Electrical characteristics – Rainbow Electronics MAX1677 User Manual
Page 4
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter
4
_______________________________________________________________________________________
Note 1: The MAX1677 operates in bootstrap mode (operates from the output voltage). Once started, it will operate down to 0.7V
input. If V
IN
exceeds the set V
OUT
, V
OUT
will follow one diode drop below V
IN
.
Note 2: C
REF
= 0.22µF for applications where I
REF
> 10µA.
Note 3: In low-power mode (CLK/SEL = GND), the output voltage regulates 1% higher than in low-noise mode (CLK/SEL = OUT or
synchronized).
Note 4: The device is in a startup mode when V
OUT
is below this value.
Note 5: Specifications to -40°C are guaranteed by design and not production tested.
ELECTRICAL CHARACTERISTICS
(V
OUT
= 3.3V, C
REF
= 0.1µF, POUT = OUT, T
A
= -40°C to +85°C, unless otherwise noted. ) (Note 5)
LBO Output Low Voltage
V
LBO(LO)
Sink current = 1mA
LCDPOL = OUT or GND
300
450
0.1
V
µA
Supply Current
Main DC On, LCD Off
Supply Current All On,
Main DC-DC in PFM Mode
I
PFM
No load, current into OUT
60
µA
V
FB Regulation Voltage
µA
LX Leakage Current
Startup to Normal Mode Transition
Voltage (Note 4)
CONDITIONS
V
LOCKOUT
2.1
2.4
V
I
LX(LEAK)
5
Output Voltage
V
OUT
FB = GND, 0
≤ I
LX
≤ 350mA,
CLK/SEL = OUT (Note 3)
3.17
3.46
V
V
FB(REG)
Adjustable mode, CLK/SEL = OUT (Note 3)
1.22
1.28
µA
Supply Current All On,
Main DC-DC in PWM Mode
Supply Current in Shutdown
5
µA
I
PWM
No load, current into OUT
300
I
LCDOFF
No load, current into OUT
40
LX Current Limit
I
LX(PWM)
N-channel PWM mode
550
900
mA
UNITS
MIN
MAX
SYMBOL
PARAMETER
I
LX(PFM)
N-channel PFM mode
250
500
Internal Oscillator
f
CLK/SEL = OUT
240
360
kHz
External Clock Frequency Range
200
400
kHz
ON Input Threshold
V
ON(LOW)
1.1V < V
OUT
< 5.5V
0.2V
OUT
V
V
ON(HIGH)
0.8V
OUT
LCDON, LCDPOL, CLK/SEL
Input Threshold
V
IL
0.2V
OUT
V
V
IH
0.8V
OUT
LBI Falling Threshold
V
LBI(TH)
599
629
mV
LCD BIAS DC-DC
LCDLX Switch Current Limit
LCDPOL connected to OUT or GND
through 50k
Ω
150
300
mA
LCDFB Set Point
Positive LCD, LCDPOL = OUT
1.22
1.28
V
-20
+20
Negative LCD, LCDPOL = GND
mV
GENERAL
MAIN
LCD BIAS DC-DC
LOGIC