Keithley 2308 - Portable Device Battery, Charger Simulator, 15V, 5A

The Model 2308 Portable Device Battery/Charger Simulator is optimized for use in testing mobile phones and other portable, battery-operated devices. When a device-under-test (DUT) transitions nearly instantaneously from a sleep or standby mode to the full power transmit state, the Model 2308’s rapid response to load changes means there’s little transient voltage drop from the programmed output voltage and the output recovers quickly. This fast response is particularly critical when testing portable devices with a pulsed mode of operation because it allows the device to perform properly while it’s being tested. In contrast, the slow-responding source voltage typical of conventional power supplies causes the DUT to perform improperly, leading to production yield problems and costly retesting.

The Model 2308 offers a complete solution for portable device sourcing and load current measurement. It has two independent power supply channels: one is optimized to simulate a battery; the second channel is optimized to perform like a charger for a rechargeable battery. The battery channel’s variable output resistance can be used to simulate the internal resistance of a battery so design and test engineers can simulate a battery’s output for testing devices under realistic operating conditions. This channel also sinks current to simulate a discharged battery. The charger channel can supply a voltage to test a portable device’s battery charge control circuitry, with the battery channel acting as the discharged battery load.

In addition to maintaining output voltage levels under difficult load conditions, the Model 2308 can measure a wide dynamic range of load current levels and can measure narrow current pulses (or pulses as narrow as 50μs). That makes it ideal for characterizing device power consumption by making low-level sleep mode measurements as well as pulsed operating load currents.
 

Maximize production yield with fast response to load changes

Mobile phones, other portable devices (such as Bluetooth headsets, MP3 players, etc.), and RF components such as power amplifiers, power transistors, and transmitter modules experience large instantaneous load changes when they transition from a standby state to full power operation. For a mobile phone, the load current can change from a 100mA standby current to a 1A transmission current or a 10× (1000%) increase in the load current. The Model 2308 maintains a reliable, stable level of voltage output, even when the DUT produces large load current changes and/or has a pulsed operating mode.

The Model 2308’s fast recovery from load changes helps prevent the causes of false failures and destroyed devices in production test as well as field failure quality problems due to compromised components. The Model 2308 assures you of a stable, constant voltage source to maximize production yield and minimize production retest and rework costs.
 

Applications

 

• Design and test of a wide range of consumer electronics, including
  • Mobile phones, mobile radios, cordless phones, and Bluetooth headsets
  • MP3 players, portable digital assistants (PDAs), digital cameras, GPS receivers, and notebook computers
• Design and test of electronic components such as RF IC power amplifiers, RF power transistors, and baseband and wireless chipsets for portable wireless devices

Compare the response of a conventional power supply (left) with the response of a Model 2308 (right) when both are powering a device operating on the EDGE mobile phone standard. Note how the conventional power supply distorts the load current and cannot maintain a stable source voltage, which in turn distorts the RF output signal.
 

Reduce test costs and increase throughput with high-speed command structure

To minimize production test times while still giving you all the information you need to characterize your devices fully, the Model 2308 is designed with a command structure optimized for speed, with voltage step times as short as 6ms and DC load current measurements in just 22ms. Commands that combine range changing and current measurement let you acquire the command, make the measurement, and transfer the data in as little as 30ms. In addition, special operating modes, such as the pulse current step mode, allow taking a number of measurements on a complex load current waveform with a single command.
 

Characterize load currents for power consumption verification

Characterizing the battery life of portable devices demands the ability to measure complex current waveforms over a wide dynamic range. The Model 2308 offers a far broader range of capabilities than conventional power supplies for measuring low current levels, peak pulse current levels, long-period load current waveforms, and multi-level current waveforms.

Measure sleep and standby currents with the accuracy of integrating A/D technology

The Model 2308 is designed for fast and accurate measurements of devices in low power modes such as the sleep, hibernate, or standby state. It can resolve currents down to 100nA and measure them with 0.2% accuracy. The Model 2308 uses an integrating A/D converter that continuously acquires the signal rather than capturing discrete samples; this provides a more accurate measurement than other A/D techniques. In addition, the averaging effect built into integrating A/D converters reduces noise and delivers highly stable current readings. You can measure low and high currents at the same speed with no degradation in accuracy, so the Model 2308 is equally well-suited for the test line and the design lab.
 

Measure load currents from pulsed-output devices

Devices like GSM-, EDGE-, WLAN-, and WiMAX-based mobile phones generate pulsed outputs. Determining their total power consumption requires measuring both the baseline current and the peak of the pulsed load current. The Model 2308 can capture peak currents of pulses as short as 50μs and as long as 833ms. Programmable trigger levels allow controlled capture of the pulse, then the Model 2308’s programmable measurement delay and acquisition times make it easy to avoid rising edge transients so the pulse peak can be measured accurately. The instrument can also measure the pulse baseline current and the pulse average load current.

A long integration current mode supports measuring pulse trains with periods longer than 850ms. In this mode, the Model 2308 can measure average current on a load current waveform with a period from 850ms to 60 seconds.

Take multiple measurements on start-up sequences or on current levels at different voltage operating levels

Need to analyze a device’s circuitry during the power-up phase as it transitions from a sleep mode or an off-state? The Model 2308’s pulse step current function has the speed needed to measure the load current start-up levels in a single device start-up so that the measurements can be performed in production without an increase in test time.

The pulse step current function also offers a fast way to determine load currents of different operating states. For example, as source voltage levels are varied over a device’s operating range.

A significant time-savings when testing integrated circuits over their allowable range of Vcc levels.

Capture the complete load current waveform Two built-in analog outputs help designers of device’s verify design performance and ensure its current draw conforms to design specifications without the need to connect any sensing circuitry in the power supply circuit. Once these outputs are connected to an oscilloscope or a data acquisition module, the load current waveform can be displayed or digitized and analyzed in a computer. When the Model 2308 is connected to a data acquisition module, the data acquisition module can sample the waveform at any sampling rate to create a record of any length desired.
 

 

Test under realistic conditions with true battery simulation

When a portable battery-operated device transitions from one load current level to another, the battery voltage supplying the current will drop by the product of the change in current and the battery’s internal resistance. During the load current pulse, the device must operate with a voltage reduced by the battery’s internal resistance. The Model 2308 allows simulating this resistance so its output is almost identical to a battery’s output, allowing design or production test engineers to test devices or components under realistic conditions. This patented1 technique permits the output resistance to be programmed between 0W and 1W with 10mW resolution. You can also decrease the voltage and increase the output resistance while the output is on to simulate the discharge of the battery.

Test a device’s charge control circuitry

Both channels of the Model 2308 sink up to 3A of current continuously. Therefore, the battery channel can act like a discharged rechargeable battery. The charger channel can supply a charging voltage for use in testing the operation of the DUT’s charging control circuitry. Because the charger channel can also act as an electronic load, the battery channel can operate the device and the charger channel can act as a load to test a battery capacity monitor or some other device function that requires a load.

Reduce testing errors and retesting costs with remote sense lead monitoring

Remote sensing capabilities let the Model 2308 ensure the voltage programmed is what is actually applied to the load. As DUTs are continuously inserted and removed from test fixtures, the instrument ensures this programmed voltage is maintained with an open sense lead detection monitor any break in a sense lead connection is detected immediately. The open sense lead detection monitor eliminates the possibility that numerous devices could be tested or calibrated at an incorrect voltage.

Reduce test system problems with low impedance cable

Keithley’s SC-182 Low Inductance Coaxial Cable is designed to minimize the impedance and reduce the susceptibility to external EMI in your DC source-DUT circuit. This cable’s characteristic impedance is nominally 15W with a low 42nH/ft of inductance and a low 182pF/ft of capacitance. In contrast, a typical coaxial cable has 50W or 75W characteristic impedance and twisted-wire pairs have at least 80W of characteristic impedance.