Typical operating characteristics, Electrical characteristics (continued) – Rainbow Electronics MAX1585 User Manual
Page 7
MAX1584/MAX1585
5-Channel Slim DSC Power Supplies
_______________________________________________________________________________________
7
STEP-UP EFFICIENCY
vs. LOAD CURRENT
MAX1584/85 toc01
LOAD CURRENT (mA)
EFFICIENCY (%)
100
10
10
20
30
40
50
60
70
80
90
100
0
1
1000
V
OUT
= 5V
V
IN
= 4.5V
V
IN
= 4.2V
V
IN
= 3.8V
V
IN
= 3.0V
STEP-DOWN EFFICIENCY
vs. LOAD CURRENT
MAX1584/85 toc02
LOAD CURRENT (mA)
EFFICIENCY (%)
100
10
10
20
30
40
50
60
70
80
90
100
0
1
1000
V
IN
= 3.0V
V
IN
= 3.8V
V
IN
= 4.2V
V
IN
= 4.5V
PVSD CONNECTED TO BATTERY
V
OUT
= 1.5V
DOES NOT INCLUDE CURRENT USED
BY THE STEP-UP TO POWER THE IC
COMBINED BOOST-BUCK
EFFICIENCY vs. LOAD CURRENT
MAX1584/85 toc03
LOAD CURRENT (mA)
EFFICIENCY (%)
100
10
10
20
30
40
50
60
70
80
90
100
1
1000
V
IN
= 4.5V
V
IN
= 4.2V
V
IN
= 3.8V
V
IN
= 3.0V
V
OUT3
= 3.3V
V
OUTSU
= 5.0V
EFFICIENCY vs. INPUT VOLTAGE
MAX1584/85 toc04
INPUT VOLTAGE (V)
EFFICIENCY (%)
4.0
3.5
75
80
85
90
95
100
70
3.0
4.5
SU = 5V, 300mA
SD = 1.5V, 250mA
SU + AUX3 = 3.3V, 300mA
AUX1 = 15V, 40mA
AUX2 = -7.5V, 40mA
AUX1 EFFICIENCY vs. LOAD CURRENT
MAX5184/85 toc05
LOAD CURRENT (mA)
EFFICIENCY (%)
100
10
40
50
60
70
80
90
100
30
1
1000
V
IN
= 4.5V
V
IN
= 4.2V
V
IN
= 3.8V
V
IN
= 3.0V
V
OUT1
= 15V
MAX1585 AUX2 EFFICIENCY
vs. LOAD CURRENT
MAX5184/85 toc06
LOAD CURRENT (mA)
EFFICIENCY (%)
100
10
40
50
60
70
80
90
30
1
1000
V
IN
= 3.0V
V
IN
= 3.8V
V
IN
= 4.2V
V
IN
= 4.5V
V
OUT2
= -7.5V
Typical Operating Characteristics
(Circuit of Figure 1, T
A
= +25°C, unless otherwise noted.)
Note 5: The step-up current limit in startup refers to the LXSU switch current limit, not an output current limit.
Note 6: The idle mode current threshold is the transition point between fixed-frequency PWM operation and idle mode operation
(where switching rate varies with load). The specification is given in terms of inductor current. In terms of output current, the
idle mode transition varies with input-output voltage ratio and inductor value. For the step-up, the transition output current is
approximately 1/3 the inductor current when stepping from 2V to 3.3V. For the step-down, the transition current in terms of
output current is approximately 3/4 the inductor current when stepping down from 3.3V to 1.8V.
Note 7: Operation in dropout (100% duty cycle) can only be maintained for 100,000 OSC cycles before the output is considered
faulted, triggering global shutdown.
Note 8: Specifications to -40°C are guaranteed by design, not production tested.
ELECTRICAL CHARACTERISTICS (continued)
(V
PVSU
= V
PV
= V
PVSD
= V
INDL2
= 3.6V, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 8)