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LTM8001

8001fb

For more information www.linear.com/LTM8001

TYPICAL APPLICATION

FEATURES DESCRIPTION

36V

, 5A µModule

Regulator with 5-Output

Configurable LDO Array

The LT M

8001 is a 36V

, 5A step-down μModule

regu-

lator with a 5-output configurable LDO array. Operating

over an input voltage range of 6V to 36V, the L

TM8001

buck regulator supports an output voltage range of 1.2V

to 24V. Following the buck regulator is an array of five

1.1A linear regulators whose outputs may be connected

in parallel to accommodate a wide variety of load combi

nations. Three of these LDOs are tied to the output of the

buck regulator, while the other two are tied together to an

undedicated input.

The low profile package (3.42mm) enables utilization of

unused space on the bottom of PC boards for high density

point of load regulation. The LTM8001 is packaged in a

thermally enhanced, compact (15mm × 15mm) and low

profile (3.42mm) overmolded ball grid array (BGA) pack

age suitable for automated assembly by standard surface

mount equipment. The L

TM8001 is available with SnPb

(BGA) or RoHS compliant terminal finish.

APPLICATIONS

Complete Step-Down Switch Mode Power Supply

with Configurable Array of Five LDOs

Step-Down Switching Power Supply

– Adjustable 10% Accurate Output Current Limit

–Constant-Current, Constant-Voltage Operation

– Wide Input Voltage Range: 6V to 36V

– 1.2V to 24V Output Voltage

Configurable Output LDO Array

– Five 1.1A Parallelable Outputs

– Outputs Adjustable from 0V to 24V

– Low Output Noise: 90μV

RMS

(100Hz to 1MHz)

15mm × 15mm × 3.42mm Surface Mount

BGA Package

FPGA, DSP, ASIC and Microprocessor Supplies

Servers and Storage Devices

RF Transceivers

L, LT, LTC, LTM, µModule, Linear Technology and the Linear logo are registered trademarks of

Linear Technology Corporation. All other trademarks are the property of their respective owners.

Protected by U.S. Patents, including 7199560, 7321203.

5A Output DC/DC µModule Converter

118k

350kHz

OUT5

SET5

LDO 5

FBO

STEP-DOWN

SWITCHING

REGULATOR

OUT4

SET4

LDO 4

OUT3

SET3

BIAS123

BIAS45

COMP

REF

ILIM

SYNC

LDO 3

19.6k

GND

10µF

IN45

510k

3.3V

OUT2

SET2

LDO 2

OUT1

SET1

1.2V

1.1V

1.5A

0.9V

1.5A

1.8V

IN0

RUN

6V TO 36V

OUT0

LTM8001

LDO 1

45.3k

4.7µF 4.7µF 2.2µF

54.9k 121k

470µF

8001 TA01

100µF

Summary of content (28 pages)

PAGE 1
LTM8001 36VIN, 5A µModule Regulator with 5-Output Configurable LDO Array FEATURES n n n n DESCRIPTION Complete Step-Down Switch Mode Power Supply with Configurable Array of Five LDOs Step-Down Switching Power Supply – Adjustable 10% Accurate Output Current Limit –Constant-Current, Constant-Voltage Operation – Wide Input Voltage Range: 6V to 36V – 1.2V to 24V Output Voltage Configurable Output LDO Array – Five 1.
PAGE 2
LTM8001 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW VOUT4 SET4 VOUT3 SET3 SET2 VOUT2 VIN0............................................................................40V VIN45, BIAS45............................................................25V BIAS123.....................................................................25V FB0, RT, COMP, ILIM, VREF..........................................3V VOUT0-5......................................................................25V RUN, SYNC, SS.
PAGE 3
LTM8001 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. RUN = 3V unless otherwise noted (Note 3). PARAMETER CONDITIONS MIN TYP MAX UNITS Buck Regulator Minimum VIN0 Input Voltage 6 l VOUT0 Output DC Voltage 0A < IOUT ≤ 3A, RFB0 Open 0A < IOUT ≤ 3A; RFB0 = 536Ω VOUT0 Output DC Current 6V < VIN0 < 36V, VOUT = 3.3V Quiescent Current Into VIN0 RUN = 0V No Load 0.1 26 1.
PAGE 4
LTM8001 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. RUN = 3V unless otherwise noted (Note 3). PARAMETER CONDITIONS Maximum VOUT0 to VOUT1-3 and VIN45 to VOUT4-5 Differential Voltage (Note 5) IOUT1-5 = 750mA IOUT1-5 = 310mA IOUT1-5 = 125mA BIAS123, BIAS45 Pin Current IOUT1-5 = 100mA IOUT1-5 = 1.
PAGE 5
LTM8001 TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted. Configured per Table 1, where applicable.) Efficiency vs Output Current, VOUT0 = 12V 100 95 95 90 90 85 80 70 0 1 2 3 95 80 70 VINO = 24V VINO = 36V 0 1 2 3 1.5 100 85 1.8 VINO = 12V VINO = 24V VINO = 36V 4 1.4 0.9 0.6 0 5 0 1 3 VOUT0 CURRENT (A) 2 4 0.5 5 8001 G10 0 1 3 2 VOUT0 CURRENT (A) 8001 G09 2.5 INPUT CURRENT (A) 3.0 2.5 2.0 1.5 0 2.0 1.5 1.0 0.
PAGE 6
LTM8001 TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted. Configured per Table 1, where applicable.) Input Current vs Output Current, VOUT0 = 24V 4.0 5.0 3.5 4.5 7 2.0 1.5 1.0 MINIMUM VIN0 VOLTAGE (V) 2.5 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 VINO = 28V VINO = 36V 0 1 2 3 VOUT0 CURRENT (A) 4 VINO = 28V VINO = 36V 0.5 0 5 0 1 3 VOUT0 CURRENT (A) 2 4 2 3 9.75 0 1 VOUT0 CURRENT (A) 2 3 13.85 13.80 13.75 13.70 13.65 25.95 25.90 25.85 25.75 19.66 19.65 25.70 25.
PAGE 7
LTM8001 TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted. Configured per Table 1, where applicable.) 600 4 500 2 0 –2 –4 0 0.25 1 0.75 0.5 ILIM VOLTAGE (V) 1.
PAGE 8
LTM8001 TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted. Configured per Table 1, where applicable.) LDO VBIAS-to-Output Dropout Voltage vs Output Current 350 300 250 200 150 100 50 0 0 200 400 800 600 OUTPUT CURRENT (mA) 1.52 1600 1.50 1400 1.48 1.46 1.44 1.42 1.40 1.38 0 200 400 800 600 OUTPUT CURRENT (mA) 8001 G31 800 600 400 0 1000 0 20 10 30 INPUT-TO-OUTPUT DIFFERENTIAL (V) 120 LDO INPUT-TO-OUTPUT DIFFERENTIAL VOLTAGE 80 0.5V 1.6V 2.4V 4V 7V 9.5V 11.
PAGE 9
LTM8001 TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted. Configured per Table 1, where applicable.) LDO VBIAS Ripple Rejection (VOUT4 = 2.5V, VBIAS45 = 4.5V, VIN45 = 3.5V) LDO Output Ripple 100 90 RIPPLE REJECTION (dB) 80 1mV/DIV 70 60 50 40 30 20 ILOAD = 100mA ILOAD = 1.1A 10 0 10 102 103 104 FREQUENCY (Hz) 105 106 2µs/DIV VOUT = 1.2V AT 700mA COUT1 = 22µF CSET1 = 1nF VIN = 12V VOUT0 = 1.
PAGE 10
LTM8001 PIN FUNCTIONS the absolute maximum voltage rating of 6V through a resistor, provided the pin current does not exceed 100µA. 20% lower than the SYNC pulse frequency. Do not leave this pin open. FB0 (Pin L5): The LTM8001 regulates its FB0 pin to 1.19V. Connect the adjust resistor from this pin to ground. The value of RFB0 is given by the equation: ILIM (Pin L8): The ILIM pin reduces the maximum regulated output current of the LTM8001. The maximum control voltage range is 1.5V.
PAGE 11
LTM8001 OPERATION The LTM8001 consists of two major parts: the first is a standalone nonisolated step-down switching DC/DC power converter that can deliver up to 5A of output current. The second part is an array of five parallelable 1.1A LDOs. The DC/DC converter provides a precisely regulated output voltage programmable via one external resistor from 1.2V to 24V. The input voltage range is 6V to 36V.
PAGE 12
LTM8001 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 VOUT0 output voltage. 2. Apply the recommended CIN0, COUT0, RFB0 and RT values. Note that ceramic and electrolytic capacitors are recommended. These are intended to work in concert to optimize performance and solution size; apply both capacitors. 3.
PAGE 13
LTM8001 APPLICATIONS INFORMATION LTM8001 Table 1: Recommended Component Values and Configuration for VOUT0 (TA = 25°C) VIN0 VOUT0 6V to 36V 1.2V 6V to 36V 1.5V 6V to 36V CIN0 COUT0 (CERAMIC) COUT0 (ELECTROLYTIC) 10µF, 50V, 1210 100µF, 6.3V, 1210 470µF, 6.3V, 9mΩ, Chemi-Con, APXF6R3ARA471MH80G RFB0 fOPTIMAL RT(OPTIMAL) fMAX RT(MIN) Open 200kHz 200k 250kHz 169k 10µF, 50V, 1210 100µF, 6.3V, 1210 470µF, 6.3V, 9mΩ, Chemi-Con, APXF6R3ARA471MH80G 38.3k 300kHz 140k 350kHz 118k 1.
PAGE 14
LTM8001 APPLICATIONS INFORMATION Programming Switching Frequency Soft-Start The LTM8001 has an operational switching frequency range between 200kHz and 1MHz. This frequency is programmed with an external resistor from the RT pin to ground. Do not leave this pin open under any condition. See Table 2 for resistor values and the corresponding switching frequencies. The soft-start function controls the slew rate of the power supply output VOUT0 voltage during start-up.
PAGE 15
LTM8001 APPLICATIONS INFORMATION Load Current Derating Using the ILIM Pin VOUT In high current applications, derating the maximum current based on operating temperature may prevent damage to the load. In addition, many applications have thermal limitations that will require the regulated current to be reduced based on the load and/or board temperature. To achieve this, the LTM8001 uses the ILIM pin to reduce the effective regulated current in the load.
PAGE 16
LTM8001 APPLICATIONS INFORMATION The RUN pin has an absolute maximum voltage of 6V. To accommodate the largest range of applications, there is an internal Zener diode that clamps this pin, so that it can be pulled up to a voltage higher than 6V through a resistor that limits the current to less than 100µA. For applications where the supply range is greater than 4:1, size R2 greater than 375k.
PAGE 17
LTM8001 APPLICATIONS INFORMATION event. The SCR latches when the input voltage threshold is exceeded, so this circuit should be used with a fuse, as shown, or employ some other method to interrupt current from the load. As mentioned, the LTM8001 sinks current by energy conversion and not dissipation. Thus, no matter what protection circuit that is used, the amount of power that the protection circuit must absorb depends upon the amount of power at the input. For example, if the output voltage is 2.
PAGE 18
LTM8001 APPLICATIONS INFORMATION inductor value is 2.2uH. If the LTM8001 negative current limit is set to 5A, for example, the energy that the input capacitance must absorb is 1/2 LI2 = 27.5μJ. Suppose the comparator circuit in Figure 5d is set to pull the RUN pin down when VTRIP = 15V. The input voltage will rise according to the capacitor energy equation: 1 C ( VIN2 – VTRIP 2 ) = 27.5µJ 2 If the total input capacitance is 10μF, the input voltage will rise to: ( 1 27.5µJ = 10µF VIN2 – 15V 2 2 VIN = 15.
PAGE 19
LTM8001 APPLICATIONS INFORMATION and damaging the part. If the input supply is poorly controlled or the user will be plugging the LTM8001 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 to VIN0, but the most popular method of controlling input voltage overshoot is to add an electrolytic bulk capacitor to the VIN0 net.
PAGE 20
LTM8001 APPLICATIONS INFORMATION 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.
PAGE 21
LTM8001 APPLICATIONS INFORMATION JUNCTION-TO-AMBIENT RESISTANCE (JESD 51-9 DEFINED BOARD) JUNCTION-TO-CASE (TOP) RESISTANCE JUNCTION CASE (TOP)-TO-AMBIENT RESISTANCE JUNCTION-TO-BOARD RESISTANCE JUNCTION-TO-CASE CASE (BOTTOM)-TO-BOARD (BOTTOM) RESISTANCE RESISTANCE At BOARD-TO-AMBIENT RESISTANCE 8001 F08 µMODULE DEVICE Figure 8. Thermal Resistances Among μModule Device Printed Circuit Board and Ambient Environment 8001fb For more information www.linear.
PAGE 22
LTM8001 TYPICAL APPLICATIONS Five Output DC/DC µModule Regulator BIAS45 BIAS123 VIN45 VIN 18V TO 36V 10µF VIN0 510k LDO 1 RUN COMP SS VREF ILIM SYNC LTM8001 12V1 300mA VOUT1 SET1 12V2 300mA VOUT2 STEP-DOWN LDO 2 SET2 SWITCHING V REGULATOR LDO 3 OUT3 SET3 LDO 4 GND (13.5V) VOUT0 + 12V4 300mA VOUT4 SET4 953Ω 68.1k 120µF 12V3 300mA VOUT5 FBO LDO 5 SET5 RT 47µF 2.2µF 2.2µF 2.2µF 2.2µF 2.2µF 1.21M 1.21M 1.21M 1.21M 1.21M 12V5 300mA 8001 TA02 600kHz Dual Input, 2.
PAGE 23
LTM8001 TYPICAL APPLICATIONS Supercapacitor Charger and Two Output Regulator VIN45 VIN 9V TO 15V 10µF VOUT0 VIN0 200k 48.7k RUN BIAS123 BIAS45 LTM8001 COMP SS VREF ILIM SYNC GND LDO 1 3.3V 1A VOUT1 SET1 VOUT2 STEP-DOWN LDO 2 SET2 SWITCHING V REGULATOR LDO 3 OUT3 SET3 LDO 4 68.1k 3.09k 2.5V 0.5A VOUT4 SET4 VOUT5 FBO LDO 5 SET5 RT 47µF 5V 1.5F 5V SUPERCAP PM-5ROV155-R 4.7µF 10µF 124k 110k 600kHz 8001 TA04 8001fb For more information www.linear.
PAGE 24
LTM8001 TYPICAL APPLICATIONS Use Two LTM8001s to Implement a 2.5VOUT 10A DC/DC µModule Converter 100µF VIN45 VIN1 12V 10µF ×2 LDO 1 RUN BIAS123 BIAS45 LTM8001 COMP SS VREF ILIM SYNC GND 3V 470µF VOUT0 VIN0 510k + 2.5V 10A VOUT1 SET1 VOUT2 STEP-DOWN LDO 2 SET2 SWITCHING V REGULATOR LDO 3 OUT3 SET3 LDO 4 VOUT4 SET4 VOUT5 FBO LDO 5 SET5 RT 82.5k 6.
PAGE 25
0.635 ±0.025 Ø 121x 2.540 SUGGESTED PCB LAYOUT TOP VIEW 1.270 PACKAGE TOP VIEW 0.3175 0.000 0.3175 4 1.270 PIN “A1” CORNER E 2.540 aaa Z 6.350 5.080 3.810 3.810 5.080 6.350 D X For more information www.linear.com/LTM8001 6.350 5.080 3.810 2.540 1.270 0.000 1.270 2.540 3.810 5.080 6.350 Y 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 15.00 1.27 12.70 12.70 0.32 2.50 A A2 MAX 3.62 0.70 2.92 0.
PAGE 26
LTM8001 PACKAGE DESCRIPTION Table 3.
PAGE 27
LTM8001 REVISION HISTORY REV DATE DESCRIPTION A 09/13 Update Features section B 02/14 PAGE NUMBER 1 Update test conditions and limits 3, 4 Correct input power pin name 11 Add SnPb BGA package option 1, 2 8001fb Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use.
PAGE 28
LTM8001 TYPICAL APPLICATION Three Output DC/DC µModule Converter VIN45 VIN 9V TO 18V 10µF VIN0 510k 10k LDO 1 RUN BIAS123 BIAS45 LTM8001 COMP SS VREF ILIM SYNC GND 1.8V 1A 1V 2.2A VOUT0 VOUT1 SET1 VOUT2 STEP-DOWN LDO 2 SET2 SWITCHING V REGULATOR LDO 3 OUT3 SET3 LDO 4 VOUT5 FBO LDO 5 SET5 RT 20.5k 118k 1.2V 1.3A VOUT4 SET4 19.6k 4.7µF 10µF 60.4k 33.