MAX1565 Datasheet, PDF (6/26 Pages) Maxim Integrated Products – Small, High-Efficiency, Five-Channel Digital Still Camera Power Supply

Small, High-Efficiency, Five-Channel
Digital Still Camera Power Supply
ELECTRICAL CHARACTERISTICS (continued)
(V_OUTSU = 3.3V, T_A = -40°C to +85°C, unless otherwise noted.)
PARAMETER
CONDITIONS
MIN TYP
FB_ to COMP_
Transconductance
FB_ = COMP_
80
FB_ Input Leakage Current
AUX1 Output Regulation Voltage
DL_ Driver Resistance
LOGIC INPUTS (ON_, FBSEL_)
Input Low Level
FB_ = 1.25V
FBSEL1 = GND, FB1 connected directly to AUX1 output
Output high
Output low
1.1V < OUTSU < 1.8V (ONSU only)
1.8V < OUTSU < 5.5V
-100
4.90
Input High Level
FBSEL_ Input Leakage Current
1.1V < OUTSU < 1.8V (ONSU only)
1.8V < OUTSU < 5.5V
FBSEL = 3.6V, OUTSU = 3.6V
FBSEL = GND, OUTSU = 3.6V
V_OUTSU
-0.2
1.6
-100
-100
MAX UNITS
185
µS
+100
nA
5.10
V
10
Ω
5
0.2
V
0.4
V
+100
nA
+100
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
The IC is powered from the OUTSU output.
Since the part is powered from OUTSU, a Schottky rectifier, connected from the input battery to OUTSU, is required for
low-voltage startup.
The step-up regulator operates in startup mode until this voltage is reached. Do not apply full load current during startup.
The step-up current limit in startup refers to the LXSU switch current limit, not an output current limit.
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 spec 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.
(Circuit of Figure 1, T_A = +25°C, unless otherwise noted.)
Typical Operating Characteristics
STEP-UP EFFICIENCY
vs. LOAD CURRENT
(5V OUTPUT)
100
90
80
70
60
50 V_IN = 4V
40
V_IN = 3.6V
V_IN = 3V
30 V_IN = 2V
20 ^{VIN = 1.5V}
10
0
1
V_OUT = 5V
10
100
1000
LOAD CURRENT (mA)
STEP-UP EFFICIENCY
vs. LOAD CURRENT
(3.3V OUTPUT)
100
90
80
70
60
50 _{VIN = 3.6V}
40 ^{VIN = 3V}
V_IN = 2V
30 V_IN = 1.5V
20
10
0
1
V_OUT = 3.3V
10
100
1000
LOAD CURRENT (mA)
STEP-DOWN EFFICIENCY
vs. LOAD CURRENT
100
90
80 ^VIN ^{= 4.2V}
V_IN = 3.6V
70 _{VIN = 3V}
60
50
40
30
INSD CONNECTED TO BATTERY
20 _{VOUT = 1.5V}
10 ^{DOES NOT INCLUDE CURRENT USED}
BY THE STEP-UP TO POWER THE IC
0
1
10
100
1000
LOAD CURRENT (mA)
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