19-1788; Rev 0; 10/00
IT
TION K
VALUA
E
BLE
AVAILA
Triple Charge-Pump TFT LCD
DC-DC Converter
General Description
MAX1747
Features
o
Adjustable Outputs
Up to +5.5V Main High-Power Output
Up to +35V Positive Charge-Pump Output
Down to -35V Negative Charge-Pump Output
o
200kHz to 2MHz Adjustable Switching Frequency
o
+2.7V to +4.5V Input Supply
o
Internal Power MOSFETs
o
0.1µA Shutdown Current
o
Internal Soft-Start
o
Power-Ready Output
o
Internal Supply Sequencing
o
Fast Transient Response
o
Ultra-Thin Solution (No Inductors)
o
Thin TSSOP Package (1.1mm max)
The MAX1747 triple charge-pump DC-DC converter
provides the regulated voltages required by active
matrix thin-film transistor (TFT) liquid-crystal displays
(LCDs) in a low-profile TSSOP package. One high-
power and two low-power charge pumps convert the
+2.7V to +4.5V input supply voltage into three indepen-
dent output voltages.
The primary high-power charge pump generates an
output voltage (V
OUT
) between 4.5V and 5.5V that is
regulated within ±1%. The low-power BiCMOS control
circuitry and the low on-resistance (R
ON
) power
MOSFETs maximize efficiency. The adjustable switch-
ing frequency (200kHz to 2MHz) provides fast transient
response and allows the use of small low-profile ceram-
ic capacitors.
The dual low-power charge pumps independently regu-
late one positive output (V
POS
) and one negative output
(V
NEG
). These additional outputs use external diode
and capacitor multiplier stages (as many stages as
required) to regulate output voltages up to +35V and
-35V.
The constant switching frequency and a proprietary
regulation algorithm minimize output ripple and capaci-
tor sizes for all three charge pumps. The MAX1747 is
available in the ultra-thin TSSOP package (1.1mm max
height).
Ordering Information
PART
MAX1747EUP
TEMP. RANGE
-40°C to +85°C
PIN-PACKAGE
20 TSSOP
Applications
TFT Active-Matrix LCDs
Passive-Matrix Displays
Personal Digital Assistants (PDAs)
INPUT
Typical Operating Circuit
SUPM
IN
CXP
CXN
MAIN OUTPUT
TO
µC
SHDN
RDY
DRVN
OUT
SUPP
SUPN
FB
Pin Configuration
TOP VIEW
TGND 1
TGND 2
RDY 3
FB 4
INTG 5
IN 6
GND 7
REF 8
FBP 9
FBN 10
20 OUT
19 CXP
18 SUPM
17 CXN
MAX1747
MAX1747
NEGATIVE
OUTPUT
DRVP
FBN
16 PGND
15 SUPP
14 DRVP
13 SUPN
12 DRVN
11 SHDN
REF
FBP
INTG
PGND
POSITIVE
OUTPUT
TGND
GND
TSSOP
________________________________________________________________
Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Triple Charge-Pump TFT LCD
DC-DC Converter
MAX1747
ABSOLUTE MAXIMUM RATINGS
IN, SUPM, OUT, TGND to GND................................-0.3V to +6V
SHDN........................................................................-0.3V
to +1V
PGND to GND.....................................................................±0.3V
SUPM to IN .........................................................................±0.3V
CXN to PGND.........................................-0.3V to (V
SUPM
+ 0.3V)
CXP to PGND ............................(V
SUPM
- 0.3V) to (V
OUT
+ 0.3V)
DRVN to GND .........................................-0.3V to (V
SUPN
+ 0.3V)
DRVP to GND..........................................-0.3V to (V
SUPP
+ 0.3V)
RDY
to GND ...........................................................-0.3V to +14V
SUPP, SUPN to GND..............................................-0.3V to +14V
INTG, REF, FB, FBN, FBP to GND ...............-0.3V to (V
IN
+ 0.3V)
Continuous Current into:
SUPM, CXN, CXP, OUT ..............................................±800mA
SUPP, SUPN, DRVN, DRVP........................................±200mA
SHDN...........................................................................+100µA
All Other Pins ....................................................................±10mA
Continuous Power Dissipation (T
A
= +70°C)
20-Pin TSSOP (derate 10.9mW/°C above +70°C) .......879mW
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
(V
IN
= V
SUPM
= +3.0V, V
SUPP
= V
SUPN
= +5V, TGND = PGND = GND, I
SHDN
= 22µA, C
OUT
= 2
✕
4.7µF, C
REF
= 0.22µF, C
INTG
=
1500pF, V
OUT
= +5V,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Input Supply Range
Input Undervoltage Threshold
Input Quiescent Supply
Current
SYMBOL
V
IN
V
UVLO
I
IN
+
I
SUPM
V
IN
falling, 40mV hysteresis (typ)
V
FB
= V
FBP
= 1.5V, V
FBN
= -0.2V, V
OUT
= 5V,
no load on DRVN and DRVP; CXN
and CXP open
V
FB
= V
FBP
= 1.5V, V
FBN
= -0.2V, V
OUT
= 5V,
no load on DRVN and DRVP; CXN and
CXP open
V
SHDN
= 0, V
SUPM
= 5V
f
OSC
V
OUT
I
OUT(MAX)
V
FB
I
FB
V
FB
= 1.25V
Rising edge
Falling edge
C
X
= 0.47µF
I
SHDN
= 22µA
0.65
4.5
200
1.237
-50
530
1.09
1.125
1.100
4.096
/ F
OSC
V
SUPN
I
SUPN
V
FBN
V
FBN
= -0.2V, no load on DRVN
V
SHDN
= 0, V
SUPN
= 13V
-50
2.7
0.6
0.1
0
13
0.8
10
+50
1.16
1.248
1.263
+50
CONDITIONS
MIN
2.7
2.2
2.4
0.9
TYP
MAX
4.5
2.6
1.0
UNITS
V
V
mA
Output Quiescent Supply
Current
Shutdown Supply Current
Operating Frequency
MAIN CHARGE PUMP
Output Voltage Range
Maximum Output Current
FB Regulation Voltage
FB Input Bias Current
Integrator Transconductance
FB Power-Ready Trip Level
FB Fault Trip Level
Main Soft-Start Period
I
Q(OUT)
2.5
0.1
1
4.0
20
1.2
5.5
mA
µA
MHz
V
mA
V
nA
µS
V
V
s
NEGATIVE LOW-POWER CHARGE PUMP
SUPN Input Supply Range
SUPN Quiescent Current
SUPN Shutdown Current
FBN Regulation Voltage
V
mA
µA
mV
2
_______________________________________________________________________________________
Triple Charge-Pump TFT LCD
DC-DC Converter
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
SUPM
= +3.0V, V
SUPP
= V
SUPN
= +5V, TGND = PGND = GND, I
SHDN
= 22µA, C
OUT
= 2
✕
4.7µF, C
REF
= 0.22µF, C
INTG
=
1500pF, V
OUT
= +5V,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
FBN Input Bias Current
DRVN PCH On-Resistance
DRVN NCH On-Resistance
FBN Power-Ready Trip Level
FBN Fault Trip Level
Negative Soft-Start Period
POSITIVE LOW-POWER CHARGE PUMP
SUPP Input Supply Range
SUPP Quiescent Current
SUPP Shutdown Current
FBP Regulation Voltage
FBP Input Bias Current
DRVP PCH On-Resistance
DRVP NCH On-Resistance
FBP Power-Ready Trip Level
FBP Fault Trip Level
Positive Soft-Start Period
REFERENCE
Reference Voltage
Reference Undervoltage
Threshold
LOGIC SIGNALS
SHDN
Input Low Voltage
SHDN
Bias Voltage
SHDN
Bias Voltage Tempco
SHDN
Input Current Range
RDY
Output Low Voltage
RDY
Output High Leakage
I
SHDN
For 200kHz to 2MHz operation
I
SINK
= 2mA
V
RDY
= 13V
3
0.25
0.01
I
SHDN
= 22µA
580
724
2
65
0.5
1
0.4
830
V
mV
mV/°C
µA
V
µA
V
REF
-2µA < I
REF
< 50µA
V
REF
rising
1.231
0.95
1.25
1.05
1.269
1.18
V
V
V
FBP
= 1.20V
V
FBP
= 1.30V
Rising edge
Falling edge
1.090
V
FBP
I
FBP
V
FBP
= 1.5V
V
SUPP
I
SUPP
V
FBP
= 1.5V, no load on DRVP
V
SHDN
= 0, V
SUPP
= 13V
1.20
-50
3
1.5
20
1.125
1.100
2.048/
F
OSC
1.160
2.7
0.6
0.1
1.25
13
0.8
10
1.30
+50
6
5
V
mA
µA
V
nA
Ω
Ω
kΩ
V
V
s
V
FBN
= 50mV
V
FBN
= -50mV
Falling edge
Rising edge
20
80
125
140
2.048/
F
OSC
165
SYMBOL
I
FBN
V
FBN
= -50mV
CONDITIONS
MIN
-50
3
1
TYP
MAX
+50
6
5
UNITS
nA
Ω
Ω
kΩ
mV
mV
s
MAX1747
_______________________________________________________________________________________
3
Triple Charge-Pump TFT LCD
DC-DC Converter
MAX1747
ELECTRICAL CHARACTERISTICS
(
V
IN
= V
SUPM
= +3.0V, V
SUPP
= V
SUPN
= +5V, TGND = PGND = GND, I
SHDN
= 22µA, C
OUT
= 2
✕
4.7µF, C
REF
= 0.22µF, C
INTG
=
1500pF, V
OUT
= +5V,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 1)
PARAMETER
Input Supply Range
Input Undervoltage Threshold
Input Quiescent Supply
Current
SYMBOL
V
IN
V
UVLO
I
IN
+
I
SUPM
V
IN
falling, 40mV hysteresis (typ)
V
FB
= V
FBP
= 1.5V, V
FBN
= -0.2V, V
OUT
= 5V,
no load on DRVN and DRVP; CXN and
CXP open
V
FB
= V
FBP
= 1.5V, V
FBN
= -0.2V, V
OUT
= 5V,
no load on DRVN and DRVP; CXN and
CXP open
V
SHDN
= 0, V
SUPM
= 5V
f
OSC
V
OUT
I
OUT(MAX)
V
FB
I
FB
V
FB
= 1.25V
Rising edge
V
SUPN
I
SUPN
V
FBN
I
FBN
V
FBN
= 0
V
FBN
= 50mV
V
FBN
= -50mV
Falling edge
V
SUPP
I
SUPP
V
FBP
I
FBP
V
FBP
= 1.5V
V
FBP
= 1.20V
V
FBP
= 1.30V
Rising edge
20
1.09
1.16
V
FBP
= 1.5V, no load on DRVP
V
SHDN
= 0, V
SUPP
= 13V
1.20
-50
20
80
2.7
165
13
0.8
10
1.30
+50
6
5
V
FBN
= -0.2V, no load on DRVN
V
SHDN
= 0, V
SUPN
= 13V
-50
-50
C
X
= 0.47µF
I
SHDN
= 22µA
0.65
4.5
200
1.222
-50
1.09
2.7
1.271
+50
1.16
13
0.8
10
+50
+50
6
5
CONDITIONS
MIN
2.7
2.2
MAX
4.5
2.6
1.0
UNITS
V
V
mA
Output Quiescent Supply
Current
Input Shutdown Current
Operating Frequency
MAIN CHARGE PUMP
Output Voltage Range
Output Current
FB Regulation Voltage
FB Input Bias Current
FB Power-Ready Trip Level
I
Q(OUT)
4.0
20
1.2
5.5
mA
µA
MHz
V
mA
V
nA
V
V
mA
µA
mV
nA
Ω
Ω
kΩ
mV
V
mA
µA
V
nA
Ω
Ω
kΩ
V
NEGATIVE LOW-POWER CHARGE PUMP
SUPN Input Supply Range
SUPN Quiescent Current
SUPN Shutdown Current
FBN Regulation Voltage
FBN Input Bias Current
DRVN PCH On-Resistance
DRVN NCH On-Resistance
FBN Power-Ready Trip Level
POSITIVE LOW-POWER CHARGE PUMP
SUPP Input Supply Range
SUPP Quiescent Current
SUPP Shutdown Current
FBP Regulation Voltage
FBP Input Bias Current
DRVP PCH On-Resistance
DRVP NCH On-Resistance
FBP Power-Ready Trip Level
4
_______________________________________________________________________________________
Triple Charge-Pump TFT LCD
DC-DC Converter
ELECTRICAL CHARACTERISTICS (continued)
(
V
IN
= V
SUPM
= +3.0V, V
SUPP
= V
SUPM
= +5V, TGND = PGND = GND, I
SHDN
= 22µA, C
OUT
= 2
✕
4.7µF, C
REF
= 0.22µF, C
INTG
=
1500pF, V
OUT
= +5V,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 1)
PARAMETER
REFERENCE
Reference Voltage
Reference Undervoltage
Threshold
LOGIC SIGNALS
SHDN
Input Low Voltage
SHDN
Bias Voltage
SHDN
Input Current Range
RDY
Output Low Voltage
RDY
Output High Leakage
I
SHDN
0.4
I
SHDN
= 22µA
For 200kHz to 2MHz operation
I
SINK
= 2mA
V
RDY
= 13V
580
3
900
65
0.5
1
V
mV
µA
V
µA
V
REF
-2µA < I
REF
< 50µA
V
REF
rising
1.222
0.95
1.269
1.18
V
V
SYMBOL
CONDITIONS
MIN
MAX
UNITS
MAX1747
Note 1:
Specifications from 0°C to -40°C are guaranteed by design, not production tested.
Typical Operating Characteristics
(Circuit of Figure 1, V
IN
= V
SUPM
= +3.3V, T
A
= +25°C, unless otherwise noted.)
MAIN OUTPUT EFFICIENCY
vs. LOAD CURRENT
(MAIN CHARGE PUMP ONLY)
MAX1747 toc01
MAIN OUTPUT EFFICIENCY
vs. LOAD CURRENT
(MAIN CHARGE PUMP ONLY)
MAX1747 toc02
MAIN OUTPUT EFFICIENCY
vs. LOAD CURRENT
(MAIN CHARGE PUMP ONLY)
V
OUT
= 5V
90
V
IN
= 2.8V
EFFICIENCY (%)
80
70
60
V
IN
= 4.0V
50
40
V
IN
= 3.3V
V
NEG
= -7V WITH I
NEG
= 10mA
V
POS
= 12V WITH I
POS
= 5mA
MAX1747 toc03
5.03
5.02
5.01
V
OUT
(V)
5.00
V
IN
= 2.8V
4.99
4.98
4.97
0
100
200
I
OUT
(mA)
300
V
IN
= 4.0V
100
V
OUT
= 5V
90
EFFICIENCY (%)
80
70
V
IN
= 4.0V
60
50
40
V
IN
= 2.8V
100
V
IN
= 3.3V
V
IN
= 3.3V
400
0
100
200
I
OUT
(mA)
300
400
0
100
200
I
OUT
(mA)
300
400
_______________________________________________________________________________________
5
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
