LTC1649_15 Datasheet, PDF (5/16 Pages) Linear Technology – 3.3V Input High Power Step-Down Switching Regulator Controller

BLOCK DIAGRA
V_IN
SHDN
DELAY
50µs
INTERNAL
SHUTDOWN
C⁺
C^–
CHARGE
PUMP
LTC1649
CP_OUT
COMP
V_CC
12µA
SS
I_LIM
I_MAX
12µA
PWM
FB
+–
1.26V
MIN
MAX
40mV
+
40mV
PV_CC1
G1
PV_CC2
G2
I_FB
FB
1649 BD
TEST CIRCUIT
V_IN
3.3V
MBR0530
22Ω
SHDN
+
10µF
C1
220pF
R_C
7.5k
C_C
0.01µF
R_IMAX
50k
0.1µF
P_VCC1
G1
P_VCC2
I_FB
V_CC
G2
LTC1649
I_MAX
FB
SHDN V_IN
C⁺
COMP
SS
C^–
GND CP_OUT
1µF
1k
1µF
Q1, Q2 ⁺
IRF7801
TWO IN
PARALLEL
C_IN
3300µF
L_EXT
1.2µH
Q3
IRF7801
R1
12.4k
V_OUT
2.5V
+ _COUT
4400µF
R2
12.7k
+
MBR0530
10µF
0.33µF
Figure 1
1649 TA03
5