Rainbow Electronics MAX1541 - Manual (Page 34)

MAX1540/MAX1541
Dual Step-Down Controllers with Saturation
Protection, Dynamic Output, and Linear Regulator
34 ______________________________________________________________________________________
Figure 12. MAX1541 Standard Application Circuit
MAX1541
+5V BIAS
SUPPLY
OUTPUT 1
V OUT(HIGH) = 1.5V
V OUT(LOW) = 1.0V
POWER GROUND
ANALOG GROUND
POWER-GOOD
ON
OFF
OPEN (I LIM(VAL) x 1.75)
OUTPUT 2
V
OUT2 = 2.5V
INPUT (V IN )*
7V TO 20V
V DD
DH1
BST1
LX1
CSP1
DL1
CSN1
OUT1
FB1
CC1
SKIP
REF
ILIM1
ILIM2
PGOOD2
LDOIN
PGOOD1
V CC
ON2
ON1
LDOON
LSAT
REF (485kHz/355kHz) TON
OVP/UVP
FB2
OUT2
CSN2
CSP2
GND
DL2
LX2
BST2
DH2
V+
R7
100k
Ω R6
100k Ω
C2
1
µF
C3
4.7
µF
R1
20 Ω
C OUT2
220 µF
R CS2
15m Ω
L2
4.3
µH
D L2 D L1
R CS1
15m Ω
L1
1.8 µH
N L1 N L2
N H1 N H2
C BST
0.1 µF
C BST1
0.1 µF
D BST D BST
C1
1 µF
C REF
0.22 µF
C OUT1
470 µF
C ILIM1
470pF
C ILIM2
470pF
R2
100k
Ω
R3
49.9k
Ω
R4
100k Ω
R5
49.9k Ω
SEE TABLE 1 FOR COMPONENT SPECIFICATIONS.
*LOWER INPUT VOLTAGES REQUIRE
ADDITIONAL INPUT CAPACITANCE.
C CC1
47pF
V OUT(LOW)
V OUT(HIGH)
GATE
FBLANK
REFIN1
OD
OPEN
(ENABLED, 140 µs)
REF
R9
75k Ω
R10
150k Ω
R8
75k Ω
C REFIN
470pF
R12
20k
Ω
+5V BIAS
SUPPLY
C IN
(2) 4.7 µF
V OUT(LOW) = V REF
V OUT(HIGH) = V REF
R9
R8 + R9 ( )
(R9 + R10)
R8 + (R9 + R10) [ ]
LDOOUT
FBLDO
+5V BIAS
SUPPLY
R13
10 Ω
R11
32.4k Ω
C4
22
µF
LDO OUTPUT
V
LDOOUT = 3.3V
( )