Electrical characteristics (continued) – Rainbow Electronics MAX1774 User Manual
Page 3
MAX1774
Dual, High-Efficiency, Step-Down
Converter with Backup Battery Switchover
_______________________________________________________________________________________
3
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Maximum Duty Cycle
100
%
Minimum On-Time
200
400
650
ns
Minimum Off-Time
200
400
650
ns
CORE REGULATOR
Input Voltage Range
V
INC
2.6
5.5
V
V
INC
rising
2.40
2.47
2.55
INC Undervoltage Lockout
V
INC
falling
2.30
2.37
2.45
V
C or e Outp ut V ol tag e Ad j ust Rang e
1.0
5.0
V
Maximum Core Load Current
V
CORE
= 1.8V (Note 1)
1
1.5
A
FBC Regulation Threshold
V
FBC
V
INC
= +2.5 to +5.5V, I
O U T C
= 0 to 200mA
0.97
1.0
1.03
V
FBC Input Current
I
FBC
V
FBC
= +1.3V
-0.1
0.1
µ
A
Dropout Voltage
I
OUTC
= 400mA
0.1
0.25
V
LXC Leakage Current
I
LXC
V
INC
= +5.5V, V
L X C
= 0 to +5.5V
-10
10
µ
A
LXC P-Channel, N-Channel On-
Resistance
0.25
0.5
Ω
LXC P-Channel Current Limit
I
CLC
1200
1800
3000
mA
LX C P - C hannel M i ni m um C ur r ent
100
250
400
mA
LXC N-Channel Valley Current
900
1400
2400
mA
LXC N-Channel Zero-Crossing
Current
40
110
170
mA
LXC Dead Time
50
ns
Max Duty Cycle
100
%
Minimum On-Time
170
400
690
ns
Minimum Off-Time
170
400
690
ns
BACKUP REGULATOR
Backup Battery Input Voltage
V
BBATT
0.9
5.5
V
LXB N-Channel On-Resistance
V
CS-
= +3.3V, I
LXB
= 50mA
1.9
3.5
Ω
LXB Current Limit
200
350
600
mA
LXB Leakage Current
V
LXB
= +5.5V, V
FBM
= +1.3V
1
µ
A
BIN Leakage Current
I
BIN
V
BIN
= +5.5V, CS- = BKOFF =
SHDNC = SHDNM = GND
1
µ
A
BIN, CS- Switch Resistance
V
CS-
= +3.3V, BKOFF = GND,
SHDNM = CVL
7.5
15
Ω
BIN Switch Zero-Crossing
Threshold
V
BIN
= + 2.5V , BKOFF = SHDNC =
SHDNM = C V L
17
35
mV
LXB Maximum On-Time
2.8
5.6
9.2
µ
s
Zero Crossing Detector Timeout
40
µ
s
ELECTRICAL CHARACTERISTICS (continued)
(Figure 1, V
IN
= V
INS
= +12V, V
INC
= V
CS-
= V
CS+
= +3.3V, V
CORE
= +1.8V,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are
at T
A
= +25°C.)