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 2s. 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 MAX
package with an
exposed paddle. The MAX9551 is available in an 8-pin
MAX package with an exposed paddle. The MAX9552
is available in a 14-pin TSSOP package. All devices are
specified over the -40C to +85C temperature range.
Applications
TFT-LCD Panels
Instrument Control Voltage Sources
Features
Operates Up To 20V
800mA Peak Output Current
Settles to Within 0.1% of V
OUT
in Less than 2s
Excellent Load Regulation
Thermal-Shutdown Protection
Short-Circuit Protection to Both Rails
Soft-Start to Reduce Inrush Current
MAX9550/MAX9551/MAX9552
High-Current VCOM Drive Buffers
for TFT LCDs
________________________________________________________________ Maxim Integrated Products
1
Ordering Information
MAX9550
16V
SUPPLY
IN+
OUT
V
OUT
TFT-LCD
CAPACITANCE
V
REF
V
DD
TFT LCD
IN-
GND
Typical Operating Circuit
19-3858; Rev 1; 2/06
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.
Pin Configuration appears at end of data sheet.
Note: All devices specified over the -40C to +85C operating
temperature range.
+Denotes lead-free package.
*Future product--contact factory for availability.
**EP = Exposed paddle.
PART
AMPS PIN-PACKAGE
PKG
CODE
TOP
MARK
MAX9550EZK+T
1
5 Thin SOT23-5
Z5-1
ADSG
MAX9550EUA+*
1
8 MAX-EP**
U8E-2
AABA
MAX9551EUA+*
2
8 MAX-EP**
U8E-2
--
MAX9552EUD+*
4
14 TSSOP-EP**
U14E-3
--
MAX is a registered trademark of Maxim Integrated Products, Inc.
MAX9550/MAX9551/MAX9552
High-Current VCOM Drive Buffers
for TFT LCDs
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
DD
= 16V, GND = 0V, V
CM
= V
OUT
= V
DD
/ 2, C
L
= 1F, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at
T
A
= +25C.) (Note 1)
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.
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
= +70C)
5-Pin Thin SOT23 (derate 9.5mW/C above +70C) ....727mW
8-Pin MAX (derate 10.3mW/C above +70C) ........824.7mW
14-Pin TSSOP (derate 20.8mW/C above +70C) .....1667mW
Operating Temperature Range ...........................-40C to +85C
Junction Temperature ......................................................+150C
Storage Temperature Range .............................-65C to +150C
Lead Temperature (soldering, 10s) .................................+300C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
Supply Voltage Range
V
DD
Inferred from PSRR test and transient
load test
7
20
V
Quiescent Current
I
CC
Per channel
2
4
mA
Low Output Voltage
V
OL
I
L
= -4mA
0.04
0.1
V
High Output Voltage
V
OH
I
H
= +4mA
V
DD
- 0.04
V
DD
- 0.1
V
Input Offset Voltage
V
OS
-10
+1
+10
mV
Input Bias Current
I
B
0.01
1
A
Input Resistance
R
IN
1
M
Common-Mode Input Voltage
CMVR
Inferred from CMRR
2
V
DD
- 2
V
Common-Mode Rejection Ratio
CMRR
2V
V
IN
(V
DD
- 2V)
80
96
dB
Power-Supply Rejection Ratio
PSRR
V
OUT
= 3.5V, V
DD
= 7V to 16V
80
96
dB
Continuous Output Current
I
O
V
DD
= 7V, V
OUT
= 3.5V, guaranteed by
load, regulation test
55
mA
I
OUT
= 0mA to 50mA
6
13
Output Load Regulation
LR1
I
OUT
= 0mA to -50mA
6
13
mV
I
OUT
= 0mA to -55mA
6.5
15
Output Load Regulation
LR2
V
DD
= 7V,
V
OUT
= 3.5V
I
OUT
= 0mA to 55mA
6.5
15
mV
Thermal Shutdown
+160
C
Thermal Hysteresis
15
C
MAX9550/MAX9551/MAX9552
High-Current VCOM Drive Buffers
for TFT LCDs
_______________________________________________________________________________________
3
Note 1: All devices are 100% production tested at T
A
= +25C. All temperature limits are guaranteed by design.
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 16V, GND = 0V, V
CM
= V
OUT
= V
DD
/ 2, C
L
= 1F, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at
T
A
= +25C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
AC CHARACTERISTICS
Settling Time
t
S
Settling to 0.1% of V
OUT
, I
L
= 0 to 600mA,
C
L
= 1F, R
S
= 2.2
, C
S
= 0.1F
(Figure 1)
2.0
s
Input Capacitance
C
IN
1.5
pF
I
OUT
= 50mA
13
Transconductance
gm
I
OUT
= 500mA
42
S
V
DD
= 7V, V
IN
= 1.5V
pulse for 100s
200
290
Transient Output Current
I
OUTMAX
A
V
= 1
V
DD
= 16V, V
IN
= 1.5V
pulse for 100s
600
830
mA
Typical Operating Characteristics
(V
DD
= 16V, GND = 0V, V
CM
= V
OUT
= V
DD
/ 2, C
L
= 1F, T
A
= +25C, unless otherwise noted.)
INPUT OFFSET VOLTAGE DEVIATION
vs. SUPPLY VOLTAGE
V
DD
(V)
V
OS
(mV)
20
15
10
-0.1
0
0.1
0.2
0.3
0.4
0.5
-0.2
5
25
MAX9550 toc01
T
A
= -40
C
T
A
= +25
C
T
A
= +85
C
INPUT OFFSET VOLTAGE DEVIATION
vs. TEMPERATURE
MAX9550 toc02
TEMPERATURE (
C)
V
OS
(mV)
75
50
25
0
-25
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
-0.4
-50
100
TRANSCONDUCTANCE
vs. OUTPUT CURRENT
MAX9550 toc03
OUTPUT CURRENT (mA)
TRANSCONDUCTANCE (S)
400
200
0
-200
-400
10
20
30
40
50
60
0
-600
600
T
A
= -40
C
T
A
= +25
C
T
A
= +85
C
MAX9550/MAX9551/MAX9552
High-Current VCOM Drive Buffers
for TFT LCDs
4
_______________________________________________________________________________________
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX9550 toc04
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
20
15
10
0.5
1.0
1.5
2.0
2.5
3.0
0
5
25
T
A
= +85
C
T
A
= -40
C
T
A
= +25
C
SUPPLY CURRENT
vs. TEMPERATURE
MAX9550 toc05
TEMPERATURE (
C)
SUPPLY CURRENT (mA)
75
50
-25
0
25
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0
-50
100
LOAD TRANSIENT (
600mA)
MAX9550 toc06
2
s/div
I
OUT
500mA/div
V
OUT
50mV/div
AC-COUPLED
R
S
= 2.2
, C
L
= 1
F, C
S
= 0.1
F
SHORT-CIRCUIT WAVEFORMS
MAX9550 toc07
5ms/div
V
CC
5V/div
V
OUT
5V/div
I
OUT
200mA/div
I
CC
200mA/div
STARTUP WAVEFORM
MAX9550 toc08
20
s/div
V
OUT
5V/div
IN+
5V/div
V
CC
10V/div
I
OUT
200mA/div
Typical Operating Characteristics (continued)
(V
DD
= 16V, GND = 0V, V
CM
= V
OUT
= V
DD
/ 2, C
L
= 1F, T
A
= +25C, unless otherwise noted.)
MAX9550/MAX9551/MAX9552
High-Current VCOM Drive Buffers
for TFT LCDs
_______________________________________________________________________________________
5
Pin Description
PIN
MAX9550
THIN
SOT23
MAX
MAX9551
MAX9552
NAME
FUNCTION
1
6
--
--
OUT
VCOM Output
2
4
4
11
GND
Ground
3
3
--
--
IN+
Positive Input
4
2
--
--
IN-
Negative Input
5
7
8
4
V
DD
Positive Supply Input
--
--
1
1
OUTA
VCOM Output A
--
--
3
3
INA+
Positive Input A
--
--
2
2
INA-
Negative Input A
--
1, 5, 8
--
--
N.C.
No Connection. Not internally connected.
--
--
5
5
INB+
Positive Input B
--
--
6
6
INB-
Negative Input B
--
--
7
7
OUTB
VCOM Output B
--
--
--
8
OUTC
VCOM Output C
--
--
--
9
INC-
Negative Input C
--
--
--
10
INC+
Positive Input C
--
--
--
12
IND+
Positive Input D
--
--
--
13
IND-
Negative Input D
--
--
--
14
OUTD
VCOM Output D
--
EP
EP
EP
EP
Exposed Paddle. EP is internally connected to GND. Connect
EP to GND.
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