19-3919; Rev 0; 1/06
KIT
ATION
EVALU
E
BL
AVAILA
TFT LCD DC-DC Converter with
Integrated Charge Pumps
General Description
Features
o
3 Integrated DC-DC Converters, 1 LDO
o
1MHz Current-Mode PWM Boost Regulator
Up to +13V Main High-Power Output
±1% Accuracy
High Efficiency (90%)
o
Dual Charge-Pump Outputs
No External Diodes for Positive Charge Pump
Up to +28V Positive Charge-Pump Output
Negative Charge-Pump Output
o
300mA Logic Linear Regulator
o
+2.6V to +5.5V Input Operating Range
o
0.8mA Quiescent Current
o
Internal Supply Sequencing and Soft-Start
o
Thermal Protection
o
Ultra-Thin, 28-Pin TQFN Package (0.8mm max)
MAX8753
The MAX8753 quadruple-output DC-DC converter pro-
vides the regulated voltages required by active-matrix,
thin-film transistor (TFT), liquid-crystal displays (LCDs).
It includes a high-power step-up regulator (V
MAIN
), two
low-power charge pumps (V
POS
and V
NEG
), and a low-
voltage 300mA linear regulator (V
LOGIC
).
The step-up DC-DC converter is a high-frequency
(1MHz) current-mode regulator with a built-in power
MOSFET that allows the use of ultra-small inductors and
ceramic capacitors. It provides fast transient response
to pulsed loads and includes an automatic pulse-skip-
ping mode that increases efficiency over a wide-load
current range. The 1.5A current limit allows a +10V out-
put at more than 300mA from a +3.3V input.
The two charge pumps independently regulate one
positive and one negative output voltage. The positive
charge pump is a voltage tripler that accepts an input
voltage up to +13V and delivers a 20mA output up to
+28V without external switches or diodes. The negative
charge pump inverts an input voltage up to +24V and
delivers a 20mA negative output using external diodes.
The logic linear regulator converts the IC’s +2.6V-to-
+5.5V input to a regulated +2.5V or adjustable output.
The MAX8753 is available in a 28-pin thin QFN pack-
age with a maximum thickness of 0.8mm for ultra-thin
LCD panel design.
Ordering Information
PART
MAX8753ETI+
TEMP RANGE
-40°C to 85°C
PIN-PACKAGE
28 Thin QFN
(5mm x 5mm)
+Denotes
lead-free package.
Applications
Notebook Computers, PDAs
Car Navigation Displays
LCD Monitors
V
IN
+2.6V TO +5.5V
Minimal Operating Circuit
V
MAIN
Pin Configuration
SUPN
N.C.
FBN
C3P
I.C.
I.C.
INTG
LX
SUPP
IN
PGND
TOP VIEW
LX
21
PGND 22
N.C. 23
DLP 24
SHDN 25
LCDON 26
C1N 27
C1P 28
1
SUPP
V
MAIN
GND
SUPN
FB
20
19
18
17
16
15
14
13
12
REF
GND
N.C.
IN
OUTL
FBL
FBP
V
LOGIC
C3P
SHDN
LCDON
OUTL
FBL
DLP
FBP
REF
V
NEG
MAX8753
FBN
MAX8753
11
10
9
8
V
POS
OUTP
C1N
C2N
2
N.C.
3
C2N
4
C2P
5
OUTP
6
INTG
7
FB
TQFN
________________________________________________________________
Maxim Integrated Products
C1P
C2P
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
TFT LCD DC-DC Converter with
Integrated Charge Pumps
MAX8753
ABSOLUTE MAXIMUM RATINGS
IN,
SHDN,
LCDON to GND ......................................-0.3V to +6V
DLP, OUTL, FBL, FBP, FBN, INTG, FB,
REF to GND ............................................-0.3V to (V
IN
+ 0.3V)
PGND to GND .......................................................-0.3V to +0.3V
LX to PGND ............................................................-0.3V to +14V
SUPP to PGND .......................................................-0.3V to +14V
C1N, C2N to PGND ................................-0.3V to (V
SUPP
+ 0.3V)
OUTP to PGND ........................................(V
SUPP
- 0.3V) to +30V
C1P to C1N, C2P to C2N, OUTP to C2P ................-0.3V to +14V
SUPN to PGND.......................................................-0.3V to +30V
C3P to PGND.........................................-0.3V to (V
SUPN
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
28-Pin 5mm x 5mm TQFN (derated 21.3mW/°C
above +70°C)............................................................1702mW
Operating Temperature Range .......................... -40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V
IN
= 3.0V,
SHDN
= LCDON = IN, V
SUPP
= V
SUPN
= 10V, PGND = GND, CREF = 0.22µF, C
INTG
= 470pF,
T
A
=
0°C to +85°C.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
INPUT SUPPLIES
Input Supply Range
Input Undervoltage Threshold
IN Quiescent Supply Current
IN Shutdown Current
SUPP Supply Range
SUPP Quiescent Current
SUPP Shutdown Current
SUPN Supply Range
SUPN Quiescent Current
SUPN Shutdown Current
MAIN BOOST CONVERTER
Output Voltage Range
FB Regulation Voltage
FB Input Bias Current
FB Undervoltage Shutdown
Threshold
Operating Frequency
Oscillator Maximum Duty Cycle
Load Regulation
Line Regulation
INTG Transconductance
LX Switch On-Resistance
LX Leakage Current
R
LX(ON)
I
LX
I
LX
= 100mA
V
LX
= 13V, V
SHDN
= 0
I
MAIN
= 0 to 100mA, V
MAIN
= 10V
f
OSC
V
MAIN
V
FB
I
FB
V
FB
= 1.25V, INTG = GND
FB falling
75
0.85
78
V
IN
1.232
1.245
125
125
1.00
85
0.2
0.1
320
0.35
0.01
0.7
20
13
1.258
275
200
1.15
90
V
V
nA
mV
MHz
%
%
%/V
µS
Ω
µA
V
SUPN
I
SUPN
V
FBN
= -0.2V
V
SHDN
= 0, V
SUPN
= 24V
V
SUPP
I
SUPP
V
FBP
= 1.5V
V
SHDN
= 0, V
SUPP
= 14V, OUTP floating
7
0.4
0.1
V
IN
V
UVLO
I
IN
V
IN
rising, 100mV hysteresis (typ)
V
FB
= V
FBP
= 1.5V, V
FBN
= -0.2V
V
SHDN
= 0, V
IN
= 5V
7
0.4
0.1
2.6
2.1
2.3
0.8
0.1
5.5
2.5
1.5
10
13
0.8
10
24
0.8
10
V
V
mA
µA
V
mA
µA
V
mA
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
TFT LCD DC-DC Converter with
Integrated Charge Pumps
MAX8753
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
IN
= 3.0V,
SHDN
= LCDON = IN, V
SUPP
= V
SUPN
= 10V, PGND = GND, CREF = 0.22µF, C
INTG
= 470pF,
T
A
=
0°C to +85°C.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
Phase I = soft-start (1.0ms)
LX Current Limit
I
LX(MAX)
Phase II = soft-start (1.0ms)
Phase III = soft-start (1.0ms)
Phase IV = fully on (> 3.0ms)
Soft-Start Period
POSITIVE CHARGE PUMP
V
SUPP
Input Supply Range
V
SUPP
Overvoltage Threshold
OUTP Operating Range
Operating Frequency
FBP Regulation Voltage
FBP Line Regulation
FBP Input Bias Current
Soft-Start Period
C1N, C2N High-Side On-
Resistance
C1N, C2N Low-Side On-
Resistance
C1P Switch On-Resistance
C2P Switch On-Resistance
OUTP Switch On-Resistance
NEGATIVE CHARGE PUMP
V
SUPN
Input Supply Range
Operating Frequency
FBN Regulation Voltage
FBN Line Regulation
FBN Input Bias Current
Soft-Start Period
C3P High-Side On-Resistance
C3P Low-Side On-Resistance
I
FBN
V
SSN
I
SINK
= 50mA
I
SINK
= 50mA
V
FBN
V
SUPN
= 8V to 24V, V
OUTN
= -10V, I
OUTN
=
5mA
V
FBN
= -0.05V
-50
1024 /
fosc
15
10
213
V
SUPN
7
0.25 x
f
OSC
250
10
+50
287
24
V
Hz
mV
mV
nA
s
Ω
Ω
I
FBP
V
SSP
I
SOURCE
= 50mA
I
SINK
= 50mA
I
SOURCE
= 50mA
I
SOURCE
= 50mA
I
SOURCE
= 50mA
V
FBP
V
SUPP
= 8V to 12V, V
OUTP
= 20V, I
OUTP
=
5mA
V
FBP
= 1.5V
-50
1024 /
f
OSC
15
5
8
8
8
1.213
V
SUPP
V
SUPP
= rising, hysteresis (typ) = 200mV
7
13.2
V
SUPP
0.25 x
f
OSC
1.250
10
+50
1.287
13.6
13
14.0
28
V
V
V
Hz
V
mV
nA
s
Ω
Ω
Ω
Ω
Ω
t
SS
Power-up to the end of phase III
1.08
MIN
TYP
0.38
0.75
1.13
1.45
3072 /
f
OSC
1.80
s
A
MAX
UNITS
_______________________________________________________________________________________
3
TFT LCD DC-DC Converter with
Integrated Charge Pumps
MAX8753
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
IN
= 3.0V,
SHDN
= LCDON = IN, V
SUPP
= V
SUPN
= 10V, PGND = GND, CREF = 0.22µF, C
INTG
= 470pF,
T
A
=
0°C to +85°C.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
V
LOGIC
REGULATOR
FBL Regulation Voltage
FBL Input Bias Current
FBL Undervoltage Lockout
FBL Dual-Mode™ Threshold
OUTL Voltage Accuracy
(Preset Mode)
OUTL Load Regulation
OUTL Line Regulation
OUTL On-Resistance
OUTL Short-Circuit Current
REFERENCE
Reference Voltage
Reference Undervoltage
Threshold
LOGIC SIGNALS
LCDON,
SHDN
Input Low Voltage
LCDON,
SHDN
Input High
Voltage
SHDN
Input Current
LCDON Input Current
SEQUENCING
DLP Capacitor Charge Current
DLP Turn-On Threshold
DLP Discharge Switch
On-Resistance
FAULT PROTECTION
Duration to Trigger Fault
FBL Fault-Trip Level
FB, FBP Fault-Trip Level
FBN Fault-Trip Level
Thermal-Shutdown Threshold
t
FAULT
Falling edge
Falling edge
Rising edge
Typical hysteresis = 15°C
0.95
1.07
450
V
DLP
= 0.5V
V
DLP
= rising
V
SHDN
= 0
4
1.20
5
1.25
40
6
1.30
µA
V
Ω
V
REF
-2µA < I
REF
< +50µA
V
REF
rising
1.231
0.9
1.250
1.05
1.269
1.2
V
V
V
FBL
I
FBL
V
FBL_UV
I
OUTL
= 0 to 300mA
V
FBL
= 1.3V
V
FBL
rising, hysteresis (typ) = 125mV
V
FBL
= rising
V
FBL
= GND, I
OUTL
= 0 to 300mA
I
OUTL
= 0 to 300mA
V
IN
= 2.6V to 5.5V
V
IN
= 3.3V, I
OUTL
= 100mA
V
OUTL
= GND, V
FBL
= 1V
0.1
0.7
500
1.5
1.225
-50
1.100
220
2.425
1.125
250
2.500
1.250
1.275
+50
1.150
280
2.575
-2
V
nA
V
mV
V
%
%
Ω
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Hysteresis = 0.15 x V
IN
(typ)
2.1
I
SHDN
I
LCDON
V
SHDN
= 0 to IN
V
LCDON
= 0 to IN
0.01
0.01
0.9
V
V
1
1
µA
µA
50
1.01
1.10
500
+160
1.08
1.14
550
ms
V
V
mV
°C
Dual-Mode is a trademark of Maxim Integrated Products, Inc.
4
_______________________________________________________________________________________
TFT LCD DC-DC Converter with
Integrated Charge Pumps
MAX8753
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V
IN
= 3.0V,
SHDN
= LCDON = IN, V
SUPP
= V
SUPN
= 10V, PGND = GND, C
REF
= 0.22µF, C
INTG
= 470pF,
T
A
=
-40°C to +85°C.
Typical values are at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
INPUT SUPPLIES
Input Supply Range
Input Undervoltage Threshold
IN Quiescent Supply Current
SUPP Supply Range
SUPP Quiescent Current
SUPN Supply Range
SUPN Quiescent Current
MAIN BOOST CONVERTER
Output Voltage Range
FB Regulation Voltage
FB Undervoltage Shutdown
Threshold
Operating Frequency
LX Switch On-Resistance
LX Current Limit
POSITIVE CHARGE PUMP
V
SUPP
Input Supply Range
V
SUPP
Overvoltage Threshold
FBP Regulation Voltage
NEGATIVE CHARGE PUMP
V
SUPN
Input Supply Range
FBN Regulation Voltage
V
LOGIC
REGULATOR
FBL Regulation Voltage
OUTL On-Resistance
REFERENCE
Reference Voltage
Reference Undervoltage
Threshold
LOGIC SIGNALS
LCDON,
SHDN
Input Low
Voltage
LCDON,
SHDN
Input High
Voltage
Hysteresis = 0.15 x V
IN
(typ)
2.1
0.9
V
V
V
REF
-2µA < I
REF
< +50µA
V
REF
rising
1.225
0.9
1.269
1.2
V
V
V
FBL
I
OUTL
= 0 to 300mA
V
IN
= 3.3V, I
OUTL
= 100mA
1.220
1.275
1.5
V
Ω
V
SUPN
V
FBN
7
213
24
287
V
mV
V
FBP
V
SUPP
V
SUPP
= rising, hysteresis (typ) = 200mV
7
13.2
1.213
13
14.0
1.287
V
V
V
f
OSC
R
LX(ON)
I
LX(MAX)
I
LX
= 100mA
Phase IV = fully on (> 3.0ms)
1.08
V
MAIN
V
FB
FB falling
V
IN
1.225
75
0.75
13
1.258
200
1.25
0.7
1.8
V
V
mV
MHz
Ω
A
V
IN
V
UVLO
I
IN
V
SUPP
I
SUPP
V
SUPN
I
SUPN
V
FBN
= -0.2V
V
FBP
= 1.5V
7
V
IN
rising, 100mV hysteresis (typ)
V
FB
= V
FBP
= 1.5V, V
FBN
= -0.2V
7
2.6
2.1
5.5
2.5
1.5
13
0.8
24
0.8
V
V
mA
V
mA
V
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
_______________________________________________________________________________________
5
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