Rainbow Electronics MAX1800 - Manual (Page 4)

MAX1800
Digital Camera Step-Up
Power Supply
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V OUT = V POUT = 3.3V, PGND = GND, V ONM = 3.3V, V ON1 = V ON2 = V ON3 = V ONA = 0, T A = -40°C to +85°C,
unless otherwise noted. Typical values are at T A = +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
ANALOG GAIN BLOCK
AI Feedback Regulation Voltage V
AO
= V
OUT
- 1.25V 1.23 1.25 1.27 V
AI Input Common-Mode Range -0.1 1.3 V
AI Input Current V AI = 1.35V 100 nA
AI to AO Voltage Gain 70 100 140 V/V
AO Output Sink Current V AI = 1V, V AO = 2V 0.5 2.5 mA
AO Output Source Current V AI = 1.5V, V AO = 2V 0.5 2.5 mA
AO Output Low Voltage V AI = 1V, I SINK = 25 µA 0.5 V
AO Output High Voltage V AI = 1.5V or V ONA = 0, I SOURCE = 25 µA
V POUT
- 0.5
V
AI to AO -3dB Bandwidth 5 MHz
AUXILIARY DC/DC CONTROLLERS 1, 2, 3
INTERNAL CLOCK
OSC Clock Low Trip Level Falling edge 0.2 0.25 0.3 V
V DCON = 0.625V 0.575 0.625 0.675
OSC Clock High Trip Level
V DCON = V OUT 1.00 1.05 1.10
V
Maximum Duty-Cycle
Adjustment Range
40 90 %
Maximum Duty Cycle V DCON _ = 0.625V 50 %
Default Maximum Duty Cycle V DCON _ = 1.25V 84 %
ERROR AMPLIFIER
FB_ Regulation Voltage FB_ = COMP_ 1.23 1.25 1.27 V
FB_ to COMP_
Transconductance
FB_ = COMP_, -5 µA < I
LOAD < +5 µA 60 100 140 µS
FB_ to COMP_ Maximum
Voltage Gain
2000 V/V
FB_ Input Leakage Current V FB _ = 1.35V 100 nA
DRIVERS (DL1, DL2, DL3)
DL_ Driver Resistance R ON Output high or low 2 6 Ω
DL_ Drive Current Sourcing or sinking, V DL _ = V OUT /2 0.5 A
SOFT-START
Soft-Start Interval 1024
OSC
cycles
SHORT-CIRCUIT PROTECTION
Fault Interval 1024
OSC
cycles
Note 1: Specifications to -40 °C are guaranteed by design and not production tested.
Note 2: Operating voltage. Since the regulator is bootstrapped to the output, once started it will operate down to +0.7V input.
Note 3: The regulator is in startup mode until the voltage is reached.