Rainbow Electronics MAX1747 User Manual
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.
General Description
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 highpower and two low-power charge pumps convert the
+2.7V to +4.5V input supply voltage into three independent 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 (RON) power
MOSFETs maximize efficiency. The adjustable switching frequency (200kHz to 2MHz) provides fast transient
response and allows the use of small low-profile ceramic capacitors.
The dual low-power charge pumps independently regulate 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 capacitor sizes for all three charge pumps. The MAX1747 is
available in the ultra-thin TSSOP package (1.1mm max
height).
MAX1747
Triple Charge-Pump TFT LCD
DC-DC Converter
________________________________________________________________ Maxim Integrated Products 1
Pin Configuration
19-1788; Rev 0; 10/00
Ordering Information
Features
♦ Adjustable Outputs
Up to +5.5V Main High-Power Output
Up to +35V Positive Charge-Pump Output
Down to -35V Negative Charge-Pump Output
♦ 200kHz to 2MHz Adjustable Switching Frequency
♦ +2.7V to +4.5V Input Supply
♦ Internal Power MOSFETs
♦ 0.1µA Shutdown Current
♦ Internal Soft-Start
♦ Power-Ready Output
♦ Internal Supply Sequencing
♦ Fast Transient Response
♦ Ultra-Thin Solution (No Inductors)
♦ Thin TSSOP Package (1.1mm max)
Applications
TFT Active-Matrix LCDs
Passive-Matrix Displays
Personal Digital Assistants (PDAs)
Typical Operating Circuit
EVALUATION KIT
AVAILABLE
TOP VIEW
TGND
TGND
RDY
INTG
GND
FBP
1
2
3
4
5
6
IN
7
8
9
10
20
OUT
19
CXP
18
SUPM
17
CXNFB
MAX1747
16
PGND
15
SUPP
14
DRVP
13
SUPNREF
12
DRVN
11
SHDNFBN
PART TEMP. RANGE PIN-PACKAGE
MAX1747EUP -40°C to +85°C 20 TSSOP
INPUT
TO µC
NEGATIVE
OUTPUT
MAX1747
CXP
CXN
OUT
SUPP
SUPN
DRVP
FBP
INTG
PGND
MAIN OUTPUT
FB
POSITIVE
OUTPUT
SUPM
IN
SHDN
RDY
DRVN
FBN
REF
TGND
GND
TSSOP
MAX1747
Triple Charge-Pump TFT LCD
DC-DC Converter
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN= 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, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°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.
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
)
Input Supply Range V
Input Undervoltage Threshold V
Input Quiescent Supply
Current
PARAMETER SYMBOL CONDITIONS MIN TYP MAX U N IT S
IN
UVLO
IIN +
I
SUPM
VIN falling, 40mV hysteresis (typ) 2.2 2.4 2.6 V
VFB = V
FBP
no load on DRVN and DRVP; CXN
and CXP open
= 1.5V, V
2.7 4.5 V
= -0.2V, V
FBN
OUT
= 5V,
0.9 1.0 mA
Output Quiescent Supply
Current
I
Q(OUT
Shutdown Supply Current V
Operating Frequency f
OSC
VFB = V
no load on DRVN and DRVP; CXN and
CXP open
SHDN
I
SHDN
= 1.5V, V
FBP
= -0.2V, V
FBN
OUT
= 5V,
2.5 4.0 mA
= 0, V
= 5V 0.1 20 µA
SUPM
= 22µA 0.65 1 1.2 MHz
MAIN CHARGE PUMP
Output Voltage Range V
Maximum Output Current I
OU T( M AX ) CX
FB Regulation Voltage V
FB Input Bias Current I
OUT
FB
FB
= 0.47µF 200 mA
VFB = 1.25V -50 +50 nA
4.5 5.5 V
1.237 1.248 1.263 V
Integrator Transconductance 530 µS
FB Power-Ready Trip Level Rising edge 1.09 1.125 1.16 V
FB Fault Trip Level Falling edge 1.100 V
Main Soft-Start Period
4.096
/ F
OSC
NEGATIVE LOW-POWER CHARGE PUMP
SUPN Input Supply Range V
SUPN Quiescent Current I
SUPN
SUPN
SUPN Shutdown Current V
FBN Regulation Voltage V
FBN
V
= -0.2V, no load on DRVN 0.6 0.8 mA
FBN
SHDN
= 0, V
= 13V 0.1 10 µA
SUPN
2.7 13 V
-50 0 +50 mV
s
MAX1747
Triple Charge-Pump TFT LCD
DC-DC Converter
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VIN= 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, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
FBN Input Bias Current I
DRVN PCH On-Resistance 36Ω
DRVN NCH On-Resistance
FBN Power-Ready Trip Level Falling edge 80 125 165 mV
FBN Fault Trip Level Rising edge 140 mV
Negative Soft-Start Period
POSITIVE LOW-POWER CHARGE PUMP
SUPP Input Supply Range V
SUPP Quiescent Current I
SUPP Shutdown Current V
FBP Regulation Voltage V
FBP Input Bias Current I
DRVP PCH On-Resistance 36Ω
DRVP NCH On-Resistance
FBP Power-Ready Trip Level Rising edge 1.090 1.125 1.160 V
FBP Fault Trip Level Falling edge 1.100 V
Positive Soft-Start Period
REFERENCE
Reference Voltage V
Reference Undervoltage
Threshold
LOGIC SIGNALS
SHDN Input Low Voltage 0.4 V
SHDN Bias Voltage I
SHDN Bias Voltage Tempco 2 mV/°C
SHDN Input Current Range I
RDY Output Low Voltage I
RDY Output High Leakage V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX U N IT S
V
FBN
SUPP
SUPP
FBP
FBP
REF
SHDN
= -50mV -50 +50 nA
FBN
V
= 50mV 1 5 Ω
FBN
= -50mV 20 kΩ
V
FBN
V
= 1.5V, no load on DRVP 0.6 0.8 mA
FBP
= 0, V
SHDN
V
= 1.5V -50 +50 nA
FBP
V
= 1.20V 1.5 5 Ω
FBP
V
= 1.30V 20 kΩ
FBP
-2µA < I
V
For 200kHz to 2MHz operation 3 65 µA
REF
rising 0.95 1.05 1.18 V
REF
= 22µA 580 724 830 mV
SHDN
= 2mA 0.25 0.5 V
SINK
= 13V 0.01 1 µA
RDY
= 13V 0.1 10 µA
SUPP
< 50µA 1.231 1.25 1.269 V
2.7 13 V
1.20 1.25 1.30 V
2.048/
F
OSC
2.048/
F
OSC
s
s
MAX1747
Triple Charge-Pump TFT LCD
DC-DC Converter
4 _______________________________________________________________________________________
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, TA= -40°C to +85°C, unless otherwise noted.) (Note 1)
Input Supply Range V
Input Undervoltage Threshold V
Input Quiescent Supply
Current
PARAMETER SYMBOL CONDITIONS MIN MAX UNITS
IN
UVLO
IIN +
I
SUPM
VIN falling, 40mV hysteresis (typ) 2.2 2.6 V
VFB = V
FBP
no load on DRVN and DRVP; CXN and
CXP open
= 1.5V, V
FBN
= -0.2V, V
OUT
= 5V,
2.7 4.5 V
1.0 mA
Output Quiescent Supply
Current
I
Q(OUT)
Input Shutdown Current V
Operating Frequency f
OSC
VFB = V
no load on DRVN and DRVP; CXN and
CXP open
SHDN
I
SHDN
= 1.5V, V
FBP
= -0.2V, V
FBN
OUT
= 5V,
4.0 mA
= 0, V
= 5V 20 µA
SUPM
= 22µA 0.65 1.2 MHz
MAIN CHARGE PUMP
Output Voltage Range V
Output Current I
OU T ( M AX ) CX
FB Regulation Voltage V
FB Input Bias Current I
OUT
FB
FB
= 0.47µF 200 mA
VFB = 1.25V -50 +50 nA
4.5 5.5 V
1.222 1.271 V
FB Power-Ready Trip Level Rising edge 1.09 1.16 V
NEGATIVE LOW-POWER CHARGE PUMP
SUPN Input Supply Range V
SUPN Quiescent Current I
SUPN
SUPN
SUPN Shutdown Current V
FBN Regulation Voltage V
FBN Input Bias Current I
FBN
FBN
V
= -0.2V, no load on DRVN 0.8 mA
FBN
= 0, V
SHDN
V
= 0 -50 +50 nA
FBN
= 13V 10 µA
SUPN
2.7 13 V
-50 +50 mV
DRVN PCH On-Resistance 6 Ω
V
= 50mV 5 Ω
DRVN NCH On-Resistance
FBN
= -50mV 20 kΩ
V
FBN
FBN Power-Ready Trip Level Falling edge 80 165 mV
POSITIVE LOW-POWER CHARGE PUMP
SUPP Input Supply Range V
SUPP Quiescent Current I
SUPP
SUPP
SUPP Shutdown Current V
FBP Regulation Voltage V
FBP Input Bias Current I
FBP
FBP
V
= 1.5V, no load on DRVP 0.8 mA
FBP
= 0, V
SHDN
V
= 1.5V -50 +50 nA
FBP
= 13V 10 µA
SUPP
2.7 13 V
1.20 1.30 V
DRVP PCH On-Resistance 6 Ω
V
= 1.20V 5 Ω
DRVP NCH On-Resistance
FBP
V
= 1.30V 20 kΩ
FBP
FBP Power-Ready Trip Level Rising edge 1.09 1.16 V
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