19-5857; Rev 0; 5/11
EVALUATION KIT AVAILABLE
MAX16929
Automotive TFT-LCD Power Supply with Boost
Converter and Gate Voltage Regulators
General Description
The MAX16929 is a highly integrated power supply for
automotive TFT-LCD applications. The device integrates
one buck converter, one boost converter, one 1.8V/3.3V
regulator controller, and two gate voltage regulators.
The device comes in several versions to satisfy com-
mon automotive power-supply requirements (see the
Ordering Information/Selector Guide
table).
Designed to operate from a single 4V to 28V supply or
5.5V to 28V supply, the device is ideal for automotive
TFT-LCD applications.
Both the buck and boost converters use spread-spec-
trum modulation to reduce peak interference and to opti-
mize EMI performance.
The sequencing input (SEQ) allows flexible sequencing
of the positive-gate and negative-gate voltage regulators.
The power-good indicator (PGOOD) indicates a failure
on any of the converters or regulator outputs. Integrated
thermal shutdown circuitry protects the device from over-
heating.
The MAX16929 is available in a 28-pin TSSOP pack-
age with exposed pad, and operates over the -40NC to
+105NC temperature range.
Features
S
Operating Voltage Range of 4V to 28V (Buck) or
3V to 5.5V (Boost)
S
Independent 28V Input Buck Converter Powers
TFT Bias Supply Circuitry and External Circuitry
S
High-Power (Up to 6W) Boost Output Providing Up
to 18V
S
1.8V or 3.3V Regulator Provides 500mA with
External npn Transistor
S
One Positive-Gate Voltage Regulator Capable of
Delivering 20mA at 28V
S
One Negative-Gate Voltage Regulator
S
High-Frequency Operation
2.1MHz (Buck Converter)
2.2MHz (Boost Converter)
S
Flexible Stand-Alone Sequencing
S
True Shutdown™ Boost Converter
S
6µA Low-Current Shutdown Mode (Buck)
S
Internal Soft-Start
S
Overtemperature Shutdown
S
-40NC to +105NC Operation
Ordering Information/Selector Guide
appears at end of data
sheet.
Typical Application Circuit
appears at end of data sheet.
Applications
Automotive Dashboards
Automotive Central Information Displays
Automotive Navigation Systems
True Shutdown is a trademark of Maxim Integrated Products, Inc.
For related parts and recommended products to use with this part, refer to:
www.maxim-ic.com/MAX16929.related
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Maxim Integrated Products
1
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.
MAX16929
Automotive TFT-LCD Power Supply with Boost
Converter and Gate Voltage Regulators
ABSOLUTE MAXIMUM RATINGS
INB, ENB to GND ..................................................-0.3V to +42V
BST to GND ...........................................................-0.3V to +47V
BST to LXB ..............................................................-0.3V to +6V
LXB to GND ..............................................................-6V to +42V
AVL, PGOOD to GND .............................................-0.3V to +6V
FBB, ENB to GND .................................................-0.5V to +12V
CP, GH to GND .....................................................-0.3V to +31V
CP, GH to GND (V
INA
= 3.3V) ..............................-0.3V to +29V
LXP to GND ...........................................................-0.3V to +20V
DRVN to GND........................................................-25V to +0.3V
INA, COMPV, FBP to GND ......................................-0.3V to +6V
ENP, DR, FB, GATE, COMPI, FBGH,
FBGL, REF, SEQ to GND .....................-0.3V to (V
INA
+ 0.3V)
GND to PGNDP ....................................................-0.3V to +0.3V
Continuous Power Dissipation (T
A
= +70NC)
TSSOP (derate 27mW/NC above +70NC)...................2162mW
Operating Temperature Range ........................ -40NC to +105NC
Junction Temperature Range........................... -40NC to +150NC
Storage Temperature Range............................ -65NC to +150NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
PACKAGE THERMAL CHARACTERISTICS (Note 1)
TSSOP
Junction-to-Ambient Thermal Resistance (B
JA
) ..........37NC/W
Junction-to-Case Thermal Resistance (B
JC
) .................2NC/W
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to
www.maxim-ic.com/thermal-tutorial.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion 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
INB
= 12V, V
INA
= 5V, V
GND
= V
PGNDP
= 0V, T
A
= T
J
= -40NC to +105NC, typical values are at T
A
= +25NC, unless otherwise noted.)
(Note 2)
PARAMETER
BUCK CONVERTER
V
OUTB
= 5V (Note 3)
Supply Voltage Range
V
INB
V
OUTB
= 3.3V (Note 3)
t < 500ms
Supply Current
Undervoltage Lockout
Undervoltage Lockout Hysteresis
PWM Switching Frequency
Spread-Spectrum Range
f
SWB
SSR
5V, continuous mode
Output-Voltage Accuracy
V
OUTB
6V
P
V
INB
P
18V, 5V, skip mode
I
LOAD
< full load 3.3V, continuous mode
3.3V, skip mode
High-Side DMOS R
DS_ON
Skip-Current Threshold
Current-Limit Threshold
R
DS_ON(LXB)
I
LXB
= 1A
I
SKIP
I
MAX
I
OUTB
= 1.2A option
I
OUTB
= 2.0A option
1.6
2.7
-3%
-3%
-3%
-3%
1.9
I
INB
V
INB,UVLO
V
ENB
= 0V
V
ENB
= V
INB
, no load, T
A
= +25NC
AVL rising
6
70
3.1
0.5
2.1
+6
5
5
3.3
3.3
180
16
2
3.4
2.4
4.08
+3%
+6%
+3%
+6%
400
mI
%I
MAX
A
V
2.3
3.5
5.5
4
28
28
42
9
FA
V
V
MHz
%
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
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Maxim Integrated Products
2
MAX16929
Automotive TFT-LCD Power Supply with Boost
Converter and Gate Voltage Regulators
ELECTRICAL CHARACTERISTICS (continued)
(V
INB
= 12V, V
INA
= 5V, V
GND
= V
PGNDP
= 0V, T
A
= T
J
= -40NC to +105NC, typical values are at T
A
= +25NC, unless otherwise noted.)
(Note 2)
PARAMETER
Soft-Start Ramp Time
Maximum Duty Cycle
Minimum Duty Cycle
Maximum Duty Cycle in Dropout
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
POWER GOOD (PGOOD)
PGOOD Threshold
PGOOD Debounce Time
Output High-Leakage Current
Output Low Level
LOGIC LEVELS
ENB Threshold
ENB Hysteresis
ENB Input Current
BOOST, POSITIVE (GH), NEGATIVE (GL), 1.8V/3.3V CONVERTERS
INA Input Supply Range
INA Supply Current
INA Undervoltage Lockout
Threshold
INA Shutdown Current
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
Duration to Trigger Fault Condition
Autoretry Time
REFERENCE (REF)
REF Output Voltage
REF Load Regulation
REF Undervoltage Lockout
Threshold
OSCILLATOR
Internal Oscillator Frequency
Spread-Spectrum Modulation
Frequency
f
OSC
f
SS
T
A
= +25NC
3.96
4.40
f
OSC
/2
4.84
MHz
MHz
V
REF
No output current
0 < I
REF
< 80FA, REF sourcing
Rising edge, hysteresis = 200mV
1.236
-2
1.25
1.264
+2
1.165
V
%
V
V
INA
I
INA
V
INA,UVLO
I
SHDN
T
SHDN
T
H
V
FBP
, V
FBGH
, or V
FBGL
below its thresh-
old
V
FBP
= V
FBGH
= 1.3V, V
FBGL
= 0V,
LXP not switching
V
INA
rising, hysteresis = 200mV,
T
A
= +25NC
V
ENP
= 0V, T
A
= +25NC
Temperature rising
2.5
3
1.5
2.7
0.5
+165
15
238
1.9
5.5
2.0
2.9
V
mA
V
FA
NC
NC
ms
s
3
ENB rising
1.4
1.8
0.2
5
9
2.2
V
V
FA
Rising
Falling
90
94
92
13
0.2
0.4
95
%
Fs
FA
V
Continuous mode
Continuous mode
Dropout
SYMBOL
CONDITIONS
MIN
TYP
3.9
80
20
95
+175
15
MAX
UNITS
ms
%
%
%
NC
NC
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Maxim Integrated Products
3
MAX16929
Automotive TFT-LCD Power Supply with Boost
Converter and Gate Voltage Regulators
ELECTRICAL CHARACTERISTICS (continued)
(V
INB
= 12V, V
INA
= 5V, V
GND
= V
PGNDP
= 0V, T
A
= T
J
= -40NC to +105NC, typical values are at T
A
= +25NC, unless otherwise noted.)
(Note 2)
PARAMETER
Spread-Spectrum Factor
BOOST CONVERTER
Switching Frequency
Maximum Duty Cycle
Low boost current-
Duty cycle = 70%, limit option
C
COMPI
= 220pF
High boost current-
limit option
LXP On-Resistance
LXP Leakage Current
Soft-Start Time
Output Voltage Range
FBP Regulation Voltage
PGOOD Threshold
FBP Load Regulation
FBP Line Regulation
FBP Input Bias Current
FBP to COMPV Transconductance
POSITIVE-GATE VOLTAGE REGULATOR (GH)
Output Voltage Range
CP Overvoltage Threshold
FBGH Regulation Voltage
PGOOD Threshold
FBGH Load Regulation
FBGH Line Regulation
FBGH Input Bias Current
GH Output Current
GH Current Limit
GH Soft-Start Time
NEGATIVE-GATE VOLTAGE REGULATOR (GL)
Output Voltage Range
FBGL Regulation Voltage
V
DRVN
V
FBGL
I
DRVN
= 100FA
-24
0.212
0.242
-2
0.271
V
V
I
GH
I
LIM_GH
V
FBGH
V
PG_FBGH
V
GH
With external charge pump, T
A
= +25NC
(maximum V
CP
= 29.5V)
T
A
= +25NC (Note 6)
I
GH
= 1mA
Measured at FBGH
I
GH
= 0 to 20mA
V
CP
= 12V to 20V at V
GH
= 10V,
I
GH
= 10mA
V
FBGH
= 1V, T
A
= +25NC
V
CP
- V
GH
= 2V
20
35
56
7.45
5
29.5
0.98
0.83
30.5
1.0
0.85
2
2
Q1
1.034
0.87
29
V
V
V
V
%
%
FA
mA
mA
ms
V
SH
V
FBP
V
PG_FBP
V
INA
= +3V to +5.5V, T
A
= +25NC
0 < I
LOAD
< full load T
A
= -40NC to +105NC
Measured at FBP
0 < I
LOAD
< full load
V
INA
= +3V to +5.5V
V
FBP
= +1V, T
A
= +25NC
DI
=
Q2.5FA
at COMPV, T
A
= +25NC
R
DS_ON(LXP)
I
LXP
= 200mA
I
LK_LXP
V
LXP
= 20V, T
A
=+25NC
(Note 4)
V
INA
0.985
0.98
0.74
1.0
1.0
0.85
-1
0.1
Q1
400
f
SW
1.98
82
0.625
1.25
0.78
A
1.56
110
8.5
30
18
1.015
1.02
0.96
1.87
250
20
mI
FA
ms
V
V
V
%
%/V
FA
FS
2.20
2.42
93.5
MHz
%
SYMBOL
SSR
CONDITIONS
As a percentage of switching frequency,
f
SW
MIN
TYP
Q4
MAX
UNITS
%
LXP Current Limit
I
LIM
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Maxim Integrated Products
4
MAX16929
Automotive TFT-LCD Power Supply with Boost
Converter and Gate Voltage Regulators
ELECTRICAL CHARACTERISTICS (continued)
(V
INB
= 12V, V
INA
= 5V, V
GND
= V
PGNDP
= 0V, T
A
= T
J
= -40NC to +105NC, typical values are at T
A
= +25NC, unless otherwise noted.)
(Note 2)
PARAMETER
PGOOD Threshold
FBGL Input Bias Current
DRVN Source Current
DRVN Source Current Limit
GL Soft-Start Time
1.8V/3.3V REGULATOR CONTROLLER
Output Voltage
V
FB
V
PG_FB
V
DR
= V
FB
Measured at FB
(Notes 5, 7)
V
FB
= 1.8V
V
FB
= 3.3V
V
FB
= 1.8V
V
GATE
= 0.5V
Measured at GATE; below this voltage, the
external p-channel FET is considered on
4.5
33
3.3V regulator option
1.8V regulator option
3.3V regulator option,
FB rising
1.8V regulator option
3.18
1.746
2.4
1.364
3.3
1.8
2.57
1.38
2.5
4.5
6
55
1.25
75
3.38
1.854
2.7
1.396
FA
mA
FA
V
V
SYMBOL
V
PG_FBGL
CONDITIONS
Measured at FBGL
V
FBGL
= +0.25V
V
FBGL
= +0.5V, V
DRVN
= -10V
2
2.5
4
7.45
MIN
0.38
TYP
0.4
MAX
0.42
Q1
UNITS
V
FA
mA
mA
ms
FB PGOOD Threshold
V
FB Input Bias Current
DR Drive Current
INPUT SERIES SWITCH CONTROL
p-Channel FET GATE Sink Current
GATE Voltage Threshold
DIGITAL LOGIC
ENP, SEQ Input Pulldown Resistor
Value
ENP, SEQ Input-Voltage Low
ENP, SEQ Input-Voltage High
PGOOD Leakage Current
PGOOD Output-Voltage Low
R
PD
V
IL
V
IH
I
LK_IN
V
OL
500
0.3 x V
INA
0.7 x V
INA
T
A
= +25NC
2mA sink current, T
A
= +25NC
Q1
0.4
kI
V
V
FA
V
Note 2:
Specifications over temperature are guaranteed by design and not production tested.
Note 3:
Operation in light-load conditions or at extreme duty cycles result in skipped cycles, resulting in lower operating frequency
and possibly limited output accuracy and load response.
Note 4:
50% of the soft-start voltage time is due to the soft-start ramp, and the other 50% is due to the settling of the output voltage.
Note 5:
Guaranteed by design; not production tested.
Note 6:
After the voltage at CP exceeds this overvoltage threshold, the entire circuit switches off and autoretry is started.
Note 7:
FB power good is indicated by PGOOD. The condition V
FB
< V
PG_FB
does not shutdown/restart the device.
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Maxim Integrated Products
5
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