
M
Low-Noise, 14V Input, 1A, PWM
S tep-Down Converters
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
AIN to AGND ............................................................-0.3 to +15V
IN to PGND................................................-0.3V to (V
AIN
+ 0.3V)
LX to PGND .................................................-0.5V to (V
IN
+ 0.3V)
PGND to AGND ..................................................................±0.3V
SHDN
to AGND .........................................-0.3V to (V
AIN
+ 0.3V)
ILIM/SS, FB, CC, BOOT, REF to AGND .....-0.3V to (V
CVL
+ 0.3V)
CVH to IN..................................................................-6V to +0.3V
CVL,
STBY
, SYNC/PWM to AGND............................-0.3V to +6V
Reference Current..............................................................±1mA
ELECTRICAL CHARACTERISTICS
(V
IN
= V
SHDN
= +6V,
STBY
= SYNC/PWM = CVL, V
BOOT
= V
OUT
, FB = AGND, circuit of Figure 1,
T
A
= 0°C to +85°C
, unless other-
wise noted. Typical values are at T
A
= +25°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.
CVL Current ..........................................................10mA to -1mA
LX Peak Current (Internally Limited) .....................................2.3A
Continuous Power Dissipation (T
A
= +70°C)
16-Pin QSOP (derate 8.3mW/°C above +70°C)............667mW
Operating Temperature Range ...........................-40°C to +85°C
J unction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10sec ) ............................+300°C
V
FB
= V
OUT
, I
LOAD
= 0 to 1A
FB = AGND, I
LOAD
= = 0 to 1A
Low-power mode,
STBY
= low,
V
BOOT
= 3.3V (Note 2)
Normal mode, SYNC/PWM = low,
V
BOOT
= 3.3V (Note 2)
PWM mode,
SYNC/PWM = high,
V
BOOT
= 3.3V
(Note 2)
SYNC/PWM = high
Low-side switch, V
IN
= 2.7V, I
LX
= 200mA
High-side switch,
I
LX
= 1A
V
FB
= V
OUT
, I
LOAD
= 0 to 1A
V
IN
= 5V to 14V
BOOT = AGND (Note 1)
V
FB
= 1.4V
SYNC/PWM = low
CONDITIONS
0.14
0.27
Quiescent Power Consumption
0.9
2
25
65
mW
13
33
mA
40
80
120
Zero Crossing Threshold
20
50
80
V
V
V
FB
V
OUT
Feedback Voltage
Output Voltage (3.3V mode)
1.238
3.3
1.251
3.333
1.264
3.365
V
2.7
14
Input Voltage Range
A
0.15
0.4
0.9
Current Limit, N-Channel
A
1.2
285
1.75
380
2.3
475
I
LIM
Current Limit in PWM Mode
Pulse-Skipping Current Threshold
3
8
On-Resistance, N-Channel
0.24
0.34
0.5
0.8
%
A
V
nA
0.01
Output Load Regulation
Output Current Capability
Output Adjust Range
FB Input Current
1
V
REF
-50
V
IN
50
I
FB
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
V
IN
= 6V
V
IN
= 2.7V
On-Resistance, P-Channel
MAX1684
MAX1685
MAX1684
MAX1685
SYNC/PWM = low
mA
STBY
= low
mA
285
380
475
I
LIMLP
Current Limit in Low-Power
Mode