Applications · Intermediate Bus Architecture · Distributed Power Architecture · Datacom · Telecom · Server, Workstation Advantages · · High Efficiency - No Heat Sink Required Area · Tape and reel packaging · Compatible with pick and place equipment · Minimize the number of parts in inventory · Low cost features · · RoHS lead-free and lead-free solder available Product Dimensions: 0.80” x 0.45” x 0.247” (20.32 x 11.43 x 6.27mm ) Weight: 0.079 oz [2.26 g] Coplanarity < 0.003” Synchronous Buck Converter Topology Startup To pre-biased output No minimum load required Programmable output voltage via external resistors accreditation and DEMKO certification according to IEC/EN 60950

Description Power point load converters are recommended for regulated bus converters in an intermediate bus architecture (IBA). The YM12SO5 non-isolated DC-DC converter provides up to 5A of output current in an industry standard surface mount package. Operating from a 9.6-14 VDC input, the YM12SO5 converter is ideal for intermediate bus architectures where point-of-load power (POL) delivery is often required. They offer extremely compact programmable output voltages ( 0.7525 V to 5.5 V). Y-Series converters provide excellent thermal performance even in high temperature environments with minimal airflow. No derating is required below 85°C (up to 70°C at 5 V and 3.3 V output) even without airflow under natural convection conditions. This is achieved through the use of advanced circuitry, packaging and processing techniques to enable designs with ultra-high efficiency, excellent thermal management and a very low body profile. The lower body profile and isolation of the heat sinks minimize resistance to system airflow, enhancing cooling for upstream and downstream equipment. 100 % automated assembly, coupled with advanced power electronics and thermal design, make the product extremely reliable.

Operating Input and Output Impedance Y-Series converters should be connected to a DC power source through low impedance. In many applications, the inductance associated with the distribution from the power supply to the converter input can affect converter stability. It is recommended to use decoupling capacitors (47µf minimum) as close as possible to the converter input pins to ensure converter stability and reduce input ripple voltage. Internally, the converter has an input capacitance of 10µF (low esr ceramic). In typical applications, low ESR tantalum or POS capacitors are sufficient to provide adequate ripple voltage filtering at the converter input. However, to reduce the input ripple voltage, it is recommended to use a very low esr ceramic capacitor 47µf 100µf at the input of the converter. They should be as close as possible to the input pins of the converter. The YM12SO5 is designed for stable operation with no external capacitors on the output. Low esr ceramic capacitors are recommended to minimize output ripple voltage. It is recommended to place low esr ceramic capacitors as close to the load as possible to improve transient performance and reduce output voltage ripple. In order to connect the load to the output pins of the converter, it is important to maintain low resistance and low inductance PCB traces. This is necessary to maintain good load regulation as the converter has no sense pins to compensate for the voltage drop associated with the power distribution system on the PCB.
ON/OFF (Pin 1) The ON/OFF pin (Pin 1) is used to remotely turn the power converter on or off via a system signal referenced to ground (Pin 4). A typical connection is shown in Figure A. The ON/OFF pin of the on/off converter should be at logic low or left open, and the ON/OFF pin of the turn-off converter should be at logic high or connected to the VIN. The open/close pin is pulled down internally. TTL or CMOS logic gates, open collector (open drain) transistors can be used to drive the on/off pins. When using an open collector (open drain) transistor the ground pin of the trimmer resistor should be connected directly to the ground pin of the converter with no voltage drop between the two.

Protection Function Input Under-Voltage Lockout Input under-voltage lockout is standard on this converter. When the input voltage drops below a predetermined voltage, the converter will shut down; when the vehicle identification number (vin) returns to the specified range, the converter will automatically start. The input voltage must typically be 9.0V for the converter to turn on. Once the converter turns on, it turns off when the input voltage drops below 8.8V.
Output Over Current Protection (OCP) The frequency converter is protected against over current and short circuit. When an overcurrent condition is sensed, the converter will enter hiccup mode. Once the overload or short-circuit condition is removed, VOUT will return to its nominal value. Over-Temperature Protection (OTP) The drive will shut down in an over-temperature condition to protect itself from overheating caused by operating outside the thermal derating curve or operating under abnormal conditions such as system fan failure. After the torque converter has cooled to a safe operating temperature, it will restart automatically.
Safety Requirements According to UL60950 and EN60950, the converter complies with North American and international safety regulations. The maximum DC voltage between any two pins is vin under all operating conditions. Therefore, the device has an extra-low voltage (ELV) output that meets SELV requirements with all input voltages at ELV. The converter has no internal fuse. To comply with safety agency requirements, an approved fuse with a maximum rating of 7.5 amps must be used in series with the input line.
Characteristics General Information Converter characteristics in many aspects of operation, including thermal derating (maximum load current as a function of ambient temperature and airflow) vertical and horizontal mounting, efficiency, startup and shutdown parameters, output ripple and noise, load step changes transient response, overload and short circuit. Plots are numbered as shown in figure xy, where x represents different output voltages and y is related to a specific curve (y=1 for vertical thermal derating, ...). For example, Figure x.1 typically refers to vertical thermal derating of all output voltages. The following pages contain specific plots or waveforms related to the converter. The following are additional comments on specific data. Test Conditions All data was obtained when the converter was soldered to the test board, specifically a 0.060" thick four-layer printed wiring (PWB). The top and bottom layers were not metallized. The two inner layers consisted of two ounces of copper, with is used to provide traces to connect to the converter. The lack of outer metallization and limited thermal connection ensures that heat transfer from the converter to the PWB is minimized. This provides a worst-case but consistent case for thermal derating purposes .All measurements requiring airflow were made in vertical and horizontal wind tunnel facilities using infrared thermal imaging and thermocouples. Ensuring that components on the converter do not exceed their ratings is important to maintain high reliability. If expected at or near Operating the converter at the maximum load specified in the derating curve, care should be taken to check the actual operating temperature in the application. Thermal imaging is best; if this capability is not available, a thermocouple can be used. AWG 40 gauge thermocouple is recommended , to ensure measurement accuracy. Careful placement of thermocouple leads will further reduce measurement errors.

Thermal derating load current versus ambient temperature and airflow velocity is shown in the graph. X.1 to X.2, maximum temperature 120°C. Ambient temperature varies from 25°C to 85°C, airflow velocities from 30 to 500 lfm (0.15m/s to 2.5 m/s), vertical and horizontal converter installations. For each set of conditions, the maximum load current is defined as the lowest of: (i) the output current at which any mosfet temperature does not exceed the maximum specified temperature (120°C) shown in the thermal image, or (ii) during normal operation, The derating curve for a maximum FET temperature of less than or equal to 120°C should not be exceeded. To operate within the derating curve, the temperature on the PCB at the thermocouple location shown in Figure c should not exceed 120°C. Efficiency graph X.3 shows the efficiency vs. load current curve at an ambient temperature of 25°C, an airflow velocity of 200 lfm (1 m/s), and input voltages of 9.6V, 12V, and 14V. The power consumption graph X.4 shows the power consumption vs. load current curve at Ta=25°C, the airflow velocity is 200 lfm (1 m/s), the vertical installation, and the input voltages are 9.6v, 12v and 14v. Ripple and Noise The output voltage ripple waveform is measured at rated load current. Note that all output voltage waveforms are measured with 1µf ceramic capacitors. The output voltage ripple and input reflected ripple current waveforms were obtained using the test setup shown in Figure d.