ETA9185

www.etasolution.com

8

Empower Thinkers

is immune to any fluctuation in VIN, since both the external voltage divider and the internal thresholds 66%VIN and

35%VIN are referenced to VIN. If the NTC pin is connected to GND will disable the temperature-sensing feature.

Ultra low current consumption at Light Load Boost Operation

Traditionally, a fixed constant frequency PWM DC/DC regulator always switches even when the output load is small.

When energy is shuffling back and forth through the power MOSFETs, power is lost due to the finite RDSONs of the

MOSFETs and parasitic capacitances. At light load, this loss is prominent and efficiency is therefore very low. ETA9185

employs a proprietary control scheme that improves efficiency in this situation by enabling the device into a power

saving mode during light load and the no load quiescent current can be lower than 10μA.

Output (5V OUT pin) Short-Circuit Protection

Unlike most step-up converters, the ETA9185 allows for short circuits on the output. In the event of a short circuit, the

device first turns off the NMOS when the sensed current reaches the current limit. When OUT drops below VBAT, the

device then enters a linear charge period with the current limited same as with the start-up period. In addition, the

thermal shutdown circuits disable switching if the die temperature rises above 140°C.

PCB GUIDELINES

4

9

8

7

BAT

ISET

ENBST

LED2

LED1

NTC

5

SW

6

OUT

10

VIN

LED3

1

3

2

GND

VIN

GND

5V

VOUT

10uF

10uF

10uF

2.2uH

VBAT

ETA9185

Via

Top Layer

Keep the power devices as close to the chip as possible to achieve the smallest power loop

area, which leads to the best EMI performance; Cin is always placed nearest to Vin and GND

Wire the ISET trace

away from SW node

or other noisy signal,

to keep minimum

parasitic capacitance.