IMS30 Series
Input to output electric strength test 1500 V DC
Input voltage ranges 32...75 VDC for -0302
Dual output
Industry standard pin-out
Fixed frequency operation
High efficiency up to 89 %
2" x 2" platform with 9.4 mm profile
Low output noise
Soft start
Shut down input, output voltages adjustable
Programmable input undervoltage lockout
Synchronisation
Outputs no-load, overload and short-circuit proof
Operating ambient temperature 40...71
o
C
Thermal protection with auto-reset (non latching)
Emissions below EN 55022, level B
Immunity to IEC/EN 61000-4-2,-3,-4,-5 and -6
Table of Contents
Page
Summary ......................................................................... 1
Type Survey and Key Data ............................................. 2
Type Key ......................................................................... 2
Functional Description ..................................................... 2
Electrical Input Data ........................................................ 3
Electrical Ouput Data ...................................................... 4
Page
Auxiliary Functions .......................................................... 6
Electromagnetic Compatibility (EMC) ............................. 7
Immunity to Environmental Conditions ............................ 8
Mechanical Data ............................................................. 9
Safety and Installation Instructions ............................... 10
Description of Option ..................................................... 11
Summary
The IMS 30 series of board mountable 30 Watt DC-DC con-
verters has been designed according to the latest industry
requirements and standards. The converters are particu-
larly suitable for applications in industry and telecommuni-
cation where variable input voltages or high transient volt-
ages are prevalent.
Features include efficient input and output filtering with un-
surpassed transient and surge protection, low output ripple
and noise, consistently high efficiency over the entire input
voltage range, high reliability as well as excellent dynamic
response to load and line changes.
The converters provide supplementary insulation with
SELV outputs as e.g. required in battery supported systems
where the bus voltage may exceed the SELV limit of
60 V DC. They are designed and built according to the in-
ternational safety standards IEC/EN 60950, UL 1950, CAN/
CSA C22.2 No.950-95. Approvals pending.
The circuit comprises integrated planar magnetics and all
components are automatically assembled and soldered
onto a single PCB without any wire connections. The pro-
prietary magnetic feedback solution ensures maximum reli-
abilityand repeatability in the control loop over all operating
conditions. Careful considerations of possible thermal
stresses ensure the absence of hot spots providing long life
in environments where temperature cycles are a reality. The
thermal design allows operation at full load up to an ambi-
ent temperature of 71C in free air without using any potting
material.
Safety according to IEC/EN 60950, UL 1950
Approvals pending
LGA
C
1/11 10130 DC
Powering Communciations and Technology
IMS30 SERIES JAN, 2001
48V
input
Dual outputs 5V & 3.3V ; 3.3V & 1.8V
Functional Description
The IMS 30 series of DC-DC converters are magnetic feed-
back controlled forward converters using current mode
PWM (Pulse Width Modulation).
This product range features synchronous rectifiers deliver-
ing in very high efficiency. The output voltage of these ver-
sions can be adjusted via the Trim input. The Trim input is
referenced to the secondary side and allows for program-
ming of the output voltage in the range of approximately 90
to 110% of
U
o nom
using an external resistor.
The voltage regulation is achieved with a magnetic feed-
back circuit providing excellent line and load regulation.
Current limitation is provided by the primary circuit, thus
limiting the total output power to approx. 130% of
P
o nom
(see:
Type Survey). The shut down input allows remote
converter on/off.
Overtemperature protection will shut down the unit in ex-
cessive overload conditions with automatic restart.
Fig. 1
Block diagram (-0503, -0302 Outputs )
PWM
4n7F
1500 V
17
1
2
4
11
15
Vi+
SD
PUL
i
Vi
Uo2+
Com
Trim
3
W
Type Key
48 IMS 30 - 0503 -9 G i
Input voltage range
U
i
.................................... 48
Series ...................................................................... IMS 30
Output voltage type output .................... ( 5.1 and 3.3Vout)
Operating ambient temperature range
T
A
40...71C .................................................. -9
Synchronous rectifier ...................................................... G
Option: Inhibit ............................................................ i
Type Survey and Key Data
Table 1: Type survey
Output 1
Output power
Input Voltage Range and Efficiency
Option
U
o1 nom
I
o1 nom
P
o nom
U
i min
...
U
i max
typ
[V DC] [A] [W]
32...75 V DC [%]
5.1 4.5 30 48 IMS 30-0503-9G 87 i
Output 2
o2 nom
U
3.3
[V DC]
o1 nom
I
[A]
6.0
Uo1+
2/11
3.3 4.0 48 IMS 30-0302-9G 83 i
1.8 5.0
22
13
32...75 V DC
Electrical Input Data
General conditions:
T
A
= 25 C, unless
T
C
is specified.
Shut down pin left open circuit (not connected).
Trim input not connected.
Table 2: Input Data
Input 48 IMS
Characteristics Conditions min typ max Unit
U
i
Input voltage range
1
T
C min
...
T
C max
75 V DC
U
i nom
Nominal input voltage
I
o
= 0...
I
o nom
48
U
i sur
Repetitive input surge max 3 s 100
voltage
t
start up
Converter
Switch on
U
i min
,
I
o
=
I
o nom
2
0.25
0.5
s
start-up time
SD high
0.1
t
rise
Rise time
5
ms
I
i NL
No load input current
I
o
= 0,
U
i min
...
U
i max
30
40
mA
SD high
C
i
Input capacitance
for surge calculation
1.5
uF
U
SD
Shut down voltage
Unit disabled
10
0.7
V DC
Unit operating
1.5
5
I
SD
Input current of SD input
1
2
mA
I
inr p
Inrush peak current
4
U
i
=
U
i nom
1.5
A
f
s
Switching frequency
U
i min
,
I
o nom
approx. 250
kHz
I
i rr
Reflected
I
o
= 0...
I
o nom
60
mA
pp
ripple current
u
i RFI
Input RFI level conducted
EN 55022
3
B
1
U
i min
will not be as stated if
U
o
is increased above
U
o nom
by use of the Trim input. If the output voltage is set to a higher value,
U
i min
will be proportionally increased.
2
Measured with a resistive and the max. admissible capacitive load.
3
Measured with a lead length of 0.1 m, leads twisted.
4
Source impedance according to prETS 300132-2, version 4.3.
U
o nom
U
o
t
start up
t
rise
t
04008
Fig. 3
Converter start-up and rise time (applying U
i nom
).
Inrush Current
The inrush current has been kept as low as possible by
choosing a very small input capacitance.
A series resistor may be installed in the input line to further
limit this current.
Fig. 2
Typical inrush current at U
i nom
, P
o nom
versus time
(48 IMS30-0503-9G). Source impedance according to
prETS 300132-2, version 4.3 at U
i nom
.
Input Undervoltage Lock-out
The IMS30 converters are fitted with a defined input under-
voltage lock-out:
48 IMS 30
turn off
31.5 V
turn on
32 V
(approx. values)
1
0
1
2
3
4
5
6
7
8
t [ms]
2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
I [A]
04058
3/11
32
Input Transient Voltage Protection
A built-in suppressor diode provides effective protection
against input transients which may be caused for example
by short-circuits accross the input lines where the network
inductance may cause high energy pulses.
Table 3: Built-in transient voltage suppressor
Type
Breakdown
Peak power
Peak pulse
voltage
at 1 ms
current
V
BR nom
[V]
P
P
[W]
I
PP
[A]
48 IMS 30
100
600
4.1
For very high energy transients as for example to achieve
IEC/EN 61000-4-5 or ETR 283 (19 Pfl1) compliance (as per
table:
Electromagnetic Immunity) an external inductor and
capacitor are required.
Vi+
Vi
C
L
V+
V
Module
+
04009
1
2
Fig. 4
Example for external circuitry to comply with
IEC/EN 61000-4-5 or ETR 283 (19 Pfl1) (48 IMS 30 types).
Table 4: Components for external circuitry to comply with
IEC/EN 61000-4-5, level 2 or ETR 283 (19Pfl1)
(48 IMS types).
Circuit Ref.
48 IMS 30
L
150 uH
C
100 uF, 100 V, 85 C
Reverse Polarity Protection at the Input
The built-in suppressor diode also provides for reverse po-
larity protection at the input by conducting current in the re-
verse direction. An external fuse is required to limit this cur-
rent:
48 IMS 30: 3.15 A (F3.15A)
Electrical Ouput Data
Table 5a: Output data.
Model 48IMS30-0503-9G 3.3 V
5.1 V
Characteristics
Conditions
min t yp max
min
typ max
Unit
U
o1
Output voltage
U
i nom
,
I
o
= 0.5
I
o nom
3.25
3.35
5.00
5.20
V
I
o nom
Output current
U
i min
...
U
i max
A
I
oL
Current limit
1
U
i nom
9
U
o
Line regulation
U
i min
...
U
i max
+/-0.5
u
o1
Output voltage noise
2
I
o
= (0...1)
I
o nom
50
75 mV
pp
C
o ext
Admissible capacitive load 2000
2000 uF
u
o d
Dynamic Voltage deviation
U
i nom
250
250 mV
t
d
load
Recovery time
I
o nom
1
/
2
I
o nom
1
1
ms
regulation
Uo
Temperature coefficient
U
i nom
,
I
o nom
0.02
0.02 %/K
U
o
/
T
C
T
C min
...
T
C max
1
The current limit is primary side controlled.
2
BW = 20 MHz
0 6
0 3.5
6
See Fig. 6
Load regulation
+/-0.5
%
+/-1
4/11
Model 48IMS30-0302-9G 3.3 V 1.8 V
Characteristics Conditions min typ max min typ max Unit
U
o1
Output voltage
U
i nom
,
I
o
= 0.5
I
o nom
3.25
3.35
1.83
1.77 V
I
o nom
Output current
U
i min
...
U
i max
A
I
oL
Current limit
1
U
i nom
6
U
o
Line regulation
U
i min
...
U
i max
+/-0.5
u
o1
Output voltage noise
2
I
o
= (0...1)
I
o nom
50 50 mV
pp
C
o ext
Admissible capacitive load 2000 2000 uF
u
o d
Dynamic Voltage deviation
U
i nom
250
150 mV
t
d
load
Recovery time
I
o nom
1
/
2
I
o nom
1
1
ms
regulation
Uo
Temperature coefficient
U
i nom
,
I
o nom
0.02
0.02 %/K
U
o
/
T
C
T
C min
...
T
C max
0 4 0 5
7
See Fig. 6
Load regulation
+/-0.5
%
+/-3
Table 5b: Output data.
Fig 6: Cross regulation and load regulation for double output units.
5/11
Unspecified Output Current (A)
Specified Output Current (A)
+/-4%
+/-3%
30W Output power limit line
+/-1%
Regulation window for unspecified output (Tab 5a,5b)
100 %
50 %
1.0
2.0
3.0
4.0
5.0
6.0
Specified Output Current (A)
Extendable output power characterisation of 48IMS30-0302
-9G
under forced air condition
20
22
24
26
28
30
32
0
100
200
300
400
500
600
700
800
Air-Flow (LFM)
Output Power (W)
Table 6: Typical values for undervoltage lockout (PUL)
settings.
48 IMS 30
R
ext
[k ]
U
i min
[V]
31
50
34
29
36
20
38
15
40
Auxiliary Functions
Shut Down Function
The outputs of the converters may be enabled or disabled
by means of a logic signal (TTL, CMOS, etc.) applied to the
shut down pin. If the shut down function is not required then
pin should be left open-circuit.
Converter operating:
2.0...5.0 V
Converter shut down:
1...0.7 V
The shut down pin can also be used as a programmable
undervoltage lockout. The undervoltage lockout values for
the 48 IMS30 series is 31 V with a 0.5V hysteresis window
which can be trimmed up by means of an external resistor
connected between the SD/PUL pin and Vi pin.
Adjustable Output Voltage
As a standard feature, the IMS 30 units offer adjustable
output voltage by using the secondary referenced control
Trim. If the control input is left open-circuit the output volt-
age is set to
U
o nom
. Adjustment of the output voltage is pos-
sible by means of an external resistor
R
ext
connected be-
tween the Trim pin and the either Vo+ or Vo.
Vo+
Vi+
Vi
Vo
06133
R
ext
SD/PUL
Fig. 8
Shut down (SD) and undervoltage lockout (PUL) function.
Vo+
Vi+
Vi
Vo
06134
Trim
R
ext 1
R
ext 2
Fig. 9
Output voltage Trim.
Table 7: U
o
versus U
ext
for U
o
= 90...110% U
o nom
;
typical values (U
i nom
, I
o1/2
= 0.5 I
o1/2 nom
)
R
ext 1
R
ext 2
U
o nom
[V]
U
o
[V]
[k]
U
o
[V]
[k]
3.3
2.97
8
3.63
5
Synchronisation
The IMS 30 provides a bi-directional synchronisation func-
tion to synchronise several IMS 30 units operated in parallel
connection. When the W pins (SYNC) are connected to-
gether, the converters will lock to the highest switching fre-
quency. The faster controller becomes the master, produc-
ing a 4.3 V, 200 ns pulse train. Only one, the highest fre-
quency SYNC signal, will appear on the Sync line.
6/11
Thermal Considerations
If a converter, mounted on a PCB, is located in free, quasi-
stationary air (convection cooling) at the indicated maxi-
mum ambient temperature
T
A max
(see table:
Temperature
specifications) and is operated at its nominal input voltage
and output power, the case temperature
T
C
measured at the
Measuring point of case temperature T
C
(see:
Mechanical
Data) will approach the indicated value T
C max
after the
warm-up phase. However, the relationship between
T
A
and
T
C
depends heavily on the conditions of operation and inte-
gration into a system. The thermal conditions are influenced
by input voltage, output current, airflow, temperature of sur-
rounding components and surfaces and the properties of
the printed circuit board.
T
A max
is therefore only an indica-
tive value and under practical operating conditions, the ad-
missible ambient temperature
T
A
may be higher or lower
than this value.
Caution: The case temperature
T
C
measured at the
Measuring point of case temperature T
C
(see:
Mechani-
cal Data) must under no circumstances exceed the
specified maximum value. The installer must ensure that
under all operating conditions
T
C
remains within the lim-
its stated in the table:
Temperature specifications.
Short Circuit Behaviour
The current limit characteristic shuts down the converter
whenever a short circuit or an overload is applied to its out-
put. It acts self-protecting and automatically recovers after
removal of the overload condition (hiccup mode).
Overtemperature Protection
The converters are protected from possible overheating by
means of an internal non latching temperature monitoring
circuit. It shuts down the unit above the internal tempera-
ture limit and attempts to automatically restart in short peri-
ods. This feature prevents excessive internal temperature
excursion which could occur in heavy overload conditions.
Typical Performance Curves
General conditions :
T
A
= 25
o
C, unless
T
C
is specified. Shut down pin left open-
circuit. Trim input not connected.
Fig. 5
Overload switch off (hiccup mode), typical values.
100
U
o
[%]
t [ms]
05162
100
10
0
Electromagnetic Immunity
Table 8: Immunity type tests
Phenomenon
Standard
1
Class
Coupling
Value
Waveform
Source
Test
In
Per-
Level
mode
2
applied
Imped.
procedure
oper. form.
3
Electrostatic
IEC/EN
2
contact discharge
4000 V
p
1/50 ns
330
10 positive and
yes
B
discharge
61000-4-2
3
air discharge
8000 V
p
10 negative
to case
discharges
Electromagnetic
IEC/EN
2
antenna
3 V/m
AM 80%
26...1000 MHz
yes
A
field
61000-4-3
1 kHz
ENV 50204
PM, 50% duty
900 MHz
cycle, 200 Hz
resp. frequ.
Electrical fast
IEC/EN
3
direct +i/i
2000 V
p
bursts of 5/50 ns
50
1 min positive
yes
A
transient/burst
61000-4-4
5 kHz rep. rate
1 min negative
transients with
transients per
15 ms burst
coupling mode
duration and a
300 ms period
Surge
IEC/EN
2
+i/i
1000 V
p
1.2/50 s
2
5 pos. and 5 neg.
yes
B
61000-4-5
5
impulses per
coupling mode
Conducted
IEC/EN
2
+i/i
3
V
rms
AM modulated
50
0.15...80 MHz
yes
A
disturbancies
61000-4-6
(130 dB V)
80%, 1 kHz
150
Transient
ETR 283
+i/i
150 V
p
0.1/0.3 ms
limited to
3 positive
yes
B
(19 Pfl 1)
4
<100 A
1
Related and previous standards are referenced in:
Technical Information: Standards.
2
i = input, o = output.
3
A = normal operation, no deviation from specification, B = temporary deviation from specs. possibe.
4
For 48 IMS 30 types (additional external components required).
5
External components required.
which typically occur in many installations, but especially in
battery driven mobile applications.
Electromagnetic Compatibility (EMC)
A suppressor diode together with an input filter form an ef-
fective protection against high input transient voltages
Fig. 10
Typical disturbance voltage (quasi-peak) at the input ac-
cording to CISPR 11/EN 55011 and CISPR 22/EN 55022,
measured at U
i nom
and I
o nom
. Output leads 10 cm, twisted.
(48 IMS30-0503-9G )
Electromagnetic Emission
07020
EN 55022 A
EN 55022 B
90
80
70
60
50
40
30
20
10
0
0
.01
0
.05
0.1
0.5
1
2
5
10
20
30
[dB V]
MHz
0
.02
7/11
Immunity to Environmental Conditions
Table 9: Mechanical stress
Test method
Standard
Test conditions
Status
Ca
Damp heat
IEC/DIN IEC 60068-2-3
Temperature:
40
2
C
Unit not
steady state
MIL-STD-810D section 507.2
Relative humidity:
93
+2/-3
%
operating
Duration:
56 days
Ea
Shock
IEC/EN/DIN EN 60068-2-27
Acceleration amplitude:
50 g
n
= 490 m/s
2
Unit
(half-sinusoidal)
MIL-STD-810D section 516.3
Bump duration:
11 ms
operating
Number of bumps:
18 (3 each direction)
Eb
Bump
IEC/EN/DIN EN 60068-2-29
Acceleration amplitude:
25 g
n
= 245 m/s
2
Unit
(half-sinusoidal)
MIL-STD-810D section 516.3
Bump duration:
11 ms
operating
Number of bumps:
6000 (1000 each direction)
Fc
Vibration
IEC/EN/DIN EN 60068-2-6
Acceleration amplitude:
0.35 mm (10...60 Hz)
Unit
(sinusoidal)
MIL-STD-810D section 514.3
5 g
n
= 49 m/s
2
(60...2000 Hz)
operating
Frequency (1 Oct/min):
10...2000 Hz
Test duration:
7.5 h (2.5 h each axis)
Kb
Salt mist, cyclic
IEC/EN/DIN IEC 60068-2-52
Concentration:
5% (30 C)
Unit not
(sodium chloride
Duration:
2 h per cycle
operating
NaCl solution)
Storage:
40 C, 93% rel. humidity
Storage duration:
22 h per cycle
Number of cycles:
3
Table 10: Temperature specifications, valid for air pressure of 800...1200 hPa (800...1200 mbar)
Temperature Standard -9G
Characteristics
Conditions
min
max
Unit
T
A
Ambient temperature
1
Operational 40 71
C
T
C
Case temperature
40
105
T
S
Storage temperature
1
Non operational
55
105
1
MIL-STD-810D section 501.2 and 502.2
Table 11: MTBF
Values at specified
Type
Ground benign
Ground fixed
Ground mobile
Device hours
Unit
case temperature
25 C
25 C
55 C
55 C
MTBF 48 IMS 30-0503-9G 927'229 331'251 179'831 272'260 n.a. h
1
Statistical values based on an average of 4300 working hours per year and in general field use, over 2 years.
8/11
Mechanical Data
Dimensions in mm. Tolerances
0.3 mm unless otherwise indicated.
European
Projection
9/11
-0503, -0302 Outputs
Uo 1
Uo 2
Com
Tc Measurement point
Safety and Installation Instructions
Installation Instruction
Installation of the DC-DC converters must strictly follow the
national safety regulations in compliance with the enclo-
sure, mounting, creepage, clearance, casualty, markings
and segregation requirements of the end-use application.
Connection to the system shall be made via a printed circuit
board with hole diameters of 1.4 mm 0.1 mm for the pins.
The units should be connected to a secondary circuit.
Check for hazardous voltages before altering any connec-
tions.
Do not open the module.
Ensure that a unit failure (e.g. by an internal short-circuit)
does not result in a hazardous conditions. See also:
Safety
of operator accessible output circuit.
Input Fuse
To prevent excessive current flowing through the input sup-
ply line in case of a short-circuit across the converter input
an external fuse should be installed in a non earthed input
supply line. We recommend a fast acting fuse F3.15A
for 48 IMS 30 types.
Standards and approvals
All DC-DC converters are pending to be UL recognized
according to UL 1950, UL recognized for Canada to CAN/
CSA C22.2 No. 950-95 and LGA approved to IEC/EN
60950 standards.
The units have been evaluated for:
Building in
Supplementary insulation input to output, based on their
maximum input voltage
The use in a pollution degree 2 environment
Connecting the input to a secondary circuit which is sub-
ject to a maximum transient rating of 1500 V
After approvals the DC-DC converters are subject to manu-
facturing surveillance in accordance with the above men-
tioned UL, CSA, EN and ISO 9001 standards.
Isolation
The electric strength test is performed as factory test in ac-
cordance with IEC/EN 60950 and UL 1950 and should not
be repeated in the field. Melcher will not honour any guar-
antee claims resulting from electric strength field tests.
Table 12: Electric strength test voltages
Characteristic Input to output Unit
Electric strength 1.1 kV
rms
test voltage 1 s
1.5
kV DC
Coupling capacitance
2.2 nF
Insulation resistance >100 M
at 500 V DC
Partial discharge Consult kV
extinction voltage
factory
Protection Degree
The protection degree of the DC-DC converters is IP 40.
Cleaning Agents
In order to avoid possible damage, any penetration of
cleaning fluids should be prevented, since the power sup-
plies are not hermetically sealed.
Safety of Operator Accessible Output Circuit
If the output circuit of a DC-DC converter is operator acces-
sible, it shall be an SELV circuit according to IEC/EN 60950
related safety standards
The following table shows some possible installation con-
figurations, compliance with which causes the output circuit
of the DC-DC converter to be an SELV circuit according to
IEC/EN 60950 up to a configured output voltage of 42 V.
However, it is the sole responsibility of the installer to en-
sure the compliance with the relevant and applicable safety
regulations. More information is given in:
Technical Infor-
mation: Safety.
10/11
AC-DC
front
end
DC-DC
con-
verter
Mains
Fuse
Battery
Earth
connection
Suppressor
diode
SELV
Earth
connection
+
~
~
10004
Fig. 13
Schematic safety concept. Use fuse, suppressor diode
and earth connection as per table: Safety concept leading
to an SELV output circuit
.
Table 14: Insulation concept leading to an SELV output circuit
Conditions Front end
DC-DC converter
Result
Supply
Minimum required grade
Maximum
Minimum required safety
Measures to achieve the
Safety status of
voltage
of isolation, to be provided DC output
status of the front end
specified safety status of the
the DC-DC
by the AC-DC front end,
voltage
output circuit
output circuit
converter output
including mains supplied
from the
circuit
battery charger
front end
1
Mains
Basic
60 V
Earthed SELV circuit
2
Operational insulation (pro-
SELV circuit
250 V AC
vided by the DC-DC converter)
ELV circuit
Input fuse
3
output suppressor
Earthed SELV
>60 V
Hazardous voltage
diode(s)
4
, and earthed
circuit
secondary circuit
output circuit(s)
2
Double or reinforced
60 V
SELV circuit
Operational insulation (pro-
SELV circuit
vided by the DC-DC converter)
>60 V
TNV-2 circuit
Supplementary insulation,
Double or reinforced insu-
based on the maximum input
lated unearthed hazardous
voltage (provided by the
voltage secondary circuit
5
DC-DC converter)
1
The front end output voltage should match the specified input voltage range of the DC-DC converter.
2
The earth connection has to be provided by the installer according to the relevant safety standard, e.g. IEC/EN 60950.
3
The installer shall provide an approved fuse (type with the lowest rating suitable for the application) in a non-earthed input line directly
at the input of the DC-DC converter (see fig.:
Schematic safety concept). For UL's purpose, the fuse needs to be UL-listed. See also:
Input Fuse.
4
Each suppressor diode should be dimensioned in such a way, that in the case of an insulation fault the diode is able to limit the output
voltage to SELV (<60 V) until the input fuse blows (see fig.:
Schematic safety concept).
5
Has to be insulated from earth by basic insulation according to the relevant safety standard, based on the maximum output voltage
from the front end.
Description of Option
Option i Inhibit
Excluces shut down
The output(s) of the converter may be enabled or disabled
by means of a logic signal (TTL, CMOS, etc.) applied to the
inhibit pin. No output voltage overshoot will occur when the
unit is turned on. If the inhibit function is not required the
inhibit pin should be connected to Vi to enable the output
(active low logic, fail safe).
Converter operating:
10 V...0.8 V
Converter inhibited or
inhibit pin left open circuit
2.4...5 V
Fig. 14
If the inhibit is not used the inhibit pin should be con-
nected to Vi
Vi+
Vi
i
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