Rainbow Electronics MAX887 User Manual
Page 2
MAX887
100% Duty Cycle, Low-Noise,
Step-Down, PWM DC-DC Converter
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V+ = +7V, PGND = GND = 0V,
SHDN = V+,
(T
A
= 0°C to T
MAX
)
, 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.
REF, FB, SYNC, VL to GND..................................... -0.3V to +6V
V+ to GND ............................................................. -0.3V to +12V
SHDN, LX to GND ....................................... -0.3V to (V+ + 0.3V)
PGND to GND ...................................................... -0.3V to +0.3V
Continuous Power Dissipation (T
A
= +70°C)
SO (derate 9.09mW/°C above +70°C) .........................471mW
Operating Temperature Ranges
MAX887HC/D.......................................................0°C to +70°C
MAX887HESA ...................................................-40°C to +85°C
Storage Temperature Range ........................... -65°C to +165°C
Lead Temperature (soldering, 10sec) ............................ +300°C
SYNC = GND or 3V
I
OUT
= 0mA, SYNC = GND
V+ rising
I
OUT
= 0mA, SYNC = 3.0V
V+ falling
V+ = floating, LX = 5V,
SHDN = GND
V+ = 12V, LX = GND to 12V
I
LX
= ±100mA
SYNC = 3.0V
FB = 1.30V
SYNC = 3.0V, PWM duty cycle = 50%
SHDN = GND
Circuit of Figure 2
I
OUT
= 0mA to 500mA
V
IN
= 4V to 11V, PWM mode
SYNC = 3.0V, FB = 1.18V
CONDITIONS
V
2.4
V
IH,
SHDN
SHDN Input High Voltage
µA
±1
I
IN, SYNC
SYNC Input Current
V
0.5
V
IL, SYNC
SYNC Input Low Voltage
V
2.5
V
IH, SYNC
SYNC Input High Voltage
V
3.1
3.5
V
+, START
Startup Voltage
V
3.0
3.3
V
+, UVLO
Undervoltage Lockout
µA
1.0
20
I
LXLKGR
LX Reverse Leakage Current,
Regulator Off
µA
-10
1.0
10
I
LXLKG
LX Leakage Current
Ω
0.6
R
ON, LX
LX On-Resistance
A
0.75
1.0
1.40
I
LIM+
High-Side Current Limit
kHz
260
300
340
f
OSC
PWM Switching Frequency
SHDN Input Low Voltage
V
IL,
SHDN
%
100
PWM, DUTY
PWM Maximum Duty Cycle
mA
0.2
0.5
I
V+, PFM
Quiescent Supply Current
(PFM Mode)
mA
2.7
4.0
I
V+, PWM
V
3.5
11.0
V+
Supply Range
Quiescent Supply Current
(PWM Mode)
ns
500
SYNC, PW
SYNC Pulse Width High or Low
kHz
25
440
f
SYNC
SYNC Frequency
µA
±0.10
I
FB
FB Input Current
V
1.225
1.250
1.275
V
FB
PWM FB Feedback Threshold
µA
2.5
5
I
V+, SHDN
Shutdown Supply Current
V
1.25
10.50
V
OUT, RANGE
Output Voltage Range
%/mA
0.005
Load Regulation
%/V
0.2
Line Regulation
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
0.8
V
SHDN Input Current, Sinking
I
IN-,
SHDN
SHDN = GND or V+
±1
µA
SHDN Input Capacitance
C
IN,
SHDN
(Note 1)
10
pF
VL Output Voltage
V
L
I
VL
= 0mA to 1mA
3.3
V
REF Output Voltage
V
REF
0µA to 30µA
1.25
V
Note 1:
Guaranteed by design and not production tested.