MAX1886EZK [MAXIM]
Operational Amplifier ; 运算放大器\n
| 型号： | MAX1886EZK |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Operational Amplifier
|
| 文件： | 总7页 (文件大小：284K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2095; Rev 0; 8/01
High-Current VCOM Drive Buffer
General Description
Features
The MAX1886 is a high-current operational transcon-
ductance amplifier. The MAX1886 is ideal for driving
the backplane of an active matrix, dot inversion thin film
transistor (TFT) liquid crystal display (LCD). The
MAX1886’s high >500mA peak-current drive capability
provides fast response to pulsed load conditions. The
MAX1886 is stable from 0.47µF to an unlimited amount
of output capacitance.
ꢀ Stable with 0.47µF to Unlimited Amount of Output
Capacitance
ꢀ Over 500mA Peak Drive Current
ꢀ Excellent Settling Characteristics with Capacitive
Load
ꢀ +4.5V to +13V Input Supply
ꢀ 0.45mA Quiescent Current
ꢀ Thermal Fault Protection
The MAX1886 is available in the low-profile (1.1mm
max) 5-pin Thin SOT23 package and fully specified
over the -40°C to +85°C extended temperature range.
ꢀ Thin SOT23-5 Package (1.1mm max)
Applications
Ordering Information
Notebook LCD Panels
Monitor LCD Panels
TOP
MARK
PART
TEMP. RANGE PIN-PACKAGE
5 Thin SOT23-5*
MAX1886EZK -40°C to +85°C
ADQL
*Requires a special solder temperature profile described in the
Absolute Maximum Ratings section.
Typical Operating Circuit
Pin Configuration
V
CC
TOP VIEW
OUT
GND
1
2
3
5
4
FB-
FB+
V
REF
FB+
FB-
MAX1886
OUT
GND
V
O
V
CC
MAX1886
THIN SOT23-5
________________________________________________________________ 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 Buffer
ABSOLUTE MAXIMUM RATINGS
CC
FB-, FB+, OUT to GND...............................-0.3V to (V
V
to GND............................................................-0.3V to +14V
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
+ 0.3V)
CC
Continuous Power Dissipation (T = +70°C)
A
5-Pin Thin SOT23 (derate 7.1mW°C above +70°C).....727mW
This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device can be exposed to during
board level solder attach and rework. Maxim recommends the use of the solder profiles recommended in the industry-standard specification, JEDEC
020A, paragraph 7.6, Table 3 for IR/VPR and convection reflow processes. Preheating, per this standard, is required. Hand or wave soldering is not
recommended.
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
= 10V, FB- = OUT, V
= 5V, C
= 0.47µF, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.)
OUT A A
CC
FB+
(Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
13
UNITS
V
V
V
Input Supply Range
Supply Current
V
4.5
CC
CC
CC
CC
I
450
900
5
µA
Input Offset Voltage
Input Bias Current
Input Offset Current
V
V
= +5V, no load
FB+
-5
mV
nA
OS
I
-100
-100
100
100
BIAS
+1.2V < V
< +8.8V
CM
I
nA
OS
V
1.2V
-
CC
Common-Mode Input Range
V
V < 10mV over CMR
| OS|
1.2
V
CM
Power-Supply Rejection Ratio
Common-Mode Rejection Ratio
Gain-Bandwidth Product
PSRR
CMRR
GBW
+4.5V < V
+1.2V < V
< +13V, V
= +2.25V
FB+
70
70
CC
CM
dB
Hz
S
< +8.8V
Small signal
1/6 C
0.3
L
Small signal ( 1mV overdrive)
Large signal ( 30mV overdrive)
Transconductance
g
m
10
T
A
T
A
= -40°C to +85°C
= 0°C to +85°C
175
250
550
100mV overdrive,
= 3V or 7V
Output Current Drive
I
mA
OUT
V
OUT
Thermal Shutdown
170
15
°C
°C
Thermal Shutdown Hysteresis
Note 1: The MAX1886 is 100% production tested at T = +25°C. Specifications over temperature are guaranteed by design.
A
SUPPLY
VOLTAGE
3
REFERENCE
4
VOLTAGE
0.47
0.47
2
1
5
V
X
R
L
C
L
MAX1886
Figure 1. Load Transient Test Circuit
_______________________________________________________________________________________
2
High-Current VCOM Drive Buffer
Typical Operating Characteristics
(V
= 10V, C
= 1µF, V
= 5V, T = +25°C, unless otherwise noted.)
CM A
CC
OUT
INPUT OFFSET VOLTAGE DEVIATION
vs. TEMPERATURE
TRANSCONDUCTANCE
vs. OUTPUT CURRENT
INPUT OFFSET VOLTAGE DEVIATION
vs. SUPPLY VOLTAGE
0.10
0.4
0.3
6
5
4
3
2
1
0
V
V
= 10V
CC
CC
CM
V
= V /2
CC
0.08
0.06
0.04
0.02
0
CM
= V /2
0.2
T = -40 C
A
0.1
T = +25 C
A
0
-0.02
-0.04
-0.06
-0.08
-0.10
-0.1
-0.2
-0.3
-0.4
T = +85 C
A
4
5
6
7
8
9
10 11 12 13 14
-40
-15
10
35
60
85
-40 -30 -20 -10
0
10 20 30 40
V
CC
(V)
TEMPERATURE ( C)
OUTPUT CURRENT (mA)
NO-LOAD SUPPLY CURRENT
vs. TEMPERATURE
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
LOAD TRANSIENT 10V
0.6
0.5
0.4
0.3
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
I
OUT
500mA/div
+85 C
+25 C
V
OUT
-40 C
200mV/div
AC-COUPLED
0.2
0.1
V
X
10V/div
R = 2.5 C = 100nF, FIGURE 1
L
L
0
-40
-15
10
35
60
85
4.5
6.5
8.5
10.5
12.5
4 s/div
TEMPERATURE ( C)
SUPPLY VOLTAGE (V)
SHORT-CIRCUIT WAVEFORMS
I
CC
500mA/div
I
OUT
500mA/div
V
OUT
5V/div
V
CC
5V/div
20ms/div
_______________________________________________________________________________________
3
High-Current VCOM Drive Buffer
Typical Operating Characteristics (continued)
(V
= 10V, C
= 1µF, V
= 5V, T = +25°C, unless otherwise noted.)
CC
OUT
CM
A
STARTUP WAVEFORMS
WITH SOFT-START
STARTUP WAVEFORM
WITHOUT SOFT-START
SUPPLY CAPACITOR
CHARGING CURRENT
I
CC
500mA/div
I
CC
500mA/div
V
V
CC
10V/div
CC
10V/div
V
V
FB+
5V/div
FB+
5V/div
V
V
OUT
5V/div
OUT
5V/div
C
OUT
= 0.47 F
C
OUT
= 0.47 F
500 s/div
5 s/div
Pin Description
PIN
NAME
DESCRIPTION
Output of Buffer Amplifier. Requires a minimum 0.47µF ceramic filter capacitor to GND. Place the
capacitor close to OUT.
1
2
3
OUT
GND
Ground
Voltage-Supply Input. Bypass to GND with a 0.47µF capacitor close to the pin. Use the output
capacitor of the preceding voltage regulator as the additional filter capacitor.
V
CC
4
5
FB+
FB-
Noninverting Input to Buffer Amplifier
Inverting Input to Buffer Amplifier. Feedback must be taken from the output filter capacitor terminal.
times, the MAX1886’s transconductance increases as
the output current increases (see Typical Operating
Characteristics).
Detailed Description
The MAX1886 operational transconductance amplifier
(OTA) provides high-current output that is ideal for dri-
ving capacitive loads such as the backplane of a TFT
LCD panel. The positive feedback input, FB+, allows
common-mode biasing to mid-supply, or other VCOM
voltage.
Applications Information
Output Filter Capacitor
The MAX1886 requires a minimum of 0.47µF output
capacitance placed close to OUT. To ensure buffer sta-
bility, the output capacitor ESR must be 50m or lower.
Ceramic capacitors are an excellent choice.
The MAX1886 unity-gain bandwidth is GBW = g /C
m
OUT
where g is the amplifier’s transconductance.
m
Transconductance is the ratio of the output current to
the input voltage. The gain of the amplifier is dependent
upon the load. The MAX1886 requires only a small
0.47µF ceramic output capacitor for stability. The band-
width is inversely proportional to the output capacitor,
so large capacitive loads improve stability; however,
lower bandwidth decreases the buffer’s transient
response time. To improve the transient response
Input Bypass Capacitor
The MAX1886 requires a 0.47µF input bypass capacitor
(C2) close to the V
supply input (see Figure 2). Place
CC
the MAX1886 close to the preceding voltage regulator
output capacitor so that the MAX1886 shares the same
capacitor (C1). Minimize trace length and use wide
4
_______________________________________________________________________________________
High-Current VCOM Drive Buffer
SWITCHING
REGULATOR
SOURCE DRIVER VOLTAGE
PC BOARD PARASITICS
V
IN
C1
3
LINEAR
C2
0.47 F
4
5
REGULATOR
2
1
0.47 F
OPTIONAL REFERENCE
VOLTAGE CIRCUIT
TO LCD
BACKPLANE
GAMMA CORRECTION
REFERENCE VOLTAGE
MAX1886
Figure 2. Typical TFT LCD Backplane Drive Circuit
traces between the voltage regulator output and the
MAX1886 V input to reduce PC board parasitics
CC
(inductance, resistance, and capacitance), which can
cause undesired ringing.
Voltage Reference
The reference voltage for the MAX1886 input can be
produced using the output of a linear regulator. The lin-
ear regulator will reject the ripple voltage produced by
the source drivers (see Figure 2). The output of this lin-
ear regulator can also be used for the gamma correc-
tion reference voltage.
Chip Information
TRANSISTOR COUNT: 121
PROCESS: BiCMOS
_______________________________________________________________________________________
5
High-Current VCOM Drive Buffer
Package Information
6
_______________________________________________________________________________________
High-Current VCOM Drive Buffer
Package Information (continued)
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7
© 2001 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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