Chip information – Rainbow Electronics MAX758A User Manual
Page 9
saturation region. When shut down, the input voltage
exceeds the emitter voltage so the inactive transistor
provides high-impedance isolation between the input
and output. Efficiency will be slightly degraded due to
the PNP transistor saturation voltage and base current.
V
IN
=
0.8V TO
V
OUT
V
NEG
-19V
V
CC
=
2.4V TO
5.5V
D3**
D2*
D1*
R1
240k
R2
16.5k
ON
OFF
SHDN
V
CC
LIM
GND
LX
FB
MAX1605
L1
10
µH
C3
0.1
µF
C6
0.1
µF
C4
0.01
µF
C1
1000pF
C2
1
µF
R3
1
Ω
C5
1
µF
*D1, D2 = CENTRAL SEMICONDUCTOR
CMPD7000 DUAL
**D3 = CENTRAL SEMICONDUCTOR
CMSD4448 (1N4148)
Figure 4. Negative Voltage for LCD Bias
MAX1605
28V Internal Switch LCD Bias Supply
in SOT23
_______________________________________________________________________________________
9
V
IN
= 0.8V TO V
OUT
R3 = 180k
V
CC
= 2.4V TO 5.5V
V
OUT
= 18V
ON
OFF
R1
R2
SHDN
V
CC
2N2907A
V
SET
= 18.3V
(V
OUT
+0.3V)
LIM
GND
LX
FB
MAX1605
L1
10
µH
Figure 5. Output Disconnected in Shutdown
Chip Information
TRANSISTOR COUNT: 2329