Analog Devices Inc. ADM8845ACP-REEL7

Overview

ADM8845ACP-REEL7 from Analog Devices is a 1×/1.5×/2× fractional charge pump LED driver IC designed to power up to six white LEDs for LCD backlighting in dual-display handheld devices. It operates from 2.6 V to 5.5 V (Li-ion), delivers up to 30 mA per LED, achieves ≤1% LED current matching, and supports independent main/sub display control via CTRL1/CTRL2 pins - used in cellular phones with main and sub displays.

For engineers reviewing the ADM8845ACP-REEL7 datasheet, ADM8845ACP-REEL7 pinout, ADM8845ACP-REEL7 application, or ADM8845ACP-REEL7 equivalent, key selection criteria include input voltage range compatibility (2.6–5.5 V), LED current matching accuracy (±1%), fractional charge pump mode auto-selection thresholds, soft-start behavior, and dual-display shutdown logic configuration.

Technical Context

The ADM8845ACP-REEL7 implements an adaptive 1×/1.5×/2× charge pump with automatic gain switching based on VCC: 1.5×→2× at 3.33 V (±4%), 2×→1.5× at 3.36 V (±4%), 1×→1.5× at 4.77 V (±4%), and 1.5×→1× at 4.81 V (±4%). It uses six independent current-controlled sinks with 0.2–0.3 V compliance voltage to regulate LED current via ISET pin (1.18 V reference) and external RSET resistor.

Control logic interprets digital inputs CTRL1/CTRL2 as a 2-bit shutdown/brightness enable code: 00 = full off, 01 = main on/sub off, 10 = main off/sub on, 11 = both on. PWM dimming is supported directly on CTRL1/CTRL2 (100 Hz–200 kHz), or via filtered VPWM/VBRIGHT analog interface - enabling precise brightness control without chromaticity shift.

Key Specifications

Pinout & Package

ADM8845ACP-REEL7 is housed in a 3 mm × 3 mm, 0.75 mm height, 16-lead LFCSP (CP-16-222) with exposed paddle thermally connected to GND. Pin count and layout match functional block diagram and Table 4 of Rev. D datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX8647ETE+ and TPS61165DRVR, the ADM8845ACP-REEL7 uniquely integrates six matched current sinks, adaptive 1×/1.5×/2× charge pump, and dual-display logic in a 3×3 mm package - making it the only option supporting simultaneous main/sub backlight control with <1% current mismatch in space-constrained portable designs.

Availability

ADM8845ACP-REEL7 is available at Aetrix Electronics and suitable for cellular phone backlighting, micro TFT display illumination, camera flash/strobe lighting, digital still camera viewfinder backlighting, and PDA display power management requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM8845ACP-REEL7 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. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision instrumentation, industrial, automotive, and communications markets.

The ADM8845ACP-REEL7 belongs to Analog Devices' LCD backlight driver product line, engineered specifically for dual-display portable electronics requiring high-efficiency, tightly matched LED current regulation from single-cell Li-ion supplies.

FAQ

What is the maximum number of LEDs the ADM8845ACP-REEL7 can drive simultaneously?

The ADM8845ACP-REEL7 can drive up to six white LEDs simultaneously - configured as up to four LEDs for the main display (FB1–FB4) and up to two for the sub display (FB5–FB6). Each channel supports up to 30 mA, with guaranteed current matching within ±1% across all six channels under specified conditions.

How does the ADM8845ACP-REEL7 select between 1×, 1.5×, and 2× charge pump modes?

The ADM8845ACP-REEL7 automatically selects charge pump gain based on input voltage: it switches from 1.5× to 2× at 3.33 V (±4%), 2× to 1.5× at 3.36 V (±4%), 1× to 1.5× at 4.77 V (±4%), and 1.5× to 1× at 4.81 V (±4%), with 40 mV hysteresis. This ensures optimal power efficiency across the full 2.6 V–5.5 V Li-ion range without external control.

Can the ADM8845ACP-REEL7 be used for camera flash applications?

Yes - the ADM8845ACP-REEL7 supports flash operation by paralleling FBx pins (e.g., FB1+FB2) to double current per channel. With RSET set to 4.27 kΩ, it delivers 60 mA to three flash LEDs. Its robust short-circuit tolerance and thermal derating (to 65°C at full 180 mA load) make it suitable for brief high-current strobe duty cycles.

What is the role of the ISET pin in the ADM8845ACP-REEL7?

The ISET pin on the ADM8845ACP-REEL7 provides a 1.18 V internal reference voltage. When an external resistor RSET connects ISET to GND, it sets a bias current (ISET = 1.18 V / RSET) that is internally amplified by 120× to determine LED current (ILED = ISET × 120). For example, RSET = 7.08 kΩ yields 20 mA per LED with ±1% accuracy.

Does the ADM8845ACP-REEL7 support PWM dimming, and how is it implemented?

Yes - the ADM8845ACP-REEL7 supports PWM dimming via three methods: (1) direct digital PWM on CTRL1/CTRL2 pins (100 Hz–200 kHz), (2) filtered PWM applied to VPWM node controlling ISET, or (3) analog DC voltage (0–2.5 V) on VBRIGHT. All preserve LED chromaticity by avoiding analog current reduction, instead modulating average on-time.