GB55-7 Peak Atlas DCA Semiconductor Component Analyser Model DCA55 User Guide © Peak Electronic Design Limited 2000/2007 In the interests of development, information in this guide is subject to change without notice - E&OE electronic design ltd
Atlas DCA User Guide October 2007 – Rev 7 Want to use it now? We understand that you want to use your Atlas DCA right now. The unit is ready to go and you should have little need to refer to this user guide, but please make sure that you do at least take a look at the notices on page 4! Contents Page Introduction....................................................................................3 Important Considerations ...............................................................
Atlas DCA User Guide October 2007 – Rev 7 Introduction The Peak Atlas DCA is an intelligent semiconductor analyser that offers great features together with refreshing simplicity. The Atlas DCA brings a world of component data to your fingertips.
Atlas DCA User Guide October 2007 – Rev 7 Important Considerations Please observe the following guidelines: • • • • • This instrument must NEVER be connected to powered equipment/components or equipment/components with any stored energy (e.g. charged capacitors). Failure to comply with this warning may result in personal injury, damage to the equipment under test, damage to the Atlas DCA and invalidation of the manufacturer’s warranty.
Atlas DCA User Guide October 2007 – Rev 7 Analysing Components The Atlas DCA is designed to analyse discrete, unconnected, unpowered components. This ensures that external connections don’t influence the measured parameters. The three test probes can be connected to the component any way round. If the component has only two terminals, then any pair of the three test probes can be used. Peak Atlas DCA is analysing.... The Atlas DCA will start component analysis when the on-test button is pressed.
Atlas DCA User Guide October 2007 – Rev 7 If the Atlas DCA cannot detect any component between any of the test probes, the following message will be displayed: No component detected If the component is not a supported component type, a faulty component or a component that is being tested incircuit, the analysis may result in the following message being displayed: Unknown/Faulty component Some components may be faulty due to a shorted junction between a pair of the probes.
Atlas DCA User Guide October 2007 – Rev 7 Diodes The Atlas DCA will analyse almost any type of diode. Any pair of the three test clips can be connected to the diode, any way round. If the unit detects a single diode, the following message will be displayed: Diode or diode junction(s) RED GREEN BLUE Anod Cath Forward voltage Vf=0.67V Test current If=4.62mA Pressing the scroll-off button will then display the pinout for the diode.
Atlas DCA User Guide October 2007 – Rev 7 Diode Networks The Atlas DCA will intelligently identify popular types of three terminal diode networks. For three terminal devices such as SOT-23 diode networks, the three test clips must all be connected, any way round. The instrument will identify the type of diode network and then display information regarding each detected diode in sequence.
Atlas DCA User Guide October 2007 – Rev 7 LEDs An LED is really just a another type of diode, however, the Atlas DCA will determine that an LED or LED network has been detected if the measured forward voltage drop is larger than 1.5V. This also enables the Atlas DCA to intelligently identify bicolour LEDs, both two-terminal and three-terminal varieties. LED or diode junction(s) Like the diode analysis, the pinout, the forward voltage drop and the associated test current is displayed.
Atlas DCA User Guide October 2007 – Rev 7 Bicolour LEDs Bicolour LEDs are automatically identified. If your LED has 3 leads then ensure they are all connected, in any order. A two terminal bicolour LED consists of two LED chips which are connected in inverse parallel within the LED body. Three terminal bicolour LEDs are made with either common anodes or common cathodes. Two terminal bicolour LED Three terminal bicolour LED Here a two terminal LED has been detected.
Atlas DCA User Guide October 2007 – Rev 7 Bipolar Junction Transistors (BJTs) Bipolar Junction Transistors are simply “conventional” transistors, although variants of these do exist such as Darlingtons, diode protected, resistor shunted types and combinations of these types. All of these variations are automatically identified by the Atlas DCA. Bipolar Junction Transistors are available in two main types, NPN and PNP. In this example, the unit has detected a Silicon PNP transistor.
Atlas DCA User Guide October 2007 – Rev 7 Pressing the scroll-off button will result in the transistor’s pinout being displayed. Here, the instrument has identified that the Base is connected to the Red test clip, the Collector is connected to the Green test clip and the Emitter is connected to the Blue test clip. RED GREEN BLUE Base Coll Emit Transistor Special Features Many modern transistors contain additional special features.
Atlas DCA User Guide October 2007 – Rev 7 Additionally, many Darlingtons and a few non-Darlington transistors also have a resistor shunt network between the base and emitter of the device. The Atlas DCA can detect the resistor shunt if it has a resistance of typically less than 60kΩ. The popular Motorola TIP110 NPN Darlington transistor contains internal resistors between the base and emitter.
Atlas DCA User Guide October 2007 – Rev 7 Faulty or Very Low Gain Transistors Faulty transistors that exhibit very low gain C may cause the Atlas DCA to only identify one or more diode junctions within the device. This B is because NPN transistors consist of a structure of junctions that behave like a common anode diode network. PNP transistors E can appear to be common cathode diode networks. The common junction represents the base terminal.
Atlas DCA User Guide October 2007 – Rev 7 Current Gain (HFE) The DC current gain (HFE) is displayed after any special transistor features have been displayed. DC current gain is simply the ratio of the collector current to the base current for a particular operating condition. The Atlas DCA measures HFE at a collector current of 2.50mA and a collector-emitter voltage of between 2V and 3V. HFE = IC IB IB IC=2.
Atlas DCA User Guide October 2007 – Rev 7 Base-Emitter Voltage Drop The DC characteristics of the base-emitter junction are displayed, both the base-emitter forward voltage drop and the base current used for the measurement. IB VBE B-E Voltage Vbe=0.77V The forward base-emitter voltage drop can aid in the identification of silicon or germanium devices. Germanium devices Test current can have base-emitter voltages as low as Ib=4.52mA 0.2V, Silicon types exhibit readings of about 0.
Atlas DCA User Guide October 2007 – Rev 7 Collector Leakage Current The collector current that takes place when no base current is flowing is referred to as Leakage Current. Most modern transistor exhibit extremely low values of leakage current, often less than 1µA, even for very high collector-emitter voltages. Leakage current Ic=0.
Atlas DCA User Guide October 2007 – Rev 7 Enhancement Mode MOSFETs MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor. Like bipolar transistors, MOSFETs are available in two main types, N-Channel and P-Channel. Most modern MOSFETs are of the Enhancement Mode type, meaning that the bias of the gate-source voltage is always positive (For N-Channel types). Enhancement mode The other (rarer) type of MOSFET is the N-Ch MOSFET Depletion Mode type which is described in a later section.
Atlas DCA User Guide October 2007 – Rev 7 Depletion Mode MOSFETs The fairly rare Depletion Mode MOSFET is very similar to the conventional Junction FET (JFET) except that the gate terminal is insulated from the other two terminals. The input resistance of these devices can typically be greater than 1000MΩ for negative and positive gate-source voltages. Depletion mode N-Ch MOSFET Depletion Mode devices are characterised by the gate-source voltage required to control the drain-source current.
Atlas DCA User Guide October 2007 – Rev 7 Junction FETs (JFETs) Junction FETs are conventional Field Effect Transistors. The voltage applied across the gate-source terminals controls current between the drain and source terminals. N-Channel JFETs require a negative voltage on their gate with respect to their source, the more negative the voltage, the less current can flow between the drain and source. Unlike Depletion Mode MOSFETs, JFETs have no insulation layer on the gate.
Atlas DCA User Guide October 2007 – Rev 7 Thyristors (SCRs) and Triacs Sensitive low power thyristors (Silicon Controlled Rectifiers - SCRs) and triacs that require gate currents and holding currents of less than 5mA can be identified and analysed with the Atlas DCA. Sensitive or low power thyristor Thyristor terminals are the anode, cathode and the gate. The pinout of the thyristor under test will be displayed on the next press of the scroll-off button.
Atlas DCA User Guide October 2007 – Rev 7 Care of your Atlas DCA The Peak Atlas DCA should provide many years of service if used in accordance with this user guide. Care should be taken not to expose your unit to excessive heat, shock or moisture. Additionally, the battery should be replaced at least every 12 months to reduce the risk of leak damage. If a low battery warning message appears, immediate replacement of the battery is recommended as measured parameters may be affected.
Atlas DCA User Guide October 2007 – Rev 7 Self Test Procedure Each time the Atlas DCA is powered up, a self test procedure is performed. In addition to a battery voltage test, the unit measures the performance of many internal functions such as the voltage and current sources, amplifiers, analogue to digital converters and test lead multiplexers. If any of these function measurements fall outside tight performance limits, a message will be displayed and the instrument will switch off automatically.
Atlas DCA User Guide October 2007 – Rev 7 Appendix A - Technical Specifications All values are at 25°C unless otherwise specified. Parameter Min Typ Max Peak test current into S/C -5.5mA 5.5mA Peak test voltage across O/C -5.1V 5.1V Transistor gain range (HFE) 4 65000 Transistor gain accuracy ±3% ±5 HFE Transistor VCEO test voltage 2.0V 3.0V Transistor VBE accuracy -2%-20mV +2%+20mV VBE for Darlington 0.95V 1.00V 1.80V VBE for Darlington (shunted) 0.75V 0.80V 1.80V Acceptable transistor VBE 1.
Atlas DCA User Guide October 2007 – Rev 7 Appendix B – Warranty Information Peak Satisfaction Guarantee If for any reason you are not completely satisfied with the Peak Atlas DCA within 14 days of purchase you may return the unit to your distributor. You will receive a refund covering the full purchase price if the unit is returned in perfect condition. Peak Warranty The warranty is valid for 12 months from date of purchase.
Atlas DCA User Guide October 2007 – Rev 7 Appendix C – Disposal Information WEEE (Waste of Electrical and Electronic Equipment), Recycling of Electrical and Electronic Products United Kingdom In 2006 the European Union introduced regulations (WEEE) for the collection and recycling of all waste electrical and electronic equipment. It is no longer permissible to simply throw away electrical and electronic equipment. Instead, these products must enter the recycling process.
