T
A
= T
MIN
to T
MAX
MIN MAX
125 300
MAX749
Digitally Adjustable LCD Bias Supply
2 ______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
V+................................................................................-0.3V, +7V
CTRL, ADJ, FB, DLOW, DHI, CS.....................-0.3V, (V+ + 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW
SO (derate 5.88mW/°C above +70°C).........................471mW
Operating Temperature Ranges:
MAX749C_A........................................................0°C to +70°C
MAX749E_A.....................................................-40°C to +85°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
ELECTRICAL CHARACTERISTICS
(2V < V+ < 6V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
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 device is in regulation when V
FB
= 0V (see Figures 3 - 6).
Note 2: These tests performed at V+ = 3.3V. Operation over supply range is guaranteed by supply rejection test of full-count current.
Note 3: V
IH
is guaranteed by design to be 1.8V min for V+ = 2V to 6V for T
A
= T
MIN
to T
MAX
. V
IL
is guaranteed by design from
T
A
= T
MIN
to T
MAX
.
PARAMETER
SYMBOL CONDITIONS MIN TYP MAX UNITS
V+ Voltage 26V
FB Source Current I
FBS
On power-up or reset, V
FB
= 0V (Note 1) 12.80 13.33 13.86 µA
Zero-Count FB Current V
FB
= 0V 0.45 0.55 I
FBS
Full-Count FB Current V
FB
= 0V 1.43 1.53 I
FBS
DAC Step Size (Note 2) Monotonicity guaranteed, V
FB
= 0V 1.00 1.56 2.12 %I
FBS
DAC Linearity (Note 2) V
FB
= 0V ±1 %I
FBS
Supply Rejection V+ = 2V to 6V, full-count current 1.5 %I
FBS
Switching Frequency 100 to 500 kHz
Logic Input Current 0V < V
IN
< V+, CTRL, ADJ ±100 nA
Logic High Threshold (Note 3) V
IH
CTRL, ADJ 1.6 V
Quiescent Current 60 µA
Shutdown Current 15 µA
V+ to CS Voltage Current-limit trip voltage 110 140 180 mV
DHI Source Current V+ = 2V, V
DHI
= 1V 24 50 mA
DHI Drive Level No load V+ - 50mV V+ V
DLOW On Resistance V+ = 2V, V
DLOW
= 0.5V 510 Ω
VLogic Low Threshold (Note 3) V
IL
CTRL, ADJ 0.4
TIMING CHARACTERISTICS
T
A
= +25°C
MIN TYP MAX
PARAMETER SYMBOL CONDITIONS UNITS
Minimum Reset Pulse Width t
R
V+ = 5V 100
Minimum Reset Setup t
RS
0 0
Minimum Reset Hold t
RH
Not tested
0 0
t
SH
V+ = 2V 15 85 100
Minimum ADJ High Pulse Width
V+ = 5V 10 85 100
t
SL
V+ = 2V 170 400 500
Minimum ADJ Low Pulse Width
V+ = 5V 60 150 200
Minimum ADJ Low to CTRL Low t
SD
V+ = 2V 70 200 250
V+ = 5V 20 85 100
ns
V+ = 2V 400
25 85
Not tested
ns
ns
ns
ns
ns
FB Offset Voltage ±15 mV
