ER3125QI Datasheet, PDF (2/30 Pages) Altera Corporation – MOSFET for Synchronous Buck or Boost Buck Converter

Page 2
Ordering Information
PART NUMBER
(Notes 1, 2)
PART
MARKING
TEMP.
RANGE (°C)
PACKAGE
(PB-Free)
PKG. DWG. #
ER3125QI
R3125
-40 to +105
20 Ld 4x4 QFN
L20.4x4C
NOTES:
1. Please refer to Packing and Marking Information: www.altera.com/support/reliability/packing/rel-packing-and-marking.html
2. These Altera Enpirion Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and
100% matte tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering
operations). Altera Enpirion Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free
requirements of IPC/JEDEC J STD-020.
Pin Configuration
ER3125QI
(20 LD QFN)
TOP VIEW
FSW
21
PAD
BOOST
Functional Pin Descriptions
PIN NAME PIN #
DESCRIPTION
EN
1 The controller is enabled when this pin is left floating or pulled HIGH. The IC is disabled when this pin is pulled LOW.
Range: 0V to 5.5V.
FSW
2 Connecting this pin to AVINO, or GND, or leaving it open will force the IC to have 500kHz switching frequency. The oscillator switching
frequency can also be programmed by adjusting the resistor from this pin to GND.
SS
3 Connect a capacitor from this pin to ground. This capacitor, along with an internal 5µA current source, sets the soft-start interval of the
converter. Also, this pin can be used to track a ramp on this pin.
FB
4 This pin is the inverting input of the voltage feedback error amplifier. With a properly selected resistor divider connected from V_OUT to FB, the
output voltage can be set to any voltage between the power rail (reduced by maximum duty cycle and voltage drop) and the 0.8V reference.
Loop compensation is achieved by connecting an RC network across COMP and FB. The FB pin is also monitored for overvoltage events.
COMP
5 Output of the voltage feedback error amplifier.
RCLX
6 Programmable current limit pin. With this pin connected to the AVINO pin, or to GND, or left open, the current limiting threshold is set to default
of 3.6A; the current limiting threshold can be programmed with a resistor from this pin to GND.
Enpirion Power Datasheet ER3125QI 2.5A Regulator with Integrated High-Side MOSFET for
Synchronous Buck or Boost Buck Converter
10040
May 28, 2014
May 2014 Altera Corporation
Rev A