Analog Devices ADP1649

Description

The ADP1649 is a very compact, highly efficient, single white LED flash driver for high resolution camera phones that improves picture and video quality in low light environments. The device integrates a programmable 1.5 MHz or 3 MHz synchronous inductive boost converter, an I2C-compatible interface, and a 1000 mA current source. The high switching frequency enables the use of a tiny, 1 mm high, low cost, 1 μH power inductor, and the current source permits LED cathode grounding for thermally enhanced, low EMI, and compact layouts.

The LED driver maximizes efficiency over the entire battery voltage range to maximize the input power-to-LED power conversion and to minimize battery current draw during flash events. A programmable dc battery current limit safely maximizes LED current for all LED VF and battery voltage conditions.

Two independent TxMASK inputs permit the flash LED current and battery current to reduce quickly during a power amplifier current burst. The I2C-compatible interface enables the pro-grammability of timers, currents, and status bit readback for monitoring the operation and for safety control.

The ADP1649 is available in a compact 12-ball, 0.5 mm pitch WLCSP package, and operates within specification over the full −40°C to +125°C junction temperature range.

Features

• Ultracompact solution

  -Small, 2 mm × 1.5 mm, 12-ball WLCSP package

  -Smallest footprint, 1 mm height, 1 μH power inductor

• LED current source for local LED grounding

  -Simplified routing to and from the LED

  -Improved LED thermals

• Synchronous 3 MHz PWM boost converter, no external diode

• High efficiency: 90% peak

  -Reduces high levels of input battery current during flash

  -Limits battery current drain in torch mode

• I2C programmable

• Currents of up to 1000 mA in flash mode for 1 LED with ±7% accuracy over all conditions

  -Currents of up to 200 mA in torch mode

• Programmable dc battery current limit (4 settings)
• Programmable flash timer up to 1600 ms
• Low VBAT mode to reduce LED current automatically
• 4-bit ADC for LED VF, die/LED temperature readback

• Control

  -I2C-compatible control registers

  -External strobe and torch input pins

  -2 transmitter mask (TxMASK) inputs

• Safety

  -Thermal overload protection

  -Inductor fault detection

  -LED short-circuit and open-circuit protection

Remarks:Table 19. Suggested InductorsRefer page no.25

Typical applications

• Camera enabled cellular phones and smart phones
• Digital still cameras, camcorders, and PDAs

More information

• Datasheet
• IC product information