Electrical characteristics (continued), Electrical characteristics – Rainbow Electronics MAX1644 User Manual
Page 3
MAX1644
2A, Low-Voltage, Step-Down Regulator with
Synchronous Rectification and Internal Switches
_______________________________________________________________________________________
3
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.)
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)
Note 2: Recommended operating frequency, not production tested.
Note 3: Specifications from 0°C to -40°C are guaranteed by design, not production tested.
R
TOFF
= 150k
Ω
V
FB
= 1.2V
V
FB
= 1.2V
I
LX
= 0.5A
V
IN
= 3.0V to 5.5V, I
LOAD
= 0,
FBSEL = GND or REF
I
LX
= 0.5A
CONDITIONS
µs
1.03
1.63
t
OFF
Off-Time Default Period
nA
0
250
I
FB
FB Input Bias Current
µA
360
I
IN
+ I
CC
No-Load Supply Current
A
0.2
0.7
I
IM
Idle Mode Current
Threshold
A
2.3
3.5
I
LIMIT
Current-Limit Threshold
m
Ω
200
R
ON, P
PMOS Switch
On-Resistance
m
Ω
150
200
R
ON, N
2.48
2.57
3.276
3.390
V
3.0
5.5
V
IN
Input Voltage
V
1.08
1.12
V
REF
Reference Voltage
V
V
REF
V
IN
Adjustable Output Voltage
1.08
1.12
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
V
IN
= V
CC
= 4V to 5.5V,
FBSEL = unconnected
V
IN
= 3V to 5.5V, FBSEL = V
CC
V
IN
= 3V to 5.5V, FBSEL = REF
V
IN
= 4.5V
V
IN
= 3V
NMOS Switch
On-Resistance
150
V
IN
= 4.5V
V
IN
= 3V
V
I
LOAD
= 0 to 2A,
V
FB
= V
OUT
V
OUT
Preset Output Voltage
Maximum Output RMS
Current
A
RMS
SS Sink Current
I
SS
100
µA
SHDN Input Current
I
SHDN
-0.5
0.5
µA
SS Source Current
I
SS
3.5
5
6.5
µA
SHDN Input Low Threshold
V
IL
0.8
V
SHDN Input High Threshold
V
IH
2.0
V
FBSEL Input Current
-5
+5
µA
0.9
1.3
5.8
V
SS
= 1V
V
SHDN
= 0 to V
CC
FBSEL = REF
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
Undervoltage Lockout
Threshold
V
UVLO
2.5
2.6
2.7
V
FB Input Bias Current
I
FB
0
80
200
nA
t
OFF
1.13
1.33
1.53
0.20
0.33
Off-Time Start-Up Period
t
OFF
4
·
t
OFF
µs
On-Time Period
t
ON
0.4
µs
CONDITIONS
V
FB
= 1.2V
R
TOFF
= 150k
Ω
R
TOFF
= 30.1k
Ω
V
IN
falling, hysteresis = 40mV
FB = GND
Off-Time Default Period
4.3
5.6
µs
R
TOFF
= 499k
Ω
FBSEL Logic Thresholds
0.2
V
FBSEL = GND
0.7
·
V
CC
0.7
·
V
CC
- 0.2
+ 0.2
FBSEL = unconnected
V
CC
- 0.2
FBSEL = V
CC