The CS5124/6 is a fixed frequency current mode controller designed specifically for DC-DC converters found in the telecommunications industry. The CS5124/6 integrates many commonly required current mode power supply features and allows the power supply designer to realize substantial cost and board space savings. The product matrix is as follows: CS5124: 400 kHz w/VBIAS Pin, 195 mV first current sense threshold. CS5126: 200 kHz w/SYNC Pin, 335 mV first current sense threshold. The CS5124/6 integrates the following features: Internal Oscillator, Slope Compensation, Sleep On/Off, Undervoltage Lock Out, Thermal Shutdown, Soft-Start Timer, Low Voltage Current Sense for Resistive Sensing, Second Current Threshold for Pulse-by-Pulse overcurrent Protection, a Direct Optocoupler Interface and Leading Edge Current Blanking.