LX1555CDT データシートの表示（PDF） - Microsemi Corporation
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LX1555CDT Datasheet PDF : 18 Pages
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PRODUCT DATABOOK 1996/1997
LX1552/3/4/5
ULTRA-LOW START-UP CURRENT, CURRENT-MODE PWM
PRODUCTION DATA SHEET
E L E C T R I C A L C H A R A C T E R I S T I C S (Con't.)
Parameter
Symbol
Test Conditions
LX155xI/155xM
LX155xC
Units
Min. Typ. Max. Min. Typ. Max.
Under-Voltage Lockout Section
Start Threshold
VST 1552/1554
1553/1555
15 16 17 15 16 17 V
7.8 8.4 9.0 7.8 8.4 9.0 V
Min. Operation Voltage After Turn-On
1552/1554
9 10 11 9 10 11 V
1553/1555
7.0 7.6 8.2 7.0 7.6 8.2 V
PWM Section
Maximum Duty Cycle
1552/1553
94 96
94 96
%
1552/1553, RT = 698Ω, CT = 22nF
1554/1555
50
50
%
47 48
47 48
%
Minimum Duty Cycle
0
0
%
Power Consumption Section
Start-Up Current
Operating Supply Current
VCC Zener Voltage
IST
ICC
VZ ICC = 25mA
150 250
150 250 µA
11 17
11 17 mA
30 35
30 35
V
Notes: 2. These parameters, although guaranteed, are not 100% tested in
production.
3. Parameter measured at trip point of latch with VFB = 0.
4. Gain defined as:
A=
∆ VCOMP
∆V
;
0 ≤ V ≤ 0.8V.
ISENSE
ISENSE
5. Adjust VCC above the start threshold before setting at 15V.
6. Output frequency equals oscillator frequency for the LX1552 and
LX1553. Output frequency is one half oscillator frequency for the
LX1554 and LX1555.
7. Temperature stability, sometimes referred to as average temperature
coefficient, is described by the equation:
V (max.) - V (min.)
Temp Stability = REF
REF
T (max.) - T (min.)
A
A
V (max.) & V (min.) are the maximum & minimum reference
REF
REF
voltage measured over the appropriate temperature range. Note that the
extremes in voltage do not necessarily occur at the extremes in
temperature.
BLOCK DIAGRAM
VCC*
GROUND**
34V
16V (1552/1554)
8.4V (1553/1555)
UVLO
S/R
5V
REF
16V (1552/1554)
8.4V (1553/1555)
VREF
INTERNAL
BIAS
VREF
GOOD LOGIC
RT/CT
VFB
COMP
ISENSE
OSCILLATOR
ERROR AMP
***
T
S
2R
1V
R
R PWM
LATCH
CURRENT SENSE
COMPARATOR
* - VCC and VC are internally connected for 8 pin packages.
** - POWER GROUND and GROUND are internally connected for 8 pin packages.
*** - Toggle flip flop used only in 1554 and 1555.
VC*
OUTPUT
POWER GROUND**
4
Copyright © 1994
Rev. 1.0a 1/01
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