MAX1620EEE+ Maxim Integrated Products, MAX1620EEE+ Datasheet - Page 11

• Manufacturer Part Number: MAX1620EEE+
• Description: IC LCD BIAS SUPP DGTL ADJ 16QSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX1620EEE+

• Applications: LCD Display
• Current - Supply: 150µA
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Output Current: 0.07 A
• Input Voltage: 1.8 V to 20 V
• Switching Frequency: 300 KHz
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 5. Typical Operating Circuit—Negative Output
Figure 6. Alternative Negative Output—Maximum Voltage
maximum switching frequency. The following equation
represents the output current for the ideal case (no
power losses) of Figure 5:
This means that a higher peak current is required to
achieve the same output current in the negative output
circuit as in the positive output circuit.
The output current for Figure 6 uses the same current
equation as the positive boost.
5.5V
I
3V
TO
OUT
5.5V
TO
3V
12V
2V
TO
15V
TO
2V
1
2
C1
0.1 F
NOTE: CONNECTIONS TO DIGITAL INPUTS NOT SHOWN.
x (k - factor / L) x V
C1
0.1 F
NOTE: CONNECTIONS TO DIGITAL INPUTS NOT SHOWN.
C2
0.1 F
C2
0.1 F
______________________________________________________________________________________
R8
10k
D3 1N6263 (ANY SCHOTTKY)
R8
10k
D3 1N6263 (ANY SCHOTTKY)
Digitally Adjustable LCD Bias Supplies
11
12
11
12
3
5
7
4
1
2
6
3
5
7
4
1
2
6
BATT
POK
V
POL
SHDN (SUS)
DN (SDA)
UP (SCL)
REF
AGND
BATT
POK
V
POL
SHDN (SUS)
DN (SDA)
UP (SCL)
REF
AGND
DD
TO REF
( ) ARE FOR MAX1621.
DD
( ) ARE FOR MAX1621.
TO REF
BATT
MAX1620
MAX1621
MAX1620
MAX1621
U1
U1
/ (V
BATT
LCDON
LCDON
PGND
DOUT
PGND
DOUT
DLO
DLO
DHI
DHI
LX
FB
LX
FB
V
OUT
14
16
15
13
10
9
8
14
16
15
13
10
9
8
)
C3
22 F
C3
22 F
300k
300k
R3
R3
The output voltage is set with a voltage divider to the
feedback pin (FB). For a positive output, the divider is
referred to GND; for a negative output, the divider is
referred to REF.
Output voltage can be adjusted with an internal DAC
summing current into FB through an external resistor.
The 5-bit DAC is controlled with a user-programmable
up/down counter. On power-up or after a reset, the
counter sets the DAC output to 10000 binary, or half-
scale.
R4
300k
R4
300k
N1
MMFT3055VL
N1
MMFT3055VL
L1
100 H
L1
100 H
2.2 F
1 F
C4
C4
D1
MBRS0540
D1
MBRS0540
MBRS0540
MBRS0540
D2
D2
100pF
100pF
1.2M
2.7M
C6
R5
C6
R5
Output Voltage Control
C5
22 F
C5
22 F
-6V
-13.5V
TO
-27V OUT
TO
-12V OUT
11