MC34271 Datasheet, PDF (1/12 Pages) ON Semiconductor – Liquid Crystal Display and Backlight Integrated Controller

MC34271
Liquid Crystal Display and
Backlight Integrated
Controller
The MC34271 is a low power dual switching voltage regulator,
specifically designed for handheld and laptop applications, to provide
several regulated output voltages using a minimum of external parts.
Two uncommitted switching regulators feature a very low standby
bias current of 5.0 µA, and an operating current of 7.0 mA capable of
supplying output currents in excess of 200 mA.
Both devices have three additional features. The first is an ELD
Output that can be used to drive a backlight or a liquid crystal display.
The ELD output frequency is the clock divided by 256. The second
feature allows four additional output bias voltages, in specific
proportions to VB, one of the switching regulated output voltages. It
t ^{allows use of mixed logic circuitry and provides a voltage bias for}
N–Channel load control MOSFETs . The third feature is an Enable
input that allows a logic level signal to turn–“off” or turn–“on” both
switching regulators.
Due to the low bias current specifications, this device is ideally
suited for battery powered computer, consumer, and industrial
equipment where an extension of useful battery life is desirable.
MC34271 Features:
• Low Standby Bias Current of 5.0 µA
• Uncommitted Switching Regulators Allow Both Positive and
Negative Supply Voltages
• Logic Enable Allows Microprocessor Control of All Outputs
• Synchronizable to External Clock
• Mode Commandable for ELD and LCD Interface
• Frequency Synchronizable
• Auxiliary Output Bias Voltages Enable Load Control via N–Channel
FETs
MAXIMUM RATINGS (TA = 25°C, unless otherwise noted.)
Rating
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ^{Input Voltage}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ^{Power Dissipation and}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ^{Thermal Characteristics}
Symbol
Value
Unit
VDD
16
Vdc
Maximum Power Dissipation – Case 873
PD
1.43
W
Thermal Resistance, Junction–to–Ambient
R_θJA
100
°C/W
Thermal Resistance, Junction–to–Case
Output #1 and #2 Switch Current
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{Output #1 and #2 “Off”–State Voltage}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{Feedback Enable MOSFETs}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{“Off”–State Voltage}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{Operating Junction Temperature}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{Operating Ambient Temperature}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{Storage Temperature Range}
R_θJC
60
°C/W
ISL & ISB
500
mA
VSL
60
Vdc
VLF
20
Vdc
TJ
125
°C
TA
0 to +70
°C
Tstg – 55 to +150 °C
http://onsemi.com
32
1
QFP–32
FB SUFFIX
CASE 873
PIN CONNECTIONS AND
MARKING DIAGRAM
32 31 30 29 28 27 26 25
1 DS1
2 Ref1
3 FB1
4 Comp1
5 SS1
6 S1
7 D1
8 Drv1
9
DS2 24
Ref2 23
FB2 22
Comp2 21
SS2 20
S2 19
D2 18
VB 17
10 11 12 13 14 15 16
(Top View)
A = Assembly Location
WL = Wafer Lot
YY = Year
WW = Work Week
ORDERING INFORMATION
Device
Package
Shipping
MC34271FB
QFP–32 250 Units / Tray
© Semiconductor Components Industries, LLC, 2000
1
April, 2000 – Rev. 0
Publication Order Number:
MC34271/D