MAXIM MAX9552EUD+

19-3858; Rev 3; 10/07
KIT
ATION
EVALU
E
L
B
A
AVAIL
High-Current VCOM Drive Buffers
for TFT LCDs
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.
Applications
TFT-LCD Panels
Instrument Control Voltage Sources
Features
♦ Operates Up To 20V
♦ 800mA Peak Output Current
♦ Settles to Within 0.1% of VOUT in Less than 2µs
♦ Excellent Load Regulation
♦ Thermal-Shutdown Protection
♦ Short-Circuit Protection to Both Rails
♦ Soft-Start to Reduce Inrush Current
Ordering Information
PART
AMPS PIN-PACKAGE
5 Thin SOT23-5
PKG
CODE
TOP
MARK
Z5-1
ADSG
MAX9550EZK+T
1
MAX9550EUA+
1
8 µMAX-EP*
U8E-2
AABA
MAX9551EUA+
2
8 µMAX-EP*
U8E-2
—
MAX9552EUD+
4
14 TSSOP-EP*
U14E-3
—
Note: All devices specified over the -40°C to +85°C operating
temperature range.
+Denotes lead-free package.
*EP = Exposed paddle.
Pin Configuration appears at end of data sheet.
Typical Operating Circuit
16V
SUPPLY
VDD
MAX9550
VREF
TFT LCD
IN+
OUT
IN-
1µF
TFT-LCD
CAPACITANCE
GND
µMAX is a registered trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX9550/MAX9551/MAX9552
General Description
MAX9550/MAX9551/MAX9552
High-Current VCOM Drive Buffers
for TFT LCDs
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VDD to GND) ................................-0.3V to +22V
Any Other Pin to GND ................................-0.3V to (VDD + 0.3V)
IN+/IN- (current) ...............................................................±20mA
OUT, OUT_ (current)................................................................1A
Continuous Power Dissipation (TA = +70°C)
5-Pin Thin SOT23 (derate 2.7mW/°C above +70°C) ...219.1mW
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
(VDD = 16V, GND = 0V, VCM = VOUT = VDD / 2, CL = 1µF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at
TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
20
V
DC CHARACTERISTICS
VDD
Inferred from PSRR test and transient
load test
Quiescent Current
ICC
Per channel
2
4
mA
Low Output Voltage
VOL
IL = -4mA
0.04
0.1
V
High Output Voltage
VOH
IH = +4mA
VDD - 0.04
VDD - 0.1
V
Input Offset Voltage
VOS
mV
Supply Voltage Range
Input Bias Current
7
+1
+10
IB
-10
0.01
1
RIN
1
µA
Input Resistance
Common-Mode Input Voltage
CMVR
Inferred from CMRR
2
Common-Mode Rejection Ratio
CMRR
2V ≤ VIN ≤ (VDD - 2V)
80
96
dB
Power-Supply Rejection Ratio
PSRR
VOUT = 3.5V, VDD = 7V to 16V
80
96
dB
VDD = 7V, VOUT = 3.5V, guaranteed by
load, regulation test
55
Continuous Output Current
IO
Output Load Regulation
LR1
Output Load Regulation
LR2
MΩ
VDD - 2
mA
IOUT = 0mA to 50mA
6
13
IOUT = 0mA to -50mA
6
13
IOUT = 0mA to -55mA
6.5
15
IOUT = 0mA to 55mA
6.5
15
VDD = 7V,
VOUT = 3.5V
V
mV
mV
Thermal Shutdown
+160
°C
Thermal Hysteresis
15
°C
2
_______________________________________________________________________________________
High-Current VCOM Drive Buffers
for TFT LCDs
(VDD = 16V, GND = 0V, VCM = VOUT = VDD / 2, CL = 1µF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at
TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
tS
Settling to 0.1% of VOUT, IL = 0 to 600mA,
CL = 1µF, RS = 2.2Ω, CS = 0.1µF
(Figure 1)
TYP
MAX
UNITS
AC CHARACTERISTICS
Settling Time
Input Capacitance
CIN
Transconductance
gm
Transient Output Current
IOUTMAX
2.0
µs
1.5
pF
IOUT = ±50mA
13
IOUT = ±500mA
42
AV = 1
VDD = 7V, VIN = 1.5V
pulse for 100µs
±200
±290
VDD = 16V, VIN = 1.5V
pulse for 100µs
±600
±830
S
mA
Note 1: All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design.
Typical Operating Characteristics
(VDD = 16V, GND = 0V, VCM = VOUT = VDD / 2, CL = 1µF, TA = +25°C, unless otherwise noted.)
0.5
VOS (mV)
0.3
0.2
0.1
0
0.2
0.1
0
TA = +85°C
TA = +25°C
-0.1
-0.2
-0.1
50
TRANSCONDUCTANCE (S)
0.4
TA = -40°C
0.3
60
MAX9550 toc02
0.4
VOS (mV)
0.6
MAX9550 toc01
0.5
TRANSCONDUCTANCE
vs. OUTPUT CURRENT
INPUT OFFSET VOLTAGE DEVIATION
vs. TEMPERATURE
MAX9550 toc03
INPUT OFFSET VOLTAGE DEVIATION
vs. SUPPLY VOLTAGE
TA = -40°C
40
TA = +25°C
30
20
TA = +85°C
10
-0.3
-0.2
-0.4
5
10
15
VDD (V)
20
25
0
-50
-25
0
25
50
TEMPERATURE (°C)
75
100
-600
-400
-200
0
200
400
600
OUTPUT CURRENT (mA)
_______________________________________________________________________________________
3
MAX9550/MAX9551/MAX9552
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics (continued)
(VDD = 16V, GND = 0V, VCM = VOUT = VDD / 2, CL = 1µF, TA = +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. TEMPERATURE
TA = +25°C
2.0
1.5
TA = -40°C
1.0
3.5
SUPPLY CURRENT (mA)
2.5
MAX9550 toc05
MAX9550 toc04
TA = +85°C
3.0
LOAD TRANSIENT (±600mA)
4.0
3.0
2.0
1.5
VOUT
50mV/div
AC-COUPLED
0.5
0
0
10
15
20
25
-50
-25
0
25
50
75
2µs/div
100
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
STARTUP WAVEFORM
MAX9550 toc07
SHORT-CIRCUIT WAVEFORMS
ICC
200mA/div
MAX9550 toc08
5
IOUT
200mA/div
IOUT
200mA/div
VCC
10V/div
VOUT
5V/div
IN+
5V/div
VOUT
5V/div
VCC
5V/div
5ms/div
4
IOUT
500mA/div
2.5
1.0
0.5
RS = 2.2Ω, CL = 1µF, CS = 0.1µF
20µs/div
_______________________________________________________________________________________
MAX9550 toc06
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY CURRENT (mA)
MAX9550/MAX9551/MAX9552
High-Current VCOM Drive Buffers
for TFT LCDs
High-Current VCOM Drive Buffers
for TFT LCDs
PIN
MAX9550
MAX9551
MAX9552
NAME
FUNCTION
THIN
SOT23
µMAX
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
VDD
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
—
EP
EP
EP
EP
VCOM Output D
Exposed Paddle. EP is internally connected to GND. Connect
EP to GND.
_______________________________________________________________________________________
5
MAX9550/MAX9551/MAX9552
Pin Description
MAX9550/MAX9551/MAX9552
High-Current VCOM Drive Buffers
for TFT LCDs
Detailed Description
The MAX9550/MAX9551/MAX9552 operational transconductance amplifiers (OTA) hold the VCOM voltage stable while providing the ability to source and sink a high
current quickly (800mA typ) into a capacitive load such
as the backplane of a TFT-LCD panel. The output settles
to within 0.1% in less than 2µs. The fast settling time is
achieved by increasing the transconductance of the
buffer as the output current increases (see the Typical
Operating Characteristics).
In addition, the MAX9550/MAX9551/MAX9552 directly
drive the capacitive load in the VCOM layer of the
TFT LCD without the need for a series resistor.
The MAX9550/MAX9551/MAX9552 unity-gain bandwidth is:
GBW = gM / 2πCOUT
To insure buffer stability, place a 1µF low-ESR capacitor as close to the OUT pin as possible. However, this
value may be reduced if the TFT-LCD panel load provides some of the capacitance and the resistance in
series when this capacitance is low. Connect the feedback at OUT using a Kelvin connection at the low-ESR
capacitor.
Thermal Shutdown with Temperature
Hysteresis
The MAX9550/MAX9551/MAX9552 are capable of high
output currents and therefore, feature thermal-shutdown
protection with temperature hysteresis. When the die temperature reaches +160°C, the devices shut down. When
the die cools down by 15°C, the devices turn on again.
where COUT is the capacitive load at the output and gM
is the transconductance.
16V
SUPPLY
*C1 = 4.7µF
*C2 = 0.1µF
16V
SUPPLY
VDD
TEST LOAD
MAX9550
VREF
IN+
VOUT
OUT
IN-
**RS = 2.2Ω
CS = 0.1µF
CL = 1µF
0V TO 1.5V AT 50kHz
GND
*PLACE 4.7µF AND 0.1µF CAPACITORS AS CLOSE TO PIN AS POSSIBLE.
**RS INCLUDES THE GENERATOR RESISTANCE.
NOTE: PLACE CL AS CLOSE TO OUT PIN AS POSSIBLE AND KELVIN
SENSE THE FEEDBACK LOOP CONNECTION AS SHOWN.
Figure 1. Settling Time Test Circuit
6
_______________________________________________________________________________________
High-Current VCOM Drive Buffers
for TFT LCDs
Output Load Capacitor
The output load capacitor must have a low ESR value
(50mΩ or lower) and it must be placed as close as possible to the OUT pin to ensure buffer stability (see
Figure 2). Ceramic capacitors are an excellent choice.
Power Supplies and Bypass Capacitors
The MAX9550/MAX9551/MAX9552 operate from a 6V to
20V single supply, or from ±3V to ±10V dual supplies.
Proper supply bypassing ensures stability while driving
high transient loads. The MAX9550/MAX9551/MAX9552
require minimum 4.7µF (C1) and 0.1µF (C2) power-supply bypass capacitors placed as close as possible to
the power-supply pin (VDD). See Figure 2. For dualsupply operation, use 4.7µF and 0.1µF bypass capacitors on both supplies (V DD and GND) with each
capacitor placed as close as possible to the VDD and
GND pins.
Layout and Grounding
The exposed paddle on the µMAX and TSSOP packages provides a low thermal resistance for heat dissipation. Solder the exposed paddle to a ground plane
for best results. Do not route traces under these packages. For dual-supply operation, the exposed paddle
(EP) must be electrically connected to the negative
supply or it can be left unconnected.
16V
SUPPLY
*C1 = 4.7µF
*C2 = 0.1µF
VDD
MAX9550
VREF
TFT LCD
IN+
VOUT
OUT
IN-
CL = 1µF
TFT-LCD
CAPACITANCE
GND
*PLACE 4.7µF AND 0.1µF CAPACITORS AS CLOSE TO PIN AS POSSIBLE.
NOTE: PLACE CL AS CLOSE TO THE OUT PIN AS POSSIBLE
AND KELVIN SENSE THE FEEDBACK LOOP CONNECTION AS SHOWN.
Figure 2. Typical TFT-LCD Backplane Drive Circuit
_______________________________________________________________________________________
7
MAX9550/MAX9551/MAX9552
Applications Information
High-Current VCOM Drive Buffers
for TFT LCDs
MAX9550/MAX9551/MAX9552
Pin Configurations
TOP VIEW
MAX9550
OUT
1
MAX9550
5
VDD
GND 2
IN+ 3
N.C.
1
8
IN-
2
7
VDD
IN+
3
6
OUT
GND
4
5
N.C.
µMAX-EP
IN-
4
N.C.
THIN SOT23
MAX9552
MAX9551
OUTA
1
8
VDD
INA-
2
7
OUTB
INA+
3
6
INB-
GND
4
5
INB+
µMAX-EP
OUTA 1
14 OUTD
INA- 2
13 IND-
INA+ 3
12 IND+
VDD 4
11 GND
INB+ 5
10 INC+
INB- 6
9 INC-
OUTB 7
8 OUTC
TSSOP-EP
Chip Information
PROCESS: BiCMOS
8
_______________________________________________________________________________________
High-Current VCOM Drive Buffers
for TFT LCDs
THIN SOT23.EPS
_______________________________________________________________________________________
9
MAX9550/MAX9551/MAX9552
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
MAX9550/MAX9551/MAX9552
High-Current VCOM Drive Buffers
for TFT LCDs
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
10
______________________________________________________________________________________
High-Current VCOM Drive Buffers
for TFT LCDs
8L, µMAX, EXP PAD.EPS
21-0107
C
1
1
______________________________________________________________________________________
11
MAX9550/MAX9551/MAX9552
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
TSSOP 4.4mm BODY.EPS
MAX9550/MAX9551/MAX9552
High-Current VCOM Drive Buffers
for TFT LCDs
XX XX
PACKAGE OUTLINE, TSSOP, 4.40 MM BODY,
EXPOSED PAD
21-0108
E
1
1
Revision History
Pages changed at Rev 3: 1, 2, 9, 10, 12
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
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© 2007 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.