LTM8054 36VIN, 5.4A Buck-Boost µModule Regulator Features Description Complete Buck-Boost Switch Mode Power Supply nn Wide Input Voltage Range: 5V to 36V nn Wide Output Voltage Range: 1.2V to 36V nn V May Be Greater than, Equal to or Less than V IN OUT nn 12V/1.8A Output from 6V IN nn 12V/3.4A Output from 12V IN nn 12V/5.4A Output from 24V IN nn Up to 94% Efficient nn Adjustable Input and Output Average Current Limits nn Input and Output Current Monitors nn Parallelable for Increased Output Current nn Selectable Switching Frequency: 100kHz to 800kHz nn Synchronization from 200kHz to 700kHz nn 11.25mm × 15mm × 3.42mm BGA Package The LTM ®8054 is a 36V IN, buck-boost µModule ® (micromodule) regulator. Included in the package are the switching controller, power switches, inductor and support components. A resistor to set the switching frequency, a resistor divider to set the output voltage, and input and output capacitors are all that are needed to complete the design. Other features such as input and output average current regulation may be implemented with just a few components. The LTM8054 operates over an input voltage range of 5V to 36V, and can regulate output voltages between 1.2V and 36V. The SYNC input and CLKOUT output allow easy synchronization. nn Applications The LTM8054 is housed in a compact overmolded ball grid array (BGA) package suitable for automated assembly by standard surface mount equipment. The LTM8054 is RoHS compliant. Buck Boost Selection Table High Power Battery-Operated Devices nn Industrial Control nn Solar Powered Voltage Regulator nn Solar Powered Battery Charging VIN (Operation) VIN Abs Max L, LT, LTC, LTM, Linear Technology, the Linear logo, µModule and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. nn LTM8054 LTM8055 LTM8056 36 36 58 40 40 60 VOUT Abs Max 40 40 60 IOUT (Peak) 24VIN, 12VOUT 5.4 8.5 5.5 15 x 11.25mm x 3.42mm BGA 15 x 15mm x 4.92mm BGA 15 x 15mm x 4.92mm BGA Package Typical Application Maximum Output Current and Efficiency vs Input Voltage 12VOUT from 5V to 35VIN Buck Boost Regulator LTM8054 100k GND CLKOUT IINMON IOUTMON FB 90 4 68µF 22µF 25V 88 2 11.0k 8054 TA01a OUTPUT CURRENT (A) 36.5k 600kHz RUN CTL SS SYNC COMP RT LL MODE 6 VOUT 12V IOUT IIN SVIN 4.7µF 50V ×2 VOUT EFFICIENCY (%) VIN VIN 6V TO 35V 92 EFFICIENCY MAX CURRENT 86 0 10 20 30 INPUT VOLTAGE (V) 40 0 8054 TA01b 8054f For more information www.linear.com/LTM8054 1 LTM8054 Absolute Maximum Ratings Pin Configuration (Note 1) VIN, SVIN, VOUT, RUN, IIN, IOUT Voltage......................40V FB, SYNC, CTL, MODE Voltage....................................6V IINMON, IOUTMON Voltage..............................................6V LL Voltage..................................................................15V Maximum Junction Temperature (Notes 2, 3)........ 125°C Storage Temperature.................................. –55 to 125°C Peak Solder Reflow Body Temperature.................. 245°C 2 1 A TOP VIEW 4 5 7 8 C D BANK 1 E GND F LL G CLKOUT 6 VOUT BANK 2 B IOUT 3 MODE H SVIN RT SYNC J VIN FB COMP K SS CTL L GND BANK 3 IINMON IOUTMON RUN IIN BGA PACKAGE 88-LEAD (15mm × 11.25mm × 3.42mm) TJMAX = 125°C, θJA = 17.6°C/W, θJCbottom = 5.9°C/W, θJCtop = 10.7°C/W, θJB = 7.8°C/W, WEIGHT = 1.4g, θ VALUES DETERMINED PER JEDEC 51-9, 51-12 Order Information PART NUMBER TERMINAL FINISH PART MARKING* FINISH CODE PACKAGE TYPE MSL RATING TEMPERATURE RANGE (SEE NOTE 2) DEVICE LTM8054EY#PBF SAC305 (RoHS) LTM8054Y LTM8054IY#PBF SAC305 (RoHS) LTM8054Y e1 BGA 3 –40°C to 125°C e1 BGA 3 –40°C to 125°C LTM8054IY SnPb(63/37) LTM8054Y e0 BGA 3 –40°C to 125°C LTM8054MPY#PBF SAC305 (RoHS) LTM8054Y e1 BGA 3 –55°C to 125°C LTM8054MPY SnPb(63/37) LTM8054Y e0 BGA 3 –55°C to 125°C Consult Marketing for parts specified with wider operating temperature ranges. *Device temperature grade is indicated by a label on the shipping container. Pad or ball finish code is per IPC/JEDEC J-STD-609. • Recommended LGA and BGA PCB Assembly and Manufacturing Procedures: www.linear.com/umodule/pcbassembly • Terminal Finish Part Marking: www.linear.com/leadfree • LGA and BGA Package and Tray Drawings: www.linear.com/packaging 2 8054f For more information www.linear.com/LTM8054 LTM8054 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. RUN = 1.5V unless otherwise noted. (Note 2) PARAMETER Minimum Input Voltage Output DC Voltage Output DC Current Quiescent Current Into VIN (Tied to SVIN) Output Voltage Line Regulation Output Voltage Load Regulation Output RMS Voltage Ripple Switching Frequency CONDITIONS VIN = SVIN FB = VOUT Through 100k RFB = 100k/3.40k VIN = 6V, VOUT = 12V VIN = 24V, VOUT = 12V RUN = 0.3V (Disabled) No Load, MODE = 0.3V (DCM) No Load, MODE = 1.5V (FCM) 5V < VIN < 36V, IOUT = 1A VIN = 24V, 0.1A < IOUT < 3A VIN = 24V, IOUT = 3A RT = 453k RT = 24.9k MIN 1.2 36 1.8 5.4 0.1 8 45 0.5 0.5 25 100 800 Voltage at FB Pin l RUN Falling Threshold RUN Hysteresis RUN Low Threshold RUN Pin Current IIN Bias Current Input Current Sense Threshold (IIN-VIN) IOUT Bias Current Output Current Sense Threshold (VOUT-IOUT) IINMON Voltage IOUTMON Voltage CTL Input Bias Current SS Pin Current CLKOUT Output High CLKOUT Output Low SYNC Input Low Threshold SYNC Input High Threshold SYNC Bias Current MODE Input Low Threshold MODE Input High Threshold LTM8054 Stops Switching LTM8054 Starts Switching LTM8054 Disabled RUN = 1V RUN = 1.6V TYP l l 1.188 1.176 1.15 MAX 5.0 1 30 100 1.212 1.220 1.25 25 2 3 0.3 5 100 90 l 44 56 20 VCTL = Open LTM8054 in Input Current Limit LTM8054 in Output Current Limit VCTL = 0V VSS = 0V 10k to GND 10k to 5V l 53 0.96 1.14 63 1.04 1.26 22 35 4 0.7 0.3 1.5 SYNC = 1V 11 0.3 1.5 Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTM8054E is guaranteed to meet performance specifications from 0°C to 125°C internal. Specifications over the full –40°C to 125°C internal operating temperature range are assured by design, characterization and correlation with statistical process controls. The LTM8054I is guaranteed to meet specifications over the full –40°C to 125°C internal operating temperature range. The LTM8054MP is guaranteed to meet specifications over the full –55°C to 125°C internal UNITS V V V A A µA mA mA % % mV kHz kHz V V V mV V µA nA µA mV µA mV V V µA µA V V V V µA V V operating temperature range. Note that the maximum internal temperature is determined by specific operating conditions in conjunction with board layout, the rated package thermal resistance and other environmental factors. Note 3: The LTM8054 contains overtemperature protection that is intended to protect the device during momentary overload conditions. The internal temperature exceeds the maximum operating junction temperature when the overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. 8054f For more information www.linear.com/LTM8054 3 LTM8054 Typical Performance Characteristics 3.3VOUT Efficiency TA = 25°C, unless otherwise noted. 8VOUT Efficiency 5VOUT Efficiency 90 90 90 80 80 80 70 60 40 70 60 6VIN 12VIN 19VIN 50 0 1 2 3 4 OUTPUT CURRENT (A) 5 EFFICIENCY (%) 100 EFFICIENCY (%) 100 EFFICIENCY (%) 100 6VIN 12VIN 24VIN 50 40 6 0 1 2 3 4 OUTPUT CURRENT (A) 5 8054 G01 100 90 EFFICIENCY (%) EFFICIENCY (%) 60 0 1 2 3 4 OUTPUT CURRENT (A) 5 100 70 6VIN 12VIN 24VIN 36VIN 60 50 6 4 6VIN 12VIN 24VIN 36VIN 70 60 0 1 2 3 OUTPUT CURRENT (A) 4 8054 G07 4 5 0 1 2 3 4 OUTPUT CURRENT (A) 5 80 70 60 40 6 6VIN 12VIN 24VIN 36VIN 0 1 2 3 4 OUTPUT CURRENT (A) 5 4 2 1 6VIN 12VIN 19VIN 0 1 2 3 4 OUTPUT CURRENT (A) 5 6 8054 G08 6 8054 G06 Input Current vs Output Current (3.3VOUT) 3 0 6 24VOUT Efficiency 50 INPUT CURRENT (A) INPUT CURRENT (A) EFFICIENCY (%) 80 2 3 4 OUTPUT CURRENT (A) 8054 G05 36VOUT Efficiency 90 1 90 8054 G04 100 0 8054 G03 18VOUT Efficiency 80 6VIN 12VIN 24VIN 35VIN 50 40 40 6 90 70 6VIN 12VIN 24VIN 8054 G02 12VOUT Efficiency 80 60 50 EFFICIENCY (%) 100 70 Input Current vs Output Current (5VOUT) 3 2 1 0 6VIN 12VIN 24VIN 0 1 2 3 4 OUTPUT CURRENT (A) 5 6 8054 G09 8054f For more information www.linear.com/LTM8054 LTM8054 Typical Performance Characteristics Input Current vs Output Current (12VOUT) 5 4 4 4 2 0 1 2 3 4 OUTPUT CURRENT (A) 5 2 6VIN 12VIN 24VIN 35VIN 1 6VIN 12VIN 24VIN 0 3 0 6 0 1 2 3 4 OUTPUT CURRENT (A) 5 8054 G10 5 4 INPUT CURRENT (A) INPUT CURRENT (A) 4 2 6VIN 12VIN 24VIN 36VIN 1 0 0 1 2 3 4 OUTPUT CURRENT (A) 5 2 1 6VIN 12VIN 24VIN 36VIN 0 1 2 3 OUTPUT CURRENT (A) 70 12VOUT 18VOUT 24VOUT 36VOUT 1 0 6 12 18 24 INPUT VOLTAGE (V) 30 36 8054 G16 2 3 4 OUTPUT CURRENT (A) 5 Junction Temperature Rise vs Output Current (3.3VOUT) Maximum Output Current vs Input Voltage (3.3VOUT, 5VOUT, 8VOUT) 4 3 100 3.3VOUT 5VOUT 8VOUT 0 5 10 15 20 INPUT VOLTAGE (V) 25 30 Junction Temperature Rise vs Output Current (5VOUT) 90 80 50 40 30 20 0 1 2 3 4 OUTPUT CURRENT (A) 5 70 60 50 40 30 20 6VIN 12VIN 19VIN 10 0 6 8054 G15 TEMPERATURE (°C) TEMPERATURE (°C) 2 1 5 2 4 60 3 0 8054 G14 Maximum Output Current vs Input Voltage (12VOUT, 18VOUT, 24VOUT, 36VOUT) 4 6VIN 12VIN 24VIN 36VIN 8054 G12 6 3 0 6 5 0 0 6 Input Current vs Output Current (36VOUT) 8054 G13 6 2 8054 G11 Input Current vs Output Current (24VOUT) 3 3 1 MAXIMUM OUTPUT CURRENT (A) 3 INPUT CURRENT (A) 5 1 MAXIMUM OUTPUT CURRENT (A) Input Current vs Output Current (18VOUT) 5 INPUT CURRENT (A) INPUT CURRENT (A) Input Current vs Output Current (8VOUT) TA = 25°C, unless otherwise noted. 6VIN 12VIN 19VIN 10 6 8054 G17 0 0 1 2 3 4 OUTPUT CURRENT (A) 5 6 8054 G18 8054f For more information www.linear.com/LTM8054 5 LTM8054 Typical Performance Characteristics Junction Temperature Rise vs Output Current (8VOUT) Junction Temperature Rise vs Output Current (12VOUT) 120 100 TEMPERATURE (°C) 40 20 1 2 3 4 OUTPUT CURRENT (A) 5 60 40 6VIN 12VIN 24VIN 35VIN 20 6VIN 12VIN 24VIN 0 TEMPERATURE (°C) 80 60 TEMPERATURE (°C) Junction Temperature Rise vs Output Current (18VOUT) 100 80 0 TA = 25°C, unless otherwise noted. 6 0 0 1 2 3 4 OUTPUT CURRENT (A) 5 8054 G19 40 6VIN 12VIN 24VIN 36VIN 20 6 0 0 1 2 3 4 OUTPUT CURRENT (A) 5 6 8054 G21 Junction Temperature Rise vs Output Current (36VOUT) 120 100 100 80 TEMPERATURE (°C) TEMPERATURE (°C) 60 8054 G20 Junction Temperature Rise vs Output Current (24VOUT) 80 60 40 6VIN 12VIN 24VIN 36VIN 20 0 80 0 1 2 3 4 OUTPUT CURRENT (A) 5 60 40 6VIN 12VIN 24VIN 36VIN 20 6 0 0 1 2 3 OUTPUT CURRENT (A) 8054 G22 4 8054 G23 Turn-On Response, Demo Board DC2016A, 3A Resistive Load Output Voltage Ripple, 12VOUT Stock DC2016A Demo Board 6VIN, 1.8A LOAD 100mV/DIV VOUT 5V/DIV 12VIN, 3.4A LOAD 100mV/DIV CSS = 0.022µF CSS = 0.1µF CSS = 0.33µF 200µs/DIV 24VIN, 5.4A LOAD 100mV/DIV 8054 G24 1µs/DIV 8054 G25 20MHz BW LIMIT, MEASURED ACROSS C8 6 8054f For more information www.linear.com/LTM8054 LTM8054 Pin Functions GND (Bank 1, Pin L1): Tie these GND pins to a local ground plane below the LTM8054 and the circuit components. In most applications, the bulk of the heat flow out of the LTM8054 is through these pads, so the printed circuit design has a large impact on the thermal performance of the part. See the PCB Layout and Thermal Considerations sections for more details. Return the RFB1/RFB2 feedback divider to this net. VOUT (Bank 2): Power Output Pins. Apply output filter capacitors between these pins and GND pins. VIN (Bank 3): Input Power. The VIN pin supplies current to the LTM8054’s internal power switches and to one terminal of the optional input current sense resistor. This pin must be locally bypassed with an external, low ESR capacitor; see Table 1 for recommended values. IOUT (Pin C1): Output Current Sense. Tie this pin to the output current sense resistor. The output average current sense threshold is 58mV, so the LTM8054 will regulate the output current to 58mV/RSENSE, where RSENSE is the value of the output current sense resistor in ohms. The load is powered through the sense resistor connected at this pin. Tie this pin to VOUT if no output current sense resistor is used. Keep this pin within ±0.5V of VOUT under all conditions. LL (Pin F1): Light Load Indicator. This open-drain pin indicates that the output current, as sensed through the resistor connected between VOUT and IOUT, is approximately equivalent to 6mV or less. Its state is meaningful only if a current sense resistor is applied between VOUT and IOUT. This is useful to change the switching behavior of the LTM8054 in light loads. LL is typically tied to MODE or left open, but not connected to other loads or signal sources. SVIN (Pins H7, H8): Controller Power Input. Apply a separate voltage above 5V if the LTM8054 is required to operate when the main power input (VIN) is below 5V. Bypass these pins with a high quality, low ESR capacitor. If a separate supply is not used, connect these pins to VIN. CLKOUT (Pin G1): Clock Output. Use this pin as a clock source when synchronizing other devices to the switching frequency of the LTM8054. When this function is not used, leave this pin open. MODE (Pin G2): Switching Mode Input. The LTM8054 operates in forced continuous mode when MODE is open, and can operate in discontinuous switching mode when MODE is low. In discontinuous switching mode, the LTM8054 will block reverse inductor current. This pin is normally left open or tied to LL. This pin may be tied to GND for the purpose of blocking reverse current if no output current sense resistor is used. RT (Pin H1): Timing Resistor. The RT pin is used to program the switching frequency of the LTM8054 by connecting a resistor from this pin to ground. The range of oscillation is 100kHz to 800kHz. The Applications Information section of the data sheet includes a table to determine the resistance value based on the desired switching frequency. Minimize capacitance at this pin. A resistor to ground must be applied under all circumstances. SYNC (Pin H2): External Synchronization Input. The SYNC pin has an internal pull-down resistor. See the Synchronization section in Applications Information for details. Tie this pin to GND when not used. FB (Pin J1): Output Voltage Feedback. The LTM8054 regulates the FB pin to 1.2V. Connect the FB pin to a resistive divider between the output and GND to set the output voltage. The output voltage is determined by the equation R VOUT = 1.2 • TOP + 1 RBOT where RTOP and RBOT are the top and bottom feedback resistors, respectively. See Table 1 for recommended FB divider resistor values. COMP (Pin J2): Compensation Pin. The LTM8054 is equipped with internal compensation that works well with most applications. In some cases, the performance of the LTM8054 can be enhanced by modifying the control loop compensation by applying a capacitor or RC network to this pin. 8054f For more information www.linear.com/LTM8054 7 LTM8054 Pin Functions SS (Pin K1): Soft-Start. Connect a capacitor from this pin to GND to increase the soft-start time. Soft-start reduces the input power source’s surge current by gradually increasing the controller’s current limit. Larger values of the soft-start capacitor result in longer soft-start times. If no soft-start is required, leave this pin open. CTL (Pin K2): Current Sense Adjustment. Apply a voltage below 1.2V to reduce the current limit threshold of IOUT. Drive CTL to less than about 50mV to stop switching. The CTL pin has an internal pull-up resistor to 2V. If not used, leave open. IOUTMON (Pin L2): Output Current Monitor. This pin produces a voltage that is proportional to the voltage between VOUT and IOUT. IOUTMON will equal 1.2V when VOUT – IOUT = 58mV. This feature is generally useful only if a current sense resistor is applied between VOUT and IOUT. IINMON (Pin L3): Input Current Monitor. This pin produces a voltage that is proportional to the voltage between IIN and VIN. IINMON will equal 1V when IIN – VIN = 50mV. This feature is generally useful only if a current sense resistor is applied between VIN and IIN. RUN (Pin L4): LTM8054 Enable. Raise the RUN pin voltage above 1.2V for normal operation. Above 1.2V (typical), but below 6V, the RUN pin input bias current is less than 1µA. Below 1.2V and above about 0.3V, the RUN pin sinks 3µA so the user can define the hysteresis with the external resistor selection. This will also reset the soft-start function. If RUN is 0.3V or less, the LTM8054 is disabled and the input quiescent current is below 1µA. IIN (Pin L6): Input Current Sense. Tie this pin to the input current sense resistor. The input average current sense threshold is 50mV, so the LTM8054 will regulate the input current to 50mV/RSENSE, where RSENSE is the value of the input current sense resistor in ohms. Tie to VIN when not used. Keep this pin within ±0.5V of VIN under all conditions. Block Diagram VIN VOUT SVIN IOUT 4.7µH IIN 0.47µF 50V 0.2µF RUN GND 2V SS 100k FB 100k CLKOUT BUCK-BOOST CONTROLLER 0.1µF IINMON IOUTMON CTL MODE COMP LL RT SYNC 8054 BD 8 8054f For more information www.linear.com/LTM8054 LTM8054 Operation The LTM8054 is a standalone nonisolated buck-boost switching DC/DC power supply. The buck-boost topology allows the LTM8054 to regulate its output voltage for input voltages both above and below the magnitude of the output, and the maximum output current depends upon the input voltage. Higher input voltages yield higher maximum output current. This converter provides a precisely regulated output voltage programmable via an external resistor divider from 1.2V to 36V. The input voltage range is 5V to 36V, but the LTM8054 may be operated at lower input voltages if SVIN is powered by a voltage source above 5V. A simplified block diagram is given on the previous page. The LTM8054 contains a current mode controller, power switching elements, power inductor and a modest amount of input and output capacitance. The LTM8054 is a fixed frequency PWM regulator. The switching frequency is set by connecting the appropriate resistor value from the RT pin to GND. The output voltage of the LTM8054 is set by connecting the FB pin to a resistor divider between VOUT and GND. In addition to regulating its output voltage, the LTM8054 is equipped with average current control loops for both the input and output. Add a current sense resistor between IIN and VIN to limit the input current below some maximum value. The IINMON pin reflects the current flowing though the sense resistor between IIN and VIN. A current sense resistor between VOUT and IOUT allows the LTM8054 to accurately regulate its output current to a maximum value set by the value of the sense resistor. In general, the LTM8054 should be used with an output sense resistor to limit the maximum output current, as buck-boost regulators are capable of delivering large currents when the output voltage is lower than the input, if demanded. Furthermore, while the LTM8054 does not require an output sense resistor to operate, it uses information from the sense resistor to optimize its performance. If an output sense resistor is not used, the efficiency or output ripple may degrade, especially if the current through the integrated inductor is discontinuous. In some cases, an output sense resistor is required to adequately protect the LTM8054 against output overload or short-circuit. A voltage less than 1.2V applied to the CTL pin reduces the maximum output current. The current flowing through the sense resistor is reflected by the output voltage of the IOUTMON pin. Drive CTL to less than about 50mV to stop switching. Driving the SYNC pin will synchronize the LTM8054 to an external clock source. The CLKOUT pin sources a signal that is the same frequency but approximately 180° out of phase with the internal oscillator. If more output current is required than a single LTM8054 can provide, multiple devices may be operated in parallel. Refer to the Parallel Operation section of Applications Information for more details. An internal regulator provides power to the control circuitry and the gate driver to the power MOSFETs. This internal regulator draws power from the SVIN pin. The RUN pin is used to place the LTM8054 in shutdown, disconnecting the output and reducing the input current to less than 1µA. The LTM8054 is equipped with a thermal shutdown that inhibits power switching at high junction temperatures. The activation threshold of this function is above 125°C to avoid interfering with normal operation, so prolonged or repetitive operation under a condition in which the thermal shutdown activates may damage or impair the reliability of the device. 8054f For more information www.linear.com/LTM8054 9 LTM8054 Applications Information For most applications, the design process is straight forward, summarized as follows: 1. Look at Table 1 and find the row that has the desired input range and output voltage. 2. Apply the recommended CIN, COUT, RFB1/RFB2 and RT values. 3. Apply the output sense resistor to set the output current limit. The output current is limited to 58mV/RSENSE, where RSENSE is the value of the output current sense resistor in ohms. While these component combinations have been tested for proper operation, it is incumbent upon the user to verify proper operation over the intended system’s line, load and environmental conditions. Bear in mind that the maximum output current is limited by junction temperature, the relationship between the input and output voltage magnitude and other factors. Please refer to the graphs in the Typical Performance Characteristics section for guidance. The maximum frequency (and attendant RT value) at which the LTM8054 should be allowed to switch is given in Table 1 in the fMAX column, while the recommended frequency (and RT value) for optimal efficiency over the given input condition is given in the fOPTIMAL column. There are additional conditions that must be satisfied if the synchronization function is used. Please refer to the Synchronization section for details. Note that Table 1 calls out both ceramic and electrolytic output capacitors. Both of the capacitors called out in the table must be applied to the output. The electrolytic capacitors in Table 1 are described by voltage rating, value and ESR. The voltage rating of the capacitor may be increased if the application requires a higher voltage stress derating. The LTM8054 can tolerate variation in the ESR; other capacitors with different ESR may be used, but the user must verify proper operation over line, load and environmental conditions. Table 2 gives the description and part numbers of electrolytic capacitors used in the LTM8054 development testing and design validation. Table 1. Table 1. Recommended Component Values and Configuration (TA = 25°C) VIN Range VOUT CIN COUT RADJ fOPTIMAL (kHz) RT(OPTIMAL) fMAX (kHz) RT(MIN) 5V to 19V 3.3V 2 × 4.7µF, 50V, 47µF, 4V, X5R, 1206 X5R, 0805 100µF, 6V, 75mΩ, Electrolytic C Case 100k/56.2k 600 36.5k 800 24.9k 5V to 25V 5V 2 × 4.7µF, 50V, 22µF, 6.3V, X5R, 0805 X5R, 0805 100µF, 6V, 75mΩ, Electrolytic C Case 100k/31.6k 550 39.2k 800 24.9k 5V to 27V 8V 2 × 4.7µF, 50V, 22µF, 10V, X7R, 1206 X5R, 0805 100µF, 16V, 100mΩ, Electrolytic D Case 100k/17.4k 500 45.3k 800 24.9k 5V to 35V 12V 2 × 4.7µF, 50V, 22µF, 25V, X5R, 0805 X5R, 0805 68µF, 16V, 200mΩ, Electrolytic C Case 100k/11k 600 36.5k 800 24.9k 5.9V to 36V 18V 2 × 4.7µF, 50V, 22µF, 25V, X5R, 0805 X5R, 0805 47µF, 25V, 900mΩ, Electrolytic D Case 100k/6.98k 500 45.3k 800 24.9k 7.5V to 36V 24V 2 × 4.7µF, 50V, 22µF, 25V, X5R, 0805 X5R, 0805 33µF, 35V, 300mΩ, Electrolytic D Case 100k/5.23k 650 31.6k 800 24.9k 7.5V to 36V 36V 2 × 4.7µF, 50V, 10µF, 50V, X5R, 1206 X5R, 0805 10µF, 50V, 120mΩ, Electrolytic 6.3mm × 6mm Case 100k/3.40k 650 31.6k 800 24.9k Notes: A input bulk capacitor is required. The output capacitance uses a combination of a ceramic and electrolytic in parallel. Other combinations of resistor values for the RFB network are acceptable. Table 2. Table 2. Electrolytic Caps Used in LTM8054 Testing DESCRIPTION 100µF, 6V, 75mΩ, Tantalum C Case 100µF, 16V, 100mΩ, Tantalum Y Case 68µF, 16V, 200mΩ, Tantalum C Case 47µF, 25V, 900mΩ, Tantalum D Case 33µF, 35V, 300mΩ, Tantalum D Case 10µF, 50V, 120mΩ, Aluminum 6.3mm × 6mm case 10 MANUFACTURER AVX AVX AVX AVX AVX SunCon PART NUMBER TPSC107M006R0075 TPSY107M016R0100 TPSC686M016R0200 TAJD476M025R TPSD336M035R0300 50HVP10M 8054f For more information www.linear.com/LTM8054 LTM8054 Applications Information Capacitor Selection Considerations Table 3. Switching Frequency vs RT Value The CIN and COUT capacitor values in Table 1 are the minimum recommended values for the associated operating conditions. Applying capacitor values below those indicated in Table 1 is not recommended, and may result in undesirable operation. Using larger values is generally acceptable, and can yield improved dynamic response, if it is necessary. Again, it is incumbent upon the user to verify proper operation over the intended system’s line, load and environmental conditions. Ceramic capacitors are small, robust and have very low ESR. However, not all ceramic capacitors are suitable. X5R and X7R types are stable over temperature and applied voltage and give dependable service. Other types, including Y5V and Z5U have very large temperature and voltage coefficients of capacitance. In an application circuit they may have only a small fraction of their nominal capacitance resulting in much higher output voltage ripple than expected. A final precaution regarding ceramic capacitors concerns the maximum input voltage rating of the LTM8054. A ceramic input capacitor combined with trace or cable inductance forms a high Q (underdamped) tank circuit. If the LTM8054 circuit is plugged into a live supply, the input voltage can ring to twice its nominal value, possibly exceeding the device’s rating. This situation is easily avoided; see the Hot-Plugging Safely section. Frequency Selection The LTM8054 uses a constant frequency PWM architecture that can be programmed to switch from 100kHz to 800kHz by tying a resistor from the RT pin to ground. Table 3 provides a list of RT resistor values and their resultant frequencies. FREQUENCY RT VALUE (kΩ) 100 453 200 147 300 84.5 400 59 500 45.3 600 36.5 700 29.4 800 20.5 An external resistor from RT to GND is required. Do not leave this pin open, even when synchronizing to an external clock. When synchronizing the switching of the LTM8054 to an external signal source, the frequency range is 200kHz to 700kHz. Operating Frequency Trade-Offs It is recommended that the user apply the optimal RT value given in Table 1 for the input and output operating condition. System level or other considerations, however, may necessitate another operating frequency. While the LTM8054 is flexible enough to accommodate a wide range of operating frequencies, a haphazardly chosen one may result in undesirable operation under certain operating or fault conditions. A frequency that is too high can reduce efficiency, generate excessive heat or even damage the LTM8054 if the output is overloaded or short circuited. A frequency that is too low can result in a final design that has too much output ripple, too large of an output capacitor or is unstable. 8054f For more information www.linear.com/LTM8054 11 LTM8054 Applications Information Parallel Operation MASTER Two or more LTM8054s may be combined to provide increased output current by configuring them as a master and a slave, as shown in Figure 1. Each LTM8054 is equipped with an IOUTMON and a CTL pin. The IOUTMON pin’s 0 to 1.2V signal reflects the current passing through the output sense resistor, while a voltage less than 1.2V applied to the CTL pin will limit the current passing through the output sense resistor. By applying the voltage of the master’s IOUTMON pin to the slave’s CTL pin, the two units will source the same current to the load, assuming each LTM8054 output current sense resistor is the same value. 2. Apply a FB resistor network to the individual slaves so that the resulting output is higher than the desired output voltage. 3. Apply the appropriate output current sense resistors between VOUT and IOUT. If the same value is used for the master and slave units, they will share current equally. 4. Connect the master IOUTMON to the slaves’ CTL pin through a unity gain buffer. The unity gain buffer is required to isolate the output impedance of the LTM8054 from the integrated pull-up on the CTL pins. 5. Tie the outputs together. Note that this configuration does not require the inputs to be tied together, making it simple to power a single heavy load from multiple input sources. Ensure that each input power source has sufficient voltage and current sourcing capability to provide the necessary power. Please refer to the Maximum Output Current vs VIN and Input Current vs Output Current curves in the Typical Performance Characteristics section for guidance. Paralleled LTM8054s should normally be allowed to switch in discontinuous mode to prevent current from flowing 12 TO LOAD VOUT IOUT IOUTMON UNITY GAIN BUFFER CTL SLAVE VOUT OUTPUT CURRENT SENSE RESISTOR IOUT 8054 F01 Figure 1. Two or More LTM8054s May Be Connected in a Master/Slave Configuration for Increased Output Current The design of a master-slave configuration is straightforward: 1. Apply the FB resistor network to the master, choosing the proper values for the desired output voltage. Suggested values for popular output voltages are provided in Table 1. OUTPUT CURRENT SENSE RESISTOR from the output of one unit into another; that is, the MODE pin should be tied to LL. In some cases, operating the master in forced continuous (MODE open) and the slaves in discontinuous mode (MODE = LL) is desirable. If so, current from the output can flow into the master’s input. Please refer to Input Precaution in this section for a discussion of this behavior. Minimum Input Voltage and RUN The LTM8054 needs a minimum of 5V for proper operation, but system parameters may dictate that the device operate only above some higher input voltage. For example, a LTM8054 may be used to produce 12VOUT, but the input power source may not be budgeted to provide enough current if the input supply voltage is below 8V. The RUN pin has a typical falling voltage threshold of 1.2V and a typical hysteresis of 25mV. In addition, the pin sinks 3µA below the RUN threshold. Based upon the above information and the circuit shown in Figure 2, the VIN rising (turn-on) threshold is: VIN = ( 3µA •R1) +1.225V R1+R2 R2 and the VIN falling turn-off threshold is: VIN = 1.2 R1+R2 R2 8054f For more information www.linear.com/LTM8054 LTM8054 Applications Information condition, especially when the output voltage is much lower than the input and the power stage is operating as a buck converter. LTM8054 VIN R1 RUN R2 8054 F02 LTM8054 VOUT Figure 2. This Simple Resistor Network Sets the Minimum Operating Input Voltage Threshold with Hysteresis IOUT Minimum Input Voltage and SVIN Soft-Start Soft-start reduces the input power sources’ surge currents by gradually increasing the controller’s current. As indicated in the Block Diagram, the LTM8054 has an internal softstart RC network. Depending upon the load and operating conditions, the internal network may be sufficient for the application. To increase the soft-start time, simply add a capacitor from SS to GND. Figure 3. Set The LTM8054 Output Current Limit with an External Sense Resistor When the voltage across the output sense resistor falls to about 1/10th of full scale, the LL pin pulls low. If there is no output sense resistor, and IOUT is tied to VOUT, LL will be active low. Applying an output sense resistor and tying the LL and MODE pins together can improve performance—see Switching Mode in this section. In high step-down voltage regulator applications, the internal current limit can be quite high to allow proper operation. This can potentially damage the LTM8054 in overload or short-circuit conditions. Apply an output current sense resistor to set an appropriate current limit to protect the LTM8054 against these fault conditions. Output Current Limit Control (CTL) Output Current Limit (IOUT) The LTM8054 features an accurate average output current limit set by an external sense resistor placed between VOUT and IOUT as shown in Figure 3. VOUT and IOUT internally connect to a differential amplifier that limits the current when the voltage VOUT – IOUT reaches 58mV. The current limit is: LOAD 8054 F03 The minimum input voltage of the LTM8054 is 5V, but this is only if VIN and SVIN are tied to the same voltage source. If SVIN is powered from a power source at or above 5VDC, VIN can be allowed to fall below 5V and the LTM8054 can still operate properly. Some examples of this are provided in the Typical Applications section. IOUT(LIM) = RSENSE 58mV RSENSE Use the CTL input to reduce the output current limit from the value set by the external sense resistor applied between VOUT and IOUT. The typical control range is between 0V and 1.2V. The CTL pin does not directly affect the input current limit. If this function is not used, leave CTL open. Drive CTL to less than about 50mV to stop switching. The CTL pin has an internal pull-up resistor to 2V. Input Current Limit (IIN) where RSENSE is the value of the sense resistor in ohms. Most applications should use an output sense resistor as shown in Figure 3, if practical. The internal buck-boost power stage is current limited, but is nonetheless capable of delivering large amounts of current in an overload Some applications require that the LTM8054 draw no more than some predetermined current from the power source. Current limited power sources and power sharing are two examples. The LTM8054 features an accurate input current limit set by an external sense resistor placed between IIN and VIN as shown in Figure 4. VIN and IIN internally con- 8054f For more information www.linear.com/LTM8054 13 LTM8054 Applications Information nect to a differential amplifier that limits the current when the voltage IIN – VIN reaches 50mV. The current limit is: CLKOUT where RSENSE is the value of the sense resistor in ohms. The CLKOUT signal reflects the internal switching clock of the LTM8054. It is phase shifted by approximately 180° with respect to the leading edge of the internal clock. If CLKOUT is connected to the SYNC input of another LTM8054, the two devices will switch 180° out of phase. If input current limiting is not required, simply tie IIN to VIN. Input Precaution 50mV IIN(LIM) = RSENSE POWER SOURCE RSENSE LTM8054 VIN IIN 8054 F04 Figure 4. Set the LTM8054 Input Current Limit with an External Sense Resistor Input Current Monitor (IINMON) The IINMON pin produces a voltage equal to approximately 20 times the voltage of IIN – VIN. Since the LTM8054 input current limit engages when IIN – VIN = 50mV, IINMON will be 1V at maximum input current. Output Current Monitor (IOUTMON) The IOUTMON pin produces a voltage proportional to the voltage of VOUT – IOUT. When output current limit engages at maximum output current, VOUT – IOUT = 58mV and IOUTMON will be 1.2V. Synchronization The LTM8054 switching frequency can be synchronized to an external clock using the SYNC pin. Driving SYNC with a 50% duty cycle waveform is a good choice, otherwise maintain the duty cycle between about 10% and 90%. When synchronizing, a valid resistor value (that is, a value that results in a free-running frequency of 100kHz to 800kHz) must be connected from RT to GND. While an RT resistor is required for proper operation, the value of this resistor is independent of the frequency of the externally applied SYNC signal. Be aware, however, that the LTM8054 will switch at the frequency prescribed by the RT value if the SYNC signal terminates, so choose an appropriate resistor value. 14 In applications where the output voltage is deliberately pulled up above the set regulation voltage or the FB pin is abruptly driven to a new voltage, the LTM8054 may attempt to regulate the voltage by removing energy from the load for a short period of time after the output is pulled up. Since the LTM8054 is a synchronous switching converter, it delivers this energy to the input. If there is nothing on the LTM8054 input to consume this energy, the input voltage may rise. If the input voltage rises without intervention, it may rise above the absolute maximum rating, damaging the part. Carefully examine the input voltage behavior to see if the application causes it to rise. In many cases, the system load on the LTM8054 input bus will be sufficient to absorb the energy delivered by the µModule regulator. The power required by other devices will consume more than enough to make up for what the LTM8054 delivers. In cases where the LTM8054 is the largest or only power converter, this may not be true and some means may need to be devised to prevent the LTM8054’s input from rising too high. Figure 5a shows a passive crowbar circuit that will dissipate energy during momentary input overvoltage conditions. The break-down voltage of the Zener diode is chosen in conjunction with the resistor R to set the circuit’s trip point. The trip point is typically set well above the maximum VIN voltage under normal operating conditions. This circuit does not have a precision threshold, and is subject to both part-to-part and temperature variations, so it is most suitable for applications where the maximum input voltage is much less than the 40VIN absolute maximum. As stated earlier, this type of circuit is best suited for momentary overvoltages. Figure 5a is a crowbar circuit, which attempts to prevent the input voltage from rising above some level by dumping energy to GND through a power device. In some cases, 8054f For more information www.linear.com/LTM8054 LTM8054 Applications Information LOAD CURRENT VIN ZENER DIODE Q VOUT LTM8054 GND SOURCING LOAD R 8054 F05a Figure 5a. The MOSFET Q Dissipates Momentary Energy to GND. The Zener Diode and Resistor Are Chosen to Ensure That the MOSFET Turns On Above the Maximum VIN Voltage Under Normal Operation LOAD CURRENT VIN VOUT LTM8054 RUN 10µF – + GND SOURCING LOAD EXTERNAL REFERENCE VOLTAGE 8054 F05b Figure 5b. This Comparator Circuit Turns Off the LTM8054 if the Input Rises Above a Predetermined Threshold. When the LTM8054 Turns Off, the Energy Stored in the Internal Inductor Will Raise VIN a Small Amount Above the Threshold it is possible to simply turn off the LTM8054 when the input voltage exceeds some threshold. An example of this circuit is shown in Figure 5b. When the power source on the output drives VIN above a predetermined threshold, the comparator pulls down on the RUN pin and stops switching in the LTM8054. When this happens, the input capacitance needs to absorb the energy stored within the LTM8054’s internal inductor, resulting in an additional voltage rise. This voltage rise depends upon the input capacitor size and how much current is flowing from the LTM8054 output to input. Switching Mode The MODE pin allows the user to select either discontinuous mode or forced continuous mode switching operation. In forced continuous mode, the LTM8054 will not skip cycles, even when the internal inductor current falls to zero or even reverses direction. This has the advantage of operating at the same fixed frequency for all load conditions, which can be useful when designing to EMI or output noise specifications. Forced continuous mode, however, uses more current at light loads, and allows current to flow from the load back into the input if the output is raised above the regulation point. This reverse current can raise the input voltage and be hazardous if the input is allowed to rise uncontrollably. Please refer to Input Precautions in this section for a discussion of this behavior. Forced continuous operation may provide improved output regulation when the LTM8054 transitions from buck, buck-boost or boost operating modes, especially at lighter loads. In such a case, it can be desirable to operate in forced continuous mode except when the internal inductor current is about to reverse. If so, apply a current sense resistor between VOUT and IOUT and tie the LL and MODE pins together. The LL pin is low when the current through the output sense resistor is about one-tenth the full-scale maximum. When the output current falls to this level, the LL pin will pull the MODE pin down, putting the LTM8054 in discontinuous mode, preventing reverse current from flowing from the output to the input. In the case where MODE and LL are tied together, a small capacitor (~0.1µF) from these pins to GND may improve the light load transient response by delaying the transition from the discontinuous to forced continuous switching modes. MODE may be tied to GND for the purpose of blocking reverse current if no output current sense resistor is used. FB Resistor Divider and Load Regulation The LTM8054 regulates its FB pin to 1.2V, using a resistor divider to sense the output voltage. The location at which the output voltage is sensed affects the load regulation. If there is a current sense resistor between VOUT and IOUT, and the output is sensed at VOUT, the voltage at the load will drop by the value of the current sense resistor multiplied by the output current. If the output voltage can be sensed at IOUT, the load regulation may be improved. 8054f For more information www.linear.com/LTM8054 15 LTM8054 Applications Information PCB Layout Most of the headaches associated with PCB layout have been alleviated or even eliminated by the high level of integration of the LTM8054. The LTM8054 is nevertheless a switching power supply, and care must be taken to minimize EMI and ensure proper operation. Even with the high level of integration, you may fail to achieve specified operation with a haphazard or poor layout. See Figure 6 for a suggested layout. Ensure that the grounding and heat sinking are acceptable. A few rules to keep in mind are: 1.Place the RFB and RT resistors as close as possible to their respective pins. 2.Place the CIN capacitor as close as possible to the VIN and GND connection of the LTM8054. 3.Place the COUT capacitor as close as possible to the VOUT and GND connection of the LTM8054. 4.Minimize the trace resistance between the optional output current sense resistor, ROUT, and VOUT. Minimize the loop area of the IOUT trace and the trace from VOUT to ROUT. 5.Minimize the trace resistance between the optional input current sense resistor, RIN and VIN. Minimize the loop area of the IIN trace and the trace from VIN to RIN. 6.Place the CIN and COUT capacitors such that their ground current flow directly adjacent or underneath the LTM8054. 7.Connect all of the GND connections to as large a copper pour or plane area as possible on the top layer. Avoid breaking the ground connection between the external components and the LTM8054. 8.Use vias to connect the GND copper area to the board’s internal ground planes. Liberally distribute these GND vias to provide both a good ground connection and thermal path to the internal planes of the printed circuit board. Pay attention to the location and density of the thermal vias in Figure 6. The LTM8054 can benefit from the heat sinking afforded by vias that connect to internal GND planes at these locations, due to their proximity to internal power handling components. The optimum number of thermal vias depends upon the printed circuit board design. For example, a board might use very small via holes. It should employ more thermal vias than a board that uses larger holes. CIN GND SVIN GND/THERMAL VIAS VIN RIN INPUT SENSE COUT IIN RUN MODE SYNC VOUT IOUT IOUT LL RT FB ROUT OUTPUT SENSE GND TO VOUT 8055 F06 Figure 6. Layout Showing Suggested External Components, GND Plane and Thermal Vias 16 8054f For more information www.linear.com/LTM8054 LTM8054 Applications Information Hot-Plugging Safely The small size, robustness and low impedance of ceramic capacitors make them an attractive option for the input bypass capacitor of LTM8054. However, these capacitors can cause problems if the LTM8054 is plugged into a live supply (see Linear Technology Application Note 88 for a complete discussion). The low loss ceramic capacitor combined with stray inductance in series with the power source forms an underdamped tank circuit, and the voltage at the VIN pin of the LTM8054 can ring to more than twice the nominal input voltage, possibly exceeding the LTM8054’s rating and damaging the part. If the input supply is poorly controlled or the LTM8054 is hot-plugged into an energized supply, the input network should be designed to prevent this overshoot. This can be accomplished by installing a small resistor in series with VIN, but the most popular method of controlling input voltage overshoot is to add an electrolytic bulk capacitor to the VIN net. This capacitor’s relatively high equivalent series resistance damps the circuit and eliminates the voltage overshoot. The extra capacitor improves low frequency ripple filtering and can slightly improve the efficiency of the circuit, though it is likely to be the largest component in the circuit. Thermal Considerations The LTM8054 output current may need to be derated if it is required to operate in a high ambient temperature or deliver a large amount of continuous power. The amount of current derating is dependent upon the input voltage, output power and ambient temperature. The temperature rise curves given in the Typical Performance Characteristics section can be used as a guide. These curves were generated by a LTM8054 mounted to a 58cm2 4-layer FR4 printed circuit board. Boards of other sizes and layer count can exhibit different thermal behavior, so it is incumbent upon the user to verify proper operation over the intended system’s line, load and environmental operating conditions. The thermal resistance numbers listed in the Pin Configuration of the data sheet are based on modeling the µModule package mounted on a test board specified per JESD 51-9 (Test Boards for Area Array Surface Mount Package Thermal Measurements). The thermal coefficients provided on this page are based on JESD 51-12 (Guidelines for Reporting and Using Electronic Package Thermal Information). For increased accuracy and fidelity to the actual application, many designers use FEA to predict thermal performance. To that end, the Pin Configuration of the data sheet typically gives four thermal coefficients: θJA – Thermal resistance from junction to ambient. θJCbottom – Thermal resistance from junction to the bottom of the product case. θJCtop – Thermal resistance from junction to top of the product case. θJB – Thermal resistance from junction to the printed circuit board. While the meaning of each of these coefficients may seem to be intuitive, JEDEC has defined each to avoid confusion and inconsistency. These definitions are given in JESD 51-12, and are quoted or paraphrased below: θJA is the natural convection junction-to-ambient air thermal resistance measured in a one cubic foot sealed enclosure. This environment is sometimes referred to as “still air” although natural convection causes the air to move. This value is determined with the part mounted to a JESD 51-9 defined test board, which does not reflect an actual application or viable operating condition. θJCbottom is the thermal resistance between the junction and bottom of the package with all of the component power dissipation flowing through the bottom of the package. In the typical µModule converter, the bulk of the heat flows out the bottom of the package, but there is always heat flow out into the ambient environment. As a result, this thermal resistance value may be useful for comparing packages but the test conditions don’t generally match the user’s application. θJCtop is determined with nearly all of the component power dissipation flowing through the top of the package. As the electrical connections of the typical µModule converter are on the bottom of the package, it is rare for an application to operate such that most of the heat flows from the junction to the top of the part. As in the case of θJCbottom, this 8054f For more information www.linear.com/LTM8054 17 LTM8054 Applications Information JUNCTION-TO-AMBIENT RESISTANCE (JESD 51-9 DEFINED BOARD) CASE (TOP)-TO-AMBIENT RESISTANCE JUNCTION-TO-CASE (TOP) RESISTANCE JUNCTION JUNCTION-TO-BOARD RESISTANCE AMBIENT JUNCTION-TO-CASE CASE (BOTTOM)-TO-BOARD (BOTTOM) RESISTANCE RESISTANCE BOARD-TO-AMBIENT RESISTANCE 8054 F06 µMODULE Figure 7 value may be useful for comparing packages but the test conditions don’t generally match the user’s application. A graphical representation of these thermal resistances is given in Figure 7. θJB is the junction-to-board thermal resistance where almost all of the heat flows through the bottom of the µModule converter and into the board, and is usually the sum of the θJCbottom and the thermal resistance of the bottom of the part through the solder joints and through a portion of the board. The board temperature is measured a specified distance from the package, using a 2-sided, 2-layer board. This board is described in JESD 51-9. The blue resistances are contained within the µModule converter, and the green are outside. Given these definitions, it should now be apparent that none of these thermal coefficients reflects an actual physical operating condition of a µModule converter. Thus, none of them can be individually used to accurately predict the thermal performance of the product. Likewise, it would be inappropriate to attempt to use any one coefficient to correlate to the junction temperature versus load graphs given in the product’s data sheet. The only appropriate way to use the coefficients is when running a detailed thermal analysis, such as FEA, which considers all of the thermal resistances simultaneously. 18 The die temperature of the LTM8054 must be lower than the maximum rating of 125°C, so care should be taken in the layout of the circuit to ensure good heat sinking of the LTM8054. The bulk of the heat flow out of the LTM8054 is through the bottom of the µModule converter and the BGA pads into the printed circuit board. Consequently a poor printed circuit board design can cause excessive heating, resulting in impaired performance or reliability. Please refer to the PCB Layout section for printed circuit board design suggestions. 8054f For more information www.linear.com/LTM8054 LTM8054 Typical Applications 12VOUT Fan Power from 3VIN to 36VIN with Analog Current Control and 2A Input Current Limiting 1µF 50V 0.022Ω VIN SVIN LTM8054 4.7µF 50V ×2 VOUT 12V MAX IOUT RUN COMP SS SYNC CTL RT MODE LL 36.5 600kHz 0.05Ω VOUT IIN FAN 100k GND CLKOUT IINMON IOUTMON FB + 68µF 25V 22µF 25V 11k 8054 TA02a DAC FAN CONTROL Maximum Output Current vs CTL Voltage, 12VIN 1.4 1.2 OUTPUT CURRENT (A) VIN 3V TO 36V 1 0.8 0.6 0.4 0.2 0 0 0.3 0.6 0.9 CTL VOLTAGE (V) 1.2 8054 TA02b 8054f For more information www.linear.com/LTM8054 19 LTM8054 Typical Applications 24VOUT from 7.5VIN to 36VIN with 1.2A Accurate Current Limit VIN VIN 7.5V TO 36V 0.05Ω VOUT LTM8054 IOUT SVIN VOUT 24V IIN 4.7µF 50V ×2 RUN CTL SS SYNC COMP RT MODE LL 31.6k 650kHz 100k + GND CLKOUT IINMON IOUTMON FB 5.23k 22µF 25V 33µF 35V 8054 TA03a Output Voltage vs Output Current 25 OUTPUT VOLTAGE (V) 20 15 10 5 0 12VIN 24VIN 36VIN 0 0.5 1 OUTPUT CURRENT (A) 1.5 8054 TA03b 20 8054f For more information www.linear.com/LTM8054 LTM8054 Typical Applications 3.3VOUT from 6VIN to 36VIN with 2.6A Accurate Current Limit and Output Current Monitor VIN VIN 6V TO 36V LTM8054 0.022Ω VOUT IOUT SVIN VOUT 3.3V IIN 100k 4.7µF 50V ×2 RUN CTL SS SYNC COMP RT MODE 36.5k 600kHz LL GND + 47µF 4V OUTPUT CURRENT MONITOR CLKOUT IINMON IOUTMON FB 56.2k 100µF 6V 8054 TA04a Output Voltage vs Output Current 4 OUTPUT VOLTAGE (V) 3.5 3 2.5 2 1.5 1 12VIN 24VIN 36VIN 0.5 0 0 1 2 OUTPUT CURRENT (A) 3 8054 TA04b 8054f For more information www.linear.com/LTM8054 21 LTM8054 Typical Applications Two LTM8054s Paralleled to Get More Output Current. The Two µModules Are Synchronized and Switching 180° Out Of Phase VIN VIN 7V TO 36V LTM8054 0.015Ω VOUT VOUT 12V IOUT SVIN IIN 4.7µF 50V ×2 36.5k 600kHz RUN CTL SS SYNC COMP RT CLKOUT MODE LL 22µF 25V IINMON + 68µF 25V IOUTMON 100k FB 11k GND LT1636 VIN LTM8054 0.015Ω VOUT IOUT SVIN IIN 4.7µF 50V ×2 36.5k 600kHz RUN COMP SS SYNC RT MODE LL GND CTL CLKOUT IINMON IOUTMON FB 22µF 25V 100k + 68µF 25V 9.31k 8054 TA05a IOUTMON Voltage vs Output Current, 24VIN 1 IOUTMON VOLTAGE (V) 0.8 0.6 0.4 0.2 MASTER SLAVE 0 0 2 4 OUTPUT CURRENT (A) 6 8054 TA05b 22 8054f For more information www.linear.com/LTM8054 LTM8054 Typical Applications Two LTM8054s Powered from Input Sources with Different Current Capabilities Share Output Current to Run a Single Load. Each LTM8054 Draws No More Than 3.1A and 1.9A from Input Supply 1 and Input Supply 2, Respectively, and Are Synchronized 180° Out Of Phase with Each Other 0.015Ω SUPPLY 1 5V TO 36VIN VIN LTM8054 IOUT V OUT 0.015Ω SVIN IIN 10µF 50V RUN CTL SS SYNC COMP RT CLKOUT LL MODE 36.5k 600kHz + 22µF 25V 6A MAX VOUT 12V 68µF 25V IINMON IOUTMON 100k FB 11k GND 0.01µF 0.025Ω SUPPLY 2 5V TO 36VIN VIN LTM8054 IOUT V OUT 0.015Ω SVIN + IIN 10µF 50V 100k RUN SS SYNC COMP RT LL MODE 36.5k 600kHz GND CTL CLKOUT IINMON IOUTMON FB 68µF 25V + – LT1636 22µF 25V 9.31k 8054 TA06a 0.01µF 3.5 14 3 12 2.5 10 2 8 1.5 6 1 4 0.5 0 0 1 OUTPUT VOLTAGE (V) INPUT CURRENT (A) Input Current and Output Voltage vs Output Current 12VIN for both LTM8054s VIN1 CURRENT VIN2 CURRENT 2 VOUT 0 2 3 4 5 6 OUTPUT CURRENT (A) 8054 TA06b 8054f For more information www.linear.com/LTM8054 23 LTM8054 Package Description Table 3. LTM8054 Pin Assignment (Arranged by Pin Number) PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION A1 VOUT B1 VOUT C1 IOUT D1 GND E1 GND F1 LL A2 VOUT B2 VOUT C2 GND D2 GND E2 GND F2 GND A3 VOUT B3 VOUT C3 GND D3 GND E3 GND F3 GND A4 VOUT B4 VOUT C4 GND D4 GND E4 GND F4 GND A5 VOUT B5 VOUT C5 GND D5 GND E5 GND F5 GND A6 GND B6 GND C6 GND D6 GND E6 GND F6 GND A7 GND B7 GND C7 GND D7 GND E7 GND F7 GND A8 GND B8 GND C8 GND D8 GND E8 GND F8 GND PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION G1 CLKOUT H1 RT J1 FB K1 SS L1 GND G2 MODE H2 SYNC J2 COMP K2 CTL L2 IOUTMON G3 GND H3 GND J3 GND K3 GND L3 IINMON G4 GND H4 GND J4 GND K4 GND L4 RUN G5 GND H5 GND J5 GND K5 GND L5 GND G6 GND H6 GND J6 GND K6 GND L6 IIN G7 GND H7 SVIN J7 VIN K7 VIN L7 VIN G8 GND H8 SVIN J8 VIN K8 VIN L8 VIN Package Photo 24 8054f For more information www.linear.com/LTM8054 1.905 3.175 SUGGESTED PCB LAYOUT TOP VIEW 0.000 aaa Z 0.630 ±0.025 Ø 88x 0.635 PACKAGE TOP VIEW E 0.635 4 1.905 PIN “A1” CORNER 4.445 3.175 4.445 Y X D Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. For more information www.linear.com/LTM8054 6.350 5.080 3.810 2.540 1.270 0.000 1.270 2.540 3.810 5.080 6.350 aaa Z // bbb Z SYMBOL A A1 A2 b b1 D E e F G H1 H2 aaa bbb ccc ddd eee H1 SUBSTRATE A1 NOM 3.42 0.60 2.82 0.75 0.63 15.00 11.25 1.27 12.70 8.89 0.32 2.50 A2 A MAX 3.62 0.70 2.92 0.90 0.66 NOTES DETAIL B PACKAGE SIDE VIEW 0.37 2.55 0.15 0.10 0.20 0.30 0.15 TOTAL NUMBER OF BALLS: 88 0.27 2.45 MIN 3.22 0.50 2.72 0.60 0.60 b1 DIMENSIONS ddd M Z X Y eee M Z DETAIL A Øb (88 PLACES) DETAIL B H2 MOLD CAP ccc Z Z Z (Reference LTC DWG # 05-08-1928 Rev B) BGA Package 88-Lead (15mm × 11.25mm × 3.42mm) e b 7 5 G 4 e 3 PACKAGE BOTTOM VIEW 6 2 1 L K J H G F E D C B A DETAILS OF PIN #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PIN #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE 4 3 TRAY PIN 1 BEVEL COMPONENT PIN “A1” 7 ! PACKAGE IN TRAY LOADING ORIENTATION LTMXXXXXX µModule BGA 88 0613 REV B PACKAGE ROW AND COLUMN LABELING MAY VARY AMONG µModule PRODUCTS. REVIEW EACH PACKAGE LAYOUT CAREFULLY 6. SOLDER BALL COMPOSITION IS 96.5% Sn/3.0% Ag/0.5% Cu 5. PRIMARY DATUM -Z- IS SEATING PLANE BALL DESIGNATION PER JESD MS-028 AND JEP95 3 2. ALL DIMENSIONS ARE IN MILLIMETERS 7 SEE NOTES PIN 1 SEE NOTES NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 F b 8 DETAIL A LTM8054 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. 8054f 25 LTM8054 Typical Application 14.4V, 3A Lead-Acid Battery Charger Input Current Limited to 2A Maximum Input and Output Current vs Input Voltage 3.5 1µF 50V VIN SVIN 0.022Ω 4.7µF 50V ×2 36.5k 600kHz 0.018Ω VOUT LTM8054 IOUT IIN 100k RUN CTL SS SYNC COMP RT MODE LL GND CLKOUT IINMON IOUTMON FB VOUT 14.4V + 68µF 25V 2.5 CURRENT (A) VIN 3V TO 36V 3 2 1.5 1 22µF 25V 0.5 9.09k 8054 TA07a 0 OUTPUT CURRENT INPUT CURRENT 0 10 20 30 INPUT VOLTAGE (V) 40 8054 TA07b Design Resources SUBJECT DESCRIPTION µModule Design and Manufacturing Resources Design: • Selector Guides • Demo Boards and Gerber Files • Free Simulation Tools µModule Regulator Products Search Manufacturing: • Quick Start Guide • PCB Design, Assembly and Manufacturing Guidelines • Package and Board Level Reliability 1. Sort table of products by parameters and download the result as a spread sheet. 2. Search using the Quick Power Search parametric table. TechClip Videos Quick videos detailing how to bench test electrical and thermal performance of µModule products. Digital Power System Management Linear Technology’s family of digital power supply management ICs are highly integrated solutions that offer essential functions, including power supply monitoring, supervision, margining and sequencing, and feature EEPROM for storing user configurations and fault logging. Related Parts PART NUMBER DESCRIPTION COMMENTS LTM4605 Higher Power Buck-Boost µModule (Up to 60W) External Inductor, Synchronous Switching Buck-Boost; Up to 20VIN, 0.8V < VOUT < 16V LTM4607 Higher Power Buck-Boost µModule (Up to 60W) External Inductor, Synchronous Switching Buck-Boost; Up to 36VIN, 0.8V < VOUT < 24V LTM4609 Higher Power Buck-Boost µModule (Up to 60W) External Inductor, Synchronous Switching Buck-Boost; Up to 36VIN, 0.8V < VOUT < 34V LTM8045 Smaller, Low Power SEPIC µModule SEPIC and Inverting; 700mA, 6.25mm × 11.25mm x 4.92mm BGA LTM8046 Isolated, Low Power µModule Flyback Topology, 550mA (5VOUT, 24VIN), UL60950, 2kVAC LTC3115 40V, 2A Synchronous Buck-Boost Monolithic Converter External Inductor; 2.7V < VIN < 40V, 2.7V < VOUT < 40V LTC3789 High Efficiency. 4 Switch Buck-Boost Controller External Inductor, External FET; 4V < VIN < 38V, 0.8V < VOUT < 38V 26 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LTM8054 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LTM8054 8054f LT 0815 • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2015