19-3858; Rev 1; 2/06
High-Current VCOM Drive Buffers
for TFT LCDs
General Description
The MAX9550/MAX9551/MAX9552 provide a VCOM
source for TFT LCDs. The MAX9550/MAX9551/
MAX9552 source and sink a large current to quickly
restore the VCOM voltage, making it ideal for TFT LCDs.
The output settles to within 0.1% in less than 2µs. In
addition, the MAX9550/MAX9551/MAX9552 directly drive
the capacitive load in the VCOM layer of the TFT LCDs
without the need for a series resistor.
The MAX9550/MAX9551/MAX9552 feature single, dual,
and quad channel VCOM amplifiers, respectively. The
MAX9550/MAX9551/MAX9552 can drive up to 800mA of
peak current per channel and operate up to 20V. The
devices feature soft-start to reduce inrush current, output
short-circuit protection, and thermal shutdown.
The MAX9550 is available in a space-saving 5-pin thin
SOT23 package, and an 8-pin µMAX
®
package with an
exposed paddle. The MAX9551 is available in an 8-pin
µMAX package with an exposed paddle. The MAX9552
is available in a 14-pin TSSOP package. All devices are
specified over the -40°C to +85°C temperature range.
♦
Operates Up To 20V
♦
800mA Peak Output Current
♦
Settles to Within 0.1% of V
OUT
in Less than 2µs
♦
Excellent Load Regulation
♦
Thermal-Shutdown Protection
♦
Short-Circuit Protection to Both Rails
♦
Soft-Start to Reduce Inrush Current
Features
MAX9550/MAX9551/MAX9552
Ordering Information
PART
MAX9550EZK+T
MAX9550EUA+*
MAX9551EUA+*
MAX9552EUD+*
AMPS PIN-PACKAGE
1
1
2
4
5 Thin SOT23-5
8 µMAX-EP**
8 µMAX-EP**
14 TSSOP-EP**
PKG
CODE
Z5-1
U8E-2
U8E-2
U14E-3
TOP
MARK
ADSG
AABA
—
—
Applications
TFT-LCD Panels
Instrument Control Voltage Sources
Pin Configuration appears at end of data sheet.
Note:
All devices specified over the -40°C to +85°C operating
temperature range.
+Denotes
lead-free package.
*Future
product—contact factory for availability.
**EP
= Exposed paddle.
Typical Operating Circuit
16V
SUPPLY
V
DD
MAX9550
V
REF
IN+
OUT
IN-
GND
V
OUT
TFT-LCD
CAPACITANCE
TFT LCD
µMAX is a registered trademark of Maxim Integrated Products, Inc.
________________________________________________________________
Maxim Integrated Products
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.
High-Current VCOM Drive Buffers
for TFT LCDs
MAX9550/MAX9551/MAX9552
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
DD
to GND) ................................-0.3V to +22V
Any Other Pin to GND ................................-0.3V to (V
DD
+ 0.3V)
IN+/IN- (current) ...............................................................±20mA
OUT, OUT_ (current)................................................................1A
Continuous Power Dissipation (T
A
= +70°C)
5-Pin Thin SOT23 (derate 9.5mW/°C above +70°C) ....727mW
8-Pin µMAX (derate 10.3mW/°C above +70°C) ........824.7mW
14-Pin TSSOP (derate 20.8mW/°C above +70°C) .....1667mW
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
DD
= 16V, GND = 0V, V
CM
= V
OUT
= V
DD
/ 2, C
L
= 1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at
T
A
= +25°C.) (Note 1)
PARAMETER
DC CHARACTERISTICS
Supply Voltage Range
Quiescent Current
Low Output Voltage
High Output Voltage
Input Offset Voltage
Input Bias Current
Input Resistance
Common-Mode Input Voltage
Common-Mode Rejection Ratio
Power-Supply Rejection Ratio
Continuous Output Current
Output Load Regulation
Output Load Regulation
Thermal Shutdown
Thermal Hysteresis
V
DD
I
CC
V
OL
V
OH
V
OS
I
B
R
IN
CMVR
CMRR
PSRR
I
O
LR1
LR2
Inferred from CMRR
2V
≤
V
IN
≤
(V
DD
- 2V)
V
OUT
= 3.5V, V
DD
= 7V to 16V
V
DD
= 7V, V
OUT
= 3.5V, guaranteed by
load, regulation test
I
OUT
= 0mA to 50mA
I
OUT
= 0mA to -50mA
V
DD
= 7V,
V
OUT
= 3.5V
I
OUT
= 0mA to -55mA
I
OUT
= 0mA to 55mA
2
80
80
55
6
6
6.5
6.5
+160
15
13
13
15
15
96
96
Inferred from PSRR test and transient
load test
Per channel
I
L
= -4mA
I
H
= +4mA
-10
7
2
0.04
V
DD
- 0.04
+1
0.01
1
V
DD
- 2
20
4
0.1
V
DD
- 0.1
+10
1
V
mA
V
V
mV
µA
MΩ
V
dB
dB
mA
mV
mV
°C
°C
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
High-Current VCOM Drive Buffers
for TFT LCDs
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 16V, GND = 0V, V
CM
= V
OUT
= V
DD
/ 2, C
L
= 1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at
T
A
= +25°C.) (Note 1)
PARAMETER
AC CHARACTERISTICS
Settling Time
Input Capacitance
Transconductance
t
S
C
IN
gm
I
OUT
= ±50mA
I
OUT
= ±500mA
V
DD
= 7V, V
IN
= 1.5V
pulse for 100µs
Transient Output Current
I
OUTMAX
A
V
= 1
V
DD
= 16V, V
IN
= 1.5V
pulse for 100µs
±200
±600
Settling to 0.1% of V
OUT
, I
L
= 0 to 600mA,
C
L
= 1µF, R
S
= 2.2Ω, C
S
= 0.1µF
(Figure 1)
2.0
1.5
13
42
±290
mA
±830
µs
pF
S
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX9550/MAX9551/MAX9552
Note 1:
All devices are 100% production tested at T
A
= +25°C. All temperature limits are guaranteed by design.
Typical Operating Characteristics
(V
DD
= 16V, GND = 0V, V
CM
= V
OUT
= V
DD
/ 2, C
L
= 1µF, T
A
= +25°C, unless otherwise noted.)
INPUT OFFSET VOLTAGE DEVIATION
vs. SUPPLY VOLTAGE
MAX9550 toc01
INPUT OFFSET VOLTAGE DEVIATION
vs. TEMPERATURE
MAX9550 toc02
TRANSCONDUCTANCE
vs. OUTPUT CURRENT
MAX9550 toc03
0.5
0.4
0.3
V
OS
(mV)
0.2
0.1
0
-0.1
-0.2
5
10
15
V
DD
(V)
20
T
A
= +25°C
T
A
= -40°C
0.6
0.5
0.4
0.3
V
OS
(mV)
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
60
50
TRANSCONDUCTANCE (S)
40
T
A
= +25°C
30
20
10
0
T
A
= -40°C
T
A
= +85°C
T
A
= +85°C
25
-50
-25
0
25
50
75
100
-600
-400
-200
0
200
400
600
TEMPERATURE (°C)
OUTPUT CURRENT (mA)
_______________________________________________________________________________________
3
High-Current VCOM Drive Buffers
for TFT LCDs
MAX9550/MAX9551/MAX9552
Typical Operating Characteristics (continued)
(V
DD
= 16V, GND = 0V, V
CM
= V
OUT
= V
DD
/ 2, C
L
= 1µF, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX9550 toc04
SUPPLY CURRENT
vs. TEMPERATURE
MAX9550 toc05
LOAD TRANSIENT (±600mA)
R
S
= 2.2Ω, C
L
= 1µF, C
S
= 0.1µF
I
OUT
500mA/div
MAX9550 toc06
4.0
3.5
SUPPLY CURRENT (mA)
3.0
2.5
2.0
1.5
1.0
0.5
0
-50
-25
0
25
50
75
3.0
SUPPLY CURRENT (mA)
2.5
T
A
= +85°C
T
A
= +25°C
2.0
1.5
1.0
0.5
0
5
10
15
SUPPLY VOLTAGE (V)
20
25
T
A
= -40°C
V
OUT
50mV/div
AC-COUPLED
100
2µs/div
TEMPERATURE (°C)
SHORT-CIRCUIT WAVEFORMS
MAX9550 toc07
STARTUP WAVEFORM
MAX9550 toc08
I
CC
200mA/div
I
OUT
200mA/div
V
OUT
5V/div
I
OUT
200mA/div
V
CC
10V/div
IN+
5V/div
V
OUT
5V/div
V
CC
5V/div
5ms/div
20µs/div
4
_______________________________________________________________________________________
High-Current VCOM Drive Buffers
for TFT LCDs
Pin Description
PIN
MAX9550
THIN
SOT23
1
2
3
4
5
—
—
—
—
—
—
—
—
—
—
—
—
—
—
µMAX
6
4
3
2
7
—
—
—
1, 5, 8
—
—
—
—
—
—
—
—
—
EP
MAX9551
—
4
—
—
8
1
3
2
—
5
6
7
—
—
—
—
—
—
EP
MAX9552
—
11
—
—
4
1
3
2
—
5
6
7
8
9
10
12
13
14
EP
NAME
FUNCTION
MAX9550/MAX9551/MAX9552
OUT
GND
IN+
IN-
V
DD
OUTA
INA+
INA-
N.C.
INB+
INB-
OUTB
OUTC
INC-
INC+
IND+
IND-
OUTD
EP
VCOM Output
Ground
Positive Input
Negative Input
Positive Supply Input
VCOM Output A
Positive Input A
Negative Input A
No Connection. Not internally connected.
Positive Input B
Negative Input B
VCOM Output B
VCOM Output C
Negative Input C
Positive Input C
Positive Input D
Negative Input D
VCOM Output D
Exposed Paddle. EP is internally connected to GND. Connect
EP to GND.
_______________________________________________________________________________________
5
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