DATA SHEET

SE4150L: GPS Receiver IC

Preliminary Datasheet

Skyworks Solutions, Inc.

• Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

202445B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • July 1, 2019

5

Pin No.

Name

Description

Connection

Die Pad

GND

Ground connection

Main IC GND connection

Functional Description

LNA

A high-performance LNA is available for use with

systems with an external passive antenna.

The LNA noise figure is the largest single contributor

to overall system sensitivity in GPS signal reception.

The internal LNA of the SE4150L allows excellent

performance to be achieved from a low-power GPS

receiver without requiring any additional active

components.

The GPS L1 input signal which is applied to LNA_IN

(pin 4), is a spread-spectrum signal centered on

1575.42 MHz with a 1.023Mbps BPSK modulation.

The signal level at the antenna is typically -130 dBm

in open-sky conditions, dropping to below -150 dBm

in masked signal areas (e.g. indoors).

The LNA input requires a minimum of external

matching components to achieve good RF gain with

minimal noise figure. Although attention should be

paid to track lengths and interference throughout the

design, the LNA input matching circuit is the only RF

circuit critically sensitive to layout.

The LNA output includes internal 50Ω matching for

connection to the mixer input, either directly or via an

optional external filter.

Antenna Switch

An antenna switch is included on the SE4150L, to

allow selection of either the LNA_IN (pin 4) RF path,

or the ANT1_IN (pin 3) RF path to connect to a single

RF output; ANT_SW_OUT (pin 7). This is useful in

systems where two antenna sources can be provided

(e.g. a PND, where an internal antenna and a socket

for an external antenna are available).

The antenna switch is driven from the antenna current

detector block. The antenna switch will transfer the

RF input from the default LNA_IN (pin 4) over to

ANT1_IN (pin 3), when the antenna current detector

block senses a current being consumed, for example,

from an external active antenna. The switching

threshold is typically 1mA with some hysteresis.

Antenna Current Detector

The antenna current detector is designed to monitor

the supply current to an external active antenna and

provide a logic output, ANT_DET (pin 8). This is used

to indicate if the current is within an expected range.

The current monitor senses the current which passes

through the ANT_BIAS (pin 2) output.

ANT_DET (pin 8) is connected to the switchover

control of the internal antenna switch. The antenna

switch will transfer the route of the RF input path from

the internal LNA (supplied from the LNA_IN (pin 4)

input) across to ANT1_IN (pin 3), through to the

ANT_SW_OUT (pin 7) output, when current is

detected.

ANT_BIAS (pin 2) should be connected to the core

connection of a coax socket via an isolating choke for

an external active antenna, in conjunction with

ANT_IN (pin 3) connected to the same core

connection of the socket via a dc-blocking capacitor.

When an external active antenna is connected, DC

current to drive the active antenna will flow through

ANT_BIAS (pin 2), and the antenna current detector.

Antenna Switch Override

The antenna switch (and antenna current detector)

can be overridden by externally driving ANT_DET

(pin 8) from a low-impedance external source, at

VDDN (pin 22) or GND levels.

This can be useful, for example, in applications where

the external antenna is not powered by the SE4150L

feed, or to facilitate user override via the host

processor man-machine interface.

The external source applied to ANT_DET (pin 8) must

be able to source >300 uA into the pin, or sink >70 uA

out of the pin to allow guaranteed levels to be set.

Mixer RF Input

The mixer RF input, MIX_IN (pin 11), is a single-

ended 50 Ω input designed to interface either to

ANT_SW_OUT (pin 7) or to the output of an external

filter. An external active antenna can also be