ltm4628 Linear Technology Corporation, ltm4628 Datasheet
ltm4628
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ltm4628 Summary of contents
Page 1
... Included in the package are the switching controller, power FETs, inductor, and all supporting components. Operating from an input voltage range of 4.5V to 26.5V, the LTM4628 supports two outputs each with an output voltage range of 0.6V to 5.5V, set by a single external resistor. Its high efficiency design delivers 8A continuous current for each output ...
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... OUT1 T JMAX PART MARKING* PACKAGE DESCRIPTION LTM4628V 144-Lead (15mm × 15mm × 4.32mm) LGA LTM4628V 144-Lead (15mm × 15mm × 4.32mm) LGA http://www.linear.com/leadfree/ http://www.linear.com/packaging/ l The denotes the specifications which apply over the full internal = 25°C (Note 2 ...
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... OUT Load 50 Full Load 12V 100μ 470μF IN OUT OUT V = 12V 1.5V IN OUT 1.5V OUT OUT , V FB2 TRACK1 (I),TRACK2 (I) Start at 0V (Note 6) , LTM4628 = 12V and RUN1 RUN2 MIN TYP 1 = 1.5V OUT2 2.9 1.18 0.575 0 l 0.010 l 0.15 ...
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... Note 3: Two outputs are tested separately and the same testing condition is applied to each output. Note 4: The switching frequency is programmable for 400kHz to 750kHz. Note 5: LTM4628 device is designed to operate from 400kHz to 750kHz Note 6: Minimum on-time and V wafer sort. Note 7: See output current derating curves for different V ...
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... I OUT 2A/DIV 100μs/DIV 12V , 1.8V AT 4A/μs LOAD STEP IN OUT C 4 100μF 6.3V X5R CERAMIC 1210 CASE SIZE OUT1 SWITCHING FREQUENCY 500kHz C CAPACITOR = 47pF FF LTM4628 24V Efficiency IN 95 FREQ = 500kHz, 700kHz for 3.3V AND OUT 65 3.3V OUT 2.5V OUT 60 1 ...
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... LTM4628 TYPICAL PERFORMANCE CHARACTERISTICS 3.3V Load Transient V OUT 100mV/DIV I OUT 2A/DIV 4628 G10 100μs/DIV 12V , 3.3V AT 4A/μs LOAD STEP IN OUT 100μF 6.3V X5R CERAMIC 1210 CASE SIZE OUT1 SWITCHING FREQUENCY 500kHz C CAPACITOR = 47pF FF Output Short-Circuit V OUT 1V/DIV 5ms/DIV INPUT ...
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... RUN pin will turn off the related chan- nel. Each RUN pin has a 1μA pull-up current, once the RUN pin reaches 1.2V an additional 4.5μA pull-up current is added to this pin. and GND pins pins together allows LTM4628 CC 4628f 7 ...
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... LTM4628 PIN FUNCTIONS (Recommended to Use Test Points to Monitor Signal Pin Connections.) DIFFOUT (F8): Internal Remote Sense Amplifier Output. Connect this pin OUTS1 OUTS2 output is using remote sense. In parallel operation connect one of the V pin to DIFFOUT for remote sensing. OUTS SW1, SW2 (G2, G11): Switching node of each channel that is used for testing purposes ...
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... OUT2 PGOOD1 MTOP1 MBOT1 POWER CONTROL MTOP2 MBOT2 XI + – INTERNAL FILTER DIFFOUT DIFFN DIFFP Figure 1. Simplified LTM4628 Block Diagram T = 25°C. Use Figure 1 configuration. A CONDITIONS I = 8A, 3× 22μ 4× 10μF OUT1 I = 8A, 3× 22μ 4× 10μF OUT2 OUT1 I ...
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... See the Applications Information section. 10 The LTM4628 is internally compensated to be stable over all operating conditions. Table 2 provides a guide line for input and output capacitances for several operating conditions. The Linear Technology μModule Power Design Tool will be provided for transient and stability analysis ...
Page 11
... V Step-Down Ratios IN OUT There are restrictions in the maximum V down ratio that can be achieved for a given input voltage. Each output of the LTM4628 is capable of 98% duty cycle, but the minimum dropout is still shown OUT function of its load current and will limit output current capability related to high duty cycle on the top side switch ...
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... LTM4628 APPLICATIONS INFORMATION Input Capacitors The LTM4628 module should be connected to a low ac- impedance DC source. For the regulator input three 22μ four 10μF input ceramic capacitors are used for RMS ripple current. A 47μF to 100μF surface mount aluminum electrolytic bulk capacitor can be used for more input bulk capacitance ...
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... In applications where low output ripple and high efficiency at intermediate currents are desired, pulse-skipping mode should be used. Pulse-skipping operation allows the LTM4628 to skip cycles at low output loads, thus increasing efficiency by reducing switching loss. Tying the MODE/ PLLIN pin to INTV enables pulse-skipping operation. At ...
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... SGND, to achieve a single high output current design. CC The LTM4628 device is an inherently current mode con- trolled device, so parallel modules will have very good current sharing. This will balance the thermals on the design. Figure 31 shows an example of parallel operation and pin connection ...
Page 15
... Minimum On-Time Minimum on-time t the LTM4628 is capable of turning on the top MOSFET on either channel determined by internal timing delays, and the gate charge required turning on the top MOSFET. Low duty cycle applications may approach this minimum ...
Page 16
... The master regulator’s output is divided down with an external resistor divider that is the same as the slave regulator’s feedback divider to implement coincident tracking. The LTM4628 uses an accurate 60.4k resistor internally for the top feedback resistor for each channel. Figure 6 shows an example of coincident tracking. Equations: ⎛ ...
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... TRACK = 0.5V. Between TRACK = 0.5V and 0.54V, it will operate in forced continuous mode and revert to the selected mode once TRACK > 0.54V. In order to track with another channel once in steady state operation, the LTM4628 is forced into continuous mode operation as soon below 0.54V regardless of the setting on FB the MODE/PLLIN pin ...
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... Temperature Diode Monitoring The LTM4628 has an on board 4148 silicon diode that can be used to monitor temperature. The diode is mounted very close to internal power switches. The forward voltage of a silicon transistor diode is temperature dependent based or V ...
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... All six diodes are very close to –2.2mV/°C to –2.4mV/°C drop while each are biased with 100μA through a 120k pull-up resistor to 12V. The Figure 9 graph can be used to calibrate and measure module temperature by measuring the diode V 127 227 4628 F08 Figure 9. The 4148 Diode VF vs Temperature LTM4628 value. F 0.8 0.7 0.6 0.5 0.4 0.3 ...
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... LTM4628 APPLICATIONS INFORMATION Thermal Considerations and Output Current Derating The thermal resistances reported in the Pin Configuration section of the data sheet are consistent with those param- eters defined by JESD51-9 and are intended for use with finite element analysis (FEA) software modeling tools that ...
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... JB BA and should accurately equal the θ proximately 100% of power loss flows from the junction through the board into ambient with no airflow or top mounted heat sink. LTM4628 CASE (TOP)-TO-AMBIENT RESISTANCE AMBIENT BOARD-TO-AMBIENT RESISTANCE 4628 F10 and θ ...
Page 22
... The 1.0V and 3.3V power loss curves in Figures 11 and 12 can be used in coordination with the load current derating curves in Figures for calculating an approximate θ thermal resistance for the LTM4628 JA with various heat sinking and airfl ow conditions. The power loss curves are taken at room temperature, and are increased with multiplicative factors according to the ambient temperature ...
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... AMBIENT TEMPERATURE (°C) Figure 15. 24V to 1V Derating Curves, No Heat Sink 4628 F11 100 120 4628 F13 100 120 4628 F15 LTM4628 8 24V TO 3.3V POWER LOSS 12V TO 3.3V POWER LOSS 3.3V POWER LOSS ...
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... LTM4628 APPLICATIONS INFORMATION 16 0 LFM 200 LFM 14 400 LFM AMBIENT TEMPERATURE (°C) Figure 17. 12V to 1V Derating with BGA Heat Sink 16 0 LFM 200 LFM 14 400 LFM AMBIENT TEMPERATURE (°C) Figure 19 ...
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... Curves, No Heat Sink 16 0 LFM 200 LFM 14 400 LFM 12 10 100 120 4628 F21 100 120 4628 F23 LTM4628 0 LFM 200 LFM 400 LFM 100 120 AMBIENT TEMPERATURE (°C) 4628 F22 Figure 22 3.3V Derating ...
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... LTM4628 APPLICATIONS INFORMATION Table 2. 1.0V Output DERATING CURVE V (V) IN Figures 13, 14 12, 24 Figures 13, 14 12, 24 Figures 13, 14 12, 24 Figures 16, 17 12, 24 Figures 16, 17 12, 24 Figures 16, 17 12, 24 Table 3. 3.3V Output DERATING CURVE V (V) IN Figures 19, 20 12, 24 ...
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... LTM4628 C PART IN (BULK) NUMBER VENDORS LOAD RECOVERY STEP R Freq. FB TIME (μs) (A/μs) (kΩ) (kHz 90.9 400 20 4 90.9 400 30 4 60.4 500 ...
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... LTM4628 APPLICATIONS INFORMATION Figures 25 and 26 show thermal images of the LTM4628 with or without BGA heat sink and no air flow or 200LFM air flow. Figure 25a.12V to 3.3V , 16A, No Heat Sink, No Air Flow IN OUT Figure 26a. 12V to 3.3V ,16A, with Heat Sink, No Air Flow IN OUT 28 These images equate to a paralleled 3.3V output at 16A design operating at 92% efficiency from 12V input ...
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... A temperature diode is provided for monitoring internal temperature. Layout Checklist/Example The high integration of LTM4628 makes the PCB board layout very simple and easy. However, to optimize its electri- cal and thermal performance, some layout considerations are still necessary. ...
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... D1 TRACK1 5.1V ZENER C5 0.1μF 30 MODE_PLLIN CLKOUT INTV IN3 R6 TEMP 22μF 120k 25V RUN1 RUN2 TRACK1 LTM4628 TRACK2 TRACK2 f SET C9 PHASMD 0.1μF R4 100k SGND GND DIFFP Figure 28 16V , 1.5V and 1.2V Outputs IN IN INTV CC C10 R2 4.7μF 10k PGOOD1 ...
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... ZENER MODE_PLLIN CLKOUT INTV TEMP 120k RUN1 RUN2 TRACK1 LTM4628 TRACK2 C9 f SET 0.1μF PHASMD R4 100k SGND GND DIFFP Figure 29. Two Phases, 1.5V at 16A Design LTM4628 INTV CC C10 R2 4.7μF 5k PGOOD1 EXTV PGOOD1 CC V OUT1 + OUTS1 100μF 1M 6.3V SW1 V FB1 R5 ...
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... D1 5.1V ZENER C5 R9 0.1μF 60.4k 1.2V 32 MODE_PLLIN CLKOUT INTV TEMP 22μF 120k 25V RUN1 RUN2 TRACK1 LTM4628 TRACK2 R7 f SET 90.9k PHASMD R4 100k SGND GND DIFFP Figure 30. 1.2V and 1V Output Tracking INTV CC C10 R2 4.7μF 10k PGOOD1 EXTV PGOOD1 CC 1. OUT1 ...
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... DIFFP CLK1 MODE_PLLIN CLKOUT INTV TEMP RUN1 RUN1 RUN2 TRACK1 LTM4628 TRACK2 C19 f SET 0.22μF PHASMD R10 100k SGND GND DIFFP Figure 31. 4-Phase, 1.2V at 32A LTM4628 INTV CC C10 R2 4.7μF 5k PGOOD1 EXTV PGOOD1 CC V OUT1 + OUTS1 1M 100μF 6.3V SW1 V V FB1 ...
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... GND G7 SGND H7 GND G8 PGOOD2 H8 INTVCC G9 PGOOD1 H9 GND G10 GND H10 GND G11 SW2 H11 GND G12 GND H12 GND PACKAGE PHOTO 34 Table 5. LTM4628 Component LGA Pinout PIN ID FUNCTION PIN ID FUNCTION C1 VOUT1 D1 GND C2 VOUT1 D2 GND C3 VOUT1 D3 GND C4 VOUT1 D4 GND C5 VOUT1S D5 VFB1 ...
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... LGA Package 144-Lead (15mm × 15mm × 4.32mm) (Reference LTC DWG # 05-08-1843 Rev Ø bbb 6.9850 5.7150 4.4450 3.1750 1.9050 0.6350 0.0000 0.6350 1.9050 3.1750 4.4450 5.7150 6.9850 LTM4628 4628f 35 ...
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... McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● C10 4.7μF MODE_PLLIN CLKOUT INTV EXTV TEMP 240k RUN1 RUN2 TRACK1 LTM4628 TRACK2 INTV f CC SET PHASMD SGND GND DIFFP DIFFN Figure 32. 24V , 5V and 3.3V Outputs IN COMMENTS 4.5V ≤ V ≤ 26.5V; 0.8V ≤ 2.375 ≤ ...