Rainbow Electronics MAX1678 User Manual
Page 2
MAX1678
1-Cell to 2-Cell, Low-Noise,
High-Efficiency, Step-Up DC-DC Converter
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
BATT
= V
SHDN
= 1.3V, I
LOAD
= 0, FB = GND,
T
A
= 0°C to +85°C
, unless otherwise noted. Typical values are at T
A
= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Note 1:
The reverse battery current is measured from the
Typical Operating Circuit’s
input terminal to GND when the battery is con-
nected backward. A reverse current of 220mA will not exceed package dissipation limits but, if left for an extended time
(more than 10 minutes), may degrade performance.
BATT, OUT,LX, SHDN to GND ..............................-0.3V to +6.0V
OUT, LX Current.......................................................................1A
FB, PFI, PFO to GND ................................-0.3V to (V
OUT
+ 0.3V)
Reverse Battery Current (T
A
= +25°C) (Note 1) ...............220mA
Continuous Power Dissipation (T
A
= +70°C)
µMAX (derate 4.1mW/°C above +70°C) .......................330mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +165°C
Lead Temperature (soldering, 10sec) .............................+300°C
V
PFI
= 650mV, V
PFO
= 6V
R
L
= 3k
Ω
, T
A
= +25°C
V
PFI
= 0, V
OUT
= 3.3V, I
SINK
= 1mA
V
PFI
= 650mV
Falling PFI hysteresis 2%
V
FB
= 1.3V
I
LOAD
= 20mA, V
BATT
= 2.5V (Figure 7)
V
BATT
= 1V
I
DIODE
= 100mA, P-channel switch off
V
OUT
= 3.5V
V
OUT
= 3.3V
V
OUT
= 3.3V
V
FB
< 0.1V
External feedback
V
OUT
= 3.5V
External feedback
0.9V < V
BATT
< 3.3V (t
ON
= K / V
BATT
)
CONDITIONS
V
0.8 x V
BATT
V
IH
SHDN Input High Voltage
V
0.2 x V
BATT
V
IL
SHDN Input Low Voltage
µA
0.01
1
PFO Leakage Current
V
0.04
0.4
V
OL
PFO Low Output Voltage
nA
0.1
10
PFI Input Current
mV
590
614
632
V
IL,PFI
PFI Trip Voltage
nA
0.1
10
FB Input Current
%
90
η
Efficiency
µA
2
3.5
I
SHDN,BATT
Shutdown Current into BATT
µA
0.1
1
I
SHDN,OUT
Shutdown Current into OUT
µA
4
8
I
Q,BATT
Quiescent Current into BATT
µA
37
65
I
Q,OUT
Quiescent Current into OUT
V-µs
5.60
8
11.2
K
On-Time Constant
V
0.87
Start-Up Voltage (Note 2)
V
5.5
V
BATT(MAX)
V
0.7
V
BATT(MIN)
Minimum Operating Input
Voltage
Maximum Operating Input
Voltage
mA
550
I
LX(MAX)
Maximum Peak LX Current
V
0.8
P-Channel Catch Diode Voltage
Ω
1.5
2.2
P-Channel On-Resistance
Ω
1
1.5
N-Channel On-Resistance
mV/°C
-2
Start-Up Voltage Tempco
V
3.16
3.3
3.44
V
OUT
Output Voltage (Fixed Mode)
V
2.0
5.5
Output Voltage Range
(Adjustable Mode)
V
1.19
1.23
1.26
V
FB
FB Set Voltage
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
SHDN = GND or BATT
nA
0.1
10
SHDN Input Current