19-1356; Rev 0; 4/98
Active-Matrix Liquid Crystal Display
(AMLCD) Supply
________________General Description
The MAX1664 integrates power-supply and backplane
drive circuitry for active-matrix thin-film-transistor (TFT) liq-
uid crystal displays. Included are a single-output, pulse-
width-modulation boost converter (0.25Ω switch), a
dual-output (positive and negative) gate-driver supply
using one inductor, an LCD backplane driver, and a sim-
ple phase-locked loop to synchronize all three outputs.
High switching frequency (1MHz nominal) and phase-
locked operation allow the use of small, minimum-
height external components while maintaining low
output noise. A +2.8V to +5.5V input voltage range
allows operation with any logic supply. Output voltages
are adjustable to +5.5V (DC-DC 1) and to +28V and
-10V (DC-DC 2). The negative output voltage can be
adjusted to -20V with additional components. Also
included are a logic-level shutdown and a “Ready” out-
put (RDY) that signals when all three outputs are in reg-
ulation.
The boost-converter operating frequency can be set at
16, 24, or 32 times the backplane clock. This flexibility
allows a high DC-DC converter frequency to be used
with LCD backplane clock rates ranging from 20kHz to
72kHz. The MAX1664 is supplied in a 1.1mm-high
TSSOP package.
____________________________Features
o
Integrates All Active Circuitry for Three DC-DC
Converters
o
Ultra-Small External Components
(ceramic capacitors, 2µH to 5µH inductors)
o
DC-DC Converters Phase-Locked to Backplane
Frequency for Lowest Noise
o
Low Operating Voltage (down to +2.8V)
o
Adjustable Output Voltage from V
IN
to +5.5V
o
Load Currents Up to 500mA
o
Adjustable TFT Gate Driver Output:
Positive, V
IN
to +28V
Negative, 0 to -10V (-20V with added
components)
o
Includes 0.35Ω Backplane Driver
o
1µA Shutdown Current
o
Power-Ready Output Signal
MAX1664
_______________Ordering Information
PART
MAX1664CUP
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
20 TSSOP
________________________Applications
LCD Modules
LCD Panels
Typical Operating Circuit
V
SUPPLY
2.8V TO 5.5V
REF
___________________Pin Configuration
TOP VIEW
SHDN 1
RDY 2
FB1 3
REF 4
GND 5
IN 6
FB2- 7
FB2+ 8
PLLC 9
BPV
SS
10
20 FPLL
19 LX1
18 PGND1
17 PGND2
28V
-10V
IN
FB2-
LX2P
INP
LX1
FB1
PGND1
5.5V
MAX1664
LX2N
FB2+
MAX1664
16 LX2N
15 LX2P
14 INP
13 BPCLK
12 BPV
DD
11 BPDRV
PLLC
GND
FPLL
RDY
BPCLK
PGND2
BPV
DD
BPDRV
BPV
SS
SHDN
REF
ON
BACKPLANE
DRIVER
OFF
TSSOP
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
Active-Matrix Liquid Crystal Display
(AMLCD) Supply
MAX1664
ABSOLUTE MAXIMUM RATINGS
RDY, IN, BPV
DD
to GND...........................................-0.3V to +6V
FB2-, PGND1, PGND2 to GND ..........................................±0.3V
LX1 to PGND1 ..........................................................-0.3V to +6V
BPV
SS
to GND .......................................................-3.3V to +0.3V
BPVDD to BPV
SS
......................................................-0.3V to +6V
BPDRV to BPV
SS
..................................-0.3V to (V
BPVDD
+ 0.3V)
LX2P to INP ............................................................-15V to +0.3V
LX2N to PGND2......................................................-0.3V to +30V
SHDN,
INP, FB1, FB2+, REF, PLLC,
BPCLK, FPLL to GND ................................-0.3V to (V
IN
+0.3V)
RDY Sink Current ................................................................20mA
LX2P, LX2N Peak Switch Currents .................................±750mA
Continuous Power Dissipation (T
A
= +70°C)
20-Pin TSSOP (derate 7mW/°C above+70°C) ..............559mW
Operating Temperature Range...............................0°C to +70°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+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
IN
= V
INP
= 3.3V,
SHDN
= IN, V
BPVDD
= 4V, V
BPVSS
= -1V, PGND1 = PGND2 = FPLL = GND, f
BPCLK
= 30kHz, T
A
= 0°C to +70°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Input Supply Range
Undervoltage Lockout
Threshold
Quiescent Current
Shutdown Current
DC-DC 1 (PWM MAIN OUTPUT)
Output Voltage Range
Operating Frequency
FB1 Regulation Voltage
FB1 Input Bias Current
LX1 On Resistance
LX1 Leakage Current
LX1 Peak Current Limit
Power-Ready Trip Level
DC-DC 2 (PFM)
Positive Output Voltage Range
Negative Output Voltage Range
Maximum Operating Frequency
V
OUT2+
V
OUT2-
FPLL = GND
f
OP2(MAX)
FPLL = REF
FPLL = IN
V
IN
-10
16 x f
BPCLK
12 x f
BPCLK
8 x f
BPCLK
Hz
28
0
V
V
V
OUT1
FPLL = GND
f
OP1
V
FB1
I
FB1
R
ON(LX1)
I
LKG(LX1)
I
LIM(LX1)
V
TH_RDY
Rising edge, 2% hysteresis
V
LX1
= 6V
1.2
1.091
FPLL = REF
FPLL = IN
0 < I
LX1
< 1.2A
V
FB1
= 1.3V
0.25
0.1
1.5
1.125
1.2125
V
IN
32 x f
BPCLK
24 x f
BPCLK
16 x f
BPCLK
1.2500
1.275
100
0.5
10
1.8
1.159
V
nA
Ω
µA
A
V
Hz
5.5
V
SYMBOL
V
IN
V
UVLO
I
Q
I
SD
V
FB1+
= V
FB2+
= 1.3V, V
FB2-
= -0.1V;
I
IN
+ I
INP
SHDN
= GND, V
IN
= 5.5V; I
IN
+ I
INP
CONDITIONS
MIN
2.8
2.5
0.5
0.01
TYP
MAX
5.5
2.8
2
10
UNITS
V
V
mA
µA
2
_______________________________________________________________________________________
Active-Matrix Liquid Crystal Display
(AMLCD) Supply
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
INP
= 3.3V,
SHDN
= IN, V
BPVDD
= 4V, V
BPVSS
= -1V, PGND1 = PGND2 = FPLL = GND, f
BPCLK
= 30kHz, T
A
= 0°C to +70°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
FB2+ Regulation Voltage
FB2- Regulation Voltage
FB2+, FB2- Input Bias Current
LX2N, LX2P On-Resistance
LX2N, LX2P Leakage Current
FB2- Power-Ready Trip Level
FB2+ Power-Ready Trip Level
BACKPLANE DRIVER
BPV
DD
Supply Range
BPV
SS
Supply Range
BPV
DD
to BPV
SS
Voltage
Range
BPV
DD
Shutdown Current
BPDRV On-Resistance
BPDRV Leakage Current
BPV
DD
Supply Current
BPCLK Input Low Voltage
BPCLK Input High Voltage
BPCLK Input Current
PLL
VCO Center Frequency
(Note 1)
BPCLK Input Frequency
Range
Reference Voltage
Undervoltage Lockout
LOGIC SIGNALS
SHDN
Input Low Voltage
SHDN
Input High Voltage
SHDN
Input Current
FPLL Input Current
RDY Output Low Voltage
RDY Output High Leakage
V
IL(SHDN)
V
IH(SHDN)
I
IN(SHDN)
I
IN(FPLL)
V
OL(RDY)
FPLL = GND or IN
I
SINK
= 2mA
(0.10 x V
IN
) typical hysteresis
0.7 x V
IN
0.01
0.01
0.05
0.01
1
1
0.4
1
0.3 x V
IN
V
V
µA
µA
V
µA
f
C
PLLC = REF, BPCLK = GND
C
PLLC
= 22nF
R
PLLC
= 100kΩ
C
SHUNT
= 2.2nF
-2µA < I
REF
< 50µA
FPLL = GND
FPLL = REF
FPLL = IN
1.63
20
27
40
1.225
0.90
1.250
1.05
1.92
2.20
36
48
72
1.275
1.20
V
V
kHz
MHz
V
BPVDD
V
BPVSS
V
VDD to VSS
I
SHDN(BP)
R
ON(BPDRV)
I
IN(BPVDD)
V
IL(BPCLK)
V
IH(BPCLK)
I
IN(BPCLK)
0.7 x V
IN
0.01
1
SHDN
= GND
Source and sink
-10
80
V
BPCLK
= 0 or 3.3V
2.5
-3
2.5
0.1
0.35
5.5
0
5.5
10
0.7
10
200
0.3 x V
IN
V
V
V
µA
Ω
µA
µA
V
V
µA
SYMBOL
V
FB2+
V
FB2-
I
FB2+
,
I
FB2-
R
ON(LX2N)
,
R
ON(LX2P)
I
LKG(LX2N)
,
I
LKG(LX2P)
V
TH(RDY)
V
TH(RDY)
VLX2N = 28V, VLX2P = -10V
Falling edge, 40mV hysteresis
Rising edge, 40mV hysteresis
85
1.091
V
FB2+
= 1.3V, V
FB2-
= -0.1V
CONDITIONS
MIN
1.225
-15
-100
0.9
0.05
120
1.125
TYP
1.25
0
MAX
1.275
15
100
1.7
10
165
1.159
UNITS
V
mV
nA
Ω
µA
mV
V
MAX1664
I
LKG(BPDRV)
SHDN
= GND
f
BPCLK
V
REF
V
REF(UVLO)
I
LKG(RDYOH)
V
RDY
= 5.5V
Note 1:
DC-DC 1 operates at one-half of the V
CO
frequency (f
C
/ 2).
_______________________________________________________________________________________
3
Active-Matrix Liquid Crystal Display
(AMLCD) Supply
MAX1664
__________________________________________Typical Operating Characteristics
(f
BPCLK
= 22.5kHz, FPLL = GND, L1 = 3.3µH, L2 = 4.7µH, T
A
= +25°C, unless otherwise noted.)
DC-DC 1 EFFICIENCY vs. LOAD CURRENT
(V
OUT1
= +5V)
MAX1664 TOC01
DC-DC 2 EFFICIENCY vs. LOAD CURRENT
(V
OUT2-
= -5V)
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
V
IN
= 5V
V
IN
= 3.3V
V
OUT2+
UNLOADED
MAX1664 TOC02
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
1
10
100
V
IN
= 4.5V
V
IN
= 3V
100
1000
1
10
LOAD CURRENT (mA)
100
LOAD CURRENT (mA)
DC-DC 2 EFFICIENCY vs. LOAD CURRENT
(V
OUT2+
= +15V)
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
1
10
LOAD CURRENT (mA)
V
OUT2-
UNLOADED
100
V
IN
= 3.3V
V
IN
= 5V
MAX1664 TOC03
V
OUT1
RIPPLE
MAX1664 TOC04
100
10mV/div
500ns/div
I
OUT1
= 250mA, L = 3.3µH
V
OUT2+
RIPPLE
MAX1664 TOC05
V
OUT2-
RIPPLE
MAX1664 TOC06
V
OUT2
100mV/
div
V
OUT2-
50mV/
div
2µs/div
V
OUT2+
= 15V, V
IN
= 3.3V, I
LOAD
= 9mA,
C
OUT2
= 0.22µF, AC COUPLED
5µs/div
V
OUT2-
= -5V, V
IN
= 3.3V, I
LOAD
= 5mA,
C
OUT2-
= 0.47µF, AC COUPLED
4
_______________________________________________________________________________________
Active-Matrix Liquid Crystal Display
(AMLCD) Supply
Typical Operating Characteristics (continued)
(f
BPCLK
= 22.5kHz, FPLL = GND, L1 = 3.3µH, L2 = 4.7µH, T
A
= +25°C, unless otherwise noted.)
V
OUT1
LINE-TRANSIENT RESPONSE
MAX1664 TOC07
MAX1664
V
OUT2+
LINE-TRANSIENT RESPONSE
MAX1664 TOC08
A
50mV/
div
A
200mV/
div
B
500mV/
div
B
500mV/
div
2ms/div
V
OUT1
= 5V, I
LOAD
= 250mA, C
OUT1
= 20µF
A: V
OUT1
, 50mV/div, AC COUPLED
B: V
IN
, 3V to 4V
2ms/div
V
OUT2+
= 15V, I
LOAD
= 5mA, C
OUT2+
= 0.22µF
A: V
OUT2+
, 200mV/div, AC COUPLED
B: V
IN
, 3V to 4V
V
OUT2-
LINE-TRANSIENT RESPONSE
MAX1664 TOC09
V
OUT1
LOAD-TRANSIENT RESPONSE
MAX1664 TOC10
A
200mV/
div
A
50mV/
div
B
500mV/
div
B
100mA/
div
2ms/div
V
OUT2-
= -5V, I
LOAD
= 5mA, C
OUT2-
= 0.47µF
A: V
OUT2-
, 200mV/div, AC COUPLED
B: V
IN
, 3V to 4V
2ms/div
V
OUT1
= 5V, V
IN
= 3.3V, C
OUT1
= 20µF
A: V
OUT1
, 50mV/div, AC COUPLED
B: I
OUT1
, 25mA TO 225mA, 100mA/div
INTERNAL FET ON-RESISTANCE
vs. TEMPERATURE
INTERNAL FET ON-RESISTANCE (mΩ)
MAX1664 TOC 11
BPDRV RISE AND FALL TIME
vs. LOAD CAPACITANCE
MAX1664 TOC12
1400
1200
1000
800
600
400
200
LX1
0
0
10
20
30
40
50
60
70
80
BPDRV P-CHANNEL
LX2P
LX2N
300
250
RISE/FALL TIME (ns)
200
RISE TIME
150
100
50
0
0.001
C
LOAD
FROM
BPDRV TO GND
0.01
0.1
1
FALL TIME
BPDRV N-CHANNEL
90
TEMPERATURE (°C)
LOAD CAPACITANCE (µF)
_______________________________________________________________________________________
5
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