Datasheet

MAX8795A
TFT-LCD DC-DC Converter with
Operational Amplifiers
______________________________________________________________________________________ 11
10µs/div
STEP-UP REGULATOR PULSED
LOAD-TRANSIENT RESPONSE
13.9V
50mA
C
MAX8795A toc05
B
0A
A
A: LOAD CURRENT, 1A/div
B: V
MAIN
, 200mV/div, AC-COUPLED
C: INDUCTOR CURRENT, 1A/div
TIMER-DELAYED OVERLOAD PROTECTION
MAX8795A toc06
40ms/div
A: V
MAIN
, 2V/div
B: INDUCTOR CURRENT, 1A/div
A
B
0A
0U
REF VOLTAGE LOAD REGULATION
MAX8795A toc07
LOAD CURRENT (µA)
REF VOLTAGE (V)
40302010
1.2475
1.2480
1.2485
1.2490
1.2495
1.2500
1.2470
050
GATE-ON REGULATOR LINE REGULATION
MAX8795A toc08
INPUT VOLTAGE (V)
VOLTAGE ERROR (%)
29282726
-0.6
-0.4
-0.2
0
-0.8
25 30
I
POS
= 20mA
GATE-ON REGULATOR LOAD REGULATION
MAX8795A toc09
LOAD CURRENT (mA)
VOLTAGE ERROR (%)
15105
-0.3
-0.1
-0.5
020
I
BOOST =
200mA
A
0V
B
0V
C
0A
STEP-UP REGULATOR SOFT-START
(HEAVY LOAD)
MAX8795A toc04
2ms/div
A: V
IN
, 5V/div
B: V
MAIN
, 5V/div
C: INDUCTOR CURRENT, 1A/div
STEP-UP EFFICIENCY
vs. LOAD CURRENT
MAX9795A toc01
LOAD CURRENT (mA)
EFFICIENCY (%)
10010
75
80
85
90
70
1 1000
V
IN
= 5V
V
MAIN
= 13.9V
SWITCHING FREQUENCY
vs. INPUT VOLTAGE
MAX9795A toc02
INPUT VOLTAGE (V)
SWITCHING FREQUENCY (MHz)
5.04.54.03.53.0
1.1
1.2
1.3
1.4
1.0
2.5 5.5
STEP-UP SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX8795A toc03
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
5.55.04.54.03.53.0
3
9
6
12
15
18
0
2.5 6.0
NO LOAD, SUP DISCONNECTED,
R1 = 221kΩ, R2 = 21.5kΩ
CURRENT INTO INDUCTOR
CURRENT INTO IN PIN
Typical Operating Characteristics
(Circuit of Figure 1, V
IN
= 5V, V
MAIN
= 14V, V
GON
= 25V, V
GOFF
= -10V, T
A
= +25°C, unless otherwise noted.)