Analog Devices Inc. DC988A-D

Overview

DC988A-D from Analog Devices (formerly Linear Technology) is a demonstration board for the LT3585EDDB-3 photoflash charger IC, integrating a high-voltage IGBT driver, adjustable input current control, and microcontroller-based flash sequencing. It delivers up to 320V output, charges photoflash capacitors in ≤779ms at 3.6V VBAT, and supports on-demand flash, red-eye reduction, and capacitor refresh - deployed in compact digital camera flash modules.

For engineers reviewing the DC988A-D datasheet, DC988A-D pinout, DC988A-D application, or DC988A-D equivalent, this page provides verified functional context, measured charge timing, microcontroller interface behavior, high-voltage safety constraints, and direct variant comparison across the LT3585EDDB-x family used in portable imaging systems.

Technical Context

The DC988A-D implements the LT3585EDDB-3 variant, which features a built-in high-voltage NPN power switch, transformer-based voltage step-up with no external zener sensing, and CHRG/IADJ pin-controlled charging current reduction. Its DONE pin signals full capacitor charge completion, and the on-board PIC microcontroller manages ON/OFF, FLASH, and REDEYE button logic with 500ms debounce.

It operates from 1.8V–4.2V battery (VBAT) and 2.8V–4.2V input (VIN), generating lethal >300V across C2 and the xenon tube secondary. JP2 selects HIGH or LOW CURRENT mode by pulling CHRG/IADJ high or tri-stating it, altering charge time from 779ms to 1550ms at 3.6V VBAT.

Key Specifications

Availability

DC988A-D is available at Aetrix Electronics and suitable for photoflash evaluation, xenon tube driver validation, and low-power high-voltage capacitor charging applications requiring stable component supply and documented reference behavior.

Supply support for DC988A-D 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 high-performance analog, power management, and signal conditioning product lines.

The LT3585EDDB-x family was designed specifically for space-constrained photoflash charging in digital cameras, enabling small transformer size and eliminating discrete HV sensing components.

FAQ

What is the function of the JP2 jumper on DC988A-D?

The JP2 jumper on DC988A-D selects between HIGH CURRENT and LOW CURRENT charging modes for the LT3585EDDB-3. In HIGH CURRENT mode, the CHRG/IADJ pin is driven high for fast charging (779ms). In LOW CURRENT mode, the pin is tri-stated to reduce input current and extend battery life, increasing charge time to 1550ms. This setting can be changed while the DC988A-D board remains powered.

How does DC988A-D differ from DC988A-B or DC988A-C?

DC988A-D uses the LT3585EDDB-3 IC, which has a nominal full-charge time of 779ms at 3.6V VBAT. In contrast, DC988A-B (LT3585EDDB-1) charges in 1180ms, DC988A-C (LT3585EDDB-2) in 779ms (same timing as -3 but different internal configuration), and DC988A-A (LT3585EDDB-0) in 468ms. Each variant targets distinct trade-offs between speed, efficiency, and transformer size in photoflash designs.

What safety precautions apply when operating DC988A-D?

DC988A-D exposes lethal voltages (>300V) across C2, T1 secondary, and the xenon tube circuitry. Users must avoid physical contact with uncovered HV nodes, never look directly at the flash, and only operate the board if trained in high-voltage handling. The READY/CHARGE LED indicates charge state, but residual >50V remains on C2 after shutdown - full discharge requires manual grounding per the quick start guide.

Can the on-board microcontroller on DC988A-D be bypassed?

Yes - the on-board microcontroller on DC988A-D can be disabled by removing VIN and VBAT, moving JP1 to short GND and CLK, then reapplying power. The READY/CHARGE LED will blink red, indicating microcontroller disable. Users may then drive CHARGE and TRIGGER signals directly via test points, allowing custom timing control and validation of the LT3585EDDB-3's native interface without firmware intervention.

What is the role of the CHRG/IADJ pin on DC988A-D?

The CHRG/IADJ pin on DC988A-D controls both charging enable and input current level for the LT3585EDDB-3. Driving it high initiates full-current charging; leaving it hi-Z reduces current and extends charge time. On DC988A-D, JP2 and the microcontroller jointly manage this pin - in HIGH CURRENT mode, it's actively driven; in LOW CURRENT mode, it's tri-stated after initial assertion, directly implementing the current-scaling function described in the LT3585EDDB-3 datasheet.