Datasheet

8
LTC1427-50
142750f LT/TP 0398 4K • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 1998
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
●
[phone]
FAX: [phone]
●
TELEX: 499-3977
●
www.linear-tech.com
TYPICAL APPLICATIONS
U
SMBus-Controlled Floating CCFL Power Supply
PART NUMBER DESCRIPTION COMMENTS
LTC1329-10/LTC1329-50 Micropower 8-Bit Current Source DAC 1-Wire, 2-Wire or Standard 3-Wire SPI Control
LTC1380/LTC1393 SMBus Single-Ended 8-Channel/Differential Single 2.7V to ±5V Supply, Low Power
4-Channel Multiplexers
LTC1426 Micropower Dual 6-Bit PWM DAC Pulse Mode and Push-Button Mode Interface
LTC1428 Micropower 8-Bit Current Sink DAC 1-Wire, 2-Wire or Standard 3-Wire SPI Control
LTC1623 SMBus Dual High Side Switch Controller Regulated Onboard Charge Pump Drives External N-Channel MOSFETs
RELATED PARTS
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
16
15
14
13
12
11
10
9
BAT
8V TO 28V
1
2
3
4
5
6
7
8
1
2
3
4
8
7
6
5
I
CCFL

DIO
CCFL V
C

AGND
SHDN
NC
CCFL V
SW

BULB
BAT
ROYER
V
IN

REF
NC
CCFL
PGND
NC
LT1184F
LAMP
UP TO 6mA
10
6
L1
R1
750Ω
L2
100µH
3

21 5
4
+
+
C7, 1µF
SHDN

C6
0.1µF
TO
SMBUS
HOST
C1*
0.1µF
D1
1N5818
C5
1000pF
R2
220k
R3
100k
C3A
2.2µF
35V
C4
2.2µF
1427 TA01
V
IN
3.3V
C3B
2.2µF
35V
C2
27pF
3kV
+
Q2* Q1*
ALUMINUM ELECTROLYTIC IS RECOMMENDED FOR C3B WITH AN 
ESR ≥ 0.5Ω TO PREVENT DAMAGE TO THE LT1184F HIGH-SIDE 
SENSE RESISTOR DUE TO SURGE CURRENTS AT TURN-ON.

C1 MUST BE A LOW LOSS CAPACITOR, C1 = WIMA MKP-20
Q1, Q2 = ZETEX ZTX849 OR ROHM 2SC5001
L1 = COILTRONICS CTX210605
L2 = COILTRONICS CTX100-4
*DO NOT SUBSTITUTE COMPONENTS
COILTRONICS [phone]

0µA TO 50µA I
CCFL
CURRENT GIVES 
0mA TO 6mA LAMP CURRENT FOR A 
TYPICAL DISPLAY.
D5
BAT85
V
CC
3.3V
LTC1427-50

NC
SHDN
AD1
AD0
GND
V
CC

I
OUT

SCL
SDA
Dimensions in inches (millimeters) unless otherwise noted.
PACKAGE DESCRIPTION
U
0.016 – 0.050
0.406 – 1.270
0.010 – 0.020
(0.254 – 0.508)
× 45°
0°– 8° TYP
0.008 – 0.010
(0.203 – 0.254)
SO8 0996
0.053 – 0.069
(1.346 – 1.752)
0.014 – 0.019
(0.355 – 0.483)
0.004 – 0.010
(0.101 – 0.254)
0.050
(1.270)
TYP
1
2
3
4
0.150 – 0.157**
(3.810 – 3.988)
8
7
6
5
0.189 – 0.197*
(4.801 – 5.004)
0.228 – 0.244
(5.791 – 6.197)
DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH 
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD 
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE


*

**