austriamicrosystems, a leading global designer and
manufacturer of high-performance analog ICs, has introduced the AS3605, a
highly integrated power management integrated circuit (PMIC) designed
specifically for portable devices powered by a single-cell Li-Ion battery. The
device integrates seven low dropout regulators (LDOs), a DC/DC converter, a
complete battery charger, LED backlight driver and an audio power amplifier on
one die.
The features and performance of the cost-efficient AS3605
Micro PMIC allow it to be used in many portable devices powered by one Li-Ion
battery such as high-end blood glucose meters, high-end remote controls, GPS
equipment, mobile meters, e-dictionaries and entry level mobile phones. It can
be used for any entry level mobile phone handset standard, including CDMA,
WCDMA, GSM, GPRS, EDGE, UTMS and other American and Japanese standards.
The seven high-performance programmable LDOs feature low
noise – typically 30 ?V RMS from 100 Hz to 100 kHz — as well as line/load
regulation < 1 mV static, < 10 mV transient, and power supply rejection
less than 70 dB @ 1 kHz. The integrated step-down DC/DC converter requires no
external Schottky diode yet provides very high efficiency (up to 95%)
throughout the whole operating range. The DC/DC converter’s 2.2 MHz switching
frequency saves PCB space by enabling the use of a tiny, low-profile inductor. In
addition, a 60 mA 5 V charge pump together with 5 programmable current sinks is
included to supply LEDs for backlighting the display. The on-chip
low-distortion audio power amplifier provides 1 W @ 8? for speaker-phone
operation, Hi-Fi ringtones or other audio uses. The AS3605 Micro PMIC also
features a battery charger for Li-Ion batteries, including the charging
algorithms for automatic trickle charging, programmable constant voltage and
constant current charging.
Processor and memory power supplies must follow precise
start-up sequences to prevent serious damage. Therefore it is critical that the
voltages are switched on and off in the correct order. Compared to a discrete
solution consisting of a collection of standalone DC/DC converters, LDOs and
chargers, the task is greatly simplified with the AS3605. With its
software-programmable start-up sequences, the AS3605 brings new flexibility to
the market for Micro PMICs. Other competitors offer PMICs with fixed start-up
sequences that must be selected with external resistors.
The AS3605’s output voltage and the timing of all regulators
are programmed via software. With the software and demo board, the AS3605’s OTP
memory can be easily programmed enabling fast prototype runs for quick market
introduction. The slope of the ramp can be set for the step-down converters.
The user can program the start-up sequence with timing steps of 1 ms or 4 ms.
In order to control other parts of the system, the general purpose I/O pins can
be programmed to a specific timing.
The AS3605 is controlled via an easy-to-use serial interface
and integrates all necessary system specific functions such as Reset, Watchdog,
and Power-On Detection. Output voltages and start-up timings can be programmed
via the internal OTP memory.
Manfred Kogler, marketing manager for power management
products at austriamicrosystems, said, “The demands placed on power management
ICs in mobile devices continues to increase but at the same time the market
requires application-specific cost-optimized solutions. So the level of
integration of the AS3605 Micro PMIC perfectly fulfills the requirements of
entry level mobile phones, but also suits applications which are becoming more
feature-rich such as high-end blood glucose meters or remote controls, where
customers use Li-Ion batteries, color displays and wireless connectivity.”
Housed in a 40-pin 5×5 mm QFN package, the AS3605 Micro
Power Management Unit is specified for operation from a battery supply range of 3.0 to 5.5 V volts over an ambient
temperature range of -40 to +85°C.