Datasheet

MAX1945R/MAX1945S
1MHz, 1% Accurate, 6A Internal Switch
Step-Down Regulators
8 _______________________________________________________________________________________
Typical Operating Characteristics
(V
IN
= V
CC
= 5V, V
OUT
= 1.8V, I
OUT
= 6A, f
SW
= 500kHz, V
DD
= V
CC
, and T
A
= +25°C, unless otherwise noted.)
EFFICIENCY vs. OUTPUT CURRENT
V
IN
= V
CC
= 5V
I
OUT
(A)
EFFICIENCY (%)
653 421
10
20
30
40
50
60
70
80
90
100
0
07
MAX1945 toc01
A
B
C
D
E
A: V
OUT
= 0.8V
B: V
OUT
= 1.5V
C: V
OUT
= 1.8V
D: V
OUT
= 2.5V
E: V
OUT
= 3.3V
V
IN
= V
CC
= 5V
f
SW
= 500kHz
EFFICIENCY vs. OUTPUT CURRENT
V
IN
= V
CC
= 3.3V
I
OUT
(A)
EFFICIENCY (%)
653 421
10
20
30
40
50
60
70
80
90
100
0
07
A
B
C
D
A: V
OUT
= 0.8V
B: V
OUT
= 1.5V
C: V
OUT
= 1.8V
D: V
OUT
= 2.5V
V
IN
= V
CC
= 3.3V
f
SW
= 500kHz
MAX1945 toc02
EFFICIENCY vs. OUTPUT CURRENT
V
IN
= 2.5V, V
CC
= 5V
I
OUT
(A)
EFFICIENCY (%)
653 421
10
20
30
40
50
60
70
80
90
100
0
07
A
B
C
A: V
OUT
= 0.8V
B: V
OUT
= 1.5V
C: V
OUT
= 1.8V
V
IN
= 2.5V, V
CC
= 5V
f
SW
= 500kHz
MAX1945 toc03
REFERENCE VOLTAGE
vs. REFERENCE SOURCE CURRENT
MAX1945 toc04
I
REF
(µA)
V
REF
(V)
3632282420161284
2.005
2.010
2.015
2.020
2.025
2.030
2.000
040
f
SW
= 500kHz
FREQUENCY vs. INPUT VOLTAGE (500kHz)
MAX1945 toc05a
V
IN
(V)
FREQUENCY (kHz)
5.04.53.0 3.5 4.0
480
490
500
510
520
530
540
550
470
2.5 5.5
+85
°
C
+25
°
C
-40
°
C
FREQUENCY vs. INPUT VOLTAGE (1MHz)
MAX1945 toc05b
V
IN
(V)
FREQUENCY (MHz)
5.04.53.0 3.5 4.0
0.925
0.950
0.975
1.000
1.025
1.050
0.900
2.5 5.5
+85
°
C
+25
°
C
-40
°
C
OUTPUT LOAD REGULATION
MAX1945 toc06
I
OUT
(A)
∆V
OUT
(mV)
54321
0.5
1.0
1.5
2.0
2.5
3.0
0
06
f
SW
= 500kHz
2.5V
1.8V
0.8V
SHUTDOWN SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX1945 toc07
V
IN
(V)
I
SHDN
(nA)
5.04.54.03.53.0
2
4
6
8
10
12
14
0
2.5 5.5
f
SW
= 500kHz
CURRENT LIMIT
vs. OUTPUT VOLTAGE
MAX1945 toc08
V
OUT
(V)
CURRENT LIMIT (A)
2.82.31.3 1.8
7
8
9
10
11
12
13
14
6
0.8 3.3
f
SW
= 500kHz