Analog Devices Inc. LTC1515IS8-3.3/5#PBF

Overview

LTC1515IS8-3.3/5#PBF from Analog Devices (formerly Linear Technology) is a micropower switched capacitor DC/DC converter that provides selectable 3.3V or 5V regulated output via logic-controlled step-up/step-down operation across 2V–10V input. It delivers up to 50mA, features open-drain POR with 200ms delay, and operates at 650kHz switching frequency. Used in GSM SIM interfaces requiring dual-voltage rail generation with reset signaling.

For engineers reviewing the LTC1515IS8-3.3/5#PBF datasheet, LTC1515IS8-3.3/5#PBF pinout, LTC1515IS8-3.3/5#PBF application, or LTC1515IS8-3.3/5#PBF equivalent, key selection criteria include input voltage range compatibility (2V–10V), programmable dual-output capability (3.3V/5V), shutdown current (<1µA), soft-start behavior (4ms turn-on), and SO-8 thermal performance (θJA = 110°C/W).

Technical Context

The LTC1515IS8-3.3/5#PBF implements a unique charge pump architecture that automatically selects step-up (voltage doubler) or step-down (gated switch) mode based on VIN–VOUT differential sensing. Internal output impedance adjustment prevents inrush spikes during high-differential transitions.

It integrates a 1.232V reference comparator with hysteresis for burst-mode regulation, an internal power-on reset timer (200ms typ after VOUT regulation), and logic-level 5/3 pin control (VIH ≥ 1.0V, VIL ≤ 0.4V) compatible with 3V systems across full VIN range.

Key Specifications

Pinout & Package

Package: 8-lead plastic SO (narrow, 0.150"), JEDEC MS-012, θJA = 110°C/W, TJMAX = 125°C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar switched-capacitor DC/DC converter applications.

Compared with LTC1515CS8-3.3/5, the LTC1515IS8-3.3/5 offers guaranteed operation down to –40°C for outdoor or automotive-adjacent deployments; compared with LTC1515IS8-3/5, it adds 3.3V rail compatibility essential for modern 3G/4G LTE SIMs and eSIMs, avoiding voltage translation overhead.

Availability

LTC1515IS8-3.3/5#PBF is available at Aetrix Electronics and suitable for GSM SIM interfaces, smart card readers, portable medical sensors, and industrial IoT local power supplies requiring stable component supply across extended temperature ranges.

Supply support for LTC1515IS8-3.3/5#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 product support, documentation, and manufacturing continuity for the LTC portfolio.

The LTC1515 series was designed specifically for low-power, dual-voltage SIM and smart card power management in space-constrained portable electronics, emphasizing micropower operation, integrated reset, and wide-input adaptability.

FAQ

What is the maximum output current capability of the LTC1515IS8-3.3/5#PBF at 3.3V and 5V?

The LTC1515IS8-3.3/5#PBF delivers up to 50mA continuous output current at both 3.3V and 5V outputs under specified conditions (VIN ≥ 3V for 3.3V mode, VIN ≥ 3.3V for 5V mode). This rating assumes proper capacitor selection (≥10µF low-ESR COUT), ambient temperature ≤85°C, and SO-8 package thermal management. Derating applies above 70°C ambient.

How does the 5/3 pin determine output voltage on the LTC1515IS8-3.3/5#PBF?

On the LTC1515IS8-3.3/5#PBF, the 5/3 pin is a logic-controlled selector: a logic high (≥1.0V) configures the internal resistor network to regulate VOUT at 5V, while a logic low (≤0.4V) selects 3.3V. The pin must not be left floating and is compatible with standard 3V CMOS logic across the full 2V–10V input range.

What is the purpose and timing behavior of the POR pin on the LTC1515IS8-3.3/5#PBF?

The POR (Power-On Reset) pin on the LTC1515IS8-3.3/5#PBF is an open-drain output that remains low until VOUT reaches regulation (within ±6.5%) and sustains it for 200ms (typical). It pulls low again during shutdown or power loss. An external pull-up resistor to VOUT is required to generate a valid reset signal for downstream logic.

Can the LTC1515IS8-3.3/5#PBF operate with input voltages below 2V?

No - the absolute minimum input voltage for the LTC1515IS8-3.3/5#PBF is 2V, as specified in Absolute Maximum Ratings and confirmed in Electrical Characteristics. Operation below 2V is not guaranteed and may result in failure to regulate or undefined POR behavior. For sub-2V inputs, alternative solutions such as the LTC3526L or discrete boost architectures are required.

What capacitor values are recommended for optimal performance of the LTC1515IS8-3.3/5#PBF?

For optimal performance, the LTC1515IS8-3.3/5#PBF requires a 0.22µF ceramic flying capacitor (C1), ≥10µF low-ESR input capacitor (CIN), and ≥10µF low-ESR output capacitor (COUT). When VIN exceeds 8V, COUT should be increased to 22µF or more to maintain output ripple ≤100mVpp. Ceramic capacitors are preferred for C1 and COUT; tantalum may be used for CIN/COUT if ESR < 0.5Ω.