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LT1248IS#PBF

P1-P3P4-P6P7-P9P10-P12
1
LT1248
Power Factor Controller
–
+
–
+
–
+
I
M
=
I
A
2
I
B
200µA
2
V
CC
VA
OUT
16V TO 10V
2.6V/
2.2V
7.5V
7.9V
12µA
5V
EA
V
REF
–
+
–
+
–
+
–
+
2.2V
32k
I
A
I
B
7µA
I
M
7.5V
V
REF
–
+
–
+
0.7V
ONE SHOT
200ns
OSC
R
R
S
Q
C
SET
R
SET
13
6
11
8
10
7
9
5
4
32
1
15
16
1214
SS
OVP
I
AC
V
SENSE
EN/SYNC
M
OUT
I
SENSE
CA
OUT
PK
LIM
V
CC
RUN
CA
RUN
1 6V
GND
–
+
GTDR
1248 BD
SYNC
M1
The LT
®
1248 provides active power factor correction for
universal off-line power systems. By using fixed high
frequency PWM current averaging, without the need for
slope compensation, the LT1248 achieves far lower line
current distortion with a smaller magnetic element than
systems that use either peak-current detection or zero
current switching approaches in both continuous and
discontinuous modes of operation.
The LT1248 uses a multiplier containing a square gain
function from the voltage amplifier to reduce the AC gain
at light output load and thus maintains low line current
distortion and high system stability. The LT1248 also
provides filtering capability to reject line switching noise
which can cause instability when fed into the multiplier.
Line current dead zone is minimized with low bias voltage
at the current input to the multiplier.
The LT1248 provides many protection features including
peak current limiting and overvoltage protection, and can
be operated at frequencies as high as 300kHz.
■
High Power Factor Over Wide Load Range
with Line Current Averaging
■
International Operation Without Switches
■
Instantaneous Overvoltage Protection
■
Minimal Line Current Dead Zone
■
Typical 250µA Start-Up Supply Current
■
Rejects Line Switching Noise
■
Synchronization Capability
■
Low Quiescent Current: 9mA
■
Fast 1.5A Peak Current Gate Driver
■
Universal Power Factor Corrected Power Supplies
■
Preregulators Up To 1500W
, LTC and LT are registered trademarks of Linear Technology Corporation.
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
BLOCK DIAGRA
W
2
LT1248
A
U
G
W
A
W
U
W
ARB
S
O
LU
T
EXI T
I
S
(Note 1)
Supply Voltage ....................................................... 27V
GTDR Current Continuous ..................................... 0.5A
GTDR Output Energy(Per Cycle) .............................. 5µJ
I
AC
, R
SET
, PK
LIM
Input Current............................. 20mA
V
SENSE
, EN/SYNC, OVP Input Voltage................... V
MAX
I
SENSE
, M
OUT
Input Current.................................. ±5mA
Operating Junction Temperature Range
LT1248C................................................ 0°C to 100°C
LT1248I ........................................... –40°C to 125°C
Thermal Resistance (Junction-to-Ambient)
N Package .................................................. 100°C/W
S Package................................................... 120°C/W
Storage Temperature Range ..................–65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
WU
U
PACKAGE
/
O
RDER I FOR ATIO
E
LECTR
IC
AL C CHARA TERIST
ICS
ORDER PART
NUMBER
The
●
denotes specifications which apply over the full operating tempera-
ture range, otherwise specifications are at T
A
= 25°C. Maximum operating voltage (V
MAX
) = 25V, V
CC
= 18V, R
SET
= 15k to GND,
C
SET
= 1nF to GND, I
AC
= 100µA, I
SENSE
= 0V, CA
OUT
= 3.5V, VA
OUT
= 5V, OVP = 7.5V, no load on any outputs, unless otherwise noted.
LT1248CN
LT1248IN
LT1248CS
LT1248IS
T
JMAX
= 125°C, θ
JA
= 100°C/W (N)
T
JMAX
= 125°C, θ
JA
= 120°C/W (S)
Consult factory for Military grade parts.
1
2
3
4
5
6
7
8
TOP VIEW
N PACKAGE
16-LEAD PDIP
S PACKAGE
16-LEAD NARROW PLASTIC SO
16
15
14
13
12
11
10
9
GND
PK
LIM
CA
OUT
I
SENSE
M
OUT
I
AC
VA
OUT
OVP
GTDR
V
CC
C
SET
SS
R
SET
V
SENSE
EN/SYNC
V
REF
PARAMETER CONDITIONS MIN TYP MAX UNITS
Overall
Supply Current (V
CC
in Undervoltage Lockout) V
CC
= Lockout Voltage – 0.2V ● 0.25 0.45 mA
Supply Current (Inactive) EN/SYNC = 0V, V
CC
≤ V
MAX
● 0.5 1.5 mA
Supply Current, On 11.5V ≤ V
CC
≤ V
MAX
, CA
OUT
= 1V ● 8.5 12.0 mA
V
CC
Turn-On Threshold (Undervoltage Lockout) ● 15.5 16.5 17.5 V
V
CC
Turn-Off Threshold ● 9.5 10.5 11.5 V
EN/SYNC Threshold, Rising ● 2.2 2.6 2.85 V
EN/SYNC Threshold Hysteresis 0.40 V
EN/SYNC Input Current EN/SYNC = 0V ● –5 –1 5 µA
3V ≤ EN/SYNC ≤ 7V –50 – 25 50 µA
Voltage Amplifier
Voltage Amp Offset Voltage VA
OUT
= 3.5V ● –8 8 mV
Input Bias Current V
SENSE
= 0V to 7V ● –25 –250 nA
Voltage Gain 70 100 dB
Voltage Amp Unity-Gain Bandwidth 3 MHz
Voltage Amp Output High (Internally Clamped) ● 11.3 13.3 V
Voltage Amp Output Low ● 1.1 2 V
Voltage Amp Short-Circuit Current VA
OUT
= 0V ● 51430 mA
SS Current SS = 2.5V ● 51230 µA
Current Amplifier
Current Amp Offset Voltage ● ±1 ±4mV
I
SENSE
Bias Current ● –25 –250 nA
Current Amp Voltage Gain 80 110 dB
Current Amp Unity-Gain Bandwidth 3 MHz
Current Amp Output High ● 7.2 8.5 V
Current Amp Output Low ● 1.1 2 V
3
LT1248
I
M
I
AC
(VA
OUT
– 2)
2
Note 2: Multiplier Gain Constant: K =
E
LECTR
IC
AL C CHARA TERIST
ICS
The
●
denotes specifications which apply over the full operating tempera-
ture range, otherwise specifications are at T
A
= 25°C. Maximum operating voltage (V
MAX
) = 25V, V
CC
= 18V, R
SET
= 15k to GND,
C
SET
= 1nF to GND, I
AC
= 100µA, I
SENSE
= 0V, CA
OUT
= 3.5V, VA
OUT
= 5V, OVP = 7.5V, no load on any outputs, unless otherwise noted.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired
PARAMETER CONDITIONS MIN TYP MAX UNITS
Current Amplifier
Current Amp Short-Circuit Current CA
OUT
= 0V ● 51430 mA
Input Range, I
SENSE
, M
OUT
(Linear Operation) ● –0.3 1 V
Reference
Reference Output Voltage I
REF
= 0mA, T
A
= 25°C 7.39 7.50 7.60 V
V
REF
Load Regulation –5mA < I
REF
< 0mA 5 mV
V
REF
Line Regulation 11.5V < V
CC
< V
MAX
● –20 5 20 mV
V
REF
Short-Circuit Current V
REF
= 0V ● 12 28 50 mA
V
REF
Worst Case Load, Line, Temperature ● 7.32 7.5 7.68 V
Current Limit
PK
LIM
Offset Voltage ● –15 15 mV
PK
LIM
Input Current PK
LIM
= –0.1V ● – 50 –100 µA
PK
LIM
to GTDR Propagation Delay PK
LIM
Falling from 50mV to –50mV 400 ns
Multiplier
Multiplier Output Current I
AC
= 100µA, R
SET
= 15k 35 µA
Multiplier Output Current Offset R
AC
= 1M from I
AC
to GND ● –0.05 –0.5 µA
Multiplier Maximum Output Current I
AC
= 450µA, R
SET
= 15k, VA
OUT
= 7V, M
OUT
= 0V ● –286 –260 –235 µA
Multiplier Gain Constant (Note 2) 0.035 V
–2
I
AC
Input Resistance I
AC
from 50µA to 1mA 15 32 50 kΩ
Oscillator
Oscillator Frequency R
SET
= 15k, C
SET
= 1000pF ● 85 100 115 kHz
R
SET
= 15k, C
SET
= 1500pF ● 58 68 78 kHz
C
SET
Ramp Peak-to-Peak Amplitude 4.35 4.7 5.0 V
C
SET
Ramp Valley Voltage 1.25 1.4 1.55 V
Synchronization Pulse Threshold on EN/SYNC Pin
Pulse Low = 3.5V, High = 7V, Width > 200ns
4.5 5.6 6.5 V
Synchronization Frequency Range
R
SET
= 15k, C
SET
= 1000pF
● 1.2 1.6 f
NOM
Overvoltage Comparator
Comparator Trip Voltage Ratio (V
TRIP
/V
REF
) ● 1.04 1.05 1.06
Hysteresis 0.35 V
OVP Bias Current OVP = 7.5V ● –50 –250 nA
OVP Propagation Delay 100 ns
Gate Driver
Max GTDR Output Voltage 0mA Load, 18V < V
CC
● 12 15 17.5 V
GTDR Output High –200mA Load, 11.5V ≤ V
CC
≤ 15V ● V
CC
– 3.0 V
GTDR Output Low (Device Unpowered) V
CC
= 0V, 50mA Load (Sinking) ● 0.9 1.5 V
GTDR Output Low (Device Active) 200mA Load (Sinking) ● 0.5 1 V
10mA Load
● 0.2 0.4 V
Peak GTDR Current 10nF from GTDR to GND 2 A
GTDR Rise and Fall Time 1nF from GTDR to GND 25 ns
GTDR Max Duty Cycle 90 96 %
P1-P3P4-P6P7-P9P10-P12

LT1248IS#PBF

Mfr. #:
Buy LT1248IS#PBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Power Factor Correction - PFC Pwr Factor Correction Controller
Lifecycle:
New from this manufacturer.
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