EVALUATION KIT AVAILABLE
MAX77596
24V, 300mA, Buck Converter with 1.1µA I
Q
General Description
The MAX77596 is a small, synchronous buck converter
with integrated switches. The device is designed to
deliver up to 300mA with input voltages from 3.5V to
24V, while using only 1.1µA quiescent current at no load
(fixed-output version). Voltage quality can be monitored
by observing the
RESET
signal. The device can operate
near dropout by running at 98% duty cycle, making it ideal
for battery-powered applications.
The device offers a fixed 3.3V output version, as well as
an adjustable version. The adjustable version allows the
user to program the output voltage between 1V and 10V
by using a resistor-divider. Frequency is fixed at 1.7MHz,
which allows for small external components and reduced
output ripple. The device offers both forced-PWM and
skip modes of operation, with ultra-low quiescent current
of 1.1µA in skip mode.
The MAX77596 is available in a small (2mm x 2.5mm)
10-pin TDFN package and operates across the -40°C to
+85°C temperature range.
Benefits and Features
●
Flexible Power for Systems That Require a Wide
Input Voltage Range
• V
IN
Range: 3.5V to 24V
• Up to 300mA Output Current
• Fixed 3.3V or Programmable 1V to 10V Output
Voltage
• 98% (Max) Duty Cycle Operation with Low
Dropout
• Operates from 5V, 12V, or 20V USB Type-C Input
Power
• Operates from 2S, 3S, or 4S Li-Ion Battery
●
Minimizes Power Consumption and Extends Battery
Life
• 1.1µA Quiescent Current (3.3V Fixed Output
Voltage)
• 86% Peak Efficiency at 12V
IN
, 3.3 V
OUT
●
Minimizes Solution Size
• 1.7MHz Operating Frequency
• Small 2.0mm x 2.5mm x 0.75mm 10-Pin TDFN
Package
●
Robust Solution
• Short-Circuit, Thermal Protections
• 6.6ms Internal Soft-Start Minimizes Inrush Current
• Current-Mode Control Architecture
• Up to 42V Input Voltage Tolerance
Applications
●
Portable Devices Powered from 2s, 3s,
or 4s Li+ Batteries
●
USB Type-C Devices
●
Point-of-Load Applications
19-7733; Rev 0;
10/15
MAX77596
24V, 300mA, Buck Converter with 1.1µA I
Q
Absolute Maximum Ratings
(Voltages Referenced to PGND)
SUP .......................................................................-0.3V to +42V
EN..............................................................-0.3V to V
SUP
+ 0.3V
BST to LX ..............................................................................+6V
BST............................................. ...........................-0.3V to +47V
MODE, OUT/FB,
RESET.................
........ -0.3V to V
BIAS
+ 0.3V
AGND................................................................ ...-0.3V to +0.3V
BIAS.................... .................................................-0.3V to +6.0V
OUT/FB Short-Circuit Duration..................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
(derate 9.8mW/°C above +70°C) ................................784mW
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
Soldering Temperature (reflow) .......................................+260°C
Package Thermal Characteristics
(Note 1)
TDFN
Junction-to-Ambient Thermal Resistance (B
JA
).........102°C/W
Junction-to-Case Thermal Resistance (B
JC
) ..................2.9°C/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.maximintegrated.com/thermal-tutorial.
Electrical Characteristic
(V
SUP
= V
EN
= 14V, V
MODE
= 0V, T
A
= T
J
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C, unless
otherwise noted.) (Note 2)
PARAMETER
Supply Voltage
Supply Voltage
SYMBOL
V
SUP
V
SUP
t < 500ms (Note 3)
Shutdown (V
EN
= 0V)
No load, fixed 3.3V V
OUT
Supply Current
I
SUP
No load, adjustable
V
OUT
T
A
= +25°C
T
A
= -40°C to +85°C
0.5
3.0
1
3.2
0.4
5
10
V
OUT
=
3.3V, 6V ≤ V
SUP
≤ 24V,
I
LOAD
= 0 to 300mA
Adjustable output versions
Adjustable output versions,
3.5V ≤ V
SUP
≤ 24V, I
LOAD
= 300µA
V
FB
= 1V
I
LOAD
= 0.3mA to 300mA
0.75
1.1
32
CONDITIONS
MIN
3.5
TYP
MAX
24
42
3.0
3.0
70
80
1.5
3.4
mA
V
V
mA
µA
UNITS
V
V
V
MODE
= V
BIAS
, no load, FPWM,
no switching
UV Lockout
BIAS Regulator Voltage
BIAS Current Limit
BUCK CONVERTER
Voltage Accuracy
Output Voltage Range
FB Voltage Accuracy
FB Input Current
FB Load Regulation
V
OUT,3.3V
V
OUT
V
FB
I
FB
ΔV
LOAD
V
UVLO
V
BIAS
V
BIAS
rising
Hysteresis
V
SUP
= 5.5V to 24V (MAX77596C/F)
3.1
1
0.98
3.3
3.4
10
V
V
V
µA
%
1.0
0.02
2
1.03
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Maxim Integrated
│
2
MAX77596
24V, 300mA, Buck Converter with 1.1µA I
Q
Electrical Characteristics (continued)
(V
SUP
= V
EN
= 14V, V
MODE
= 0V, T
A
= T
J
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C, unless
otherwise noted.) (Note 2)
PARAMETER
FB Line Regulation
High-Side DMOS R
DSON
Low-Side DMOS R
DSON
DMOS High-Side Current-Limit
Threshold
DMOS High-Side Skip-Mode
Peak-Current Threshold
DMOS Low-Side Zero-Crossing
Threshold
DMOS Low-Side Negative
Current-Limit Threshold
Soft-Start Ramp Time
LX Rise Time
Minimum On-Time
Maximum Duty Cycle
PWM Switching Frequency
RESET OUTPUT (RESET)
RESET
Threshold
RESET
Debounce
RESET
High Leakage Current
RESET
Low Level
LOGIC LEVELS
EN Input High Threshold
EN Input Low Threshold
EN Input Current
MODE Input High Threshold
MODE Input Low Threshold
MODE Internal Pulldown
THERMAL PROTECTION
Thermal Shutdown
Thermal-Shutdown Hysteresis
T
SHDN
T
SHDN,HYS
(Note 3)
(Note 3)
+175
+15
°C
°C
V
IH,EN
V
IL,EN
I
IN,EN
V
IH,MODE
V
IL,MODE
R
PD,MODE
1000
1.4
0.4
0.1
2.4
0.4
V
V
µA
V
V
kΩ
V
THR_RES
V
THF_RES
t
DEB
I
LEAK,RES
V
OUT,RES
T
A
= +25°C
Sinking 1mA
V
OUT
rising
V
OUT
falling
90
88
92
90
12
1
0.4
94
92
%V
OUT
µs
µA
V
SYMBOL
ΔV
LINE
R
ON,HS
R
ON,LS
I
MAX
I
SKIP
I
ZX
I
NEG
t
SS
t
RISE,LX
t
ON_MIN
DC
MAX
f
SW
1.58
(Note 3)
FPWM mode
CONDITIONS
6V ≤ V
SUP
≤ 24V
V
BIAS
= 5V, I
LX
= 200mA
V
BIAS
= 5V, I
LX
= 200mA
425
70
MIN
TYP
0.02
1000
500
500
100
40
-320
6.67
6
34
98
1.7
1.82
2200
1200
575
130
MAX
UNITS
%/V
mΩ
mΩ
mA
mA
mA
mA
ms
ns
ns
%
MHz
Note 2:
Limits are 100% tested at T
A
= +25°C. Limits over the operating temperature range and relevant
supply voltage range are guaranteed by design and characterization.
Note 3:
Guaranteed by design; not production tested.
www.maximintegrated.com
Maxim Integrated
│
3
MAX77596
24V, 300mA, Buck Converter with 1.1µA I
Q
Typical Operating Characteristics
NO-LOAD SUPPLY CURRENT
vs. SUPPLY VOLTAGE
(FIXED-OUTPUT, SKIP MODE)
4
V
OUT
= 3.3V
(V
SUP
= V
EN
= 12V, T
A
= +25
°
C, unless otherwise noted.)
NO-LOAD SUPPLY CURRENT
vs. TEMPERATURE (SKIP MODE)
V
OUT
= 3.3V
MAX77596 toc02
toc01
2.5
SUPPLY CURRENT (μA)
2.0
1.5
1.0
0.5
SUPPLY CURRENT (μA)
SUPPLY CURRENT (μA)
3
1.6
1.2
0.8
0.4
0
2
1
0
0
5
10
15
20
25
SUPPLY VOLTAGE (V)
0
-40 -20
0
20
40
60
80 100 120 140
-40 -20
0
20
40
60
80 100 120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
EFFICIENCY vs. LOAD
3.3V FIXED-OUTPUT
100
90
80
EFFICIENCY (%)
toc04
EFFICIENCY vs. LOAD
3.3V FIXED-OUTPUT
100
90
80
EFFICIENCY (%)
toc05
V
SUP
= 5V
SKIP
V
SUP
= 12V
SKIP
70
60
50
40
30
20
0.001
FPWM
70
60
FPWM
50
40
30
20
0.001
0.01
0.1
1
10
100
0.01
0.1
1
10
100
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
EFFICIENCY vs. LOAD
3.3V FIXED-OUTPUT
100
90
80
EFFICIENCY (%)
toc06
LOAD REGULATION
3.3V FIXED-OUTPUT
3.34
V
SUP
= 5V
3.32
toc07
V
SUP
= 20V
SKIP
OUTPUT VOLTAGE (V)
70
60
FPWM
50
40
30
20
0.001
3.30
3.28
FPWM
3.26
3.24
3.22
SKIP
0.01
0.1
1
10
100
0
50
100
150
200
250
300
OUTPUT CURRENT (mA)
OUTPUT CURRENT(mA)
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Maxim Integrated
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MAX77596 toc03
3.0
2.0
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX77596
24V, 300mA, Buck Converter with 1.1µA I
Q
Typical Operating Characteristics (continued)
(V
SUP
= V
EN
= 12V, T
A
= +25
°
C, unless otherwise noted.)
LOAD REGULATION
3.3V FIXED-OUTPUT
3.34
3.32
SKIP
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
toc08
LOAD REGULATION
3.3V FIXED-OUTPUT
3.34
3.32
FPWM
3.30
3.28
3.26
3.24
3.22
0
50
100
150
200
250
SKIP
toc09
START-UP WAVEFORM
3.3V ADJUSTABLE-OUTPUT
(SKIP, 0mA LOAD)
24V
V
EN
5V/div
I
SUP
0.1A/div
V
BIAS
5V/div
toc10
V
SUP
= 12V
V
SUP
= 20V
3.9V
3.30
3.28
3.26
3.24
3.22
0
50
100
150
200
250
300
OUTPUT CURRENT (mA)
FPWM
3.3V
V
OUT
1V/div
300
0V
1ms/div
OUTPUT CURRENT (mA)
3.34
3.32
3.30
OUTPUT VOLTAGE (V)
LINE REGULATION
3.3V FIXED-OUTPUT
toc11
LOAD TRANSIENT RESPONSE
3.3V FIXED-OUTPUT (SKIP)
V
SUP
= 12V
toc12
I
OUT
= 100mA
I
OUT
V
OUT
200mA/div
100mV/div
(3.3V offset)
3.28
3.26
3.24
3.22
3.20
3.18
0
5
10
15
20
25
I
OUT
= 300mA
100µs/div
SUPPLY VOLTAGE (V)
LOAD TRANSIENT RESPONSE
3.3V FIXED-OUTPUT (FPWM)
toc13
LOAD TRANSIENT RESPONSE
3.3V ADJUSTABLE-OUTPUT (SKIP)
toc14
V
SUP
=V
12V = 12V
SUP
V
SUP
= V
12V = 12V
SUP
I
OUT
V
OUT
200mA/div
100mV/div
(3.3V offset)
I
OUT
200mA/div
V
OUT
100mV/div
(3.3V offset)
100µs/div
100µs/div
www.maximintegrated.com
Maxim Integrated
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