CUI VPOL15A-5-SIP

rev.
page
1 of 12
date
08/2007
DESCRIPTION: point of load converter
PART NUMBER: VPOL15A-5-SIP
features
* industry standard pin out
* high efficiency to 94%
* 300 KHz switching frequency
* 3.0-5.5 VDC input range
* 0.9-3.63 VDC wide output range
* over temperature protection
* continuous short circuit protection
* remote on/off
* cost-efficient open frame design
* UL/C-UL60950 (E222736) certified
Content
1. INTRODUCTION
2. VPOL15A-5-SIP CONVERTER FEATURES
3. GENERAL DESCRIPTION
7. APPLI CATIONS
3.1 Electrical Description
7.3 Thermal Considerations
3.2 Thermal Packaging and Physical Design.
7.4 Power De-Rating Curves
4. TECHNICAL SPECIFICATIONS
5. MAIN FEATURES AND FUNCTI ONS
7.5 Efficiency vs Load Curves
5.1 Operating Temperature Range
7.7 Test Set-Up
5.2 Over-Temperature Protection (OTP)
7.8 Remote Sense Compensation
5.3 Output Voltage Adjustment
7.9 VPOL15A-5-SIP Series Output Voltage Adustment.
5.4 Safe Operating Area (SOA)
7.10 Output Ripple and Noise Measurement
5.5 Over Current Protection
7.11 Output Capacitance
5.6 Remote On/Off
8. MECHANICAL OUTLINE DIAGRAMS
5.7 UVLO (Under-Voltage Lockout)
8.1 VPOL15A-5-SIP Mechanical Outline Diagrams
7.1 Layout Design Challenges.
7.2 Convection Requirements for Cooling
7.6 Input Capacitance at the Power Module
6. SAFETY
6.1 Input Fusing and Safety Considerations.
7. APPLI CATIONS
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382
rev.
PART NUMBER: VPOL15A-5-SIP
page
2 of 12
date
08/2007
DESCRIPTION: point of load converter
The converter is also protected against over-temperature conditions. If
1. Introduction
the converter is overloaded or the ambient temperature gets too high,
the converter will shut down to protect the unit.
This application note describes the features and functions of V-Infinity’s
VPOL15A-5-SIP series of non-isolated dc-dc converters. These are
L1
Q1
+VIN
+VO
highly efficient, reliable and compact, high power density, single output
dc-dc converters. These “Point of Load” modules serve the needs
Q2
C1
specifically of the fixed and mobile telecommunications and computing
D1
C2
R sense
market, employing economical distributed power architectures. The
+SENSE
VPOL15A-5-SIP series provide precisely regulated output voltage range
from 0.9V to 3.63Vdc over a wide range of input voltage (Vi=3.0 –
COM
COM
5.5Vdc) and can operate over an ambient temperature range of –40°C
R1
to +85°C. Ultra-high efficiency operation is achieved through the use of
synchronous rectification and drive control techniques.
PWM IC
ON/OFF
R trim
TRIM
ERR AMP
The modules are fully protected against short circuit and over-
R2
temperature conditions. V-Infinity’s world class automated
manufacturing methods, together with an extensive testing and
Figure 1. Electrical Block Diagram
qualification program, ensure that all VPOL15A-5-SIP series converters
are extremely reliable.
2. VPOL15A-5-SIP Converter Features
High efficiency topology, typically 94% at 3.3Vdc
Industry standard footprint
Wide ambient temperature range, -40°C to +85°C
Cost efficient open frame design
Programmable output voltage via external resistor from 0.9 to
3.63Vdc
3.2 Thermal Packaging and Physical Design.
The VPOL15A-5-SIP series uses a multi-layer FR4 PCB construction.
All surface mount power components are placed on one side of the
PCB, and all low-power control components are placed on the other
side. Thus, the Heat dissipation of the power components is optimized,
ensuring that control components are not thermally stressed. The
converter is an open-frame product and has no case or case pin. The
open-frame design has several advantages over encapsulated closed
devices. Among these advantages are:
No minimum load requirement (Stable at all loads)
Efficient Thermal Management: the heat is removed from the
Remote On/Off
heat generating components without heating more sensitive, small
Remote sense compensation
signal control components.
Fixed switching frequency
Environmental: Lead free open-frame converters are more easily
Continuous short-circuit protection and over current protection
re-cycled.
Over-temperature protection (OTP)
Cost Efficient: No encapsulation. Cost efficient open-frame
Monotonic Startup with pre-bias at the output.
construction.
UL/IEC/EN60950 Certified.
3. General Description
Reliable: Efficient cooling provided by open frame construction
offers high reliability and easy diagnostics.
3.1 Electrical Description
A block diagram of the VPOL15A-5-SIP Series converter is shown in
Figure 1. Extremely high efficiency power conversion is achieved
through the use of synchronous rectification and drive techniques.
Essentially, the powerful VPOL15A-5-SIP series topology is based on a
non-isolated synchronous buck converter. The control loop is optimized
for unconditional stability, fast transient response and a very tight line
and load regulation. In a typical pre-bias application the VPOL15A-5SIP series converters do not draw any reverse current at start-up. The
output voltage can be adjusted from 0.9 to 3.63vdc, using the TRIM pin
with a external resistor. The converter can be shut down via a remote
on/off input that is referenced to ground. This input is compatible with
popular logic devices; a 'positive' logic input is supplied as standard.
Positive logic implies that the converter is enabled if the remote on/off
input is high (or floating), and disabled if it is low.
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382
rev.
page
3 of 12
date
08/2007
DESCRIPTION: point of load converter
PART NUMBER: VPOL15A-5-SIP
4. Technical Specifications
(All specifications are typical at nominal input, full load at 25°C unless otherwise noted.)
PARAMETER
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Continuous
Operating Temp erature
See Thermal Considerations Section
NOTES and CONDITIONS
Device
Min.
Typical Max.
Units
ALL
0
5.8
Vdc
ALL
-40
+85
°C
ALL
-55
+125
°C
ALL
3.0
4.5
5.5
5.5
Vdc
Storage Temperature
INPUT CHARACTERISTICS
Operating Input Voltage
Vo=2.7V
Vo=3.0V
Input Under-Voltage Lockout
Turn-On Voltage Threshold
Turn-Off Voltage Threshold
Lockout Hysteresis Voltage
Maximum Input Current
Vin=3.0 to 5.5Vdc , Io=Io,max.
No-Load Input Current
Vo=1.0V
Vo=1.2V
Vo=1.5V
Vo=1.8V
Vo=2.0V
Vo=2.5V
Vo=3.3V
Off Converter Input Current
Shutdown input idle current
ALL
ALL
ALL
ALL
5.0
5.0
Vdc
Vdc
Vdc
2.8
2.7
0.1
15.5
60
60
60
70
70
70
70
ALL
ALL
5
A
mA
10
mA
0.4
As
Inrush Current (I t)
ALL
Input Reflected-Ripple Current
P-P thru 1uH inductor, 5Hz to 20MHz
ALL
150
mA
Output Voltage Set Point
Vin=Nominal Vin , Io=Io.max, Tc=25°C
ALL
-1.5% Vo,set +1.5%
Vdc
Output Voltage Trim Adjustment Range
Selected by an external resistor
ALL
Io=Io.min to Io.max
ALL
VPOL15A-5-SIP
2
2
OUTPUT CHARACTERISTIC
0.9
3.63
Vdc
-0.5
+0.5
%
-0.2
-0.4
+0.2
+0.4
%
±0.03
%/°C
Output Voltage Regulation
Load Regulation
Line Regulation
Vin=low line to high line
Tempera ture Coefficient
Ta=-40°C to 85°C
Output Voltage Ripple and Noise
5Hz to 20MHz bandwidth
ALL
Peak-to-Peak
Full Load, 1uF ceramic and 10uF tantalum
ALL
50
mV
RMS
Full Load, 1uF ceramic and 10uF tantalum
ALL
20
mV
Low ESR
ALL
10000
uF
ALL
0
Output DC Current-Limit Inception
Output Voltage =90% Nominal Output Voltage
ALL
18
Shout Circuit Protection
Continuous with Hiccup Mode
External Capacitive Load
Operating Output Current Range
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382
22
15
A
28
A
rev.
4 of 12
date
08/2007
DESCRIPTION: point of load converter
PART NUMBER: VPOL15A-5-SIP
PARAMETER
DYNAMIC CHARACTERISTICS
page
NOTES and CONDITIONS
Device
Min.
Typical Max.
Units
Output Voltage Transient Response
Error Brand
25% Step Load Change, di/dt=0.1A/us
ALL
Setting Time (within 1% Vout nominal)
25% Step Load Change, di/dt=0.1A/us
ALL
±5
%
200
us
EFFICIENCY
100% Load
Vo=1.0V
Vo=1.2V
Vo=1.5V
Vo=1.8V
Vo=2.0V
Vo=2.5V
Vo=3.3V
82
84
87
88
89
92
94
ALL
%
ISOLATION CHARACTERISTICS
Input to Output
Non-isolation
0
Vdc
FEATURE CHARACTERISTICS
Switching Frequency
On/Off Control, Positive Logic Remote On/Off
Logic Low (Module Off)
Logic High (Module On)
On/Off Control, Negative Logic Remote On/Off
Logic Low (Module On)
Logic High (Module Off)
On/Off Current (for both remote on/off logic)
Leakage Current (for both remote on/off logic)
Turn-On Delay and Rise Time
Turn-On Delay Time, From On/Off Control
Turn-On Delay Time, From Input
Output Voltage Rise Time
Over Temperature Protection
300
ALL
0
0.4
Vin
Vdc
Vdc
ALL
0
2.8
0.4
Vin
Vdc
Vdc
1
1
mA
mA
or Open Circuit
or Open Circuit
KHz
Ion/off at Von/off =0.0V
Logic High, Von/off=5V
Von/off to 10%Vo,set
Vin,min. to 10%Vo,set
10%Vo,set to 90%Vo,set
1
1
3.5
120
Io=100%of Io.max;Ta=25 °C per MIL-HDBK-217F
1.5
6.8
6
ms
ms
ms
°C
GENERAL SPECIFICATIONS
MTBF
Weight
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382
M hours
grams
rev.
page
5 of 12
date
08/2007
DESCRIPTION: point of load converter
PART NUMBER: VPOL15A-5-SIP
current protection. The unit operates normally once the fault condition is
5. Main Features and Functions
removed. The power module will supply up to 150% of rated current. In
the event of an over current converter will go into a hiccup mode
5.1 Operating Temperature Range
protection.
V-Infinity’s VPOL15A-5-SIP series converters highly efficient converter
5.6 Remote On/Off
design has resulted in its ability to operate over a wide ambient
The remote on/off input feature of the converter allows external circuitry
temperature environment ( -40°C to 85°C). Due consideration must be
to turn the converter on or off. Active-high remote on/off is available as
given to the de-rating curves when ascertaining maximum power that can
standard. The VPOL15A-5-SIP series converters are turned on if the
be drawn from the converter. The maximum power drawn is influenced
remote on/off pin is high, or left open or floating. Setting the pin low will
by a number of factors, such as:
turn the converter ‘Off’. The signal level of the remote on/off input is
defined with respect to ground. If not using the remote on/off pin, leave
Input voltage range.
the pin open (module will be on). The part number suffix “N” is Negative
Output load current.
Air velocity (forced or natural convection).
Mounting orientation of converter PCB with respect to the airflow.
Motherboard PCB design, especially ground and power planes.
These can be effective heat sinks for the converter.
remote on/off version. The unit is guaranteed off over the full temperature
range if this voltage level exceeds 2.8Vdc. The converters are turned on
If the on/off pin input is low or left open. The recommended VPOL15A-5SIP remote on/off drive circuit is shown as figure 3, 4.
5.2 Over-Temperature Protection (OTP)
The VPOL15A-5-SIP series converters are equipped with non-latching
over-temperature protection. A te mperature sensor monitors the
temperature of the hot spot (typically, top switch). If the temperature
exceeds a threshold of 120°C (typical) the converter will shut down,
disabling the output. When the temperature has decreased the converter
will automatically restart.
The over-temperature condition can be induced by a variety of reasons
such as external overload condition or a system fan failure.
5.3 Output Voltage Adjustment
Section 7.9 describes in detail as to how to trim the output voltage with
respect to its set point. The output voltage on all models is trimmable in
the range 0.9 – 3.63Vdc.
5.4 Safe Operating Area (SOA)
Figure 2 provides a graphical representation of the safe operating area
(SOA) of the converter. This representation assumes ambient operating
conditions such as airflow are met as per thermal guidelines provided in
Sections 7.2 and 7.3.
Vo
VOLTAGE (V)
Vo,nom
Safe Operating Area
Io,max Io,CL Io
CURRENT (A)
Figure 2. Maximum Output Current Safe Operating Area
5.5 Over Current Protection
All different voltage models have a full continuous short-circuit protection.
The unit will auto recover once the short circuit is removed. To provide
protection in a fault condition, the unit is equipped with internal over-
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382
rev.
+Vin
+Vo
date
08/2007
7. Applications
7.1 Layout Design Challenges.
Remote ON/OFF
In optimizing thermal design the PCB is utilized as a heat sink. Also
Q1
VPOL15A-5-SIP
Common
6 of 12
DESCRIPTION: point of load converter
PART NUMBER: VPOL15A-5-SIP
ON/OFF
Control
page
Common
some heat is transferred from the VPOL15A-5-SIP module to the main
board through connecting pins. The system designer or the end user
must ensure that other components and metal in the vicinity of the
VPOL15A-5-SIP series meet the spacing requirements to which the
system is approved.
Figure 3. Positive Remote On/Off Input Drive Circuit
Low resistance and low inductance PCB layout traces are the norm and
should be used where possible. Due consideration must also be given to
+Vin
+Vo
proper low impedance tracks between power module, input and output
grounds. The recommended VPOL15A-5-SIP footprint is shown as figure
Q1
VPOL15A-5-SIP
ON/OFF
Control
5.
Remote ON/OFF
0.29(7.4)
Common
Common
Figure 4. Negative Remote On/Off Input Drive Circuit
5.7 UVLO (Under-Voltage Lockout)
The voltage on the Vcc pin determines the start of the operation of the
LAYOUT PATTERN
TOP VIEW
All Dimmension In Inches(mm)
Tole rance :
.XX= ±0.04
.XXX= ±0.010
0.33(8.4)
1.1mm PLATED THROUGH HOLE
1.6mm PAD SIZE
Figure 5. Recommended VPOL15A-5-SIP Footprint
Converter. When the input Vcc rises and exceeds about 2.8V the
converter initiates a soft start. The UVLO function in the converter has a
hysteresis (about 100mV) built in to provide noise immunity at start-up.
6. Safety
6.1 Input Fusing and Safety Considerations.
Agency Approvals: The power supply shall be submitted to and receive
formal approval from the following test agencies.
1.The power supply shall be approved by a nationally recognized testing
rd
laboratory to UL/CSA 60950 3 Edition (North America) and EN60950
(International)
2. CB Certificate from an internationally recognized test house in
accordance with EN 60950.
The VPOL15A-5-SIP series converters do not have an internal fuse.
However, to achieve maximum safety and system protection, always
use an input line fuse. The safety agencies require a time-delay fuse
with a maximum rating of 20A.
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382
rev.
page
7 of 12
date
08/2007
DESCRIPTION: point of load converter
PART NUMBER: VPOL15A-5-SIP
7.2 Convection Requirements for Cooling
Pin6
Inductor Pin
To predict the ap proximate cooling needed for the module, refer to the
Power De-rating curves in Figures 8 to 10 . These de-rating curves are
approximations of the ambient temperatures and airflows required to
keep the power module temperature below its maximum rating. Once the
module is assembled in the actual system, the module’s temperature
should be checked as shown in Figure 6 to ensure it does not exceed
110°C.
Proper cooling can be verified by measuring the power module’s
Airflow
temperature at Q1-pin 6 and Q2-pin 6 as shown in Figure 7.
W ind
Tunnel
Figure 7. Temperature Measurement Location for
VPOL15A-5-SIP
25.4(1.0)
Bakelite
7.3 Thermal Considerations
The power module operates in a variety of thermal environments;
however, sufficient cooling should be provided to help ensure reliable
Power Module
operation of the unit. Heat is removed by conduction, convection, and
radiation to the surrounding environment. The thermal data presented is
based on measurements taken in a set-up as shown in Figure 6. Figures
8 to 10 represent the test data. Note that the airflow is parallel to the long
axis of the module as shown in Figure 6 for the VPOL15A-5-SIP.
76.2(3.0)
The temperature at either location should not exceed 110 °C. The output
power of the module should not exceed the rated power for the module
(VO, set x IO, max). The SMT15 thermal data presented is based on
Thermocuple Location
for measuring
ambient temperature
and airflow
measurements taken in a wind tunnel. The test setup shown in Fig 6 and
EUT need to solder on 33mm x 40.38mm(1.300'' x 1.59'') test pcb. Note
that airflow is parallel to the long axis of the module as shown in Fig 6.
12.7(0.5)
Air
flow
Note : Dimensions are in millimeters and (inches)
Figure 6. Thermal Test Setup
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382
rev.
TYPICAL POWER DERATING FOR 5 Vin 3.3 Vout
SIP15-05S33A Derating Curve
16
14
Output Current(A)
12
10
0LFM
6
100LFM
4
200LFM
2
0
0
10
20
30
40
50
60
70
Ambient Temperature( oC)
8 of 12
date
08/2007
DESCRIPTION: point of load converter
PART NUMBER: VPOL15A-5-SIP
8
page
80
90
100
NOTE:
1. specific input & output derating curves available, please
contact V-Infinity for detail
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382
rev.
page
9 of 12
date
08/2007
DESCRIPTION: point of load converter
PART NUMBER: VPOL15A-5-SIP
7.5 Efficiency vs Load Curves (Fig. 10)
VPOL15A-5-SIP Vo=2.5V (Eff Vs Io)
VPOL15A-5-SIP Vo=3.3V (Eff Vs Io)
95%
95%
90%
85%
4.5V
5.0V
5.5V
80%
75%
Efficincy (%)
100%
Efficincy (%)
100%
90%
85%
3.0V
5.0V
5.5V
80%
75%
70%
70%
0
1
2
3
4
5
6
7
8
0
9 10 11 12 13 14 15
1
2
3
4
VPOL15A-5-SIP Vo=1.8V (Eff Vs Io)
95%
90%
85%
3.0V
5.0V
5.5V
Efficincy (%)
95%
Efficincy (%)
100%
75%
7
8
9 10 11 12 13 14 15
90%
85%
3.0V
5.0V
5.5V
80%
75%
70%
70%
0
1
2
3
4
5
6
7
8
0
9 10 11 12 13 14 15
1
2
3
4
VPOL15A-5-SIP Vo=1.2V (Eff Vs Io)
95%
95%
90%
90%
85%
80%
3.0V
5.0V
5.5V
65%
Efficincy (%)
100%
70%
6
7
8
9 10 11 12 13 14 15
VPOL15A-5-SIP Vo=1.0V (Eff Vs Io)
100%
75%
5
Current Load (A)
Current Load (A)
Efficincy (%)
6
VPOL15A-5-SIP Vo=1.5V (Eff Vs Io)
100%
80%
5
Current Load (A)
Current Load (A)
85%
80%
3.0V
5.0V
5.5V
75%
70%
65%
60%
60%
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15
Current Load (A)
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15
Current Load (A)
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382
rev.
page
10 of 12
date
08/2007
DESCRIPTION: point of load converter
PART NUMBER: VPOL15A-5-SIP
7.6 Input Capacitance at the Power Module
The VPOL15A-5-SIP converters must be connected to a low AC source
The value of line regulation is defined as:
impedance. To a void problems with loop stability source inductance
should be low. Also, the input capacitors should be placed close to the
Line.reg =
converter input pins to de-couple distribution inductance. However, the
external input capacitors are chosen for suitable ripple handling
Where: VHL is the output voltage of maximum input voltage at full load.
capability. Low ESR polymers are a good choice. They have high
VLL is the output voltage of minimum input voltage at full load.
capacitance, high ripple rating and low ESR (typical <20mohm).
Current Meter
Electrolytic capacitors should be avoided. Circuit as shown in Figure 11
A
A
+Vo
+Sense
Power +
of 1uH. Current is measured at the input of the module.
Supply
+
Voltage
V 100uF
Meter
Tant.
VPOL15A-5-SIP
Common
To Oscilloscope
Voltage Meter
V
R-Load
Common
Figure 12. VPOL15A-5-SIP Series Test Setup
L1
+Vin
1uH
Power
Current Meter
+Vin
represents typical measurement methods for ripple current. Input
reflected-ripple current is measured with a simulated source Inductance
VHL _ VLL
x 100%
VLL
7.8 Remote Sense Compensation
Remote Sense regulates the output voltage at the point of load. It
+
2*100uF
Tantalum
Supply
VPOL15A-5-SIP
220uF
ESR<0.1ohm
minimizes the effects of distribution losses such as drops across the
connecting pin and PCB tracks (see Figure 13). Please note however,
the maximum drop from the output pin to the point of load should not
exceed 500mV for remote compensation to work.
Common
The amount of power delivered by the module is defined as the output
voltage multiplied by the output current (VO x IO).
When using “trim up”, the output voltage of the module will increase
Figure 11. Input Reflected-Ripple Test Setup
which, if the same output current is maintained, increases the power
7.7 Test Set-Up
output by the module. Make sure that the maximum output power of the
The basic test set-up to measure parameters such as efficiency and
module remains at or below the maximum rated power.
load regulation is shown in Figure 12. Things to note are that this
When the remote sense feature is not being used, leave sense pin
converter is non-isolated, as such the input and output share a common
disconnected.
ground. These grounds should be connected together via low
impedance ground plane in the application circuit. When testing a
Figure 13. Circuit Configuration for Remote Sense Operation
converter on a bench set-up, ensure that -Vin and -Vo are connected
together via a low impedance short to ensure proper efficiency and load
regulation measurements are being made. When testing the V-Infinity’s
VPOL15A-5-SIP series under any transient conditions please ensure
Distribution Losses
that the transient response of the source is sufficient to power the
equipment under test. We can calculate the
+Vin
Efficiency
+Sense
Load regulation and line regulation.
The value of efficiency is defined as:
ç=
Where:
Vo x Io
x 100%
Vin x Iin
+Vo
VPOL15A-5-SIP
Common
Common
R-Load
Distribution Losses
Vo is output voltage,
Io is output current,
Vin is input voltage,
Iin is input current.
The value of load regulation is defined as:
Load .reg =
Where:
VFL _ VNL
x 100%
VNL
VFL is the output voltage at full load
VNL is the output voltage at no load
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382
rev.
page
11 of 12
date
08/2007
DESCRIPTION: point of load converter
PART NUMBER: VPOL15A-5-SIP
7.9 VPOL15A-5-SIP Series Output Voltage Adustment.
7.10 Output Ripple and Noise Measurement
The output voltage of the VPOL15A-5-SIP can be adjusted in the range
The test set-up for noise and ripple measurements is shown in Figure
0.9V to 3.63V by connecting a single resistor on the motherboard
15. a coaxial cable with a 50ohm termination was used to prevent
(shown as Rtrim) in Figure 14. When trim resistor is not connected the
impedance mismatch reflections disturbing the noise readings at higher
output voltage defaults to 0.75V
frequencies.
+Vin
+Vo
+Vin
Trim
R-Load
VPOL15A-5-SIP
VPOL15A-5-SIP
10uF
Tant.
1uF
Ceramic
R-Load
Test Jack
R trim-up
Common
+Vo
Common
Common
Common
Figure 15. Output Voltage Ripple and Noise Measurement Set-Up
Figure 14. Trim-up Voltage Setup
7.11 Output Capacitance
The value of Rtrim-up defined as:
V-Infinity’s VPOL15A-5-SIP series converters provide unconditional
21070 _
5110 )
Rtrim = ( _
Vo 0.75
Where:
Rtrim-up is the external resistor in ohm,
Vo is the desired output voltage
To give an exa mple of the above calculation, to set a voltage of 3.3Vdc,
stability with or without external capacitors. For good transient response
low ESR output capacitors should be located close to the point of load.
For high current applications point has already been made in layout
considerations for low resistance and low inductance tracks.
Output capacitors with its associated ESR values have an impact on
loop stability and bandwidth. V-Infinity’s converters are designed to
work with load capacitance up-to 10,000uF. It is rec ommended that any
Rtrim is given by:
additional capacitance, typically 1,000uF and low ESR (<20mohm), be
Rtrim = (
21070 _
5110 )
Vo _ 0.75
connected close to the point of load and outside the remote
compensation point.
Rtrim = 3153 ohm
For various output values various resistors are calculated and provided
in Table 3 for co nvenience.
Vo,set (V)
0.90
1.00
1.20
1.50
1.80
2.00
2.50
3.30
3.63
Rtrim (Kohm)
135.36
79.17
41.71
22.98
14.96
11.75
6.93
3.15
2.20
Table 3 – Trim Resistor Values
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382
rev.
page
12 of 12
date
08/2007
DESCRIPTION: point of load converter
PART NUMBER: VPOL15A-5-SIP
8. Mechanical Outline Diagrams
8.1 VPOL15A-5-SIP Mechanical Outline Diagrams
Dimensions are in millimeters and inches
Tolerance: x.xx ±0.02 in. (0.5mm) , x.xxx ±0.010 in. (0.25 mm) unless
otherwise noted
SIZE VPOL15A-5-SIP
2.00(50.8)
0.335(8.50)max.
0.23(5.8)
6 7 8 9 10 11
1 2 3 4 5
0.139(3.52)
0.500(12.70)
0.100(2.54)
0.025(0.64)
1.000(25.40)
0.400(10.20)
0.050(1.30)
0.28(7.1)
0.025(0.64)
PIN CONNECTION
Pin FUNCTION
+Output
1
+Output
2
3
+Sense
+Output
4
5
6
7
8
9
10
11
Common
Common
+V Input
+V Input
No Pin
Trim
On/Off Control
Figure 16 VPOL15A-5-SIP Mechanical Outline Diagram
20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382