Rainbow Electronics MAX1639 User Manual
Page 2
FREQ Input Voltage
MAX1639
High-Speed Step-Down Controller with
Synchronous Rectification for CPU Power
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
DD
= V
CC
= +5V, PGND = AGND = 0V, FREQ = REF,
T
A
= 0°C to +85°C
, unless otherwise noted.)
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.
V
DD
, V
CC
, PWROK to AGND ....................................-0.3V to +6V
PGND to AGND ..................................................................±0.3V
CSH, CSL to AGND ....................................-0.3V to (V
CC
+ 0.3V)
DL to PGND................................................-0.3V to (V
DD
+ 0.3V)
REF, CC1, CC2, FREQ, FB to AGND .........-0.3V to (V
CC
+ 0.3V)
BST to PGND..........................................................-0.3V to +12V
BST to LX..................................................................-0.3V to +6V
DH to LX.............................................(LX - 0.3V) to (BST + 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
16-Pin Narrow SO (derate 8.70mW/°C above +70°C) ....696mW
SO
θ
JC
...........................................................................65°C/W
Operating Temperature Range
MAX1639ESE....................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
FREQ = AGND
FREQ = REF
V
CC
= V
DD
FREQ = V
CC
PWROK = 5.5V
Includes line and load
regulation errors
I
SINK
= 2mA, V
CC
= 4.5V
Falling FB, 1% hysteresis with respect to V
REF
Rising FB, 1% hysteresis with respect to V
REF
0µA < I
REF
< 100µA
No load
V
CC
= V
DD
= 5.5V, FB forced 60mV above
regulation point, operating or standby mode
V
CC
rising edge, 1% hysteresis
V
REF
= 0V
Rising edge, 1% hysteresis
CONDITIONS
kHz
255
300
345
Switching Frequency
540
600
660
850
1000
1150
µA
1
PWROK Output Current High
V
0.4
PWROK Output Voltage Low
%
6.5
8
9.5
PWROK Trip Level
-7.5
-6
-4.5
mA
0.5
4.0
Reference Short-Circuit Current
V
2.7
3.0
Reference Undervoltage Lockout
V
4.5
5.5
Input Voltage Range
V
1.083
1.117
1.089
1.111
FB Voltage
mV
10
Reference Load Regulation
V
3.465
3.5
3.535
Reference Voltage
mA
0.1
V
DD
Supply Current (I
DD
)
V
4.0
4.2
Input Undervoltage Lockout
UNITS
MIN
TYP
MAX
PARAMETER
T
A
= +25°C to +85°C
T
A
= 0°C to +85°C
2.5
5
CSH - CSL = 0mV to 80mV
%
1
AC Load Regulation
CSH - CSL = 0mV to 80mV
%
0.1
DC Load Regulation
FB overdrive = 60mV
FB overdrive = 0V
Operating
mode
mA
3.6
10
V
CC
= V
DD
= 5.5V
V
REF
= 0V
Shutdown
mode
V
CC
Supply Current (I
CC
)
V
CC
(high)
GND (low)
FREQ = V
CC
%
V
CC
- 0.1
Maximum Duty Cycle
0.2
85
90
FREQ Input Voltage
V
REF (mid)
3.3
3.7