POWERINT LNK625DG

LNK623-626
LinkSwitch-CV Family
®
Energy-Efficient, Off-line Switcher with Accurate
Primary-side Constant-Voltage (CV) Control
Product Highlights
*
Dramatically Simplifies CV Converters
• Eliminates optocoupler and all secondary CV control circuitry
• Eliminates bias winding supply – IC is self biasing
Advanced Performance Features
• Compensates for external component temperature variations
• Very tight IC parameter tolerances using proprietary trimming
technology
• Continuous and/or discontinuous mode operation for design
flexibility
• Frequency jittering greatly reduces EMI filter cost
• Even tighter output tolerances achievable with external resistor
selection/trimming
Wide Range
HV DC Input
FB
LinkSwitch-CV
BP
S
PI-5195-080808
(a) Typical Application Schematic
Advanced Protection/Safety Features
• Auto-restart protection reduces delivered power by >95% for
output short circuit and all control loop faults (open and shorted
components)
• Hysteretic thermal shutdown – automatic recovery reduces
power supply returns from the field
• Meets HV creepage requirements between Drain and all other
pins, both on the PCB and at the package
EcoSmart ® – Energy Efficient
• No-load consumption <200 mW at 230 VAC and down to
below 70 mW with optional external bias
• Easily meets all global energy efficiency regulations with no
added components
• ON/OFF control provides constant efficiency down to very light
loads – ideal for mandatory EISA and ENERGY STAR 2.0
regulations
• No primary or secondary current sense resistors – maximizes
efficiency
D
±5%
VO
art
est
-R
uto
A
PI-5196-080408
IO
(b) Output Characteristic
Figure 1.
Typical Application Schematic (a) and Output Characteristic Envelope (b).
*Optional with LNK623-624PG/DG. (see Key Application Considerations section for
clamp and other external circuit design considerations).
Output Power Table
230 VAC ±15%
Product3
85-265 VAC
Adapter1
Peak or
Open
Frame2
Adapter1
Peak or
Open
Frame2
9W
5.0 W
6W
6.5 W
Green Package
• Halogen free and RoHS compliant package
LNK623PG/DG
6.5 W
LNK624PG/DG
7W
11 W
5.5 W
Applications
• DVD/STB
• Adapters
• Standby and auxiliary supplies
• Home appliances, white goods and consumer electronics
• Industrial controls
LNK625PG/DG
8W
13.5 W
6.5 W
8W
LNK626PG/DG
10.5 W
17 W
8.5 W
10 W
Description
The LinkSwitch-CV dramatically simplifies low power, constant
voltage (CV) converter design through a revolutionary control
technique which eliminates the need for both an optocoupler and
secondary CV control circuitry while providing very tight output
voltage regulation. The combination of proprietary IC trimming
and E-Shield™ transformer construction techniques enables
Clampless™ designs with the LinkSwitch-CV LNK623/4.
www.powerint.com
Table 1. Output Power Table. Based on 5 V Output.
Notes:
1. Minimum continuous power in a typical non-ventilated enclosed adapter
measured at +50 °C ambient.
2. Maximum practical continuous power in an open frame design with adequate
heatsinking, measured at 50 °C ambient (see Key Application Considerations
section for more information).
3. Packages: P: DIP-8C, D: SO-8C.
LinkSwitch-CV provides excellent cross-regulation for multipleoutput flyback applications such as DVDs and STBs. A 700 V
power MOSFET and ON/OFF control state machine, self-biasing,
frequency jittering, cycle-by-cycle current limit, and hysteretic
thermal shutdown circuitry are all incorporated onto one IC.
September 2009
LNK623-626
DRAIN
(D)
REGULATOR
6V
BYPASS
(BP)
+
+
FEEDBACK
(FB)
VTH
D
Q
FB
OUT
STATE
MACHINE
-
6V
5V
Reset
-
VILIMIT
tSAMPLE-OUT
ILIM
Drive
DCMAX
6.5 V
FAULT
Auto-Restart
Open-Loop
FB
THERMAL
SHUTDOWN
DCMAX
SAMPLE
DELAY
tSAMPLE-OUT
OSCILLATOR
SOURCE
(S)
+
SOURCE
(S)
ILIM
-
VILIMIT
Current Limit
Comparator
LEADING
EDGE
BLANKING
PI-5197-110408
Figure 2
Functional Block Diagram.
Pin Functional Description
DRAIN (D) Pin:
This pin is the power MOSFET drain connection. It provides
internal operating current for both start-up and steady-state
operation.
BYPASS (BP) Pin:
This pin is the connection point for an external bypass capacitor
for the internally generated 6 V supply.
FEEDBACK (FB) Pin:
During normal operation, switching of the power MOSFET is
controlled by this pin. This pin senses the AC voltage on the
bias winding. This control input regulates the output voltage
based on the flyback voltage of the bias winding.
SOURCE (S) Pin:
This pin is internally connected to the output MOSFET source
for high voltage power and control circuit common returns.
P Package (DIP-8C)
FB
1
8
S
BP
2
7
S
6
D
5
4
3a
D Package (SO-8C)
FB
1
8
S
BP
2
7
S
S
S
D
4
6
S
5
S
3b
PI-5198-071608
Figure 3.
Pin Configuration.
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www.powerint.com
LNK623-626
LinkSwitch-CV Functional Description
The LinkSwitch-CV combines a high voltage power MOSFET
switch with a power supply controller in one device. Similar to
the LinkSwitch-LP and TinySwitch-III it uses ON/OFF control to
regulate the output voltage. The LinkSwitch-CV controller
consists of an oscillator, feedback (sense and logic) circuit, 6 V
regulator, over-temperature protection, frequency jittering,
current limit circuit, leading-edge blanking, and ON/OFF state
machine for CV control.
Constant Voltage (CV) Operation
The controller regulates the feedback pin voltage to remain at
VFBth using an ON/OFF state-machine. The feedback pin
voltage is sampled 2.5 μs after the turn-off of the high voltage
switch. At light loads the current limit is also reduced to
decrease the transformer flux density.
Auto-Restart and Open-Loop Protection
In the event of a fault condition such as an output short or an
open loop condition the LinkSwitch-CV enters into an
appropriate protection mode as described below.
In the event the feedback pin voltage during the Flyback period
falls below VFBth-0.3 V before the feedback pin sampling delay
(~2.5 μs) for a duration in excess of 200 ms (auto-restart ontime (t AR-ON) the converter enters into Auto-restart, wherein the
power MOSFET is disabled for 2.5 seconds (~8% Auto-Restart
duty cycle). The auto-restart alternately enables and disables
the switching of the power MOSFET until the fault condition is
removed.
In addition to the conditions for auto-restart described above, if
the sensed feedback pin current during the Forward period of
the conduction cycle (switch “on” time) falls below 120 μA, the
converter annunciates this as an open-loop condition (top
resistor in potential divider is open or missing) and reduces the
Auto-restart time from 200 ms to approximately 6 clock cycles
(90 μs), whilst keeping the disable period of 2.5 seconds. This
effectively reduces the Auto-Restart duty cycle to less than 0.01%.
Over-Temperature Protection
The thermal shutdown circuitry senses the die temperature. The
threshold is set at 142 °C typical with a 60 °C hysteresis. When
the die temperature rises above this threshold (142 °C) the
power MOSFET is disabled and remains disabled until the die
temperature falls by 60 °C, at which point the MOSFET is
re-enabled.
Current Limit
The current limit circuit senses the current in the power
MOSFET. When this current exceeds the internal threshold
(ILIMIT ), the power MOSFET is turned off for the remainder of that
cycle. The leading edge blanking circuit inhibits the current limit
comparator for a short time (tLEB) after the power MOSFET is
turned on. This leading edge blanking time has been set so that
current spikes caused by capacitance and rectifier reverse
recovery time will not cause premature termination of the
MOSFET conduction.
6.0 V Regulator
The 6 V regulator charges the bypass capacitor connected to the
BYPASS pin to 6 V by drawing a current from the voltage on the
DRAIN, whenever the MOSFET is off. The BYPASS pin is the
internal supply voltage node. When the MOSFET is on, the
device runs off of the energy stored in the bypass capacitor.
Extremely low power consumption of the internal circuitry allows
the LinkSwitch-CV to operate continuously from the current
drawn from the DRAIN pin. A bypass capacitor value of 1 μF is
sufficient for both high frequency decoupling and energy storage.
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Rev. E 09/09
LNK623-626
Applications Example
L1
3.5 × 7.6 mm
Ferrite Bead
D1
FR106
1
R1
5.1 k7
1/8 W
D2
FR106
3
C3
820 pF
1 kV
VR1
1N5272B
L
F1
3.15 A
C1
22 MF
400 V
85 - 265
VAC
C2
22 MF
400 V
T1
EEL19
D8
UF4003
6
12 V, 0.1 A
C9
47 MF
25 V
7
D7 SB540
11
8,9,10
R2
390 7
12
D5
1N4007
5
C13
270 pF
R10
47 7
R8
24 k7
1/8 W
L3
10 MH
C8
1000 MF
10 V
C11
47 MF
50 V
D9
UF4003
5 V, 1.7 A
R7
510 7
1/8 W
C10
470 MF
10 V
R9
39 k7
1/8 W
RTN
-22 V, 15 mA
D6
1N4148
4
N
RT1
10 7
RV1
275 V
2
D3
1N4007
D4
1N4007
D
LinkSwitch-CV
U1
LNK626PG
R3
6.34 k7
1%
FB
BP
R4
6.2 k7
S
L2
680 uH
C4
1 MF
50 V
R5
47 k7
1/8 W
R6
4.02 k7
C5
1%
680 pF
50 V
C6
10 MF
50 V
PI-5205-102208
Figure 4.
7 W (10 W peak) Multiple Output Flyback Converter for DVD Applications with Primary Sensed Feedback.
Circuit Description
This circuit is configured as a three output, primary-side
regulated flyback power supply utilizing the LNK626PG. It can
deliver 7 W continuously and 10 W peak (thermally limited) from
an universal input voltage range (85 – 265 VAC). Efficiency is
>67% at 115 VAC/230 VAC and no-load input power is
<140 mW at 230 VAC.
Input Filter
AC input power is rectified by diodes D1 through D4. The
rectified DC is filtered by the bulk storage capacitors C1 and
C2. Inductor L1, L2, C1 and C2 form a pi (π) filter, which
attenuates conducted differential-mode EMI noise. This
configuration along with Power Integrations transformer
E-shield™ technology allow this design to meet EMI standard
EN55022 class B with good margin without requiring a
Y capacitor. Fuse F1 provides protection against catastrophic
failure. Negative temperature coefficient thermistor RT1 limits
the inrush current when AC is first applied to below the
maximum rating of diodes D1 through D4. Metal oxide varistor
RV1 clamps the AC input during differential line transients,
protecting the input components and maintaining the peak
drain voltage of U1 below its 700 V BVDSS rating. For differential
surge levels at or below 2 kV this component may be omitted.
LNK626 Primary
The LNK626PG device (U1) incorporates the power switching
device, oscillator, CV control engine, startup, and protection
functions. The integrated 700 V MOSFET provides a large drain
voltage margin in universal input AC applications, increasing
reliability and also reducing the output diode voltage stress by
allowing a greater transformer turns ratio. The device can be
completely self-powered from the BYPASS pin and decoupling
capacitor C4. In this design a bias circuit (D6, C6 and R4) was
added to reduce no load input power below 140 mW.
The rectified and filtered input voltage is applied to one side of
the primary winding of T1. The other side of the transformer’s
primary winding is driven by the integrated MOSFET in U1. The
leakage inductance drain voltage spike is limited by the clamp
circuit D5, R1, R2, C3 and VR1. The zener bleed clamp
arrangement was selected for lowest no-load input power but in
applications where higher no-load input power is acceptable
VR1 may be omitted and the value of R1 increased to form a
standard RCD clamp.
Output Rectification
The secondaries of the transformer are rectified by D7, D8 and
D9. A Schottky barrier type was used for the main 5 V output
for higher efficiency. The +12 V and -22 V outputs use an
ultrafast rectifier diode. The main output is post filtered by L3
and C10 to remove switching frequency ripple. Resistors R7,
R8 and R9 provide a preload to maintain the output voltages
within their respective limits when unloaded. To reduce high
frequency ringing and associated radiated EMI an RC snubber
formed by R10 and C13 was added across D7.
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LNK623-626
Output Regulation
The LNK626 regulates the output using ON/OFF control,
enabling or disabling switching cycles based on the sampled
voltage on the FEEDBACK pin. The output voltage is sensed
using a primary referenced winding on transformer T1 eliminating
the need for an optocoupler and a secondary sense circuit. The
resistor divider formed by R3 and R6 feeds the winding voltage
into U1. Standard 1% resistor values were used to center the
nominal output voltages. Resistor R5 and C5 reduce pulse
grouping by creating an offset voltage that is proportional to the
number of consecutive enabled switching cycles.
Key Application Considerations
Output Power Table
The data sheet maximum output power table (Table 1)
represents the maximum practical continuous output power
level that can be obtained in a Flyback converter under the
following assumed conditions:
1. The minimum DC input voltage is 100 V or higher at 90 VAC
input. The value of the input capacitance should be large
enough to meet these criteria for AC input designs.
2. Secondary output of 5 V with a Schottky rectifier diode.
3. Assumed efficiency of 80%.
4. Continuous conduction mode operation (KP = 0.4).
5. Reflected Output Voltage (VOR) of 110 V.
6. The part is board mounted with SOURCE pins soldered to a
sufficient area of copper to keep the SOURCE pin temperature at or below 110 °C for P package and 100 °C for D
packaged devices.
7. Ambient temperature of 50 °C for open frame designs and
an internal enclosure temperature of 60 °C for adapter
designs.
Note: Higher output power are achievable if the efficiency is
higher than 80%, typically for high output voltage designs.
Bypass Pin Capacitor
A 1 μF Bypass pin capacitor (C4) is recommended. The
capacitor voltage rating should be equal to or greater than
6.8 V. The capacitor’s dielectric material is not important. The
capacitor must be physically located close to the
LinkSwitch-CV BYPASS pin.
Circuit board layout
LinkSwitch-CV is a highly integrated power supply solution that
integrates on a single die, both the controller and the high
voltage MOSFET. The presence of high switching currents and
voltages together with analog signals makes it especially
important to follow good PCB design practice to ensure stable
and trouble free operation of the power supply.
When designing a board for the LinkSwitch-CV based power
supply, it is important to follow the following guidelines:
Single Point Grounding
Use a single point (Kelvin) connection at the negative terminal of
the input filter capacitor for the LinkSwitch-CV SOURCE pin and
bias winding return. This improves surge capabilities by
returning surge currents from the bias winding directly to the
input filter capacitor.
Bypass Capacitor
The BYPASS pin capacitor should be located as close as
possible to the SOURCE and BYPASS pins.
Feedback Resistors
Place the feedback resistors directly at the FEEDBACK pin of
the LinkSwitch-CV device. This minimizes noise coupling.
Thermal Considerations
The copper area connected to the source pins provide the
LinkSwitch-CV heat sink. A rule of thumb estimate is that the
LinkSwitch-CV will dissipate 10% of the output power. Provide
enough copper area to keep the source pin temperature below
110° C to provide margin for part to part RDS(ON) variation.
Secondary Loop Area
To minimize leakage inductance and EMI, the area of the loop
connecting the secondary winding, the output diode and the
output filter capacitor should be minimized. In addition,
sufficient copper area should be provided at the anode and
cathode terminal of the diode for heatsinking. A larger area is
preferred at the quiet cathode terminal. A large anode area can
increase high frequency radiated EMI.
Electrostatic Discharge Spark Gap
In chargers and adapters ESD discharges may be applied to
the output of the supply. In these applications the addition of a
spark gap is recommended. A trace is placed along the
isolation barrier to form one electrode of a spark gap. The other
electrode, on the secondary side, is formed by the output return
node. The arrangement directs ESD energy from the secondary
to the primary side AC input. A 10 mil gap is placed near the
AC input. The gap decouples any noise picked up on the spark
gap trace to the AC input. The trace from the AC input to the
spark gap electrode should be spaced away from other traces
to prevent unwanted arcing occurring and possible circuit
damage.
5
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Rev. E 09/09
LNK623-626
Primary Side
Secondary Side
Drain trace area
miniminzed
Clamp
Isolation Barrier
Components
Input Filter
Capacitor
C11
VR1 R2
C1
Copper area
maximized for
heatsinking
Output Filter
Capacitor
Output
Rectifiers
C3
L1
T1
Y1Capacitor
(optional)
C12
D9
C13
R10
D7
R1
C2
D1
D3
L2
D5
D
S
BP R3
Transformer
S
D4
S
D2
JP1
FB
C4
R4
RV1
C5
R5
R6 C6
Figure 5.
J2
D6
1
ESD
spark gap
+
AC
IN
10 mil
gap
-
R9
R8
R7
RT1
J1
C10
C9
D8
F1
L3
C8
U1
S
6
Bypass
Feedback
Capacitor
Resistors close
close to device
to device
DC Outputs
PI-5269-122408
PCB Layout Example.
B+
B+
CLAMP
CLAMP
Small FB
pin node
area
D
D
FB
FB
BP
BP
S
PRI RTN
Bias currents
return to bulk
capacitor
Figure 6.
Kelvin connection at
Source pin, no power
currents in signal traces
S
Minimize FB
pin node
area
PI-5265-110308
Schematic Representation of Recommended Layout Without
External Bias.
Bias resistor
PRI RTN
Bias currents
return to bulk
capacitor
Figure 7.
Kelvin connection at
Source pin, no power
currents in signal traces
PI-5266-110308
Schematic Representation of Recommended Layout With
External Bias.
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LNK623-626
B+
CLAMP
Drain trace in close
proximity of feedback trace
will couple noise into
feedback signal
Power currents
flow in signal
source trace D
FB
BP
PRI RTN
Trace
impedance
S
Isource
$VS
Voltage drops across trace impedance
may cause degraded performance
Figure 8.
Line surge
currents can
flow through
device
Bias winding
currents flow in
signal source traces
PI-5267-111008
Schematic Representation of Electrical Impact of Improper Layout.
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LNK623-626
Drain Clamp
Recommended Clamp Circuits
RC2
CC1
RC2
CC1
DC2
RC1
RC1
DC1
DC1
PI-5107-110308
Figure 9.
RCD Clamp, Low Power or Low Leakage Inductance Designs.
Components R1, R2, C3, VR1 and D5 in figure 4 comprise the
clamp. This circuit is preferred when the primary leakage
inductance is greater than 125 μH to reduce drain voltage
overshoot or ringing present on the feedback winding. For best
output regulation, the feedback voltage must settle to within 1%
at 2.1 μs from the turn off of the primary MOSFET. This requires
careful selection of the clamp circuit components. The voltage of
VR1 is selected to be ~20% above the reflected output voltage
(VOR). This is to clip any turn off spike on the drain but avoid
conduction during the flyback voltage interval when the output
diode is conducting. The value of R1 should be the largest value
that results in acceptable settling of the feedback pin voltage and
peak drain voltage. Making R1 too large will increase the
discharge time of C3 and degrade regulation. Resistor R2
dampens the leakage inductance ring. The value must be large
enough to dampen the ring in the required time but must not be
too large to cause the drain voltage to exceed 680 V.
PI-5108-110308
RCD Clamp With Zener Bleed. High Power or High Leakage Inductance Designs.
RC2
CC1
RC1
DC1
PI-5107-110308
If the primary leakage inductance is less than 125 μH, VR1 can
be eliminated and the value of R1 increased. A value of 470 kΩ
with an 820 pF capacitor is a recommended starting point.
Verify that the peak drain voltage is less than 680 V under all
line and load conditions. Verify the feedback winding settles to
an acceptable limit for good line and load regulation.
Effect of Fast (500 ns) versus Slow (2 μs) Recovery
Diodes in Clamp Circuit on Pulse Grouping and Output
Ripple.
A slow reverse recovery diode reduces the feedback voltage
ringing. The amplitude of ringing with a fast diode represents
8% error in Figure 10.
Black Trace: DC1 is a FR107 (fast type, trr = 500 ns)
Gray Trace: DC1 is a 1N4007G (standard recovery, trr = 2 us)
Figure 10. Effect of Clamp Diode on Feedback Pin Settling. Clamp Circuit (top).
Feedback Pin Voltage (bottom).
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LNK623-626
Clampless Designs
Clampless designs rely solely on the drain node capacitance to
limit the leakage inductance induced peak drain-to-source
voltage. Therefore the maximum AC input line voltage, the value
of VOR, the leakage inductance energy, (a function of leakage
inductance and peak primary current), and the primary winding
capacitance determine the peak drain voltage. With no significant dissipative element present, as is the case with an external
clamp, the longer duration of the leakage inductance ringing can
increase EMI.
The following requirements are recommended for a universal
input or 230 VAC only Clampless design:
1. Clampless designs should only be used for PO ≤5 W using a
VOR of ≤90 V
2. For designs with PO ≤5 W, a two-layer primary must be used
to ensure adequate primary intra-winding capacitance in the
range of 25 pF to 50 pF. A bias winding must be added to
the transformer using a standard recovery rectifier diode
(1N4003– 1N4007) to act as a clamp. This bias winding may
also be used to externally power the device by connecting a
resistor from the bias winding capacitor to the BYPASS pin.
This inhibits the internal high-voltage current source,
reducing device dissipation and no-load consumption.
3. For designs with PO >5 W, Clampless designs are not practical
and an external RCD or Zener clamp should be used.
4. Ensure that worst-case, high line, peak drain voltage is below
the BVDSS specification of the internal MOSFET and ideally
≤650 V to allow margin for design variation.
VOR (Reflected Output Voltage), is the secondary output plus
output diode forward voltage drop that is reflected to the primary
via the turns ratio of the transformer during the diode conduction
time. The VOR adds to the DC bus voltage and the leakage spike
to determine the peak drain voltage.
Pulse Grouping
Pulse grouping is defined as 6 or more consecutive pulses
followed by two or more timing state changes. The effect of
pulse grouping is increased output voltage ripple. This is
Top Trace: Drain Waveform (200 V/div)
Bottom Trace: Output Ripple Voltage (50 mV/div)
Figure 11. Not Pulse Grouping (<5 Consecutive Switching Cycles).
shown on the right of Figure 11 where pulse grouping has
caused an increase in the output ripple.
To eliminate group pulsing verify that the feedback signal settles
within 2.1 μs from the turn off of the internal MOSFET. A Zener
diode in the clamp circuit may be needed to achieve the desired
settling time. If the settling time is satisfactory, then a RC
network across RLOWER (R6) of the feedback resistors is
necessary.
The value of R (R5 in the Figure 12) should be an order of
magnitude greater than RLOWER and selected such that
R×C = 32 μs where C is C5 in Figure 12.
Quick Design Checklist
As with any power supply design, all LinkSwitch-CV designs
should be verified on the bench to make sure that component
specifications are not exceeded under worst-case conditions.
5
D6
1N4148
4
R3
6.34 k7
1%
2
D
LinkSwitch-CV
U1
LNK626PG
FB
BP
R4
6.2 k7
S
C4
1 MF
50 V
R5
47 k7
1/8 W
R6
4.02 k7
C5
1%
680 pF
50 V
C6
10 MF
50 V
PI-5268-110608
Figure 12. RC Network Across RBOTTOM (R6) to Reduce Pulse Grouping.
Split Screen with Bottom Screen Zoom
Top Trace: Drain Waveform (200 V/div)
Bottom Trace: Output Ripple Voltage (50 mV/div)
Pulse Grouping (>5 Consecutive Switching Cycles).
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LNK623-626
The following minimum set of tests is strongly recommended:
1. Maximum drain voltage – Verify that peak VDS does not exceed
680 V at highest input voltage and maximum output power.
2. Maximum drain current – At maximum ambient temperature,
maximum input voltage and maximum output load, verify
drain current waveforms at start-up for any signs of transformer saturation and excessive leading edge current spikes.
LinkSwitch-CV has a leading edge blanking time of 215 ns to
prevent premature termination of the ON-cycle. Verify that
the leading edge current spike is below the allowed current
limit envelope for the drain current waveform at the end of
the 215 ns blanking period.
3. Thermal check – At maximum output power, both minimum
and maximum input voltage and maximum ambient temperature; verify that temperature specifications are not exceeded
for LinkSwitch-CV, transformer, output diodes and output
capacitors. Enough thermal margin should be allowed for
the part-to-part variation of the RDS(ON) of LinkSwitch-CV, as
specified in the data sheet. It is recommended that the
maximum source pin temperature does not exceed 110 °C.
Design Tools
Up-to-date information on design tools can be found at the
Power Integrations web site: www.powerint.com
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LNK623-626
Absolute Maximum Ratings(1,4)
DRAIN Voltage .................................. ......... ..............-0.3 V to 700 V
DRAIN Peak Current: LNK623 ......................... 400 (600) mA(4)
LNK624 ......................... 400 (600) mA(4)
LNK625 ..........................528 (790) mA(4)
LNK626 ........................720 (1080) mA(4)
Peak Negative Pulsed DRAIN Current ................... ...... -100 mA(2)
Feedback Voltage ................................................. ....... -0.3 V to 9 V
Feedback Current ................................................. .............. 100 mA
BYPASS Pin Voltage ..................................... ............. -0.3 V to 9 V
Storage Temperature ........................................... -65 °C to 150 °C
Operating Junction Temperature.........................-40 °C to 150 °C
Lead Temperature(3) .................................................................260 °C
Notes:
1. All voltages referenced to SOURCE, TA = 25 °C.
2. Duration not to exceed 2 msec.
3. 1/16 in. from case for 5 seconds.
4. The higher peak DRAIN current is allowed while the DRAIN
voltage is simultaneously less than 400 V.
5. Maximum ratings specified may be applied, one at a time
without causing permanent damage to the product.
Exposure to Absolute Maximum ratings for extended
periods of time may affect product reliability.
Thermal Resistance
Thermal Resistance: P Package:
(θJA) ....................................70 °C/W(2); 60 °C/W(3)
(θJC)(1) ............................................... ......... 11 °C/W
D Package:
(θJA .....................................100 °C/W(2); 80 °C/W(3)
(θJC)(1) .......................... ...........................30 °C/W
Parameter
Symbol
Notes:
1. Measured on pin 8 (SOURCE) close to plastic interface.
2. Soldered to 0.36 sq. in. (232 mm2), 2 oz. (610 g/m2) copper clad.
3. Soldered to 1 sq. in. (645 mm2), 2 oz. (610 g/m2) copper clad.
Conditions
SOURCE = 0 V; TJ = -40 to 125 °C
(Unless Otherwise Specified)
Min
Typ
Max
Units
93
100
106
kHz
Control Functions
Output Frequency
fOSC
Frequency Jitter
TJ = 25 °C, VFB = VFBth
LNK623/6
Peak-Peak Jitter Compared to
Average Frequency, TJ = 25 °C
±7
%
80
%
Ratio of Output
Frequency at Auto-RST
fOSC(AR)
TJ = 25 °C
Relative to fOSC (See Note 3)
Maximum Duty Cycle
DCMAX
(Note 2,3) TJ = 25 °C
TJ = 25 °C
See Figure 15,
CBP = 1 μF
LNK623-624P
LNK623-624D
LNK625P, LNK625D
LNK626P, LNK626D
54
1.815
1.855
1.835
1.775
%
1.840
1.880
1.860
1.800
1.865
1.905
1.885
1.825
Feedback Pin Voltage
VFBth
Feedback Pin Voltage
Temperature
Coefficient
TCVFB
-0.01
%/°C
Feedback Pin Voltage
at Turn-Off Threshold
VFB(AR)
1.45
V
Power Coefficient
I2f = I2LIMIT(TYP) × fOSC(TYP)
LNK623/6P
TJ = 25 °C
0.9 × I2f
I2f = I2LIMIT(TYP) × fOSC(TYP)
LNK623/6D
TJ = 25 °C
0.9 × I2f
I2f
I2f
V
1.17 × I2f
A2Hz
I2f
1.21 × I2f
11
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Rev. E 09/09
LNK623-626
Symbol
Conditions
SOURCE = 0 V; TJ = -40 to 125 °C
(Unless Otherwise Specified)
Minimum Switch
“On”-Time
tON(min)
(See Note 3)
Feedback Pin
Sampling Delay
tFB
(See Figure 19)
IS1
FB Voltage > VFBth
Parameter
Min
Typ
Max
Units
Control Functions (cont.)
DRAIN Supply
Current
BYPASS Pin
Charge Current
IS2
FB Voltage = VFBth -0.1,
Switch ON-Time = tON
(MOSFET Switching at fOSC)
ICH1
VBP = 0 V
ICH2
VBP = 4 V
700
2.35
ns
2.55
2.75
280
330
LNK623/4
440
520
LNK625
480
560
LNK626
520
600
LNK623/4
-5.0
-3.4
-1.8
LNK625/6
-7.0
-4.5
-2.0
LNK623/4
-4.0
-2.3
-1.0
LNK625/6
-5.6
-3.2
-1.4
μs
μA
mA
BYPASS Pin
Voltage
VBP
5.65
6.00
6.25
V
BYPASS Pin
Voltage Hysteresis
VBPH
0.70
1.00
1.20
V
VSHUNT
6.2
6.5
6.8
V
LNK623
di/dt = 50 mA/μs , TJ = 25 °C
196
210
225
LNK624
di/dt = 60 mA/μs , TJ = 25 °C
233
250
268
LNK625
di/dt = 80 mA/μs , TJ = 25 °C
307
330
353
LNK626
di/dt = 110 mA/μs , TJ = 25 °C
419
450
482
TJ = 25 °C
(See Note 3)
170
215
135
142
BYPASS Pin
Shunt Voltage
Circuit Protection
Current Limit
ILIMIT
Leading Edge
Blanking Time
tLEB
Thermal Shutdown
Temperature
TSD
Thermal Shutdown
Hysteresis
TSDH
mA
60
ns
150
°C
°C
12
Rev. E 09/09
www.powerint.com
LNK623-626
Parameter
Symbol
Conditions
SOURCE = 0 V; TJ = -40 to 125 °C
(Unless Otherwise Specified)
Min
Typ
Max
TJ = 25 °C
24
28
TJ = 100 °C
36
42
TJ = 25 °C
24
28
TJ = 100 °C
36
42
TJ = 25 °C
16
19
TJ = 100 °C
24
28
TJ = 25 °C
9.6
11
TJ = 100 °C
14
17
Units
Output
LNK623
ID = 50 mA
ON-State
Resistance
LNK624
ID = 50 mA
RDS(ON)
LNK625
ID = 62 mA
LNK626
ID = 82 mA
OFF-State
Leakage
Breakdown
Voltage
IDSS1
VDS = 560 V (See Figure 20)
TJ = 125 °C (See Note 1)
IDSS2
VDS = 375 V (See Figure 20)
TJ = 50 °C
BVDSS
TJ = 25 °C
(See Figure 20)
DRAIN Supply
Voltage
Auto-Restart
ON-Time
tAR-ON
Auto-Restart
OFF-Time
tAR-OFF
Open-Loop FB Pin
Current Threshold
IOL
Open-Loop
ON-Time
Ω
50
μA
15
700
V
50
V
VFB = 0
(See Note 3)
200
ms
2.5
s
(See Note 3)
-120
μA
(See Note 3)
90
μs
NOTES:
1. IDSS1 is the worst case OFF state leakage specification at 80% of BVDSS and maximum operating junction temperature. IDSS2 is a
typical specification under worst case application conditions (rectified 265 VAC) for no-load consumption calculations.
2. When the duty cycle exceeds DCMAX the LinkSwitch-CV operates in on-time extension mode.
3. This parameter is derived from characterization.
13
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Rev. E 09/09
LNK623-626
Typical Performance Characteristics
0.800
0.600
0.400
0.200
-15
10
35
60
85
110 135
1.000
0.800
0.600
0.400
0.200
0.000
-40
-15
10
Figure 13. Output Frequency vs, Temperature.
85
110 135
PI-2213-012301
300
Drain Current (mA)
1.0
TCASE=25 °C
TCASE=100 °C
250
200
150
100
Scaling Factors:
LNK623
1.0
LNK624
1.0
LNK625
1.5
LNK626
2.5
50
0.9
0
-50 -25
0
25
50
75 100 125 150
0
Junction Temperature (°C)
4
6
8
10
Figure 16. Output Characteristic.
40
Power (mW)
100
Scaling Factors:
LNK623
1.0
LNK624
1.0
LNK625
1.5
LNK626
2.5
PI-5212-080708
50
PI-5201-071708
1000
10
2
DRAIN Voltage (V)
Figure 15. Breakdown vs. Temperature.
Drain Capacitance (pF)
60
Figure 14. Feedback Voltage vs, Temperature.
1.1
Breakdown Voltage
(Normalized to 25 °C)
35
Temperature (°C)
Temperature (°C)
PI-5211-080708
0.000
-40
PI-5089-040508
1.000
1.200
Feedback Voltage
(Normalized to 25 °C)
PI-5086-041008
Frequency
(Normalized to 25 °C)
1.200
Scaling Factors:
LNK623
1.0
LNK624
1.0
LNK625
1.5
LNK626
2.5
30
20
10
0
1
0
100
200
300
400
Drain Voltage (V)
Figure 17. COSS vs. Drain Voltage.
500
600
0
200
400
600
DRAIN Voltage (V)
Figure 18. Drain Capacitance Power.
14
Rev. E 09/09
www.powerint.com
LNK623-626
LinkSwitch-CV
VIN +
FB
S
BP
S
D
S
10 MF
+
6.2 V
VOUT
S
500 7
+
2V
PI-5202-073108
1) Raise VBP voltage from 0 V to 6.2 V, down to 4.5 V, up to 6.2 V
2) Raise VIN until cycle skipping occurs at VOUT to measure VFBth
3) Apply 1.6 V at VIN and measure tFB delay from start of cycle falling edge to the next falling edge
Figure 19. Test Set-up for Feedback Pin Measurements.
LinkSwitch-CV
5 MF
50 k7
10 k7
1 MF
FB
S
BP
S
D
S
.1 MF
4 k7
VIN
S1
S
S2
+
16 V
Curve
Tracer
To measure BVDSS, IDSS1, and IDSS2 follow these steps:
1) Close S1, open S2
2) Power-up VIN source (16 V)
3) Open S1, close S2
4) Measure I/V characteristics of Drain pin using the curve tracer
PI-5203-071408
Figure 20. Test Set-up for Leakage and Breakdown Tests.
15
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Rev. E 09/09
LNK623-626
DIP-8C (P Package)
⊕D S
.004 (.10)
-E-
.240 (6.10)
.260 (6.60)
Pin 1
-D-
.367 (9.32)
.387 (9.83)
.057 (1.45)
.068 (1.73)
(NOTE 6)
.125 (3.18)
.145 (3.68)
Notes:
1. Package dimensions conform to JEDEC specification
MS-001-AB (Issue B 7/85) for standard dual-in-line (DIP)
package with .300 inch row spacing.
2. Controlling dimensions are inches. Millimeter sizes are
shown in parentheses.
3. Dimensions shown do not include mold flash or other
protrusions. Mold flash or protrusions shall not exceed
.006 (.15) on any side.
4. Pin locations start with Pin 1, and continue counter-clockwise to Pin 8 when viewed from the top. The notch and/or
dimple are aids in locating Pin 1. Pin 3 is omitted.
5. Minimum metal to metal spacing at the package body for
the omitted lead location is .137 inch (3.48 mm).
6. Lead width measured at package body.
7. Lead spacing measured with the leads constrained to be
perpendicular to plane T.
.015 (.38)
MINIMUM
-TSEATING
PLANE
.120 (3.05)
.140 (3.56)
.100 (2.54) BSC
.014 (.36)
.022 (.56)
.048 (1.22)
.053 (1.35)
⊕T E D
.137 (3.48)
MINIMUM
S .010 (.25) M
.008 (.20)
.015 (.38)
.300 (7.62) BSC
(NOTE 7)
.300 (7.62)
.390 (9.91)
P08C
PI-3933-101507
16
Rev. E 09/09
www.powerint.com
LNK623-626
SO-8C
4
B
0.10 (0.004) C A-B 2X
2
DETAIL A
4.90 (0.193) BSC
A
4
8
D
5
GAUGE
PLANE
2 3.90 (0.154) BSC
SEATING
PLANE
6.00 (0.236) BSC
0-8
C
1.04 (0.041) REF
0.10 (0.004) C D
2X
1
Pin 1 ID
4
0.25 (0.010)
BSC
0.40 (0.016)
1.27 (0.050)
0.20 (0.008) C
2X
7X 0.31 - 0.51 (0.012 - 0.020)
0.25 (0.010) M C A-B D
1.27 (0.050) BSC
1.25 - 1.65
(0.049 - 0.065)
1.35 (0.053)
1.75 (0.069)
o
DETAIL A
0.10 (0.004)
0.25 (0.010)
0.10 (0.004) C
H
7X
SEATING PLANE
0.17 (0.007)
0.25 (0.010)
C
Reference
Solder Pad
Dimensions
+
2.00 (0.079)
+
4.90 (0.193)
+
+
1.27 (0.050)
D07C
Notes:
1. JEDEC reference: MS-012.
2. Package outline exclusive of mold flash and metal burr.
3. Package outline inclusive of plating thickness.
4. Datums A and B to be determined at datum plane H.
5. Controlling dimensions are in millimeters. Inch dimensions
are shown in parenthesis. Angles in degrees.
0.60 (0.024)
PI-4526-040207
Part Ordering Information
• LinkSwitch Product Family
• CV Series Number
• Package Identifier
P
Plastic DIP
D
Plastic SO-8
• Package Material
G
GREEN: Halogen Free and RoHS Compliant
• Tape & Reel and Other Options
Blank
LNK 625
D G - TL
TL
Standard Configurations
Tape & Reel, 2.5 k pcs for D Package. Not available for P Package.
17
www.powerint.com
Rev. E 09/09
Revision
Notes
Date
B
Release data sheet
11/08
C
Correction made to Figure 5
12/08
D
Introduced Max current limit when V DRAIN is below 400 V
07/09
E
Introduced LNK626DG
09/09
For the latest updates, visit our website: www.powerint.com
Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability. Power
Integrations does not assume any liability arising from the use of any device or circuit described herein. POWER INTEGRATIONS MAKES
NO WARRANTY HEREIN AND SPECIFICALLY DISCLAIMS ALL WARRANTIES INCLUDING, WITHOUT LIMITATION, THE IMPLIED
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT OF THIRD PARTY RIGHTS.
Patent Information
The products and applications illustrated herein (including transformer construction and circuits external to the products) may be covered by
one or more U.S. and foreign patents, or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A
complete list of Power Integrations patents may be found at www.powerint.com. Power Integrations grants its customers a license under
certain patent rights as set forth at http://www.powerint.com/ip.htm.
Life Support Policy
POWER INTEGRATIONS PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR
SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF POWER INTEGRATIONS. As used herein:
1. A Life support device or system is one which, (i) is intended for surgical implant into the body, or (ii) supports or sustains life, and (iii)
whose failure to perform, when properly used in accordance with instructions for use, can be reasonably expected to result in significant
injury or death to the user.
2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause
the failure of the life support device or system, or to affect its safety or effectiveness.
The PI logo, TOPSwitch, TinySwitch, LinkSwitch, DPA-Switch, PeakSwitch, EcoSmart, Clampless, E-Shield, Filterfuse, StakFET, PI Expert
and PI FACTS are trademarks of Power Integrations, Inc. Other trademarks are property of their respective companies.
©2008, Power Integrations, Inc.
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