC3265IDHC#TRPBF from Analog Devices (formerly Linear Technology) is a low-noise dual-polarity power supply IC integrating a boost charge pump, inverting charge pump, and two post-regulating LDOs - delivering ±15V outputs from a single 12V input. It supports up to 50mA per rail, operates with ceramic capacitors only, and features programmable 50–500kHz switching frequency and 135µA quiescent current in Burst Mode® with both LDOs active.

For engineers reviewing the LTC3265IDHC#TRPBF datasheet, LTC3265IDHC#TRPBF pinout, LTC3265IDHC#TRPBF application, or LTC3265IDHC#TRPBF equivalent, key selection criteria include bipolar output noise performance (100µVRMS), dual independent enable control (EN+/EN–), MODE-selectable operation (Burst vs constant-frequency), and DFN-18 package thermal design with exposed GND pad.

Technical Context

The LTC3265IDHC#TRPBF implements two independent charge pump stages: a boost stage (VIN_P → VOUT+, regulated to 2•VIN_P or 0.94•2•VIN_P) and an inverting stage (VIN_N → VOUT–, regulated to –VIN_N or –0.94•VIN_N), each feeding a dedicated low-noise LDO (LDO+ and LDO–). The MODE pin selects between Burst Mode® (hysteretic regulation, 135µA IQ) and constant-frequency mode (50–500kHz, fixed 500kHz when RT = GND).

Each LDO uses external resistor dividers for adjustable output (1.2–32V for LDO+, –32V to –1.2V for LDO–), with ADJ+/ADJ– pins referenced to precise ±1.200V internal references (±2.4mV tolerance). Soft-start, short-circuit protection (220mA/160mA), and thermal shutdown (175°C trip) are integrated.

Key Specifications

Pinout & Package

Package: 18-lead (5mm × 3mm × 0.75mm) plastic DFN with exposed GND pad (Pin 19), rated θJA = 42°C/W. Requires soldering of exposed pad to PCB ground plane for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-polarity regulator applications.

Compared with LT3467EDD#TRPBF and MAX1759EUB+T, the LTC3265IDHC#TRPBF uniquely integrates dual charge pumps *and* dual LDOs in one package, enabling true low-noise bipolar supplies with independent rail control - a capability neither alternative provides.

Availability

LTC3265IDHC#TRPBF is available at Aetrix Electronics and suitable for industrial data acquisition, portable medical instrumentation, automated test equipment, and high-voltage sensor excitation requiring stable component supply with guaranteed long-term availability.

Supply support for LTC3265IDHC#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LTC3265 belongs to Linear's precision power management product line, designed specifically for low-noise, bipolar supply generation in instrumentation, medical, and test equipment where EMI-sensitive analog performance is critical.

FAQ

What is the maximum allowable input voltage on the VIN_N pin for the LTC3265IDHC#TRPBF?

The absolute maximum rating for VIN_N is 36V, but the specified operating range is 4.5V to 32V. Exceeding 32V may cause parametric degradation or reliability risk, even if below the absolute maximum. For robust design, VIN_N should be kept within 4.5V–32V, and typical applications use it tied to either VIN_P (for asymmetric outputs) or VOUT+ (for symmetric ±VOUT+ outputs).

Can the LTC3265IDHC#TRPBF generate ±15V outputs from a 12V input, and what external components are required?

Yes, the LTC3265IDHC#TRPBF can generate ±15V from a 12V input: VIN_P = 12V yields VOUT+ ≈ 24V (constant freq) or 22.6V (Burst), then LDO+ regulates to +15V; VIN_N tied to VOUT+ yields VOUT– ≈ –24V or –22.6V, then LDO– regulates to –15V. Required components include two 1µF flying caps (CBST±, CINV±), two 10µF output caps (VOUT±), two ≥2µF LDO output caps (LDO±), two resistor dividers (e.g., 604kΩ/52.3kΩ), and optional 100nF BYP± caps.

How does Burst Mode® operation affect output voltage ripple on the LTC3265IDHC#TRPBF LDO outputs?

Burst Mode® increases VOUT± ripple (due to hysteretic regulation), which propagates to LDO± outputs. Measured LDO+ and LDO– ripple is ~10mV_P-P (AC-coupled) under 20mA load at 500kHz, versus <1mV_P-P in constant-frequency mode. The 100µVRMS broadband noise remains unchanged, but low-frequency ripple rises - acceptable for most analog biasing but not for ultra-low-noise references.

Is the exposed pad (Pin 19) on the LTC3265IDHC#TRPBF electrically connected, and how must it be handled on the PCB?

Yes, the exposed pad (Pin 19) is internally connected to GND and is essential for both electrical functionality and thermal performance. It must be soldered to a solid PCB ground plane using multiple thermal vias. Failure to do so risks exceeding θJA = 42°C/W, leading to thermal shutdown under load and increased output noise due to ground impedance.

What is the purpose of the RT pin on the LTC3265IDHC#TRPBF, and what happens if it is left unconnected?

The RT pin programs the charge pump oscillator frequency from 50kHz to 500kHz via a resistor to GND. If left unconnected (floating), the internal circuitry cannot regulate the oscillator, causing undefined or unstable switching behavior - potentially damaging external capacitors or violating EMI limits. Always tie RT to GND (for 500kHz) or to a defined resistor value; never leave it floating.