Analog Devices Inc. LTC1682CS8-5#TRPBF

Overview

LTC1682CS8-5#TRPBF from Analog Devices (formerly Linear Technology) is a fixed 5V, low-noise charge pump doubler with integrated LDO regulator. It accepts 2.7V–4.4V input, delivers up to 50mA output current, features 64µV_RMS (10Hz–100kHz) output noise, and operates at 550kHz switching frequency. It powers noise-sensitive VCOs in cellular phones and wireless PCMCIA cards.

For engineers reviewing the LTC1682CS8-5#TRPBF datasheet, LTC1682CS8-5#TRPBF pinout, LTC1682CS8-5#TRPBF application, or LTC1682CS8-5#TRPBF equivalent, key selection criteria include fixed 5V output accuracy (±2%), dropout voltage ≤90mV at 10mA, shutdown current <5µA, thermal/short-circuit protection, and compatibility with 0.22µF flying and ≥2µF ceramic output capacitors.

Technical Context

The LTC1682CS8-5#TRPBF integrates a switched-capacitor doubler generating ~2×VIN at CPO, followed by a low-dropout linear regulator that filters ripple and regulates to a precise 5V output. Its internal 550kHz oscillator drives nonoverlapping clock phases for low EMI switching, and Burst Mode operation engages below 100µA load to reduce quiescent current.

Power-on reset ensures safe startup when VIN exceeds ~1V; internal comparators monitor CPO (disable LDO if <1.45×VIN, enable if >1.75×VIN). The FILT pin connects to a 1nF capacitor to stabilize the internal reference, critical for achieving specified 64µV_RMS noise performance.

Key Specifications

Pinout & Package

Package: 8-pin SO (Small Outline, narrow 0.150"), RoHS-compliant, surface-mountable.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise boosted supply applications.

Compared with LTC1682IMS8-5, the LTC1682CS8-5#TRPBF offers identical noise, regulation, and protection but is limited to commercial temperature range; compared with LT3008EDC-5#TRMPBF, it uniquely provides voltage boosting from sub-5V sources-essential when powering 5V VCOs from 3.3V or single-cell Li-ion rails.

Availability

LTC1682CS8-5#TRPBF is available at Aetrix Electronics and suitable for cellular phone RF modules, wireless PCMCIA cards, and portable medical instruments requiring stable component supply with full traceability and lifecycle management.

Supply support for LTC1682CS8-5#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 acquired Linear Technology in 2017 and maintains its legacy of high-performance analog ICs for precision power, signal conditioning, and RF applications.

The LTC1682 family was designed specifically to solve noise-sensitive voltage boosting challenges in wireless infrastructure and portable RF systems-delivering clean, regulated outputs without inductors or complex layout.

FAQ

What is the maximum output current capability of the LTC1682CS8-5#TRPBF?

The LTC1682CS8-5#TRPBF delivers up to 50mA of continuous output current at 5V while maintaining regulation and specified noise performance. At higher loads, dropout voltage increases and thermal limits may engage; the device includes internal current limiting and thermal shutdown to protect against overload conditions. For sustained 50mA operation, ensure adequate PCB copper area on GND and VIN pins per Linear's thermal guidelines.

Does the LTC1682CS8-5#TRPBF require an external resistor divider to set the output voltage?

No. The LTC1682CS8-5#TRPBF is the fixed 5V version of the LTC1682 family and contains an internal resistor network that sets VOUT to 5.0V ±2%. Unlike the adjustable LTC1682 variant (which uses FB pin and external resistors), this part uses Pin 3 as FILT and requires only a 1nF capacitor to ground for optimal noise performance-no feedback resistors are needed or used.

What capacitor values are required for stable operation of the LTC1682CS8-5#TRPBF?

The LTC1682CS8-5#TRPBF requires: (1) a 0.22µF low-ESR ceramic flying capacitor between C+ (Pin 7) and C– (Pin 5); (2) a 1nF ceramic capacitor from FILT (Pin 3) to GND; and (3) ≥2µF low-ESR ceramic capacitors on VIN (Pin 6), VOUT (Pin 1), and CPO (Pin 8). C2 (VOUT) and C3 (CPO) should be ≥4.7µF in typical applications to ensure low noise and transient response.

How does the LTC1682CS8-5#TRPBF achieve its low output noise specification?

The LTC1682CS8-5#TRPBF achieves 64µV_RMS (10Hz–100kHz) noise through dual-stage noise reduction: first, a precisely controlled 550kHz charge pump minimizes switching spike energy; second, an integrated LDO with optimized pole-zero compensation filters residual ripple. Critical to this performance is the 1nF capacitor on the FILT pin, which stabilizes the internal 1.235V reference and prevents noise coupling into the feedback path-omitting it degrades noise by >30%.

Can the LTC1682CS8-5#TRPBF be used with input voltages below 2.7V?

No. The LTC1682CS8-5#TRPBF is specified for 2.7V to 4.4V input operation. Attempting to operate below 2.7V violates the absolute minimum input rating and will cause the LDO to drop out, resulting in unregulated, noisy output and potential instability. For lower-input applications, consider the adjustable LTC1682 (2.5V–5.5V output range) or LTC1682CS8 (2.5V–5.5V adjustable version), both supporting down to 1.8V input.