F
EATURES
• _55°C to +125°C
• 12 to 50 VDC input
• Works through transients of
up to 80 V for up to 20 ms.
• Powers DC/DC converters
requiring 28 Vin nominal
• Undervoltage lockout
• Inhibit function
• Sync function
L
INE
C
ONDITIONING
M
ODULE
28 V
OLT
I
NPUT
LCM-120
LCM-120
120 WATT
MODEL
Output 24
to 36 VDC
Size (max.): 1.505 x 3.005 x 0.400 inches
(38.23 x 76.33 x 10.16 mm)
See Section B8, case U1, for dimensions.
Weight:
95 grams max.
Screening: Standard or ES. See Section C2 for screening
options, see Section A5 for ordering information.
DESCRIPTION
The LCM-120™ Line Conditioning Module is a non-isolated DC/DC
converter used to extend the input voltage range of Interpoint’s
DC/DC converters. The LCM-120 delivers up to 120 watts of
throughput power from a 12 to 50 volt DC source in one of three
modes:
1. 12 to 24 volts input – internal boost converter delivers 24 volts
2. 24 to 36 volts input – input is connected directly to output
3. 36 to 50 volts input – internal buck converter delivers 36 volts.
converters and opens the output power path while leaving the power
fail flag unaffected. Inhibit is normally left open or pulled up with a
resistor. The sync input allows synchronization of the LCM-120
module’s internal clock to an external pulse source with LSTTL level
voltages and a 40% to 60% duty cycle. When unused, the sync
should be left unconnected. The power fail flag output is a fully
isolated NPN opto-coupler transistor rated to 18 volts DC. It will
drive an external LSTTL load low if the LCM-120 module’s input
voltage drops below 10 volts DC and will remain active until the
module output voltage also drops below 10 volts DC.
C
ONVERTER
D
ESIGN
The LCM-120 module is protected by internal current limit circuitry
which limits current according to input voltage. This feature also
allows safe charging of large external capacitors. Because current is
sensed between input common and output common there is
normally no external connection made between these pins. (Note: If
an external connection between input and output common is
desired, the resistance of this external connection must be greater
than 1 ohm.) The LCM module will work through up to an 80 volt
transient for up to 120 milliseconds while holding the output at 36
VDC.
L
OW
V
IN AND
H
EAVY
L
OADS
When the LCM-120 module is operated at 12 volts in and 120 watts
output, line loss can become a major concern. The module will
output 24 volts at 120 watts. Allowing for efficiency, the input current
will be [(120 watts / 0.88 / 12] = 11.36 A. If the resistance in the line
from the power source to the LCM-120 is 0.05 ohms, the line loss at
12 volts from the power source will be (0.05 • 11.36) = 0.57 volts.
The LCM-120 module will see 11.43 volts and will not start up.
F
EATURES
Features include an under voltage lockout, an inhibit input, a
synchronization input and a power fail flag output. Under voltage
lockout prevents start-up for inputs less than 12 volts DC and will
shut down the converter for an input of less than 10 volts DC. The
inhibit input, when connected to input common, disables the internal
E
XTERNAL
C
APACITANCE
Interpoint recommends a minimum output capacitance of 330 uF
and a total ESR of at least 0.25 ohms to ensure stability of the LCM-
120 module’s boost converter. For very low ESR capacitors, an
external series resistor (non-inductive) may be used to obtain the
minimum total ESR. The maximum recommended capacitance is
1F.
B6-9
LCM-120
120 WATT
L
INE
C
ONDITIONING
M
ODULE
SYNC AND INHIBIT
Sync (550 to 650 kHz.)
• Duty cycle 40% to 60%
• Logic low 0.8V, max
• Logic high 4.5 V, min
• Referenced to input common
• If sync is not used, leave unconnected
Inhibit: TTL Open Collector
• Logic low (output disabled)
Logic low voltage 1.3 V max
• Referenced to input common
• Logic high (output enabled)
ABSOLUTE MAXIMUM RATINGS
Input Voltage Range
• 12 to 50 continuous
Output Power
• 120 watts
Lead Soldering Temperature (10 sec per lead)
• 300°C
Storage Temperature Range (Case)
• –65°C to +150°C
TYPICAL CHARACTERISTICS
Output Voltage Temperature Coefficient
• 0.01%/°C, typical
Isolation: Any pin to case
• 100 megohm minimum at 500 V
Conversion Frequency
• Free run mode 600 kHz, typical
• External sync range 550 to 650 kHz
Inhibit Pin Voltage (unit enabled)
• 10 V typical
RECOMMENDED OPERATING CONDITIONS
Input Voltage Range
• 12 to 50 VDC continuous
• 80 V for 120 msec transient
Case Operating Temperature (Tc)
• –55°C to +125°C full power
• –65°C to +135°C absolute
Derating Output Power/Current
• Derate linearly from 100% at 125°C to 0% at 135°C
Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, free run, unless otherwise specified.
PARAMETERS
OUTPUT VOLTAGE
CONDITIONS
CONTINUOUS
TRANSIENT 120 ms MAX
OUTPUT POWER
OUTPUT RIPPLE
FULL LOAD
BW = 1O kHz TO 2 MHz
CONTINUOUS
TRANSIENT 120 ms
NO LOAD
INHIBITED, PIN 11 = 0 V
12
24
36
12
24
36
—
12
24
36
12 TO 80
< 9.5
INPUT VOLTAGE
AS A CONDITION
12 TO 24
24 TO 36
36 TO 50
50 TO 80
12 TO 50
12 TO 24
24 TO 36
36 to 50
MIN
23
—
35
—
—
—
—
—
12
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
330
LCM-120
TYP
24
V
IN
36
36
—
150
50
1500
28
—
125
50
20
50
24
18
150
88
95
90
1
0.4, PIN 9
9.5
11.5
—
MAX
24.5
—
37.5
—
120
—
—
—
50
80
160
85
—
—
—
—
—
—
—
—
—
—
10
12
1,000,000
UNITS
VDC
V
W
mV p-p
VDC
INPUT VOLTAGE
INPUT CURRENT
mA
INPUT RIPPLE
EFFICIENCY
FULL LOAD
BW = 10 kHz TO 10 MHz
FULL LOAD
mA p-p
%
mA
VDC
VDC
VDC
µF
INHIBIT CURRENT
POWER FAIL FLAG
POWER FAIL
THRESHOLD V
UNDERVOLTAGE
LOCKOUT
OUTPUT
CAPACITOR
INHIBITED, PIN 11 = 0 VDC
V
OUT
> 10, PIN 6
FLAG CURRENT = 0.4 mA
V
IN
FALLING
V
IN
RISING
ESR > 0.25 OHMS
B6-10
LCM-120
120 WATT
L
INE
C
ONDITIONING
M
ODULE
PIN OUT
Angled corner indicates pin one.
Pin
1
2
3
4
5
6
7
8
9
10
11
12
LCM-120
Positive Input
Positive Input
Input Common
Input Common
Output Common
Positive Output
No Connection
No Connection
Power Fail Flag Return
Power Fail Flag Output
Inhibit
Sync
1
2
3
4
5
6
12
11
TOP VIEW
LCM-120
(Pin side, marked side)
See Section B8, case U1, for dimensions.
10
9
8
7
F
IGURE
3: P
IN
O
UT
MODEL NUMBERING KEY
LCM – 120 / ES
Base Model
Output Power
Screening
(Standard screening has no
designator in this position.)
Note: There is only one LCM-120 model.
B6-12
27221-001-DTS Rev A
DQ# 3001
All technical information is believed to be accurate, but no responsibility is
assumed for errors or omissions. Interpoint reserves the right to make changes in
products or specifications without notice. LCM-120 is a trademark of Interpoint.
Copyright © 1995 - 1999 Interpoint. All rights reserved.
CASE
U
C
ASES
Angled corner indicates pin one
1.505 max (38.23)
CASE U
TOP VIEW
(PIN SIDE)
See Figures 55 and 56 for dimensions
3.005 (76.33) max.
Note:
Pins are shown for Case U1.
Materials
Header Cold Rolled Steel/Nickel/Gold
Cover Kovar/Nickel
Pins
#52 alloy/Gold
compression glass seal
Case dimensions in inches (mm)
Tolerance
±0.005
(0.13) for three decimal places
±0.01
(0.2) for two decimal places
unless otherwise specified
CAUTION
Heat from reflow or wave soldering may damage
the device. Solder pins individually with heat
application not exceeding 300°C for 10 seconds
per pin.
F
IGURE
54: C
ASE
U M
AXIMUM
D
IMENSIONS
B8-36
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