EC2630QI 12V DC-DC Intermediate Voltage Bus Converter, 27W and 4.5A Description The Enpirion EC2630QI is a high density DCDC Intermediate Voltage Bus Converter which generates a highly efficient output voltage. EC2630QI that tracks one half the input voltage and is designed to work with Enpirion's highly integrated DC to DC point-of-load converter products for a complete 12V solution. EC2630QI provides the means to condition power from a 12V input, to supply multiple lower voltage converters while enabling high efficiency and small PCB area. Due to its extremely high efficiency, it avoids the common two stage power conversion penalty and is equivalent or better than direct regulation. Features * * * * * * * * * * This Enpirion solution significantly helps in system design and productivity by offering greatly simplified board design, layout and manufacturing requirements. In addition, a reduction in the number of vendors required for the complete power solution helps to enable an overall system cost savings. All Enpirion products are RoHS compliant and use a leadfree manufacturing environment. EC2630QI VIN PVIN 22F 3x 1206 30.1 0402 ENA 22F 1206 0.1F * * VOUT 47F 3x 1206 AVIN PGND CFLYN V3P3 VBOOT AGND Applications VOUT CFLYP Complete power conditioning solution from a 12 volt power bus. Wide system input voltage range of 8V to 13.2V. High and flat efficiency, up to 97.5%. 4.5A Continuous Output Current Capability Adjustable operating frequency with optional external clock input. Master/Slave Mode for Parallel Operation Output Enable pin, VOUT_OK, VIN_OK Pre-programmed soft-start time. Thermal shutdown, short circuit, Overload, OVLO and UVLO protection. RoHS compliant, MSL level 3, 260C reflow. * 47F** 3x 1206 * 0.1F PGND FADJ Applications requiring down conversion from a 12V bus to a well regulated output voltage with high efficiency, in a compact foot print (Note: The total system application involves two or more Enpirion products.) Enterprise, Industrial, Embedded, and Telecommunication applications Multi-rail computer & network interface applications such as PCIe and ATCA AMC cards. 12V Industrial and Consumer Applications such as Audio/Video Home Theater, Tuners 100k 0402 Figure 1: Typical Application Schematic Optimized for Maximum Efficiency ** 1-2 of Cout can be eliminated using downstream input bypass capacitance (e.g. PoL converters). 1 05996 10/04/2011 www.enpirion.com Rev: A EC2630QI Ordering Information Part Number EC2630QI Temp Rating (C) -40 to +85 EC2630QI-E Package 36 pin 5.5 x5.5 QFN Package QFN Evaluation Board Pin Configuration Below is a top view diagram of EC2630QI package. Figure 2: Pin-out diagram, top view of EC2630QI QFN Package. NOTE: NC pins are not to be electrically connected to each other or to any external signal, ground, or voltage. Failure to follow this guideline may result in damage to the Device. NOTE: All pins must be soldered to PCB. 2 (c)Enpirion 2011 all rights reserved, E&OE 05996 10/04/2011 www.enpirion.com Rev: A EC2630QI Pin Descriptions PIN 1 NAME V3P3 2 FADJ 3, 8 GND 4 VIN_OK 5 VOUT_OK 6 ENABLE 7 NC 9 M/S 10 NC 11 SYNCH_I 12 SYNCH_O 13-18 19-21 22-24 25-27 28-33 34 PGND CFLYN VOUT CFLYP PVIN VBOOT 35 36 AVIN NC 37 TGND FUNCTION Internal Regulated Supply Output. Connect bypass capacitor from V3P3 to GND. Frequency Adjust pin used to set the switching frequency. See Theory of Operation Section for selecting the required resistor. Internal Regulated Supply Ground. Must tie directly to ground plane with a via right next to each pin. Vin OK is an open drain transistor for power system state indication for nominal 12V operation. VIN_OK is a logic high when Vin is greater than 9V. VOUT_OK is an open drain transistor for power system state indication. VOUT_OK is a logic high when Vout is greater than 85% of expected nominal Vout. This pin should be used to control the ENABLE signals of downstream converters powered by the EC2630. This pin should be tied to VIN all the time. Contact Enpirion Applications Support for more information. NO CONNECT -- Do not electrically connect these pins to each other or to any other electrical signal. CAUTION: May be internally connected. Master/Slave pin for clock synchronization. Logic low = Master. Logic high = Slave. NO CONNECT -- Do not electrically connect these pins to each other or to any other electrical signal. CAUTION: May be internally connected. External Synchronizing Clock Input, input accepted in Slave mode. From an IBC in master mode. Synchronizing Clock Output. Frequency scaled output of internal oscillator. Power ground for the switching voltage attenuator Negative Terminal of Flying Capacitor Converter Output Voltage Positive Terminal of Flying Capacitor Main Input Supply Internal power Supply for high-side drive to which boot-strap capacitor is tied. Input Supply for Controller NO CONNECT - Do not electrically connect these pins to each other or to any other electrical signal. CAUTION: May be internally connected. This pad is a thermal gnd. Needs to be thermally and electrically connected to the ground plane through a matrix of vias. 3 (c)Enpirion 2011 all rights reserved, E&OE 05996 10/04/2011 www.enpirion.com Rev: A EC2630QI Block Diagram Figure 3: Block diagram. 4 (c)Enpirion 2011 all rights reserved, E&OE 05996 10/04/2011 www.enpirion.com Rev: A EC2630QI Absolute Maximum Ratings CAUTION: Absolute Maximum ratings are stress ratings only. Functional operation beyond recommended operating conditions is not implied. Stress beyond absolute maximum ratings may cause permanent damage to the device. Exposure to absolute maximum rated conditions for extended periods may affect device reliability. PARAMETER Input Supply Voltage - PVIN, AVIN Transient Input Supply Voltage, 2 ms maximum duration, 100 Hz repetition rate Input Voltage - ENA, VIN_OK, VOUT_OK, CFLYN, CFLYP, Vout Input Voltage - V3P3, FADJ, M_S, SYNC_I, SYNC_O Input Voltage - VBOOT Storage Temperature Range Maximum Operating Junction Temperature Reflow Temp, 10 Sec, MSL3 JEDEC J-STD-020A ESD Rating (based on Human Body Model): AVIN SYMBOL MIN MAX VIN -0.5 15 V 20 V -0.5 VIN V -0.5 -0.5 -65 3.5 VIN + 8 150 150 260 V V C C C V TSTG TJ-ABS MAX Positive Negative UNITS 1500 2000 ESD Rating (based on Human Body Model): All other pins ESD Rating (based on Charged Device Model) V 2000 V 500 Thermal Characteristics PARAMETER SYMBOL MIN TJ TSD TSDH JC JA -40 Operating Junction Temp Thermal Shutdown Thermal Shutdown Hysteresis Thermal Resistance: Junction to Case Thermal Resistance: Junction to Ambient TYP MAX UNITS +125 C C C C/W C/W 155 25 1 19 Electrical Characteristics NOTE: VIN=12.0V over operating temperature range unless otherwise noted. Typical values are at TA = 25C. PARAMETER Operating Input Voltage Operating Boot Strap Voltage Internal Regulated Supply Output Under Voltage Lockout Input Voltage Indication Rising Input Voltage Indication Falling Over Voltage Lockout No Load Operating Current SYMBOL TEST CONDITIONS VIN VBOOT V3P3 @ Vin =12V, with 0.1uF capacitor between VBOOT and CFLYN @ Vin =12V VUVLO VIN_OK VOVLO IOP TYP MAX UNITS 8 12 17 13.2 V V 2.97 3.3 3.63 V 4.5 5 9 8 14.2 2 5.5 V V V V mA 13.35 @ 12V input and 125kHz switching 5 (c)Enpirion 2011 all rights reserved, E&OE 05996 MIN 10/04/2011 15.05 www.enpirion.com Rev: A EC2630QI PARAMETER SYMBOL TEST CONDITIONS Switching Frequency (Internal Oscillator) Frequency Adjust Voltage Output Voltage FOSC FADJ VOUT RFADJUST= 100 K, MIN TYP MAX UNITS 68 115 165 kHz Fraction of input voltage with no load current 1.2 50 V % Output Voltage Indication Threshold Rising VOUT_OK As a percentage of expected output voltage 85% V Output Voltage Indication Threshold Falling VOUT_OK As a percentage of expected output voltage 70% V 90 m Output Impedance ROUT Continuous Output Current Overload Trip Level IOUT Max VOCP Enable Threshold Logic Low ENA_VIL Enable Threshold Logic High Logic Threshold Low M_S Logic Threshold High M_S External Clock frequency ENA_VIH Clock Input Logic Low SYNC_I_VIL Clock Input Logic High SYNC_I_VIH Clock Output Logic Low VOUT_OK 0 Vin=12V, Overload sensed as a drop in output voltage Max voltage to ensure the converter is disabled 6V VIN 13.2V VIL V3P3 1.8 SYNC_O_VOH sink V3P3 - 0.6 @ 1mA POK low voltage = 0.1V 6 (c)Enpirion 2011 all rights reserved, E&OE 05996 1.8 -0.3 V3P3 - 0.6 0.01 VIH FEXT 10/04/2011 4.5 A V 0.3 V VIN 0.3 V V V3P3 + 0.3 1 V MHz 0.3 V 3.3 V 0.3 V 5.2 SYNC_O_VOL Clock Output Logic High VIN_OK, capability VOUT/ILOAD RFADJUST= 100 K, V 1 mA www.enpirion.com Rev: A EC2630QI Typical Performance Characteristics 98 97 96 Efficiency (%) 95 Vin=13.2 Vin=12 Vin=11 Vin=10 Vin=9 Vin=8 94 93 92 91 3 5 4. 9 1 3. 4. 4. 5 7 3. 3. 1 3 3. 3. 7 9 2. 2. 3 5 2. 2. 9 1 1. 2. 5 7 1. 1. 1 3 1. 1. 7 9 0. 0. 3 5 0. 0. 1 0. 90 Iout (A) Fig. 4: Nominal Efficiency (%) vs. Load (A) @ VIN = 13.2/12/10/8V, CIN=3x22uF, COUT=3X47uF, CFLY=3x47uF with RFADJUST= 100 K, Start-up / Shutdown Wave forms with Enable tied to VIN Fig. 6b: Ch.1: VOUT, Ch.4: VIN Fig. 6a: Ch.1: VOUT, Ch.4: VIN Theory of Operation Bus Voltage Divider The EC2630QI is an open loop voltage divider. It generates an output voltage which is approximately half the input voltage value. The device uses switched capacitors to divide the input voltage by a factor of 2. External capacitors are charged in series during one half of a clock cycle and the capacitors are then connected in parallel during the second 7 (c)Enpirion 2011 all rights reserved, E&OE 05996 half of the clock cycle. Since there is no feedback to regulate the output voltage, the output voltage depends on the input voltage as well as the load current. Temperature dependence is a function of load current. This device has been designed specifically for use along with the Enpirion's point-of-load products for output voltage regulation. The Voltage Divider has the following features: 10/04/2011 www.enpirion.com Rev: A EC2630QI * * * * * * * * Over-current protection (to protect the IC from excessive load current) Thermal shutdown with hysteresis. Under-voltage lockout circuit to disable the converter output when the input voltage is less than approximately 5V Over-voltage lockout circuit to disable the converter output when the input voltage is greater than approximately 14.2V Switching frequency is internally generated. However, a clock signal may be applied externally when the device is configured in Slave mode. When in Master mode, the device will output its internal frequency scaled clock to the SYNCH_O pin. Soft-start circuit, to limit the in-rush current when the converter is powered up. VIN_OK and VOUT_OK indicator signals. Enable Operation A logic high on this pin will turn the device on, and logic low will disable the output. Under normal operation, the ENABLE pin needs to be tied to PVIN. The device is then turned on and off by ramping the input voltage up and down. Contact Enpirion Applications Support for further details. Frequency Synch (Master/Slave) In Slave mode, an external clock may be used for switching the bus converter by connecting such a source to SYNC_I pin when the device is configured. In Master mode, the internal switching frequency of the Master device is outputted through SYNCH_O pin. This clock signal can be used to drive other EC2630QI devices for synchronization or parallel operation. programmed and not user programmable. Overload Protection The overload function is achieved by sensing the output voltage. An overload state is entered when the device is out of soft start and the output voltage drops below ~85% of the expected voltage. This overload state will initiate a fresh soft-start and the device will stay looping in soft-start as long as the overload condition exists. Over-Voltage Protection When the input voltage exceeds 14.2V, the flying capacitor is placed in parallel with the output capacitor during OVLO and the device does not switch. Thermal Overload Protection Thermal shutdown will disable operation when the Junction temperature exceeds the value given in the Electrical Characteristics table. Once the junction temperature drops by the hysteresis temperature, the converter will restart with a normal soft-start. Input Under-voltage Lock-out Internal circuits ensure that the converter will not start switching until the input voltage is above the specified minimum voltage of ~5V. Frequency Adjustment The device is optimized to run at 125kHz switching frequency (with RFADJ= 100 K) independent of load current. The internal oscillator frequency can be adjusted by altering the value of the resistor between the FADJ pin and AGND (see chart below). Contact Enpirion Applications Support for further details. Frequency vs. Resistance Soft-Start Operation 10/04/2011 500 450 400 350 300 250 200 150 100 50 0 0 25 50 75 100 125 150 175 200 225 Resistance (K-Ohms) 8 (c)Enpirion 2011 all rights reserved, E&OE 05996 Oscillator Frequency (KHz) Soft start is a means to reduce the in-rush current when the device is enabled. When the device is enabled by ramping up the input voltage, and the output capacitors are discharged, a large current flow is averted by modulating the gate drive of the NFET during the soft start interval. This interval is pre- www.enpirion.com Rev: A 250 EC2630QI Application Schematic Figure 7: EC2630 connected to a 12V input supply supplying 3 point-of-load Enpirion DC-DC switchers. Figure 7 shows a typical application where the EC2630 is powering up three downstream Enpirion point-of-load (POL) converters. As shown in Figure 7, the EC2630 VOUT_OK signal should be used to control the ENABLE pins of the downstream converters. This ensures that the intermediate bus voltage is up before the POL converters start switching. In addition please use only POL converters rated for up to 6.6V input voltage operation. 9 (c)Enpirion 2011 all rights reserved, E&OE 05996 10/04/2011 www.enpirion.com Rev: A EC2630QI Capacitor Selection The EC2630QI requires a range of capacitance depending on application configuration. Capacitor selection is dependent upon power level, efficiency, space, and cost requirements. Low-cost, low-ESR X5R or X7R ceramic capacitors should be used. Either 1206 or 1210 case sizes are recommended. In general, 1210 capacitors exhibit less voltage coefficient than 1206 capacitors, providing more capacitance per unit volume-volt. Y5V or equivalent dielectric formulations must not be used as they lose capacitance with frequency, temperature and bias voltage. * * * * Input Capacitors- a typical implementation might use 3x22F, 1206 MLCC capacitors Output Capacitorsa typical implementation might use 3X47F, 1206 output a typical Flying Capacitorsimplementation might use 3x47F 1206. A portion of the output capacitance or flying capacitance can be allocated to the underside of the board. In addition, a portion of Cout can be shared with downstream input bypass capacitance (e.g. PoL converters). Capacitor selection guidelines to support full output load (4.5A) optimized for efficiency: Optional External Over-Current Protection (OCP) For some applications, output load levels that drive the EC2630 into very high-current conditions with VOUT at nominal VIN/2 voltages can lead to EC2630 device damage. Enpirion has observed that high-current conditions over 6A - while VOUT is regulating at VIN/2 - can lead to device failure. When the EC2630 fails, the device will stop regulating to VOUT=VIN/2, and the output will drop to approximately 2V. A failure event has not been found to damage downstream devices since VOUT drops during the event. When an EC2630 device fails, it draws excessive current from the 12V input supply at its PVIN pin. Figure 8 shows a recommended circuit for external over-current protection. Applications that implement other means of over-current and short-circuit protection by using other supervisory or control circuits do not need to use the circuit shown in Figure 8. Please contact Enpirion Applications support for more details. This circuit interfaces to the following pins on the EC2630: AVIN, FADJ, ENABLE, VOUTOK, and GND. It uses the VOUT_OK signal to decide if there is an over-current condition. If VOUT_OK is high, then the circuit allows the EC2630 to (c)Enpirion 2011 all rights reserved, E&OE 05996 operate normally. As soon as VOUT_OK goes to a logic low, it is interpreted as an over-current condition, and the circuit lowers the device operating frequency, and causes it to go into a hiccup mode. The hiccup mode continues indefinitely until VOUT_OK goes high. There are two timers in this circuit. C1 and its associated resistors sets up a soft-start timer, and C2 and its associated resistors set up a hiccup timer. The active components in this circuit were chosen based on device availability. Similar components can be used as long as the performance is comparable to the ones shown in Figure 8. Please note the circuit also requires an external 3.3V, low-current rail. If an over-current or short-circuit condition is encountered while using the circuit of Figure 8 with the EC2630, leave the power on for at least 2 seconds before turning it off, and wait an additional 2 seconds before re-applying power. Please note when using the circuit of Figure 8, the EC2630 ENABLE pin is not tied to VIN any more. This pin needs be toggled by the circuit for proper OCP operation. 10 10/04/2011 www.enpirion.com Rev: A EC2630QI Figure 8: Optional External Over-Current Protection Circuit (c)Enpirion 2011 all rights reserved, E&OE 05996 11 10/04/2011 www.enpirion.com Rev: A EC2630QI Mechanical Information Figure 9: EC2630 Package Dimensions Figure 10: Recommended PCB footprint. (c)Enpirion 2011 all rights reserved, E&OE 05996 12 10/04/2011 www.enpirion.com Rev: A EC2630QI Contact Information Enpirion, Inc. Perryville III Corporate Park 53 Frontage Road, Suite 210 Hampton, NJ 08827 USA Phone: +1-908-894-6000 Fax: +1-908-894-6090 www.enpirion.com Enpirion reserves the right to make changes in circuit design and/or specifications at any time without notice. Information furnished by Enpirion is believed to be accurate and reliable. Enpirion assumes no responsibility for its use or for infringement of patents or other third party rights, which may result from its use. Enpirion products are not authorized for use in nuclear control systems, as critical components in life support systems or equipment used in hazardous environment without the express written authority from Enpirion. (c)Enpirion 2011 all rights reserved, E&OE 05996 13 10/04/2011 www.enpirion.com Rev: A