L4981A
L4981B
POWER FACTOR CORRECTOR
CONTROL BOOST PWM UP TO 0.99P.F.
LIMITLINE CURRENT DISTORTION TO < 5%
UNIVERSAL INPUT MAINS
FEED FORWARD LINE AND LOAD REGULA-
TION
AVERAGE CURRENT MODE PWM FOR
MINIMUM NOISE SENSITIVITY
HIGH CURRENT BIPOLAR AND DMOS TO-
TEM POLE OUTPUT
LOW START-UP CURRENT (0.3mA TYP.)
UNDER VOLTAGE LOCKOUT WITH HYS-
TERESIS AND PROGRAMMABLE TURN ON
THRESHOLD
OVERVOLTAGE, OVERCURRENT PROTEC-
TION
PRECISE 2% ON CHIP REFERENCE EX-
TERNALLY AVAILABLE
SOFT START
DESCRIPTION
The L4981 I.C. provides the necessary features
to achieve a very high power factor up to 0.99.
Realized in BCD 60II technology this power factor
corrector (PFC) pre-regulator contains all the con-
trol functions for designing a high efficiency-mode
power supply with sinusoidal line current con-
sumption.
The L4981 can be easily used in systems with
mains voltages between 85V to 265V without any
line switch. This new PFC offers the possibility to
work at fixed frequency (L4981A) or modulated
frequency (L4981B) optimizing the size of the in-
September 1998
BLOCK DIAGRAM
ORDERING NUMBERS: L4981X (DIP20)
L4981XD (SO20)
DIP20 SO20
MULTIPOWER BCD TECHNOLOGY
1/17
put filter; both the operating frequency modes
working with an average current mode PWM con-
troller, maintaining sinusoidal line current without
slope compensation.
Besides power MOSFET gate driver, precise volt-
age reference (externally available), error ampli-
fier, undervoltage lockout, current sense and the
soft start are included. To limit the number of the
external components, the device integrates pro-
tections as overvoltage and overcurrent. The
overcurrent level can be programmed using a
simple resistor for L4981A. For a better precision
and for L4981B an external divider must be used.
ABSOLUTE MAXIMUM RATINGS
Symbol Pin Parameter Value Unit
VCC 19 Supply Voltage (ICC ≤50mA) (*) selflimit V
IGDRV 20 Gate driv. output peak current (t = 1µs) SINK 2 Α
. SOURCE 1.5 A
VGDRV Gate driv. output voltage t = 0.1µs -1 V
Voltages at pins 3, 14, 7, 6, 12, 15 -0.3 to 9 V
VVA-OUT 13 Error Amplifier Voltage -0.3 to 8.5 V
IAC 4 AC Input Current 5 mA
Voltages at pin 8, 9 -0.5 to 7 V
VCA-OUT 5 Current Amplifier Volt. (Isource = -20mA; Isink = 20mA) -0.3 to 8.5 V
VROSC 17 Voltage at pin 17 -0.3 to 3 V
11, 18 Voltage at pin 11, 18 -0.3 to 7 V
ICOSC 18 Input Sink Current 15 mA
IFREQ-MOD 16 Frequency Modulation Sink Current (L4981B) 5 mA
VSYNC 16 Sync. Voltage (L4981A) -0.3 to 7 V
VIPK 2 Voltage at pin 2
Voltage at Pin 2 t = 1µs
-0.3 to 5.5
-2
V
V
Ptot Power Dissipation at Tamb = 70°C (DIP20) 1 W
Power Dissipation at Tamb = 70°C (SO20) 0.6 W
Top Operating Ambient Temperature -40 to 125 °C
Tstg StorageTemperature -55 to 150 °C
(*) Maximum package power dissipation limits must be observed.
PIN CONNECTIONS (Top views)
L4981A L4981B
L4981A - L4981B
2/17
THERMAL DATA
Symbol Parameter DIP 20 SO 20 Unit
Rth j-amb Thermal Resistance Junction-ambient 80 120 °C/W
PIN FUNCTIONS
N. Name Description
1 P-GND Power ground.
2 IPK L4981A peak current limiting. A current limitation is obtained using a single resistor connected
between Pin 2 and the sense resistor. To have a better precision another resistor between Pin
2 and a reference voltage (Pin 11) must be added.
L4981B peak current limiting. A precise current limitation is obtained using two external
resistor only. These resistors must be connected between the sense resistor, Pin 2 and the
reference voltage.
3 OVP Overvoltage protection. At this input are compared an internal precise 5.1V (typ) voltage
reference with a sample of the boost output voltage obtained via a resistive voltage divider in
order to limit the maximum output peak voltage.
4 IAC Input for the AC current. An input current proportional to the rectified mains voltage generates,
via a multiplier, the current reference for the current amplifier.
5 CA-OUT Current amplifier output. An external RC network determinates the loop gain.
6 LFF Load feedforward; this voltage input pin allows to modify the multiplier output current
proportionally to the load, in order to give a faster response versus load transient. The best
control is obtained working between 1.5V and 5.3V. If this function is not used, connect this pin
to the voltage reference (pin = 11).
7 VRMS Input for proportional RMS line voltage. the VRMS input compesates the line voltage changes.
Connecting a low pass filter between the rectified line and the pin 7, a DC voltage proportional
to the input line RMS voltage is obtained. The best control is reached using input voltage
between 1.5V and 5.5V. If this function is not used connect this pin to the voltage reference
(pin = 11).
8 MULT-OUT Multiplier output. This pin common to the multiplier output and the current amplifier N.I. input is
an high impedence input like ISENSE. The MULT-OUT pin must be taken not below -0.5V.
9 ISENSE Current amplifier inverting input. Care must be taken to avoid this pin goes down -0.5V.
10 S-GND Signal ground.
11 VREF Output reference voltage (typ = 5.1V).Voltage refence at ± 2% of accuracy externally available,
it’s internally current limited and can deliver an output current up to 10mA.
12 SS A capacitor connected to ground defines the soft start time. An internal current generator
delivering 100µA (typ) charges the external capacitor defining the soft start time constant. An
internal MOS discharge, the external soft start capacitor both in overvoltage and UVLO
conditions.
13 VA-OUT Error amplifier output, an RC network fixes the voltage loop gain characteristics.
14 VFEED Voltage error amplifier inverting input. This feedback input is connected via a voltage divider to
the boost output voltage.
15 P-UVLO Programmable under voltage lock out threshold input. A voltage divider between supply
voltage and GND can be connected in order to program the turn on threshold.
16 SYNC
(L4981A)
This synchronization input/output pin is CMOS logic compatible. Operating as SYNC in, a
rectangular wave must be applied at this pin. Opearting as SYNC out, a rectangular clock
pulse train is available to synchronize other devices.
FREQ-MOD
(L4981B)
Frequency modulation current input. An external resistor must be connected between pin 16
and the rectified line voltage in order to modulate the oscillator frequency. Connecting pin 16 to
ground a fixed frequency imposed by ROSC and COSC is obtained.
17 ROSC An external resistor connected to ground fixes the constant charging current of COSC.
18 COSC An external capacitor connected to GND fixes the switching frequency.
19 VCC Supply input voltage.
20 GDRV Output gate driver. Bipolar and DMOS transistors totem pole output stage can deliver peak
current in excess 1A useful to drive MOSFET or IGBT power stages.
L4981A - L4981B
3/17
ELECTRICAL CHARACTERISTICS (Unless otherwise specified VCC = 18V, COSC = 1nF,
ROSC = 24KΩ, CSS = 1µF, VCA-OUT = 3.5V, VISENSE = 0V, VLFF = VREF, IAC = 100µA, VRMS = 1V,
VFEED = GND, VIPK = 1V, VOVP = 1V, TJ = 25°C
Symbol Prameter Test Condition Min. Typ. Max. Unit
ERROR AMPLIFIER SECTION
VIO Input Offset Voltage –25°C < TJ < 85°C ±8 mV
IIB Input Bias Current VFEED = 0V -500 -50 500 nA
Open Loop Gain 70 100 dB
V13H Output High voltage VFEED = 4.7V
IVA-OUT = -0.5mA
5.5 6.5 7.5 V
V13L Output Low Voltage VFEED = 5.5V
IVA-OUT = 0.5mA
0.4 1 V
-I13 Output Source Current VFEED = 4.7V; VVA-OUT = 3.5V 2 10 mA
I13 Output Sink Current VFEED = 5.5V; VVA-OUT = 3.5V 4 20 mA
REFERENCE SECTION
Vref Reference Output Voltage –25°C < TJ < 85°C 4.97 5.1 5.23 V
Tj = 25°C Iref = 0 5.01 5.1 5.19 V
∆Vref Load Regulation 1mA ≤ Iref ≤ 10mA
–25°C < TJ < 85°C
3 15 mV
∆Vref Line Regulation 12V ≤ VCC ≤ 19V
–25°C < TJ < 85°C
3 10 mV
Iref sc Short Circuit Current Vref = 0V 20 30 50 mA
OSCILLATOR SECTION
fosc Initial Accuracy Tj = 25°C 85 100 115 KHz
Frequency Stability 12V ≤ VCC ≤ 19V
–25°C < TJ < 85°C
80 100 120 KHz
Vsvp Ramp Valley to Peak 4.7 5 5.3 V
I18C Charge Current VCOSC = 3.5V 0.45 0.55 0.65 mA
I18D Discharge Current VCOSC = 3.5V 11.5 mA
V18 Ramp Valley Voltage 0.9 1.15 1.4 V
SYNC SECTION (Only for L4981A)
tW Output Pulse Width 50% Amplitude 0.3 0.8 µs
I16 Sink Current with Low Output
Voltage
VSYNC = 0.4V
VCOSC = 0V
0.4 0.8 mA
-I16 Source Current with High Output
Voltage
VSYNC = 4.5V
VCOSC = 6.7V
1 6 mA
V16L Low Input Voltage 0.9 V
V16H High Input Voltage 3.5 V
td Pulse for Synchronization 800 ns
FREQUENCY MODULATION FUNCTION (Only for L4981B)
f18max Maximum Oscillation Frequency VFREQ-MOD = 0V (Pin 16) Ifreq = 0 85 100 115 KHz
f18min Minimum Oscillator Frequency IFREQ-MOD = 360µA (Pin 16)
VVRMS = 4V (Pin 7)
74 KHz
IFREQ-MOD = 180µA (Pin 16)
VVRMS = 2V (Pin 7)
76 KHz
SOFT START SECTION
ISS Soft Start Source Current VSS = 3V 60 100 140 µA
V12sat Output Saturation Voltage V3 = 6V, ISS = 2mA 0.1 0.25 V
L4981A - L4981B
4/17
ELECTRICAL CHARACTERISTICS (continued)
Symbol Parameter Test Condition Min. Typ. Max. Unit
SUPPLY VOLTAGE
VCC Operating Supply Voltage 19.5 V
OVER VOLTAGE PROTECTION COMPARATOR
Vthr Rising Threshold Voltage Vref
-20mV
5.1 Vref
+20mV
V
V3Hys Hysteresis 180 250 320 mV
I3 Input Bias Current 0.05 1 µA
td Propagation delay to output VOVP = Vthr +100mV 1 2 µs
OVER CURRENT PROTECTION COMPARATOR
Vth Threshold Voltage ±30 mV
td Propagation delay to Output VOCP = Vthr -0.2V 0.4 0.9 µs
Iipk Current Source Generator VIPK = -0.1V only for L4981A 65 85 105 µA
IL Leakage Current VIPK = -0.1V only for L4981B 5 µA
CURRENT AMPLIFIER SECTION
Voffset Input Offset Voltage VMULT OUT = VSENSE = 3.5V ±2 mV
I9bias Input Bias Current VSENSE = 0V -500 50 500 nA
Open Loop Gain 1.1V ≤ VCA OUT ≤ 6V 70 100 dB
SVR Supply Voltage Rejection 12V ≤ VCC ≤ 19V
VMULT OUT = 3.5V VSENSE = 3.5V
68 90 dB
V5H Output High Voltage VMULT OUT = 200mV
ICA OUT = -0.5mA, VIAC = 0V
6.2 V
V5L Output Low Voltage VMULT OUT = -200mV
ICA OUT = 0.5mA, VIAC = 0V
0.9 V
-I5 Output Source Current VMULT OUT = 200mV,
VIAC = 0V, VCA-OUT = 3.5V
2 10 mA
I5 Output Sink Current 2 10 mA
OUTPUT SECTION
V20L Output Voltage Low ISINK = 250mA 0.5 0.8 V
V20H Output Voltage High ISOURCE = 250mA
VCC = 15V
11.5 12.5 V
tr Output Voltage Rise Time COUT = 1nF 50 150 ns
tf Output Voltage Fall Time COUT = 1nF 30 100 ns
VGDRV Voltage Clamp ISOURCE = 0mA 13 16 19 V
TOTAL STANDBY CURRENT SECTION
I19start Supply Current before start up VCC = 14V 0.3 0.5 mA
I19on Supply Current after turn on VIAC = 0V, VCOSC = 0,
Pin17 = Open
8 12 mA
I19 Operating Supply Current Pin20 = 1nF 12 16 mA
VCC Zener Voltage (*) 20 25 30 V
UNDER VOLTAGE LOCKOUT SECTION
Vth ON Turn on Threshold 14.5 15.5 16.5 V
Vth OFF Turn off Threshold 9 10 11 V
Programmable Turn-on Threshold Pin 15 to VCC = 220K
Pin15 to GND = 33K
10.6 12 13.4 V
LOAD FEED FORWARD
ILFF Bias Current V6 = 1.6V 70 140 µA
V6 = 5.3V 200 300 µA
VI Input Voltage Range 1.6 5.3 V
(*) Maximum package power dissipation limits must be observed.
L4981A - L4981B
5/17
ELECTRICAL CHARACTERISTICS (continued)
Symbol Prameter Test Condition Min. Typ. Max. Unit
MULTIPLIER SECTION
Multipler Output Current VVA-OUT = 4V, VRMS = 2V,
VMULTOUT = 0, VLFF = 5.1V
IAC = 50µA, COSC = 0V
20 35 52 µA
VVA-OUT = 4V, VRMS = 2V,
VMULTOUT = 0, VLFF = 5.1V
IAC = 200µA, COSC = 0V
100 135 170 µA
VVA-OUT = 2V, VRMS = 2V,
VMULTOUT = 0, VLFF = 5.1V
IAC = 100µA, COSC = 0V
10 20 30 µA
VVA-OUT = 2V, VRMS = 4V,
VMULTOUT = 0, VLFF = 5.1V
IAC = 100µA, COSC = 0V
2 5.5 11 µA
VVA-OUT = 4V, VRMS = 4V,
VMULTOUT = 0, VLFF = 5.1V
IAC = 100µA, COSC = 0V
10 22 34 µA
VVA-OUT = 4V, VRMS = 2V,
VMULTOUT = 0, VLFF = 2.5V
COSC = 0V, IAC = 200µA
20 37 54 µA
VVA-OUT = 4V, VRMS = 4V
VMULTOUT = 0, VLFF = 5.1V
IAC = 200µA, COSC = 0V
20 39 54 µA
VVA-OUT = 2V, VRMS = 4V,
VMULTOUT = 0, VLFF = 5.1V
IAC = 0, COSC = 0V
-2 0 2 µA
K Multiplier Gain 0.37
IMULT−OUT = K ⋅ IAC
(VVA−OUT − 1.28) ⋅ (0.8 ⋅ VLFF − 1.28)
(VVRMS)2
if VLFF = VREF; IMULT−OUT = IAC (VVA−OUT − 1.28)
(VVRMS)2
⋅ K1
where: K1 = 1V
Figure 1: MULTI-OUT vs. IAC (VRMS = 1.7V;
VLFFD = 5.1V)
Figure 2: MULTI-OUT vs. IAC (VRMS = 2.2V;
VLFFD = 5.1V)
L4981A - L4981B
6/17
Figure 3: MULTI-OUT vs. IAC (VRMS = 4.4V;
VLFFD = 5.1V)
Figure 4: MULTI-OUT vs. IAC (VRMS = 5.3V;
VLFFD = 5.1V)
Figure 6: MULTI-OUT vs. IAC (VRMS = 2.2V;
VLFFD = 2.5V)
Figure 5: MULTI-OUT vs. IAC (VRMS = 1.7V;
VLFFD = 2.5V)
Figure 7: MULTI-OUT vs. IAC (VRMS = 4.4V;
VLFFD = 2.5V)
Figure 8: MULTI-OUT vs. IAC (VRMS = 5.3V;
VLFFD = 2.5V)
L4981A - L4981B
7/17
C7
C8
R8
R7
R6
R14
7 4
BRIDGE
C1 L4981A
15
16
R15
19
C12 D4
D3 C5
T
13 14
C9
R12
3
C11
R13
MOS
D5 R17
20
R11 R3
R5 C3
R4 C4 R16 C6 C10
1
R2 R10
R1 R9
D1
6
11121710189582
FUSE
Vi
C2
+
-
Vo=400V
D93IN029B
85VAC-265VAC
D2
RS
R21
Figure 9A: L4981A Power Factor Corrector (200W)
C1 470nF 400V
C2 100µF 450V
C3 2.2nF
C4 1nF
C5 100µF 25V
C6 1µF 16V
C7 220nF 63V
C8 220nF 63V
C9 330nF
C10 1µF 16V
C11 270pF 400V
C12 8.2nF 100V
D1 STTA506D
D2, D3 1N4148
D4 18V 1/2W
D5 BYT11-600
MOS STH/STW15NA50
FUSE = 4A/250V
RS 0.07(3 x .22) 1/2W 5%
R1 820kΩ 1/4W 1%
R2 10kΩ 1/4W 1%
R3 1.8kΩ 1/4W 5%
R4 1.8kΩ 1/4W 5%
R5 18kΩ 1/4W 5%
R6 1.2MΩ 1/4W 5%
R7 360kΩ 1/4W 5%
R8 33kΩ 1/4W 5%
R9 1.8MΩ 1/4W 1%
R10 21kΩ 1/4W 1%
R11 402Ω 1/4W 1%
R12 120kΩ 1/4W 5%
R13 27Ω 1/4W 5%
R14 1MΩ 1/4W 1%
R15 120kΩ 1/2W 5%
R16 30kΩ 1/4W 5%
R17 1.8kΩ 4W 1%
R21 5.1kΩ 1/4W 1%
BRIDGE = 4 x P600M
PART LIST
T= primary: 88 turns of 12 x 32 AWG (0.2mm)
secondary: 9 turns of # 27AWG (0.15mm)
core: B1ET3411A THOMSON - CSF
gap: 1,6mm for a total primary inductance of
0.9mH
fSW = 80kHz PO = 200W
VOUT = 400V Irms max = 2.53A
VOVP = 442V IPK max = 6.2A
L4981A - L4981B
8/17
C7
C8
R8
R7
R6
R14
7 4
BRIDGE
C1 L4981B
15
16
R15
19
C12 D4
D3 C5
T
13 14
C9
R12
3
C11
R13
MOS
D5 R17
20
R11 R3
R5 C3
R4 C4 R16 C6 C10
1
R2 R10
R1 R9
D1
6
11121710189582
FUSE
Vi
C2
+
-
Vo=400V
D95IN220
85VAC-265VAC
D2
RS
R21
R22
Figure 9B: L4981B Power Factor Corrector (200W)
C1 470nF 400V
C2 100µF 450V
C3 2.2nF
C4 1.1nF
C5 100µF 25V
C6 1µF 16V
C7 220nF 63V
C8 220nF 63V
C9 330nF
C10 1µF 16V
C11 270pF 400V
C12 8.2nF 100V
D1 STTA506D
D2, D3 1N4148
D4 18V 1/2W
D5 BYT11-600
MOS STH/STW15NA50
FUSE = 4A/250V
RS 0.07(3 x .22) 1/2W 5%
R1 820kΩ 1/4W 1%
R2 10kΩ 1/4W 1%
R3 1.8kΩ 1/4W 5%
R4 1.8kΩ 1/4W 5%
R5 18kΩ 1/4W 5%
R6 1.2MΩ 1/4W 5%
R7 360kΩ 1/4W 5%
R8 33kΩ 1/4W 5%
R9 1.8MΩ 1/4W 1%
R10 21kΩ 1/4W 1%
R11 402Ω 1/4W 1%
R12 120kΩ 1/4W 5%
R13 27Ω 1/4W 5%
R14 1MΩ 1/4W 1%
R15 120kΩ 1/2W 5%
R16 24kΩ 1/4W 5%
R17 1.8kΩ 4W 1%
R21 5.1kΩ 1/4W 1%
R22 1.1MΩ 1/4W 1%
BRIDGE = 4 x P600M
PART LIST
T= primary: 88 turns of 12 x 32 AWG (0.2mm)
secondary: 9 turns of # 27AWG (0.15mm)
core: B1ET3411A THOMSON - CSF
gap: 1,6mm for a total primary inductance of
0.9mH
fSW = 80 to 92kHz PO = 200W
VOUT = 400V Irms max = 2.53A
VOVP = 442V IPK max = 6.2A
L4981A - L4981B
9/17
Figure 10: Reference Voltage vs. Source Refer-
ence Current
Figure 12: ReferenceVoltage vs. Junction Tem-
perature
Figure 14: Gate Driver Rise and Fall Time
Figure 11: Reference Voltage vs. Supply Voltage
Figure 13: Switching Frequency vs. Junction
Temperature
Figure 15: OperatingSupply Current vs. Supply
Voltage
L4981A - L4981B
10/17
Figure 16: Programmable Under Voltage Lock-
out Thresholds
Table 1: Programmable Under Voltage Lockout Thresholds.
VCC ON VCC OFF R22 R23
11V 10V 82kΩ 12kΩ
12V 10.1V 220kΩ 33kΩ
13V 10.5V 430kΩ 62kΩ
14V 10.8V 909kΩ 133kΩ
14.5V 10.9V 1.36MΩ 200kΩ
15V 11V 2.7MΩ 390kΩ
Vl
0.8
1
0.4
0.2
0
0 45 90 135
Electrical degrees
180
0.8
1
0.4
0.2
0
fsw
Figure 17: ModulationFrequency Normalized in
an Half Cycle of the Mains Voltage
Figure 18: Oscillator Diagram
R22 = R23 ⋅ 6.8
R23 (Kohm)
L4981A - L4981B
11/17
Figure 19: 200W Evaluation Board Circuit.
T= primary: 75 turns of litz wire 20 x 32 AWG (0.2mm)
secondary: 8 turns of # 27AWG (0.15mm)
core: B1ET3411A THOMSON - CSF
gap: 1.4mm for a total primary inductance of 0.7mH
fsw = 100kHz; VO = 400V; PO = 200W
NOTE:
Start Up Circuit
Usually the VCC capacitor (C11 in fig. 19)can be charged by a resistor
drawing current from the rectified mains. In the evaluation board
instead the start up circuit composed by (Q2+R19+R15+Dz) has
been designed to perform a fast and effective supply in all the
conditions. Once that the L4981A/B has started, the reference
voltage available at pin 6 by R20 and Q3, ensures Q2 to be turned
off.
Programmable Under voltage Lockout
The PCB allows to insert a couple of resistor (R22, R23) to modify
the threshold input voltage. Please refer to fig. 16 and table1.
L4981A - L4981B
12/17
Figure 20: P.C. Board and Component Layout of Evaluation Board Circuit (1:1 scale).
L4981A - L4981B
13/17
The evaluation board has been designed using: a
faster not dissipative start-up circuit, a diode (D2)
to speed-up the MOS start-off time and (even if a
single resistor can be used) an external divider to
improve the precision of the overcurrent thresh-
old.
Further there is a possibility to change the input
threshold voltage using an external divider (R23
and R22) and if an inrush current problem arises
a NTC resistor can be used.
The PFC demoboard performances has been
evaluated testing the following parameters:
PF (power factor), A-THD (percentage of current
total harmonic distortion), H3..H9 (percentage of
current’s nth harmonic amplitude), ∆Vo (output
voltage ripple), Vo (output voltage), η (efficiency).
The test configuration, equipments and results
are:
AC POWER
SOURCE
LARCET /3KW
PM1200
AC POWER
ANALYSER
EMI
FILTER
PFC
L4981
DEMO
LOAD
D94IN057
Vi f Pi PF A-THD H3 H5 H7 H9 VO ∆VO PO η
(Vrms) (Hz) (W) (%) (%) (%) (%) (%) (V) (V) (W) (%)
88 60 222 0.999 2.94 1.98 0.61 0.55 0.70 390 8 200 90.2
110 60 220 0.999 1.79 1.40 0.40 0.31 0.28 392 8 201 91.6
132 60 218 0.999 1.71 1.16 0.40 0.35 0.31 394 8 202 92.8
180 50 217 0.999 1.88 1.52 0.65 0.40 0.34 396 8 203 93.8
220 50 217 0.997 2.25 1.68 0.83 0.57 0.48 398 8 204 94.2
260 50 216 0.995 3.30 1.84 1.30 0.39 0.73 400 8 205 95.2
EMI/RFI FILTER
The harmonic content measurement has been
done using an EMI/RFI filter interposed between
the AC source and the demoboard under test,
while the efficiency has been calculated without
the filter contribution.
C1
D94IN052
T1 T2
C
LINE PFC
EARTH
where:
T1 = 1mH C1 = 0.33µF, 630V
T2 = 27mH C2 = 2.2nF, 630V
L4981A - L4981B
14/17
SO20 PACKAGE MECHANICAL DATA
DIM.
mm inch
MIN. TYP. MAX. MIN. TYP. MAX.
A 2.35 2.65 0.093 0.104
A1 0.1 0.3 0.004 0.012
B 0.33 0.51 0.013 0.020
C 0.23 0.32 0.009 0.013
D 12.6 13 0.496 0.512
E 7.4 7.6 0.291 0.299
e 1.27 0.050
H 10 10.65 0.394 0.419
h 0.25 0.75 0.010 0.030
L 0.4 1.27 0.016 0.050
K 0 (min.)8 (max.)
1 10
1120
A
eB
D
E
L
K
H
A1 C
SO20MEC
h x 45°
L4981A - L4981B
15/17
DIP20 PACKAGE MECHANICAL DATA
DIM.
mm inch
MIN. TYP. MAX. MIN. TYP. MAX.
a1 0.254 0.010
B 1.39 1.65 0.055 0.065
b 0.45 0.018
b1 0.25 0.010
D 25.4 1.000
E 8.5 0.335
e 2.54 0.100
e3 22.86 0.900
F 7.1 0.280
I 3.93 0.155
L 3.3 0.130
Z 1.34 0.053
L4981A - L4981B
16/17
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