EVALUATION KIT AVAILABLE
MAX16956
36V, 300mA, Mini Buck Converter with
1.1µA I
Q
General Description
The MAX16956 is a small, synchronous buck converter
with integrated high-side and low-side switches. The
device is designed to deliver up to 300mA with input
voltages from 3.5V to 36V, while using only 1.1µA
quiescent current at no load (fixed-output versions).
Voltage quality can be monitored by observing the
RESET
signal. The device can operate near dropout by
running at 97% duty cycle, making it ideal for automotive
applications under cold-crank.
The device offers fixed-output voltages of 5V and 3.3V,
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 2.1MHz, which allows for small external components,
reduced output ripple, and minimized AM radio interfer-
ence. The device offers both forced-PWM and skip modes
of operation, with ultra-low quiescent current of 1.1µA
in skip mode. The device can be ordered with spread-
spectrum frequency modulation designed to minimize
EMI-radiated emissions due to the switching frequency.
The MAX16956 is available in a small (3mm x 3mm)
10-pin µMAX
®
package and operates across the full auto-
motive temperature range of -40°C to +125°C. The device
is AEC-Q100 qualified.
Benefits and Features
●
Integration and High-Switching Frequency Saves
Space
• DC-DC Converter Up to 300mA Capability
• Fixed 5V/3.3V or Programmable Output-Voltage
Options (1V to 10V)
• Current-Mode-Control Architecture
• 2.1MHz Operating Frequency
• Fixed 5.4ms Internal Soft-Start
●
Spread-Spectrum Frequency Modulation Reduces
EMI Emissions
●
Low I
Q
Enables Designers to Meet Stringent OEM
Module Power-Consumption Requirements
• 1.1µA Quiescent Current in Standby Mode
(Fixed-Output-Voltage Versions Only)
●
Wide Input Voltage Range Supports Automotive
Applications
• Operating V
IN
Range: 3.5V to 36V (42V Tolerant)
• 97% (Max) Duty-Cycle Operation with Low
Dropout
●
Robust Performance Supports Wide Range of
Automotive Applications
• Short-Circuit, Thermal Protections
• -40°C to +125°C Automotive Temperature Range
• AEC-Q100 Qualified
Typical Application Circuits, Ordering Information, and
Selector Guide appear at end of data sheet.
Applications
●
Automotive Body ECUs
●
Point-of-Load Applications
●
Distributed DC Power Systems
µMAX is a registered trademark of Maxim Integrated Products,
Inc.
19-6737; Rev 5; 10/15
MAX16956
36V, 300mA, Mini 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 12.9mW/ºC above +70
°
C) ............................1031mW
Operating Temperature Range ......................... -40
°
C to +125
°
C
Junction Temperature ......................................................+150
°
C
Storage Temperature Range ............................ -65
°
C to +150
°
C
Lead Temperature (soldering, 10s) ...................................300
°
C
Soldering Temperature (reflow) ....................................... +260ºC
Package Thermal Characteristics
(Note 1)
µMAX
Junction-to-Ambient Thermal Resistance (B
JA
)....... 77.6
°
C/W
Junction-to-Case Thermal Resistance (B
JC
) .................... 5
°
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 Characteristics
(V
SUP
= V
EN
= 14V, V
MODE
= 0V, T
A
= T
J
= -40
°
C to +125
°
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)
V
EN
= 0V
No load, fixed 3.3V V
OUT
Supply Current
I
SUP
No load, fixed 5V V
OUT
No load, adjustable V
OUT
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,5V
V
OUT,3.3V
V
OUT
V
FB
I
FB
ΔV
LOAD
V
OUT
= 5V
V
OUT
= 3.3V
Adjustable output versions
Adjustable output versions, 6V ≤ V
SUP
≤ 36V
V
FB
= 1V
I
LOAD
= 0.3mA to 300mA
6V ≤ V
SUP
≤
36V, I
LOAD
= 0 to
300mA
4.9
3.2
1
0.98
1.0
0.02
1
5.0
3.3
5.2
3.4
10
1.03
V
V
V
µA
%
V
BIAS
V
BIAS
rising
Hysteresis
V
SUP
= 5.5V to 36V (MAX16956C/F only)
10
0.5
3.0
0.75
1.1
1.8
32
1
3.2
0.4
5
CONDITIONS
MIN
3.5
TYP
MAX
36
42
3.0
3.0
5.0
70
1.5
3.4
mA
V
V
mA
µA
UNITS
V
V
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Maxim Integrated
│
2
MAX16956
36V, 300mA, Mini 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 +125
°
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
Spread-Spectrum Range
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
SS
Spread-spectrum option only
1.95
(Note 3)
FPWM mode
CONDITIONS
6V ≤ V
SUP
≤ 36V
V
BIAS
= 5V, I
LX
= 200mA
V
BIAS
= 5V, I
LX
= 200mA
0.425
70
MIN
TYP
0.02
1000
500
0.5
100
40
-0.320
5.4
6
60
97
2.1
±6
2.25
2200
1200
0.575
130
MAX
UNITS
%/V
mΩ
mΩ
A
mA
mA
A
ms
ns
ns
%
MHz
%
Note 2:
Limits are 100% tested at T
A
= +25°C (and/or T
A
= +125°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.
Note 4:
When the typical minimum on-time of 80ns is violated, the device skips pulses.
www.maximintegrated.com
Maxim Integrated
│
3
MAX16956
36V, 300mA, Mini Buck Converter with
1.1µA I
Q
Typical Operating Characteristics
(V
SUP
= V
EN
= 14V, T
A
= +25
°
C, unless otherwise noted.)
MAX16956 toc02
MAX16956 toc01
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
SKIP
PWM
0
0.00005
0.0001
0.00015
I
OUT1
(A)
0.0002
0.00025
0.0003
0
0.00005
0.0001
0.00015
I
OUT1
(A)
0.0002
0.00025
0.0003
0
0.000001
0.0001
0.01
0.00001
0.001
I
OUT1
(A)
0.1
1
MAX16956 toc04
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
5V EFFICIENCY vs. LOAD CURRENT
SKIP
PWM
3.3V FIXED-OUTPUT STARTUP
WAVEFORM (PWM, 300mA LOAD)
MAX16956 toc05
V
SUP
10V/div
V
OUT
2V/div
V
RESET
5V/div
V
LX
10V/div
0
0.000001
0.0001
0.01
0.00001
0.001
I
OUT1
(A)
0.1
1
2ms/div
5V FIXED-OUTPUT STARTUP
WAVEFORMS (SKIP, 300mA LOAD)
MAX16956 toc06
NO-LOAD SUPPLY CURRENT (μA)
V
SUP
10V/div
V
OUT
5V/div
V
RESET
5V/div
V
LX
10V/div
2ms/div
2.5
2.0
1.5
1.0
0.5
0
V
OUT
= 3.3V
-40 -20
0
20
40
60
80 100 120 140
TEMPERATURE (°C)
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Maxim Integrated
│
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MAX16956 toc07
3.0
NO-LOAD SUPPLY CURRENT
vs. TEMPERATURE (SKIP MODE)
MAX16956 toc03
3.3V EFFICIENCY vs. LOAD
CURRENT—SKIP MODE (1μA to 300μA)
5V EFFICIENCY vs. LOAD
CURRENT—SKIP MODE (1μA to 300μA)
100
3.3V EFFICIENCY vs. LOAD CURRENT
MAX16956
36V, 300mA, Mini Buck Converter with
1.1µA I
Q
Typical Operating Characteristics (continued)
(V
SUP
= V
EN
= 14V, T
A
= +25
°
C, unless otherwise noted.)
MAX16956 toc08
MAX16956 toc09
I
LOAD
= 300mA
OUTPUT-VOLTAGE CHANGE (%)
OUTPUT-VOLTAGE CHANGE (%)
2
1
0
-1
-2
-3
SKIP
PWM
2
1
0
-1
-2
-3
SKIP
PWM
OUTPUT-VOLTAGE CHANGE (%)
2
1
0
-1
-2
-3
0
0.05
0.10
0.15
0.20
0.25
0.30
0
0.05
0.10
0.15
0.20
0.25
0.30
6
11
16
21
26
31
36
LOAD CURRENT (A)
LOAD CURRENT (A)
INPUT VOLTAGE (V)
I
LOAD
= 300mA
OUTPUT-VOLTAGE CHANGE (%)
2
1
0
-1
-2
-3
MAX16956 toc11
3
LINE REGULATION (5V OUTPUT)
LOAD-TRANSIENT RESPONSE
(3.3V, SKIP MODE)
MAX16956 toc12
I
LOAD
200mA/div
3.3V
V
OUT
100mV/div
AC-COUPLED
3.3V
V
PGOOD
5V/div
6
11
16
21
26
31
36
200µs/div
INPUT VOLTAGE (V)
LOAD-TRANSIENT RESPONSE
(3.3V, PWM MODE)
MAX16956 toc13
LOAD-TRANSIENT RESPONSE
(5V, SKIP MODE)
MAX16956 toc14
I
LOAD
200mA/div
V
OUT
50mV/div
AC-COUPLED
V
PGOOD
5V/div
I
LOAD
200mA/div
V
OUT
100mV/div
AC-COUPLED
V
PGOOD
5V/div
3.3V
5V
5V
5V
200µs/div
200µs/div
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Maxim Integrated
│
5
MAX16956 toc10
3
LOAD REGULATION (3.3V OUTPUT)
3
LOAD REGULATION (5V OUTPUT)
3
LINE REGULATION (3.3V OUTPUT)
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