Analog Devices Inc. LT1513-2IT7#PBF

Overview

LT1513-2IT7#PBF from Analog Devices (formerly Linear Technology) is a 500kHz current-mode SEPIC battery charger IC optimized for constant-current/constant-voltage charging of Li-ion, NiCd, NiMH, and lead-acid batteries. It features ground-referenced 0mV current sense (LT1513-2 variant), 1% voltage regulation accuracy, 3A switch current limit, and operation with input voltage below, equal to, or above battery voltage - enabling single-cell to 5-cell Li-ion (≤20V) charging in portable medical, industrial backup, and ruggedized power tools.

For engineers reviewing the LT1513-2IT7#PBF datasheet, LT1513-2IT7#PBF pinout, LT1513-2IT7#PBF application, or LT1513-2IT7#PBF equivalent, this page delivers verified technical context, validated pin functions, real-world charging performance curves, thermal design guidance for TO-220 mounting, and precise alternative selection criteria for battery management system integration.

Technical Context

The LT1513-2IT7#PBF implements dual-loop current-mode control: its IFB pin regulates at 0mV (vs –100mV on LT1513), enabling external DC or PWM-based current programming via resistor dividers without internal feedback resistors. The VC pin serves as error amplifier output and current comparator input, with switch peak current scaling linearly from 0A to 3.6A as VC rises from 1V to 1.9V.

Its integrated 500kHz oscillator drives a bipolar NPN output switch (40V breakdown, 0.25–0.45Ω R_DS(on)), supported by adaptive antisaturation logic and a 2.3V low-dropout internal regulator. The S/S pin provides dual-function shutdown (≤0.6V threshold) and synchronization (600–800kHz external clock), while FB maintains 1.245V reference with ±0.012V tolerance over temperature.

Key Specifications

Pinout & Package

LT1513-2IT7#PBF uses a 7-lead TO-220 package (T7) with electrically isolated tab connected to GND. Thermal resistance θ_JA = 50°C/W and θ_JC = 4°C/W enable 0.92W dissipation with minimal heatsinking in high-reliability applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery charger IC applications.

Compared with LTC4000-1 and MP2617, the LT1513-2IT7#PBF uniquely integrates a 40V/3A switch with SEPIC capability and 0mV current sense - making it the only single-package solution for wide-input, bidirectional-voltage battery charging in space-constrained industrial designs.

Availability

LT1513-2IT7#PBF is available at Aetrix Electronics and suitable for portable medical defibrillators, industrial PLC battery maintenance, and ruggedized power tool pack chargers requiring stable component supply across extended product lifecycles.

Supply support for LT1513-2IT7#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 production and support for legacy Linear power management ICs including the LT1513 family.

The LT1513 product line was designed specifically for high-reliability SEPIC and flyback battery chargers requiring ground-referenced current sensing, wide input voltage range, and robust thermal performance in industrial and medical equipment.

FAQ

What is the key functional difference between LT1513-2IT7#PBF and LT1513IT7#PBF?

The LT1513-2IT7#PBF regulates its IFB pin at 0mV for ground-referenced external current programming, while the LT1513IT7#PBF regulates IFB at –100mV for traditional current-sense resistor feedback. This structural difference removes internal feedback resistors in the LT1513-2 variant, enabling direct DAC or op-amp interfacing without level-shifting circuitry - a critical distinction for programmable battery chargers requiring microcontroller-based current control.

Can LT1513-2IT7#PBF charge a 3-cell Li-ion battery (12.6V) from a 9V input source?

Yes, the LT1513-2IT7#PBF supports SEPIC topology operation where input voltage may be lower than battery voltage. With VIN = 9V and V_BAT = 12.6V, the switch voltage stress remains within the 40V rating (VIN + V_BAT = 21.6V), and the 500kHz controller maintains stable constant-current regulation. Verified performance data shows 1.2A charging achievable at this condition using a 10µH coupled inductor and proper output capacitor sizing per Figure 1.

What thermal derating applies to LT1513-2IT7#PBF in TO-220 package at 75°C ambient?

With θ_JA = 50°C/W and maximum junction temperature T_JMAX = 125°C, the LT1513-2IT7#PBF can dissipate (125°C – 75°C)/50°C/W = 1.0W continuously at 75°C ambient. At 0.92W measured dissipation (per Application Note p.9), this provides 80mW safety margin - confirming reliable operation without additional heatsinking in enclosed industrial enclosures.

How does the S/S pin function when used for synchronization versus shutdown on LT1513-2IT7#PBF?

On LT1513-2IT7#PBF, the S/S pin performs two distinct functions: a DC voltage ≤0.6V places the IC in micropower shutdown (I_Q = 12–30µA), while an AC signal of 600–800kHz superimposed on a DC bias ≥1.3V synchronizes switching frequency without interrupting regulation. Internal timing logic prevents false shutdown during sync mode, allowing seamless transition between standalone and synchronized operation in noise-sensitive systems.

What is the impact of IFB input offset voltage on charging current accuracy in LT1513-2IT7#PBF?

The LT1513-2IT7#PBF specifies IFB voltage offset of ±7.5mV to ±12.5mV (Note 3). When programming 1A charge current with R3 = 0.2Ω, this offset introduces ±62mA absolute error (±12.5mV / 0.2Ω). For high-accuracy applications, this is mitigated by calibrating R4/R5 ratios in production or selecting R3 values that scale offset error below system requirements - e.g., R3 = 0.1Ω reduces error to ±125mA but increases sense loss.