Analog Devices Inc. LTC3202EDD#PBF

Overview

LTC3202EDD#PBF from Analog Devices (formerly Linear Technology) is a low-noise, constant-frequency fractional charge pump DC/DC converter designed for white LED backlighting. It delivers up to 125mA output current with regulated voltage or current mode operation, operates from 2.7V–4.5V input, features 1.5MHz switching, and requires no inductors-ideal for compact battery-powered displays.

For engineers reviewing the LTC3202EDD#PBF datasheet, LTC3202EDD#PBF pinout, LTC3202EDD#PBF application, or LTC3202EDD#PBF equivalent, key selection criteria include programmable 0.2V/0.4V/0.6V feedback set points, thermal shutdown protection, automatic soft-start, exposed-pad DFN thermal performance (θ_JA = 44°C/W), and compatibility with ceramic flying capacitors only.

Technical Context

The LTC3202EDD#PBF implements a 2-phase nonoverlapping 1.5MHz oscillator to drive a 2:3 fractional charge pump, generating up to 1.5×VIN at VOUT. Regulation is achieved via error amplification of FB voltage against one of three DAC-set reference voltages (0.2V/0.4V/0.6V), modulating pump strength to maintain set-point accuracy.

It integrates a 2-bit digital control interface (D0/D1) for feedback programming, internal soft-start circuitry limiting inrush over ~500µs, and robust protection including indefinite VOUT-to-GND short-circuit tolerance and thermal shutdown at ~160°C with auto-recovery. The exposed PGND pad (Pin 11) must be soldered to a ground plane for thermal and electrical integrity.

Key Specifications

Pinout & Package

Package: 10-Lead (3mm × 3mm) Plastic DFN with exposed power ground pad (Pin 11). Requires solder connection of exposed pad to PCB ground plane for thermal management and low-impedance return path.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar white LED charge pump driver applications.

Compared with LTC3201EMS#PBF and LTC3200EMS#PBF, the LTC3202EDD#PBF offers superior thermal dissipation (θ_JA = 44°C/W), lower quiescent current (5mA vs 6.5mA/8mA), and optimized 1.5MHz operation for balanced efficiency and capacitor size-making it the preferred choice for thermally constrained, battery-sensitive portable displays.

Availability

LTC3202EDD#PBF is available at Aetrix Electronics and suitable for smartphone backlighting, tablet display drivers, portable medical monitor illumination, and industrial HMI panels requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC3202EDD#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 LTC3202EDD#PBF belongs to Linear's precision charge pump LED driver family, engineered specifically for low-noise, inductorless white LED backlighting in portable consumer and medical electronics where size, efficiency, and reliability are critical.

FAQ

What is the maximum continuous output current supported by the LTC3202EDD#PBF?

The LTC3202EDD#PBF supports up to 125mA continuous output current under typical conditions (VIN = 3.6V, TA = 25°C, COUT = 1µF). At elevated ambient temperatures or with reduced input voltage, derating applies-e.g., ~100mA at +70°C ambient due to thermal limits. The device includes short-circuit current limiting (~250mA) and thermal shutdown to protect against overload.

Can the LTC3202EDD#PBF drive LEDs in voltage regulation mode instead of current regulation mode?

Yes, the LTC3202EDD#PBF can operate in voltage regulation mode by connecting a resistive divider from VOUT to FB and GND. The output voltage is calculated as VOUT = VFB × (1 + R1/R2), where VFB is selected as 0.2V, 0.4V, or 0.6V via D0/D1. For example, using R1 = 1kΩ and R2 = 3.9kΩ with 0.6V FB yields VOUT ≈ 4.2V. Closed-loop output resistance increases proportionally with gain, so higher ratios reduce regulation accuracy.

Why does the LTC3202EDD#PBF require ceramic capacitors for flying capacitors, and what happens if tantalum is used?

The LTC3202EDD#PBF requires non-polar ceramic capacitors for C1 and C2 because its 2-phase charge pump reverses voltage polarity across these terminals during startup and operation. Tantalum or aluminum electrolytic capacitors are polarized and will fail catastrophically (leakage, explosion) under reverse bias. Ceramic capacitors (X5R/X7R, ≥0.7µF each) ensure safe, reliable operation and optimal charge pump strength.

How does the soft-start function of the LTC3202EDD#PBF work, and when is it activated?

The LTC3202EDD#PBF implements linear soft-start over ~500µs by gradually increasing available output current during power-up or whenever D0/D1 logic states change. This prevents large inrush currents into LED string capacitance and avoids visible display flash. Soft-start activates on any transition of D0 or D1 (e.g., brightness step change), not just initial enable-ensuring smooth transitions across all dimming steps.

What is the role of the exposed pad (Pin 11) on the LTC3202EDD#PBF DFN package, and how must it be connected?

The exposed pad (Pin 11) on the LTC3202EDD#PBF is PGND-Power Ground for the charge pump switches-and is electrically and thermally connected to the internal die substrate. It must be soldered to a solid, low-impedance PCB ground plane covering ≥80% of the pad area. Failure to do so degrades thermal performance (θ_JA rises from 44°C/W to >70°C/W) and may cause instability or premature thermal shutdown under load.