Electrical characteristics, Electrical characteristics (continued) – Rainbow Electronics MAX1843 User Manual
Page 3
MAX1843
2.7A, 1MHz, Low-Voltage, Step-Down Regulator with
Internal Synchronous Rectification in QFN Package
_______________________________________________________________________________________
3
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Idle-Mode Current Threshold
0.3
0.6
0.9
A
Switching Frequency
f
(Note 2)
1
MHz
No-Load Supply Current
I
IN
+ I
CC
V
FB
= 1.2V
350
600
µA
Shutdown Supply Current
I
IN
+ I
CC
SHDN = GND, includes PMOS leakage
<1
15
µA
Thermal Shutdown Threshold
T
SHDN
Hysteresis = 15°C
160
°C
Undervoltage Lockout
V
UVLO
V
IN
falling, hysteresis = 90mV
2.5
2.6
2.7
V
FB Input Bias Current
V
FB
= 1.2V
0
60
250
nA
R
TOFF
= 110k
Ω
0.9
1.00
1.1
R
TOFF
= 30.1k
Ω
0.24
0.30
0.37
Off-Time
t
OFF
R
TOFF
= 499k
Ω
3.8
4.5
5.2
µs
Off-Time Startup Period
FB = GND
4 t
OFF
µs
On-Time
t
ON
(Note 2)
0.4
µs
SS Source Current
I
SS
4
5
6
µA
SS Sink Current
I
SS
V
SS
= 1V
100
µA
SHDN Input Current
I
SHDN
V
SHDN
= 0 to V
CC
-1
1
µA
SHD N Log i c Inp ut Low V ol tag e
V
IL
0.8
V
SHD N Log i c Inp ut H i g h V ol tag e
V
IH
2.0
V
FBSEL Input Current
I
FB
V
FBSEL
= 0 to V
CC
-4
4
µA
FBSEL = GND
0.2
FBSEL = REF
0.9
1.3
FBSEL = unconnected
0.7V
CC
- 0.2
0.7V
CC
+ 0.2
FBSEL Logic Thresholds
FBSEL = V
CC
V
CC
- 0.2
V
M axi m um O utp ut RM S C ur r ent
3.1
A
RMS
ELECTRICAL CHARACTERISTICS
(V
IN
= V
CC
= +3.3V, FBSEL = GND, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
MAX
UNITS
Input Voltage
V
IN
, V
CC
3.0
5.5
V
FBS E L = V
C C
2.475
2.756
FBS E L = unconnected
1.485
1.545
FBS E L = RE F
1.782
1.854
Preset Output Voltage
V
OUT
V
IN
= +3V to + 5.5V,
I
LOAD
= 0 to 2.5A,
V
FB
= V
OU T
FBS E L = GN D 1.078
1.122
V
Adjustable Output Voltage
Range
V
IN
= V
CC
= +3V to +5.5V, FBS E L = GN D V
REF
V
IN
V
Reference Voltage
V
REF
1.078
1.122
V
V
IN
= +4.5V
200
PMOS Switch On-Resistance
R
ON,P
I
LX
= 0.5A
V
IN
= +3V
250
m
Ω
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
CC
= +3.3V, FBSEL = GND, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)