Rainbow Electronics MAX1774 - Manual (Page 3)

MAX1774
Dual, High-Efficiency, Step-Down
Converter with Backup Battery Switchover
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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.)