Text preview for : HP AN 1310 Application Note.pdf part of Agilent HP AN 1310 Application Note Agilent HP AN 1310 Application Note.pdf
Back to : HP AN 1310 Application No | Home
Agilent AN 1310
Mobile Communications Device Testing
Application Note
Considerations when selecting a System Power Supply for Mobile
Communications Device Testing
Abstract
Pulsed battery drain currents, reg-
ulated charge currents, and remote
DUT (Device Under Test) fixtures,
dictate the need for specialized
power sourcing, loading, and meas-
urement capabilities for testing
mobile communications devices.
Many of these capabilities are not
available in general-purpose system
power supplies.
This guide will assist the test sys-
tem designer in selecting a system
power supply by properly evaluat-
ing test system and power supply
needs that are unique to the appli-
cation and not immediately obvi-
ous. In this way, many problems
likely to arise in production can be
avoided.
Overview
Mobile Communications System Power Supplies
The growth of the mobile communica- In the production testing of mobile Section One
tions market is clearly in the newer communications products, a system Considerations when Sourcing Power to
digital wireless products. The con- power supply replaces the battery. the DUT
sumer advantages are significant-- High volume manufacturing often dic- A. Transient Voltage Drop at the DUT
improved transmission quality, acces- tates that the DUT fixture is remotely Fixture
sibility, security, and operating time. located from the test system, intro-
ducing significant impedance due to B. Pulsed Current Sourcing for DUT
Digital mobile communications long wiring length. This, in combina- Transmit Burst Current Drain
devices transmit in short bursts tion with pulsed current drain, makes
which conserves power between it challenging to maintain a stable, Section Two
transmissions, thus extending talk transient-free voltage at the fixture Considerations when Loading the DUT
time of the battery. Likewise, during just as if the DUT were operating Battery Charger
standby, some digital devices also directly from a battery. In addition to A. Constant Voltage Loading
"wake up" and listen for incoming emulating the battery, the power sup- Capability
calls in short bursts, again extending ply can also provide current and volt-
battery life. The resulting battery age measurements required for test- Section Three
drain is pulsed current, ranging from ing and calibrating the DUT. Considerations when Making DUT Current
milliamperes to amperes. Accurate Measurements
current drain measurements are All of these things dictate the need A. Talk-mode Current Drain
important to assure proper battery for a system power supply with power Measurements
life for these different operating sourcing, loading, and measurement
modes. capabilities specially tailored for this B. Standby-mode Current Drain
application. By properly evaluating Measurements
Mobile communications devices incor- these unique needs of the test system
porate a wide variety of battery and power supply, the test system
C. Off-mode Current Leakage
charging schemes. Constant and designer can avoid production test
Measurement
pulsed charge currents ranging from problems by selecting a power supply
milliamperes to amperes are charac- suited for the application.
D. Battery Charger Current
teristic of rapid, slow, and trickle bat-
Measurement
tery charge modes of these devices. Considerations when Selecting a
There are a variety of charge termina-
tion methods all primarily deter-
System Power Supply The following references are useful in
There are several unique needs to the selection of any system power
mined by battery voltage.
consider in the system current supply supply:
selection, specific to mobile commu-
nications device testing.