AVO75 Series DC/DC Converter TRN
TEL: (86) 755-86010808 www.emersonnetworkpower.com.cn 1/32
BOM: 31020683 DATE: 2008-12-03 REV1.3
AVO75 Series DC/DC Converter
Technical Reference Notes
Industry Standard Eighth Brick: 36~75V Input, 1.2V~12V Single Output
Industry standard eighth brick: 2.28” × 0.9’’ × 0.34’’
Options
• Choice of positive logic or negative logic
for CNT function
• Choice of short pins or long pins
Description
The AVO75 series DC/DC converter is a new open frame DC/DC converter for optimum efficiency
and power density. The series provides up to 25A output current in an industry standard eighth brick,
which makes it an ideal choice for small space, high current and low voltage applications. The
AVO75 series uses an industry standard eighth brick: 57.9mm × 22.9mm × 8.9mm (2.28” × 0.9” ×
0.35”) and standard pin-out configuration, provides CNT and trim functions. AVO75 series can
provide 1.2V ~ 12V single output, and outputs are isolated from inputs. The series can achieve ultra
high efficiency, and for most applications, a heat sink is not required.
Features
• Delivers up to 25A output current
• Industry standard eighth brick foot print
57.9mm × 22.9mm × 8.5mm
(2.28” × 0.9” × 0.34”)
• Basic isolation
• Ultra high efficiency: 92% at 5V full load
(Vin = 48Vdc)
• Improved thermal performance:
full load at 55ºC at 1m/s (200LFM) for 5Vo
• High power density
• Low output noise
• 2:1 wide input voltage of 36V-75V
• CNT function
• Remote sense
• Trim function: +10%/-20%
• Input under-voltage lockout
• Output over-current protection
• Output over-voltage protection
• Over-temperature protection
• RoHS compliant
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Module Numbering
AVO -S 1V5 P 4
Pin length
.
Output rated voltage: 1V2--1.2V, 1V5--1.5V, 1V8--1.8V,
2V5--2.5V, 3V3--3.3V, 05--5V, 12--12V
Output number: S ---single output, D---dual output
Input rated voltage
Output rated power
Series name
75 48 -
CNT logic, P---positive logic control,
default is negative logic control
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Electrical Specifications
Unless otherwise indicated, specifications apply over all operating input voltage and temperature
conditions. Standard test condition on a single unit is as follows:
Tc (board): 25 °C
+Vin: 48V± 2%
-Vin: return pin for +Vin
CNT: connected to -Vin for negative logic
open for positive logic
+Vout: connected to load
-Vout: connected to load (return)
+Sense: connected to +Vout
-Sense: connected to -Vout
Trim (Vadj): open
Input Specifications
Parameter Symbol Min Typ Max Unit
Operating Input Voltage V
I
36 48 75 V
DC
Maximum Input Current
(V
I
= 0 to V
I,max
, Io = Io,max) I
I,max
- - 2.5 A
Input Reflected-ripple Current
(5Hz to 20MHz, 12µH source impedance,
T
A
= 25 ºC)
I
I
- - 20 mAp-p
Supply Voltage Rejection
(1kHz) - 50 60 - dB
Caution: This power module is not internally fused. An input line fuse must always be used.
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Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device.
These are absolute stress ratings only. Functional operation of the device is not implied at these or
any other conditions in excess of those given in the operational sections of the IPS. Exposure to
absolute maximum ratings for extended periods can adversely affect device reliability.
Parameter Device
Symbol Min Typ Max Unit
Continuous All V
I
0 - 75 Vdc
Input Voltage Transient
(100ms)
All V
I, trans
0 - 100 Vdc
Operating Ambient Temperature
(See Thermal Consideration)
All Ta -40 - 85 °C
Operating Board Temperature All Tc - - 100 °C
Storage Temperature All T
STG
-55 - 125 °C
Operating Humidity All - - - 85 %
Basic Input-Output Isolation
(Conditions: 1mA for 60 sec, slew rate of
1500V/10sec)
All - 2000 Vdc
Output Power
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
Po,max 0 -
30
37.5
45
62.5
66
75
75
W
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Output Specifications
Parameter Device Symbol
Min Typ Max Unit
Output ripple and noise peak-to-peak (5Hz
to 20MHz)
(across 1µF @50V, X7R ceramic capacitor &
470µF @25V LOW ESR aluminum
capacitor)
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
- -
50
55
45
50
50
55
55
- mVp-p
External load capacitance
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
- 220 470
10,000
10,000
10,000
10,000
10,000
5000
1000
µF
Output voltage setpoint
(V
I
=V
I,min
to V
I,max
: I
o
=I
o,max
; Ta=25°C)
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
V
o,set
1.18
1.48
1.77
2.46
3.25
4.95
11.85
1.2
1.5
1.8
2.5
3.3
5
12
1.22
1.52
1.83
2.54
3.35
5.05
12.15
Vdc
Output
regulation Line (V
I,min
to V
I,max
)
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
- -
1
1
1
1
1
4
9
- mV
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Parameter Device Symbol
Min Typ Max Unit
Load (I
o,min
to I
o,max
)
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
- -
1
1
1
1
1
5
5
- mV
Temperature
(Tc=-40 °C to +100°C) All - - - 0.02 %V
o
/°C
Rated output current
1.2V,
1.5V
1.8V
2.5V
3.3V
5V
12V
Io 0 -
25
25
25
25
20
15
6.3
A
Output current-limit inception
(hiccup)
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
Io
28
28
28
28
22
16.5
6.9
-
35
35
35
35
28
21
10
A
Efficiency
(V
I
=V
I,nom
; 100%I
o,max
; T
A
=25°C)
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
- -
88
87
89
90.5
91
92
91
- %
Efficiency
(V
I
=V
I,nom
; 50%I
o,max
; T
a
=25°C)
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
- -
87
88
88.5
89.5
91
91
90
- %
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Output Specifications (Cont)
Parameter Device
Symbol
Min Typ
Max
Unit
Load change from Io =
50% to 75% to 50%
Io,max
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
-
60
50
50
60
85
110
150
mV
Dynamic response
(∆Io/∆t=1A/10µs,
V
I
=V
I,nom
; Ta=25°C)
Peak deviation settling Time
(to V
o,nom
)
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
-
300
115
125
70
70
120
120
- µsec
Load change from
I
o
=50% to 75% to 50%
I
o,max
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
-
130
130
120
170
130
130
120
- mv
Dynamic response
(∆Io/∆t=1A/1µs;
V
I
=V
I,nom
; Ta=25°C,
additional 220µF
load capacitor)
Peak deviation settling
time (to V
o,nom
)
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
-
300
100
115
150
80
130
320
- µsec
Turn-On time
(I
o
=I
o,max
; V
o
within 1%) All - - - 20 msec
Output voltage overshoot
(I
o
=I
o,max
; T
a
=25°C) All - - 0 %Vo
Switching frequency All - 310 kHz
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Feature Specifications
Parameter Device
Symbol Min Typ Max Unit
Logic low All -0.7 - 1.2 V
Enable pin voltage
Logic high All 3.5 - 12 V
Logic low All - - 1.0 mA Enable pin current
(leakage current,
@10V) Logic high All - - - µA
Output voltage adjustment range All* - 80 - 110 %V
o
Output over-voltage
(hiccup)
1.2V
1.5V
1.8V
2.5V
3.3V
5V
12V
V
o,clamp
1.4
1.8
2.2
3.0
3.9
6.0
14.4
-
2.0
2.5
3.0
3.8
5.0
7.5
18
V
Over-temperature protection
(auto-recovery) All 110 120 135 C
Turn-on point All - 31 34 36 V
Under-voltage
Lockout Turn-off point All - 30 33 35 V
Turn-on point All - 34.8 37 38 V AVO75-48S12-6/D
under-voltage
lockout Turn-off point All - 33.8 35.5 37 V
Isolation capacitance All - - 1000 - PF
Isolation resistance All - 10 - - MΩ
Calculated MTBF
(I
o
=I
o,max
; Tc=25°C) All - - 2,500,000
- Hours
Weight All - - - 30 g(oz.)
Note: Output voltage adjustment rang of 12V module is 90% to 110%.
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Characteristic Curves
70
75
80
85
90
0 5 10 15 20 25
Load(A)
Effiency(%)
Vin=36V
Vin=48V
Vin=75V
55
60
65
70
75
80
85
90
0 5 10 15 20 25
Load (A)
Efficiency (%)
36V
48V
75V
Fig. 1 Typical efficiency of AVO75-48S1V2 Fig. 2 Typical efficiency of AVO75-48S1V5
70
75
80
85
90
0 5 10 15 20 25
Load(A)
Effiency(%)
Vin=36V
Vin=48V
Vin=75V
70
75
80
85
90
95
0 5 10 15 20 25
Load(A)
Effiency(%)
Vin=36V
Vin=48V
Vin=75V
Fig. 3 Typical efficiency of AVO75-48S1V8 Fig. 4 Typical efficiency of AVO75-48S2V5
75
80
85
90
95
2 4 6 8 10 12 14 16 18 20
Load (A)
Ef f icienc y(% )
36V
48V
75V
70
75
80
85
90
95
0 3 6 9 12 15
Load(A)
Effiency(%)
Vin=36V
Vin=48V
Vin=75V
Fig. 5 Typical efficiency of AVO75-48S3V3 Fig. 6 Typical efficiency of AVO75-48S05
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70
75
80
85
90
95
0 1 2 3 4 5 6
Output current(A)
Effiency(%)
Vin=36V
Vin=48V
Vin=75V
Fig. 7 Typical efficiency of AVO75-48S12
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 5 10 15 20 25 30 35
Output Current (A)
Output Voltage (V)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 5 10 15 20 25 30 35 40
Output current (A)
Output voltage (V)
Fig. 8 Typical output over-current of AVO75-48S1V2 Fig. 9 Typical output over-current of AVO75-48S1V5
0
0.3
0.6
0.9
1.2
1.5
1.8
0 5 10 15 20 25 30 35
Output Current (A)
Output Voltage (V)
0
0.5
1
1.5
2
2.5
3
0 5 10 15 20 25 30 35
Output Current (A)
Output Voltage (V)
Fig. 10 Typical output over-current of AVO75-48S1V8 Fig. 11 Typical output over-current of AVO75-48S2V5
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0
0.5
1
1.5
2
2.5
3
3.5
0 5 10 15 20 25 30 35 40
Output Current（A）
Output Voltage（V）
0
1
2
3
4
5
6
0 4 8 12 16 20
Output Current (A)
Output Voltage (V)
Fig. 12 Typical output over-current of AVO75-48S3V3 Fig. 13 Typical output over-current of AVO75-48S05
0
2
4
6
8
10
12
14
0 2 4 6 8 10
Output Current (A)
Output Voltage (V)
Fig. 14 Typical output over-current of AVO75-48S12
0
1
2
3
4
5
0 5 10 15 20 25
Load(A)
Dissipation(W)
Vin=36V
Vin=48V
Vin=75V
0
1
2
3
4
5
6
7
0 5 10 15 20 25
Load (A)
Power dissipation (W)
36V
48V
75V
Fig. 15 Typical power dissipation of AVO75-48S1V2 Fig. 16 Typical power dissipation of AVO75-48S1V5
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0
1
2
3
4
5
6
7
0 5 10 15 20 25
Load(A)
Dissipation(W)
Vin=36V
Vin=48V
Vin=75V
0
1
2
3
4
5
6
7
8
9
0 5 10 15 20 25
Load
(A)
Dissipation(W)
Vin=36V
Vin=48V
Vin=75V
Fig. 17 Typical power dissipation of AVO75-48S1V8 Fig. 18 Typical power dissipation of AVO75-48S2V5
0
2
4
6
8
2 4 6 8 10 12 14 16 18 20
Load (A)
Pow er Dissipation (W)
36V
48V
75V
0
2
4
6
8
0 3 6 9 12 15
Load(A)
Dissipation(W)
Vin=36V
Vin=48V
Vin=75V
Fig. 19 Typical power dissipation of AVO75-48S3V3 Fig. 20 Typical power dissipation of AVO75-48S05
0
2
4
6
8
10
0 1 2 3 4 5 6
Output current(A)
Dissipation(W)
Vin=36V
Vin=48V
Vin=75V
Fig. 21 Typical power dissipation of AVO75-48S12
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Fig. 22 AVO75-48S1V2 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input
Fig. 23 AVO75-48S1V2 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input
Fig. 24 AVO75-48S1V5 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input
Fig. 25 AVO75-48S1V5 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
Fig. 26 AVO75-48S1V5 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
Fig. 27 AVO75-48S1V5 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
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Fig. 28 AVO75-48S1V5 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
Fig. 29 AVO75-48S1V5 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
Fig. 30 AVO75-48S1V8 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
Fig. 31 AVO75-48S1V8 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
Fig. 32 AVO75-48S1V8 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
Fig. 33 AVO75-48S1V8 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
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Fig. 34 AVO75-48S2V5 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
Fig. 35 AVO75-48S2V5 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
Fig. 36 AVO75-48S2V5 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
Fig. 37 AVO75-48S2V5 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
Fig. 38 AVO75-48S3V3 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
Fig. 39 AVO75-48S3V3 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
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Fig. 40 AVO75-48S3V3 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
Fig. 41 AVO75-48S3V3 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
Fig. 42 AVO75-48S05 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
Fig. 43 AVO75-48S05 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
Fig. 44 AVO75-48S05 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
Fig. 45 AVO75-48S05 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
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Fig. 46 AVO75-48S12 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
Fig. 47 AVO75-48S12 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=0.1A/1µs)
Fig. 48 AVO75-48S12 typical transient response to
step decrease in load from 50% to 25% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
Fig. 49 AVO75-48S12 typical transient response to
step increase in load from 50% to 75% of full load,
room temperature, 48Vdc input (∆Io/∆t=1A/1µs)
Fig. 50 Typical output ripple voltage of
AVO75-48S1V2 room temperature, I
o
=I
o,max
Fig. 51 Typical output ripple voltage of
AVO75-48S1V5 room temperature, I
o
=I
o,max
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Fig. 52 Typical output ripple voltage of
AVO75-48S1V8 room temperature, I
o
=I
o,max
Fig. 53 Typical output ripple voltage of
AVO75-48S2V5 room temperature, I
o
=I
o,max
Fig. 54 Typical output ripple voltage of
AVO75-48S3V3 room temperature, I
o
=I
o,max
Fig. 55 Typical output ripple voltage of AVO75-48S05
room temperature, I
o
=I
o,max
Fig. 56 Typical output ripple voltage of AVO75-48S12
room temperature, I
o
=I
o,max
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Fig. 57 AVO75-48S1V2 typical start-up from power on Fig. 58 AVO75-48S1V2 typical start-up from CNT on
Fig. 59 AVO75-48S1V5 typical start-up from power on Fig. 60 AVO75-48S1V5 typical start-up from CNT on
Fig. 61 AVO75-48S1V8 typical start-up from power on Fig. 62 AVO75-48S1V8 typical start-up from CNT on
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Fig. 63 AVO75-48S2V5 typical start-up from power on Fig. 64 AVO75-48S2V5 typical start-up from CNT on
Fig. 65 AVO75-48S3V3 typical start-up from power on Fig. 66 AVO75-48S3V3 typical start-up from CNT on
Fig. 67 AVO75-48S05 typical start-up from power on Fig. 68 AVO75-48S05 typical start-up from CNT on
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Fig. 69 AVO75-48S12 typical start-up from power on Fig. 70 AVO75-48S12 typical start-up from CNT on
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Feature Description
CNT Function
The converter is equipped with a primary
ON/OFF pin used to remotely turn the
converter on or off via a system signal. Two
CNT logic options are available. For the
positive logic model a system logic low signal
will turn the unit off. For the negative logic
model a system logic high signal will turn the
converter off. For negative logic models where
no control signal will be used the ON/OFF pin
should be connected directly to -Vin to ensure
proper operation. For positive logic models
where no control signal will be used the
ON/OFF pin should be left unconnected.
The following Fig. shows a few simple CNT
circuits.
CNT
-Vin
CNT
-Vin
Simple CNT Transistor CNT
CNT
-Vin
CNT
-Vin
Isolated CNT Relay CNT
Fig. 71 CNT circuits
Remote Sense
The AVO75 converter can remotely sense both
lines of its output which moves the effective
output voltage regulation point from the output
terminals of the unit to the point of connection
of the remote sense pins. This feature
automatically adjusts the real output voltage of
the AVO75 in order to compensate for voltage
drops in distribution and maintain a regulated
voltage at the point of load.
When the converter is supporting loads far
away, or is used with undersized cabling,
significant voltage drop can occur at the load.
The best defense against such drops is to
locate the load close to the converter and to
ensure adequately sized cabling is used. When
this is not possible, the converter can
compensate for a drop of up to 10%Vo, through
use of the sense leads.
When used, the + Sense and - Sense leads
should be connected from the converter to the
point of load as shown in Fig. 72, using
twisted pair wire, or parallel pattern to reduce
noise effect. The converter will then regulate its
output voltage at the point where the leads are
connected. Care should be taken not to
reverse the sense leads. If reversed, the
converter will trigger OVP protection.
When not used, the +Sense lead must be
connected with +Vo, and -Sense with -Vo.
Although the output voltage can be increased
by both the remote sense and by the trim, the
maximum increase for the output voltage is not
the sum of both.
The maximum increase is the larger of either
the remote sense or the trim.
Note that at elevated output voltages the
maximum power rating of the module remains
the same, and the output current capability will
decrease correspondingly.
-Vo
+Vo
Load
+Sense
-Sense
Twisted pair
+S
-S
Fig. 72 Sense connections
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Trim
The +Vo output voltage of the AVO75 series
can be trimmed with the trim pin provided.
Applying a resistor to the trim pin through a
voltage divider from the output will cause the
+Vo output to increase by up to 10%or
decrease by up to 20%. Trimming up by more
than 10% of the nominal output may activate
the OVP circuit or damage the converter.
Trimming down more than 20% can cause the
converter to regulate improperly. If the trim pin
is not needed, it should be left open.
Trim up
With an external resistor connected between
the TRIM and +SENSE pins, the output voltage
set point increases (see Fig. 73).
R
LOAD
R
adj-up
Vo(+)
SENSE(+)
TRIM
SENSE(-)
Vo(-)
Vi(+)
CNT
Vi(-)
Fig. 73 Trim up circuit
The following equation determines the required
external-resistor value to obtain a percentage
output voltage change of 1%.
For Output Voltage: 1.5V ~ 12V
(
)
)(2.10
%
510
%
225
.
1
%1001.5 Ω−
∆
−
∆×
∆
+
×
×
=
−
k
V
R
nom
upadj
For output voltage: 1.2V
(
)
)(2.10
%
510
%
6
.
0
%1001.5 Ω−
∆
−
∆×
∆
+
×
×
=
−
k
V
R
nom
upadj
Note: △=(Vnom-Vo)×100/V
nom
V
trim
tolerance: < ±2%,
R
adj
tolerance: ±1%
For example: trim up the output of
AVO75-48S1V8 to 1.98V.
△=(1.98-1.8)×100/1.8=10
(
)
)(2.10
10
510
10
225
.
1
101008.11.5 Ω−−
×
+
×
×
=
−
kR
upadj
)(23.21 Ω=
−
kR
upadj
Trim down
With an external resistor between the TRIM
and -SENSE pins, the output voltage set point
decreases (see Fig. 74).
R
LOAD
R
adj-down
Vo(+)
SENSE(+)
TRIM
SENSE(-)
Vo(-)
Vi(+)
CNT
Vi(-)
Fig. 74 Trim down circuit
The following equation determines the required
external-resistor value to obtain a percentage
output voltage change of 1%.
For output voltage: 1.2V ~ 12V
)(2.10
%
510 Ω−
∆
=
−
kR
downadj
Note: △= (Vnom-Vo) % 100/Vnom
V
trim
tolerance: <±2%,
R
adj
tolerance: ±1%
For example: trim down the output of
AVO75-48S1V8 to 1.62V.
△=(1.8-1.62)×100/1.8=10
)(2.10
10
510 Ω−=
−
kR
downadj
)(8.40
Ω
=
−
kR
downadj
Although the output voltage can be increased
by both the remote sense and by the trim, the
maximum increase for the output voltage is not
the sum of both. The maximum increase is the
larger of either the remote sense or the trim.
AVO75 Series DC/DC Converter TRN
TEL: (86) 755-86010808 www.emersonnetworkpower.com.cn 24/32
Note that at elevated output voltages the
maximum power rating of the module remains
the same, and the output current capability will
decrease correspondingly.
Minimum Load Requirements
There is no minimum load requirement for the
AVO75 series modules.
Output Capacitance
High output current transient rate (high di/dt) of
changing loads might require high values of
output capacitance to supply the instantaneous
energy requirement to the load. To minimize
the output voltage transient drop during this
transient, low Equivalent Series Resistance
(ESR) capacitors may be required, since a high
ESR will produce a correspondingly higher
voltage drop during the current transient.
When the load is sensitive to ripple and noise,
an output filter can be added to minimize the
effects. A simple output filter to reduce output
ripple and noise can be made by connecting a
capacitor C1 across the output as shown in
Fig.75. The recommended value for the output
capacitor C1 is 470µF.
+V
out
-V
out
Load
C1
Fig. 75 Output ripple filter
Extra care should be taken when long leads or
traces are used to provide power to the load.
Long lead lengths increase the chance for
noise to appear on the lines. Under these
conditions C1 can be added across the load,
with a 1µF ceramic capacitor C2 in parallel
generally as shown in Fig. 76.
+V
out
-V
out
Load
C1 C2
Fig. 76 Output ripple filter for a distant load
Decoupling
Noise on the power distribution system is not
always created by the converter. High speed
analog or digital loads with dynamic power
demands can cause noise to cross the power
inductor back onto the input lines. Noise can be
reduced by decoupling the load. In most cases,
connecting a 10µF tantalum or ceramic
capacitor in parallel with a 0.1µF ceramic
capacitor across the load will decouple it. The
capacitors should be connected as close to the
load as possible.
Ground Loops
Ground loops occur when different circuits are
given multiple paths to common or earth
ground, as shown in Fig.77. Multiple ground
points can gave slightly different potentials and
cause current flow through the circuit from one
point to another. This can result in additional
noise in all the circuits. To eliminate the
problem, circuits should be designed with a
single ground connection as shown in Fig.78.
-Vo
+Vo
Load Load
R
Line
R
Line
R
Line
R
Line
R
Line
R
Ground
Loop
Fig. 77 Ground loops
AVO75 Series DC/DC Converter TRN
TEL: (86) 755-86010808 www.emersonnetworkpower.com.cn 25/32
-Vo
+Vo
Load Load
R
Line
R
Line
R
Line
R
Line
R
Line
Fig. 78 Single point ground
Output Over-current Pro tection
AVO75 series DC/DC converters feature
foldback current limiting as part of their
Over-current Protection (OCP) circuits. When
output current exceeds 110 to 140% of rated
current, such as during a short circuit condition,
the module will work on intermittent mode, also
can tolerate short circuit conditions indefinitely.
When the over-current condition is removed,
the converter will automatically restart.
Output Over-Voltage Protection
The output over-voltage protection consists of
circuitry that monitors the voltage on the output
terminals. If the voltage on the output terminals
exceeds the over voltage protection threshold,
then the module will work on intermittent mode.
When the over-voltage condition is removed,
the converter will automatically restart.
The protection mechanism is such that the unit
can continue in this condition until the fault is
cleared.
Over-Temperature Protection
These modules feature an over-temperature
protection circuit to safeguard against thermal
damage. The module will work on intermittent
mode when the maximum device reference
temperature is exceeded. When the
over-temperature condition is removed, the
converter will automatically restart.
Design Consideration
Typical Application
LOAD
+Vin
-Vin
CNT1
+Vout
-Vout
+Sense
-Sense
TRM
F1
Cin
Vin Co1Co2
S1
Fig. 79 Typical application
F1: Fuse. Use external fuse with a rating of 5A
(fast blow type) for each unit.
Cin: Recommended input capacitor. Use
47µF/100V high frequency low ESR electrolytic
type capacitor
Co1: Recommended 1µF/10V ceramic
capacitor
Co2: Recommended output capacitor
Use 470µF/10V high frequency low ESR
electrolytic type capacitor.
If Ta<-5°C, use 220µF tantalum capacitor
parallel with a 470µF/10V high frequency low
ESR electrolytic capacitor.
Note: The AVO75 modules cannot be used in
parallel mode directly!
Fusing
The AVO75 power modules have no internal
fuse. An external fuse must always be
employed! To meet international safety
requirements, a 250 Volt rated fuse should be
used. If one of the input lines is connected to
chassis ground, then the fuse must be placed
in the other input line.
AVO75 Series DC/DC Converter TRN
TEL: (86) 755-86010808 www.emersonnetworkpower.com.cn 26/32
Standard safety agency regulations require
input fusing. Recommended fuse ratings is 5A
for the AVO75 Series.
Note: the fuse is fast blow type.
Input Reverse Voltage Protection
Under installation and cabling conditions where
reverse polarity across the input may occur,
reverse polarity protection is recommended.
Protection can easily be provided as shown in
Fig. 80. In both cases the diode used is rated
for 10A/100V. Placing the diode across the
inputs rather than in-line with the input offers an
advantage in that the diode only conducts in a
reverse polarity condition, which increases
circuit efficiency and thermal performance.
+V
in
-V
in
+V
in
-V
in
Fig. 80 Reverse polarity protection circuit
EMC
For conditions where EMI is a concern, a
different input filter can be used. Fig. 81
shows a filter designed to reduce EMI effects.
AVO75 series can meet EN55022 CLASS A
shown Fig. 81.
-Vin
+Vin +Vout
-Vout
CY8
CX2
CY5CY7
CY2
CY1 U
+Sense
CNT
Vout+Vin+
-Sense
Vin- Vout-
Trim
CX1
CY10
CY6
CY9
Cin1
**
L1
CY3
CY4
Cout2Cout1
Fig. 81 EMI reduction filter
Recommended values:
Component Value/Rating
Component Value/Rating
CY1, CY2, CY5, CY6 4700PF/250VAC Cin1 47µF/100V
CX1 2.2µ/100V CX2 1µF/100V
CY7, CY8, CY9, CY10
1000PF/250VAC Cout1 470µF/10V (low ESR
capacitor)
CY3, CY4 0.47µ Cout2 1µF/10V
L1 1.8mH
AVO75 Series DC/DC Converter TRN
TEL: (86) 755-86010808 www.emersonnetworkpower.com.cn 27/32
Safety Consideration
For safety-agency approval of the system in
which the power module is used, the power
module must be installed in compliance with
the spacing and separation requirements of the
end-use safety agency standard, i.e., UL1950,
CSA C22.2 No. 950-95, and EN60950. The
AVO75 series input-to-output isolation is a
basic insulation. The DC/DC power module
should be installed in end-use equipment, in
compliance with the requirements of the
ultimate application, and is intended to be
supplied by an isolated secondary circuit.
When the supply to the DC/DC power module
meets all the requirements for SELV(<60Vdc),
the output is considered to remain within SELV
limits (level 3). If connected to a 60Vdc power
system, double or reinforced insulation must be
provided in the power supply that isolates the
input from any hazardous voltages, including
the AC mains. One input pin and one output pin
are to be grounded or both the input and output
pins are to be kept floating. Single fault testing
in the power supply must be performed in
combination with the DC/DC power module to
demonstrate that the output meets the
requirement for SELV. The input pins of the
module are not operator accessible.
Note: Do not ground either of the input pins of
the module, without grounding one of the
output pins. This may allow a non-SELV
voltage to appear between the output pin and
ground.
Note:
To comply with the published safety standards,
the following must be observed when using this
built-in converter.
1. The built-in converter is intended for use as
a component part of other equipment. When
installing the power supply and marking input
and output connections, the relevant safety
standards e.g. UL 60950-1; IEC 60950-1/VDE
0805; EN60950-1; CAN/CSA-22.2NO.
60950-1-03 must be complied with, especially
the requirements for creepage distances,
clearances and distance through insulation
between primary and earth or primary and
secondary.
2. The output power taken from the built-in
converter must not exceed the rating given on
the built-in converter.
3. The built-in converter is not intended to be
repaired by service personnel in case of failure
or component defect (unit can be thrown
away).
4. The maximum ambient temperature around
the converter must not exceed 55°C.
5. An external forced air cooling (CFM: 80.2,
Speed: 1m/s, distance from unit: 20cm) shall
be used for unit operate with full load and
ambient up to 55°C.
6. The built-in converter has no in-line fuse. For
safety purpose, a fast acting UL listed fuse or
UL recognized fuse rated 5A/250V needs to be
connected to the input side as external
protection.
Thermal Consideration
Thermal management is an important part of
the system design. AVO75 series modules
have ultra high efficiency at full load, and the
module exhibit good performance during
pro-longed exposure to high temperatures.
However, to ensure proper and reliable
operation, sufficient cooling of the power
module and power derating is needed over the
entire temperature range of the module.
Considerations includes ambient temperature,
airflow and module power derating.
AVO75 Series DC/DC Converter TRN
TEL: (86) 755-86010808 www.emersonnetworkpower.com.cn 28/32
Measuring the thermal reference point of the
module as the method shown in Fig. 82 can
verify the proper cooling.
Notice: The thermocouple must not touch the
pads of the thermistor
Thermocouple
Thermistor
Thermocouple
location
Fig. 82 Temperature measurement location
Module Derating
With 48V input, 55°C ambient temperature, and
200LFM airflow, AVO75 series are rated for full
power. For operation above ambient
temperature of 55°C, the output power must be
derated as shown in Fig.83 to Fig.89.
Meantime, airflow at least 200LFM over the
converter must be provided to make the
module working properly.
It is recommended that the temperature of the
thermal reference point be measured using a
thermocouple. Temperature on the PCB at the
thermocouple location shown in Fig. 82 should
not exceed 125°C in order to operate inside the
derating curves as shown Fig. 83 to Fig 89.
The use of output power derating curve is
shown in the following example.
Example
What is the minimum airflow necessary for a
AVO75-48S3V3 operating at VI = 48V, an
output current of 20A, and a maximum ambient
temperature of 55°C?
Solution
Given: V
I
=48V, Io=20A, Ta=55°C
Determine airflow (v) (use Fig. 83 to Fig.89):
v=1m/s. (200ft/min)
0
5
10
15
20
25
25 40 55 70 85
TEMPERATURE, Ta (℃)
Output Current Io (A)
2m/s
1.5m/s
1m/s
0.5m/s
0m/s
Fig. 83 AVO75-48S1V2 output power derating
Airflow direction from -Vin to +Vin; Vin=48V
0
5
10
15
20
25
25 40 55 70 85
TEMPERATURE, Ta (℃)
Output Current Io (A)
2m/s
1.5m/s
1m/s
0.5m/s
0m/s
Fig. 84 AVO75-48S1V5 output power derating
Airflow direction from -Vin to +Vin; Vin=48V
0
5
10
15
20
25
25 40 55 70 85
TEMPERATURE, Ta (℃)
Output Current Io (A)
2m/s
1.5m/s
1m/s
0.5m/s
0m/s
Fig. 85 AVO75-48S1V8 output power derating
Airflow direction from -Vin to +Vin; Vin=48V
AVO75 Series DC/DC Converter TRN
TEL: (86) 755-86010808 www.emersonnetworkpower.com.cn 29/32
0
5
10
15
20
25
25 40 55 70 85
TEMPERATURE, Ta (℃)
Output Current Io (A)
2m/s
1.5m/s
1m/s
0.5m/s
0m/s
Fig. 86 AVO75-48S2V5 output power derating
Airflow direction from –Vin to +Vin; Vin=48V
0
5
10
15
20
25 40 55 70 85
TEMPERATURE, Ta (℃)
Output Current Io (A)
2m/s
1.5m/s
1m/s
0.5m/s
0m/s
Fig. 87 AVO75-48S3V3 output power derating
Airflow direction from -Vin to +Vin; Vin=48V
0
3
6
9
12
15
25 40 55 70 85
TEMPERATURE, Ta (℃
℃℃
℃)
Output Current Io (A)
2m/s
1.5m/s
1m/s
0.5m/s
0m/s
Fig. 88 AVO75-48S05 output power derating
Airflow direction from -Vin to +Vin; Vin=48V
0
1
2
3
4
5
6
7
25 40 55 70 85
TEMPERATURE, Ta (℃
℃℃
℃)
Output Current Io (A)
2m/s
1.5m/s
1m/s
0.5m/s
0m/s
Fig. 89 AVO75-48S12 output power derating
Airflow direction from -Vin to +Vin; Vin=48V
MTBF
The MTBF, calculated in accordance with
Bellcore TR-NWT-000332, is 2,500,000 hours.
Obtaining this MTBF in practice is entirely
possible. If the board temperature is expected
to exceed +25°C, then we also advise an
oriented for the best possible cooling in the air
stream.
Emerson Network Power can supply
replacements for converters from other
manufacturers, or offer custom solutions.
Please contact the factory for details.
Mechanical
Considerations
Installation
Although AVO75 series converters can be
mounted in any orientation, free air-flowing
must be taken. Normally power components
are always put at the end of the airflow path or
have the separate airflow paths. This can keep
other system equipment cooler and increase
component life spans.
AVO75 Series DC/DC Converter TRN
TEL: (86) 755-86010808 www.emersonnetworkpower.com.cn 30/32
Soldering
AVO75 series converters are compatible with
standard wave soldering techniques. When
wave soldering, the converter pins should be
preheated for 20 ~ 30 seconds at 110°C, and
wave soldered at 260°C for less than 10
seconds.
When hand soldering, the iron temperature
should be maintained at 425°C and applied to
the converter pins for less than 5 seconds.
Longer exposure can cause internal damage to
the converter. Cleaning can be performed with
cleaning solvent IPA or with water.
AVO75 Series DC/DC Converter TRN
TEL: (86) 755-86010808 www.emersonnetworkpower.com.cn 31/32
Mechanical Chart
(Top & pin side view)
57.9[2.28]
50.80[2.000]
TOP VIEW
Φ1.0
7.62[0.300]
1
2
3
See Note 2
±0.10
See note 3
Φ1.5
±0.10
8.5[0.34]
Φ2.0
±0.1
Device
Code Suffix
Pin Length Option
NONE
-4
-6
-8
L
TOLERANCES: XXmm=+/-0.5mm
X.XXmm=+/-0.25mm
4.8mm+/-0.5mm
3.8mm+/-0.5mm
2.8mm+/-0.25mm
5.8mm+/-0.5mm
22.9[0.90]
15.24[0.600]
15.24[0.600]
4
5
6
7
8
L
8.5[0.34]
Notes:
1, Un-dimensioned components are for visual reference only.
2, Pins 1~3, 5~7 are 1.0mm diameter with 2.0mm diameter standoff shoulders.
3. Pins 4, 8 are 1.5mm diameter with no standoff shoulders.
Pin No. Function Pin No. Function
1 +Vin 5 +Sense
2 CNT 6 Trim
3 -Vin 7 -Sense
4 +Vo 8 -Vo
AVO75 Series DC/DC Converter TRN
TEL: (86) 755-86010808 www.emersonnetworkpower.com.cn 32/32
Ordering Information
Ripple and noise
(mV pp)
Model number
Input
voltage
(V)
Output
voltage
(V)
Output
current
(A) Typ.
Efficiency
(%)
Typ.
AVO75-48S1V2 36~75 1.2 25 50 87
AVO75-48S1V5 36~75 1.5 25 55 88
AVO75-48S1V8 36~75 1.8 25 45 89
AVO75-48S2V5 36~75 2.5 25 50 90
AVO75-48S3V3 36~75 3.3 20 50 91
AVO75-48S05 36~75 5 15 55 92
AVO75-48S12 36~75 12 6.3 55 91
有毒有害物质或元素标识表
有毒有害物质或元素标识表有毒有害物质或元素标识表
有毒有害物质或元素标识表
有毒有害物质或元素
有毒有害物质或元素有毒有害物质或元素
有毒有害物质或元素
铅
铅铅
铅 汞
汞汞
汞 镉
镉镉
镉 六价铬
六价铬六价铬
六价铬 多溴联苯
多溴联苯多溴联苯
多溴联苯 多溴联苯醚
多溴联苯醚多溴联苯醚
多溴联苯醚
部件
部件部件
部件
名称
名称名称
名称 Pb Hg Cd Cr
6
＋
＋＋
＋
PBB PBDE
制成板 ○ ○ ○ ○ ○ ○
○：表示该有毒有害物质在该部件所有均质材料中的含量在 SJ/T-11363-2006 规定的限量要求以下。
×：表示该有毒有害物质至少在该部件的某一均质材料中的含量超出 SJ/T-11363-2006 规定的限量要求
艾默生网络能源有限公司一直致力于设计和制造环保的产品，我们会通过持续的研究来减少和消除产品中的有毒有害
物质。以下部件或应用中含有有毒有害物质是限于目前的技术水平无法实现可靠的替代或者没有成熟的解决方案：
1．焊料（含器件的高温焊料）中含有铅。
2．电子器件的玻璃中含有铅。
3．插针的铜合金中含有铅
适用范围：AVO75 系列
