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LTM8048

8048ff

For more information www.linear.com/LTM8048

INPUT VOLTAGE (V)

OUT1

CURRENT (mA)

330

230

130

280

180

10 20

8048 TA01b

5 15 25

TYPICAL APPLICATION

FEATURES DESCRIPTION

3.1V

to 32V

Isolated

µModule DC/DC Converter

with LDO Post Regulator

The LT M

8048 is an isolated flyback µModule DC/DC

converter with LDO post regulator. The LTM8048 has an

isolation rating of 725VDC. Included in the package are

the switching controller, power switches, transformer, and

all support components. Operating over an input voltage

range of 3.1V to 32V, the LTM8048 supports an output

voltage range of 2.5V to 13V, set by a single resistor. There

is also a linear post regulator whose output voltage is ad

justable from 1.2V to 12V as set by a single resistor. Only

output,

input,

and bypass capacitors are needed to finish

the design. Other components may be used to control the

soft-start control and biasing.

The LTM8048 is packaged in a thermally enhanced, com

pact (11.25mm × 9mm × 4.92mm) over-molded ball grid

array (BGA) package suitable for automated assembly by

standard sur

face mount equipment. The L

TM8048 is avail

able with SnPb (BGA) or RoHS compliant terminal finish.

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

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

APPLICATIONS

Complete Switch Mode Power Supply

725VDC Isolation

Wide Input Voltage Range: 3.1V to 32V

OUT1

Output:

Up to 440mA (V

OUT1

= 2.5V, 24V

)

2.5V to 13V Output Range

OUT2

Low Noise Linear Post Regulator:

Up to 300mA

1.2V to 12V Output Range

Current Mode Control

Programmable Soft-Start

User Configurable Undervoltage Lockout

SnPb or RoHS Compliant Finish

Low Profile (11.25mm × 9mm × 4.92mm) Surface

Mount BGA Package

Industrial Sensors

Industrial Switches

Ground Loop Mitigation

Total Output Current vs V

725V DC Isolated Low Noise µModule Regulator

725VDC ISOLATION

LTM8048

8048 TA01

3.1V TO 29V

OUT2

5.7V

10µF

22µF

2.2µF

4.7µF

6.19k

162k

OUT1

OUT2

RUN

ADJ1

BYPBIAS

GND

ADJ2

OUT

–

ISOLATION BARRIER

Summary of content (20 pages)

PAGE 1
LTM8048 3.1VIN to 32VIN Isolated µModule DC/DC Converter with LDO Post Regulator FEATURES n n n n n n n n n n DESCRIPTION Complete Switch Mode Power Supply 725VDC Isolation Wide Input Voltage Range: 3.1V to 32V VOUT1 Output: Up to 440mA (VOUT1 = 2.5V, 24VIN) 2.5V to 13V Output Range VOUT2 Low Noise Linear Post Regulator: Up to 300mA 1.2V to 12V Output Range Current Mode Control Programmable Soft-Start User Configurable Undervoltage Lockout SnPb or RoHS Compliant Finish Low Profile (11.25mm × 9mm × 4.
PAGE 2
LTM8048 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) VIN, RUN, BIAS .........................................................32V ADJ1, SS......................................................................5V VOUT1 Relative to VOUT–.............................................16V (VIN – GND) + (VOUT1 – VOUT–)..................................36V VOUT2 Relative to VOUT–...........................................+20V ADJ2 Relative to VOUT–..............................................
PAGE 3
LTM8048 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, RUN = 12V (Note 3). PARAMETER CONDITIONS Minimum Input DC Voltage BIAS = VIN l VOUT1 DC Voltage RADJ1 = 12.4k RADJ1 = 6.98k RADJ1 = 3.16k l VIN Quiescent Current VRUN = 0V Not Switching MIN 4.75 TYP 2.5 5 12 850 MAX UNITS 3.1 V 5.25 V V V 1 µA µA VOUT1 Line Regulation 6V ≤ VIN ≤ 31V, IOUT = 0.15A 1.
PAGE 4
LTM8048 TYPICAL PERFORMANCE CHARACTERISTICS Unless otherwise noted, operating conditions are as in Table 1 (TA = 25°C). VOUT1 = 2.5V BIAS = 5V 80 12VIN 70 24VIN 100 300 200 400 VOUT1 CURRENT (mA) 50 500 100 300 200 VOUT1 CURRENT (mA) 0 90 50 400 EFFICIENCY (%) 24VIN 8.5 24VIN 60 60 100 150 200 250 VOUT1 CURRENT (mA) 300 350 8048 G03 BIAS Current vs VOUT1 Load 12VIN 7.5 80 70 50 VOUT1 = 2.5V 8.
PAGE 5
LTM8048 TYPICAL PERFORMANCE CHARACTERISTICS Unless otherwise noted, operating conditions are as in Table 1 (TA = 25°C). BIAS Current vs VOUT1 Load 10 24VIN 8 7 6 0 300 250 200 50 100 150 200 VOUT1 CURRENT (mA) 250 100 2.5VOUT1 3.3VOUT1 5VOUT1 0 5 10 8048 G10 Minimum Load vs VIN 15 2.5VOUT1 3.
PAGE 6
LTM8048 TYPICAL PERFORMANCE CHARACTERISTICS Unless otherwise noted, operating conditions are as in Table 1 (TA = 25°C). Junction Temperature Rise vs Load Current 8 7 6 5 4 3 3.3VIN 5VIN 12VIN 24VIN 2 1 0 50 100 150 200 250 VOUT2 LOAD CURRENT (mA) 8 7 6 5 4 3 3.3VIN 5VIN 12VIN 24VIN 2 1 0 300 0 8048 G18 7 6 5 4 3 3.3VIN 5VIN 12VIN 24VIN 2 1 0 0 50 100 150 200 250 VOUT2 LOAD CURRENT (mA) 300 4 3.
PAGE 7
LTM8048 PIN FUNCTIONS VOUT1 (Bank 1): VOUT1 and VOUT– comprise the isolated output of the LTM8048 flyback stage. Apply an external capacitor between VOUT1 and VOUT–. Do not allow VOUT– to exceed VOUT1. VOUT– (Bank 2): VOUT– is the return for both VOUT1 and VOUT2. VOUT1 and VOUT– comprise the isolated output of the LTM8048.
PAGE 8
LTM8048 BLOCK DIAGRAM VOUT1 VIN VOUT2 • • 0.1µF 499k 1µF LOW NOISE LDO ADJ2 BYP RUN BIAS* SS CURRENT MODE CONTROLLER VOUT– ADJ1 GND 8048 BD *DO NOT ALLOW BIAS VOLTAGE TO BE ABOVE VIN 8048ff 8 For more information www.linear.
PAGE 9
LTM8048 OPERATION The LTM8048 is a stand-alone isolated flyback switching DC/DC power supply that can deliver up to 440mA of output current. This module provides a regulated output voltage programmable via one external resistor from 2.5V to 13V. It is also equipped with a high performance linear post regulator. The input voltage range of the LTM8048 is 3.1V to 32V.
PAGE 10
LTM8048 APPLICATIONS INFORMATION For most applications, the design process is straight forward, summarized as follows: 1. Look at Table 1a (or Table 1b, if the post linear regulator is used) and find the row that has the desired input range and output voltage. 2. Apply the recommended CIN, COUT1, COUT2, RADJ1, RADJ2 and CBYP if required. 3. Connect BIAS as indicated, or tie to an external source up to 15V or VIN, whichever is less.
PAGE 11
LTM8048 APPLICATIONS INFORMATION LTM8048 Table 1b. Recommended Component Values and Configuration for Specific VOUT2 Voltages (TA = 25°C) VIN VOUT1 VOUT2 VBIAS CIN COUT1 COUT2 RADJ1 RADJ2 3.1V to 32V 1.71V 1.2V 3.1V to 15V or Open 2.2µF, 50V, 1206 100µF, 6.3V, 1210 10µF, 6.3V, 1206 16.5k Open 3.1V to 32V 2.02V 1.5V 3.1V to 15V or Open 2.2µF, 50V, 1206 100µF, 6.3V, 1210 10µF, 6.3V, 1206 14.7k 2.32M 3.1V to 32V 2.34V 1.8V 3.1V to 15V or Open 2.2µF, 50V, 1206 100µF, 6.
PAGE 12
LTM8048 APPLICATIONS INFORMATION Isolation and Working Voltage The LTM8048 isolation is tested by tying all of the primary pins together, all of the secondary pins together and subjecting the two resultant circuits to a differential of ±725VDC for one second. This establishes the isolation voltage rating, but it does not determine the working voltage rating, which is subject to the application board layout and possibly other factors.
PAGE 13
LTM8048 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 LTM8048. The LTM8048 is nevertheless a switching power supply, and care must be taken to minimize electrical noise to 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 1 for a suggested layout.
PAGE 14
LTM8048 APPLICATIONS INFORMATION Thermal Considerations The LTM8048 output current may need to be derated if it is required to operate in a high ambient temperature. 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 the LTM8048 mounted to a 58cm2 4-layer FR4 printed circuit board.
PAGE 15
LTM8048 APPLICATIONS INFORMATION A graphical representation of these thermal resistances is given in Figure 2. The blue resistances are contained within the µModule converter, and the green are outside. The die temperature of the LTM8048 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 LTM8048.
PAGE 16
LTM8048 TYPICAL APPLICATIONS VOUT2 Output Current vs VIN 3.3V Flyback Converter 340 LTM8048 VOUT1 RUN VOUT2 BIAS 4.7µF 8.66k ADJ1 SS 320 3.9V VOUT2 3.3V BYP 47µF ADJ2 294k 10µF OUTPUT CURRENT (mA) 2.2µF VIN ISOLATION BARRIER VIN 9V TO 15V – VOUT GND VOUT1 RUN VOUT2 ADJ1 SS 11 12 VIN (V) 14 13 15 8048 TA02b VOUT2 Output Current vs VIN 13V 210 VOUT2 12V 0.01µF BYP 10µF ADJ2 10µF 56.2k 190 170 150 130 110 90 VOUT– GND 10 250 OUTPUT CURRENT (mA) 2.
PAGE 17
LTM8048 PACKAGE DESCRIPTION Pin Assignment Table (Arranged by Pin Number) PIN FUNCTION PIN FUNCTION PIN FUNCTION PIN FUNCTION PIN FUNCTION PIN B1 VOUT2 C1 VOUT2 D1 E1 GND F1 A1 VOUT2 A2 ADJ2 B2 BYP C2 VOUT2 D2 E2 GND F2 A3 VOUT– B3 VOUT– C3 VOUT– D3 E3 GND F3 B4 VOUT– C4 VOUT– D4 E4 GND F4 A4 VOUT– B5 VOUT– C5 VOUT– D5 E5 GND F5 A5 VOUT– B6 VOUT1 C6 VOUT1 D6 E6 GND F6 A6 VOUT1 B7 VOUT1 C7 VOUT1 D7 E7 GND F7 A7 VOUT1 FUNCTION RUN GND GND GND GND PIN G1 G2 G3 G4 G5 G6 G7 FUNCTION PIN FUNCTION VIN H1 VIN VI
PAGE 18
4 For more information www.linear.com/LTM8048 E SUGGESTED PCB LAYOUT TOP VIEW 2.540 PACKAGE TOP VIEW 1.270 PIN “A1” CORNER 0.3175 0.000 0.3175 aaa Z 1.270 Y 4.445 3.175 1.905 0.635 0.000 0.635 1.905 3.175 4.445 D X 4.7625 4.1275 aaa Z 3.95 – 4.05 SYMBOL A A1 A2 b b1 D E e F G aaa bbb ccc ddd eee NOM 4.92 0.60 4.32 0.78 0.63 11.25 9.0 1.27 8.89 7.62 DIMENSIONS 0.15 0.10 0.20 0.30 0.15 MAX 5.12 0.70 4.42 0.85 0.
PAGE 19
LTM8048 REVISION HISTORY REV DATE DESCRIPTION A 6/12 Added storage temperature range PAGE NUMBER 2 Clarify VOUT2 and ADJ1 pin function description 8 Clarify RADJ2 equation 13 Updated Related Parts table 20 B 8/12 Add Safety Rated Capacitors section 12 C 9/12 Correct Pin Assignment Table 17 D 3/13 E 1/14 F 1/14 Updated Typical Application schematic 1 Added Operating Conditions to Output Ripple graph 5 Updated Related Parts table 20 Revised RADJ1 value for 5VOUT and added mini
PAGE 20
LTM8048 TYPICAL APPLICATION Total Output Current vs VIN 5V Flyback Converter with Low Noise Bypass VIN VOUT1 RUN VOUT2 6.19k ADJ1 SS 5.7V 360 VOUT2 5V 0.01µF BYP 22µF ADJ2 162k 10µF 340 320 300 280 260 240 VOUT– GND OUTPUT CURRENT (mA) 2.2µF BIAS 4.