19-3944; Rev 1; 5/06
IT
TION K
VALUA
E
BLE
AVAILA
2.2MHz, 2A Buck Converters with an
Integrated High-Side Switch
Features
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
4.5V to 5.5V or 5.5V to 23V Input Voltage Range
Output Voltage Adjustable Down to 0.6V
2A Output Current
Synchronous Rectifier Driver Output (MAX5089)
for Higher Efficiency
Resistor-Programmable Switching Frequency
from 200kHz to 2.2MHz
External Synchronization and Enable (On/Off)
Inputs
Clock Output for Driving Second Converter 180°
Out-Of-Phase (MAX5089)
Integrated 150mΩ High-Side n-Channel Power
MOSFET
Power-On Reset Output (MAX5088)/Power-Good
Output (MAX5089)
Short-Circuit Protection
Thermal-Shutdown Protection
Thermally Enhanced 16-Pin TQFN Package
Dissipates 2.7W
General Description
The MAX5088/MAX5089 high-frequency, DC-DC con-
verters with an integrated n-channel power MOSFET
provide up to 2A of load current. The MAX5088
includes an internal power MOSFET to enable the
design of a nonsynchronous buck topology power sup-
ply. The MAX5089 is for the design of a synchronous
buck topology power supply. These devices operate
from a 4.5V to 5.5V or 5.5V to 23V input voltage and a
200kHz to 2.2MHz resistor-programmable switching
frequency. The voltage-mode architecture with a peak
switch current-limit scheme provides stable operation
up to a 2.2MHz switching frequency. The MAX5088
includes a clock output for driving a second DC-DC
converter 180° out-of-phase and a power-on-reset
(RESET) output. The MAX5089 includes a power-good
output and a synchronous rectifier driver to drive an
external low-side MOSFET in the buck converter config-
uration for high efficiency.
The MAX5088/MAX5089 protect against overcurrent
conditions by utilizing a peak current limit as well as
overtemperature shutdown providing a very reliable
and compact power source for point-of-load regulation
applications. Additional features include synchroniza-
tion, internal digital soft-start, and an enable input. The
MAX5088/MAX5089 are available in a thermally
enhanced, space-saving 16-pin TQFN (5mm x 5mm)
package and operate over the -40°C to +125°C tem-
perature range.
MAX5088/MAX5089
Ordering Information
PART
MAX5088ATE+
MAX5089ATE+
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
PIN-
PACKAGE
16 TQFN
16 TQFN
PKG
CODE
T1655-2
T1655-2
Applications
xDSL Modem Power Supply
Servers and Networks
IP Phones/WLAN Access Points
Automotive Radio Power Supply
+Denotes
lead-free package.
Pin Configurations
PGND
SGND
10
CKO
9
TOP VIEW
12
SOURCE
11
Selector Guide
PART
MAX5088ATE
CONFIGURATION
Nonsynchronous
Buck
Synchronous Buck
FEATURES
RESET
Output,
Clock Output
PGOOD Output,
Synchronous FET
Driver
SYNC 13
RESET 14
BST/VDD 15
EN 16
8
7
V
L
V+
BYPASS
OSC
MAX5088
6
5
+
EP*
1
DRAIN
2
DRAIN
3
COMP
4
FB
MAX5089ATE
Pin Configurations continued at end of data sheet.
*EXPOSED PAD.
THIN QFN
5mm x 5mm
________________________________________________________________
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.
2.2MHz, 2A Buck Converters with an
Integrated High-Side Switch
MAX5088/MAX5089
ABSOLUTE MAXIMUM RATINGS
V+ to PGND............................................................-0.3V to +25V
BST/VDD, DRAIN to SGND ....................................-0.3V to +30V
SGND to PGND .....................................................-0.3V to +0.3V
BST/VDD to SOURCE...............................................-0.3V to +6V
SOURCE to SGND..................................................-0.6V to +25V
SOURCE or DRAIN Maximum Peak Current...............5A for 1ms
V
L
to SGND ................-0.3V to the lower of +6V and (V+ + 0.3V)
SYNC, EN, DL, CKO, OSC, COMP,
FB to SGND...............................................-0.3V to (V
L
+ 0.3V)
BYPASS, CKO, OSC, COMP, FB, EN, SYNC, RESET,
PGOOD Maximum Input Current .................................±50mA
*As per JEDEC51 Standard (multilayer board).
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.
RESET,
PGOOD to SGND ........................................-0.3V to +6V
BYPASS to SGND..................................................-0.3V to +2.2V
V
L
and BYPASS Short-Circuit Duration to SGND ......Continuous
Continuous Power Dissipation* (T
A
= +70°C)
16-Pin TQFN (derate 33mW/°C above +70°C) ..........2666mW
Package Thermal Resistance (junction to case) ............1.7°C/W
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature Range ............................-65°C to +150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS
(V+ = V
L
= 5V or V+ = 5.5V to 23V, V
EN
= 5V, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Circuits of Figures 5 and 6. Typical
values are at T
A
= T
J
= +25°C.) (Note 1)
PARAMETER
SYSTEM SPECIFICATIONS
Input Voltage Range
V+ Operating Supply Current
V+
I
Q
5.5
V+ = V
L
V+ = 12V, V
FB
= 0.8V
R
OSC
= 10kΩ, no switching
V+ = 12V, V
EN
= 0V, PGOOD (MAX5089),
RESET,
CKO unconnected (MAX5088),
R
OSC
= 10kΩ
Nonsynchronous (MAX5088),
f
SW
= 1.25MHz, V+ = 12V, I
OUT
= 1.5A,
V
OUT
= 3.3V
Synchronous (MAX5089),
f
SW
= 300kHz, V+ = 12V, I
OUT
= 1.5A,
V
OUT
= 3.3V
V
L
REGULATOR (V
L
)/BYPASS OUTPUT (BYPASS)
V
L
Undervoltage Lockout
V
L
Undervoltage Lockout
Hysteresis
V
L
Output Voltage
BYPASS Output Voltage
BYPASS Load Regulation
V
UVLO
V
HYST
V
L
V
BYPASS
∆V
BYPASS
V+ = 5.5V to 23V, I
VL
= 0 to 40mA
V+ = V
L
= 5.2V
I
BYPASS
steps from 0 to 50µA,
V+ = V
L
= 5.2V
5.0
1.98
0
V
L
falling
4.1
137
5.2
2
1.2
5.5
2.02
10
4.3
V
mV
V
V
mV
4.5
1.8
23.0
5.5
2.5
V
V
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V+ Standby Supply Current
I
STBY
1
1.4
mA
79
%
90
Efficiency
η
2
_______________________________________________________________________________________
2.2MHz, 2A Buck Converters with an
Integrated High-Side Switch
ELECTRICAL CHARACTERISTICS (continued)
(V+ = V
L
= 5V or V+ = 5.5V to 23V, V
EN
= 5V, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Circuits of Figures 5 and 6. Typical
values are at T
A
= T
J
= +25°C.) (Note 1)
PARAMETER
SOFT-START
Digital Soft-Start Period
Soft-Start Steps
ERROR AMPLIFIER (FB and COMP)
FB to COMP Transconductance
FB Input Bias Current
FB Input Voltage Set Point
COMP Sink-and-Source Current
Capability
INTERNAL MOSFETs
On-Resistance n-Channel Power
MOSFET
Leakage Current
Minimum Output Current
Current Limit
On-Resistance Internal Low-Side
Switch
On-Resistance nMOS
On-Resistance pMOS
Peak Sink Current
Peak Source Current
Clock Output-High Level
Clock Output-Low Level
Switching Frequency
Minimum Controllable On-Time
Maximum Duty Cycle
R
ON
I
LEAK
I
OUT
I
LIMIT
R
ONLSW
I
SWITCH
= 50mA, V+ = V
L
= 5.2V
V+ = V
L
= 5.2V, I
SINK
= 100mA
V
EN
= 0V, V
DRAIN
= 23V,
SOURCE = PGND
V
OUT
= 3.3V, V+ = 12V (Note 2)
2.2
2
2.8
20
3.5
38
0.150
0.302
20
Ω
µA
A
A
Ω
g
M
I
FB
V
FB
I
COMP
0.5940
100
0.601
150
1.20
1.8
2.75
250
0.6095
mS
nA
V
µA
Internal 6-bit DAC
4096
64
Clock
periods
Steps
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5088/MAX5089
SYNCHRONOUS RECTIFIER DRIVER (DL) (MAX5089 Only)
R
ONDLN
R
ONDLP
I
IDL_SINK
I
IDL_SOURCE
V
CKOH
V
CKOL
f
SW
t
ON_MIN
D
MAX
f
SW
= 2.2MHz
MAX5088
MAX5089
82
82
V
L
= 5.2V, I
SOURCE
= 5mA
V
L
= 5.2V, I
SINK
= 5mA
R
OSC
= 5.62kΩ
V+ = V
L
= 5.2V
R
OSC
= 41.2kΩ
R
OSC
= 10kΩ
1900
275
1130
2100
312
1250
120
87.5
87.5
3.54
0.4
2400
350
1380
ns
%
kHz
I
SINK
= 0.1A
I
SOURCE
= 0.1A
1
1.9
1
0.75
6.7
11.1
Ω
Ω
A
A
V
V
OSCILLATOR (OSC)/SYNCHRONIZATION (SYNC)/CLOCK OUTPUT (CKO) (MAX5088 Only)
_______________________________________________________________________________________
3
2.2MHz, 2A Buck Converters with an
Integrated High-Side Switch
MAX5088/MAX5089
ELECTRICAL CHARACTERISTICS (continued)
(V+ = V
L
= 5V or V+ = 5.5V to 23V, V
EN
= 5V, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Circuits of Figures 5 and 6. Typical
values are at T
A
= T
J
= +25°C.) (Note 1)
PARAMETER
SYNC Frequency Range
(Note 3)
Sync Input to SOURCE Rising-
Edge Phase Delay (Note 4)
Clock Output Phase Delay With
Respect to SOURCE Waveform
(Note 5)
SYNC High Threshold
SYNC Low Threshold
Minimum SYNC High Pulse Width
SYMBOL
f
SYNC
SYNC
PHASE
R
OSC
= 10kΩ, f
SYNC
= 1.2MHz
R
OSC
= 10kΩ, SYNC = GND
(MAX5088 only)
2.0
0.8
100
CONDITIONS
MIN
200
65
TYP
MAX
2200
UNITS
kHz
degrees
CKO
PHASE
V
SYNCH
V
SYNCL
t
SYNC_H
115
degrees
V
V
ns
EN,
RESET
(MAX5088)/PGOOD (MAX5089)
EN Threshold
EN Input Bias Current
RESET
Threshold (Note 6)
PGOOD Threshold (Note 6)
FB to
RESET
or FB to PGOOD
Propagation Delay
RESET
Active Timeout Period
RESET,
PGOOD Output Voltage
RESET,
PGOOD Output Leakage
Current
THERMAL SHUTDOWN
Thermal Shutdown
Thermal-Shutdown Hysteresis
T
SHDN
Temperature rising
+170
25
°C
°C
V
IH
V
IL
I
EN
V
TH
V
TH
t
FD
t
RP
V
OL
I
LEAK
I
SINK
= 3mA
V+ = V
L
= 5.2V, V
RESET
or
V
PGOOD
= 6V, V
FB
= 0.8V
140
V
FB
= V
OUT
V
FB
= V
OUT
90
90
92.5
92.5
3
200
254
0.4
2
2.0
0.8
250
95
95
V
nA
% V
OUT
% V
OUT
µs
ms
V
µA
Note 1:
100% tested at +125°C. Limits over temperature are guaranteed by design.
Note 2:
Output current may be limited by the power dissipation of the package. See the
Power Dissipation
section in the
Applications
Information
section.
Note 3:
SYNC input frequency is equal to the switching frequency.
Note 4:
From the SYNC rising edge to SOURCE rising edge.
Note 5:
From the rising edge of the SOURCE waveform to the rising edge of the CKO waveform.
Note 6:
RESET
goes high 200ms after V
OUT
crosses this threshold, PGOOD goes high after V
OUT
crosses this threshold.
4
_______________________________________________________________________________________
2.2MHz, 2A Buck Converters with an
Integrated High-Side Switch
MAX5088/MAX5089
Typical Operating Characteristics
(V+ = V
L
= 5.2V, T
A
= +25°C, Figures 5 and 6, unless otherwise noted.)
MAX5088 BUCK EFFICIENCY vs. OUTPUT
CURRENT (V
IN
= 5V, f
SW
= 2.2MHz)
MAX5088/89 toc01
MAX5088 BUCK EFFICIENCY vs. OUTPUT
CURRENT (V
IN
= 12V, f
SW
= 2.2MHz)
MAX5088/89 toc02
MAX5088 BUCK EFFICIENCY vs. OUTPUT
CURRENT (V
IN
= 16V, f
SW
= 2.2MHz)
3.3V
MAX5088/89 toc03
90
80
70
EFFICIENCY (%)
60
50
40
30
20
10
0
0
500
1000
1500
2000
3.3V
2.5V
80
3.3V
70
60
EFFICIENCY (%)
50
40
30
20
10
0
0
500
1000
1500
2000
2.5V
70
60
50
EFFICIENCY (%)
40
30
20
10
0
2500
2500
0
500
1000
1500
2000
2500
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
MAX5089 SYNCHRONOUS
EFFICIENCY vs. OUTPUT CURRENT
(V
IN
= 12V, f
SW
= 330kHz, L = 15µH)
MAX5088/89 toc04
MAX5089 SYNCHRONOUS EFFICIENCY vs. OUTPUT
CURRENT (V
IN
= 12V, f
SW
= 2.2MHz, L = 4.7µH)
75
70
EFFICIENCY (%)
65
60
55
50
45
40
35
30
3.3V
MAX5088/89 toc05
MAX5088/89 toc07
95
90
85
EFFICIENCY (%)
80
75
70
65
60
55
50
0
500
1000
1500
2000
1.2V
2.5V
3.3V
80
2500
0
500
1000
1500
2000
2500
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
MAX5089 OUTPUT VOLTAGE vs. OUTPUT
CURRENT (V
IN
= 12V, V
OUT
= 3.3V, f
SW
= 2.2MHz)
MAX5088/89 toc06
V
L
OUTPUT VOLTAGE
vs. SWITCHING FREQUENCY
5.190
5.185
5.180
5.175
V
L
(V)
V
IN
= 23V
3.315
3.310
OUTPUT VOLTAGE (V)
3.305
3.300
3.295
3.290
3.285
3.280
0
500
1000
1500
2000
OUTPUT CURRENT (mA)
5.170
5.165
5.160
5.155
5.150
100
600
V
IN
= 5.5V
1100
1600
2100
SWITCHING FREQUENCY (kHz)
_______________________________________________________________________________________
5
