ADM8839 Analog Devices, ADM8839 Datasheet - Page 9

• Manufacturer Part Number: ADM8839
• Description: Charge Pump Regulator for Color TFT Panel
• Manufacturer: Analog Devices

Specifications of ADM8839

• Peak Efficiency (%): 82%
• Switching Freq: 100kHz
• Vin Max (v): 4.2V
• Vin Min (v): 2.7V
• Package: 20-Lead LFCSP
• Out Voltage (v): 5V; 15V; -15V
• Ripple Out (p-p): 10mV p-p; 50mV p-p; 50mV p-p

It is possible to configure the ADM8839 to supply up to 400 μA
on the ±15 V outputs by changing its configuration slightly, as
shown in Figure 17.
LDO_ON/OFF
SHDN
OSCILLATOR
GENERATOR
SHUTDOWN
ADM8839
CONTROL
CONTROL
TIMING
LOGIC
Figure 17. Current Boost Configuration
V
DISCHARGE
CC
GND
C5, 2.2µF
REGULATOR
VOLTAGE
TRIPLER
DOUBLE
VOLTAGE
DOUBLER
TRIPLE
VOLTAGE
INVERTER
VOLTAGE
LDO
C1+
C1–
VOUT
LDO_IN
+5VOUT
+5VIN
C2+
C2–
C3+
C3–
+15VOUT
C4+
C4–
–15VOUT
C1, 2.2µF
C2, 0.22µF
C3, 0.22µF
C4, 0.22µF
C8, 0.22µF
C9, 0.22µF
C6, 2.2µF
+15V
–15V
C7, 2.2µF
CURRENT BOOST
CONFIGURATION
CONNECTION
+5V
Rev. C | Page 9 of 12
The configuration in Figure 17 can supply up to 400 μA of
current on both the +15 V and the −15 V outputs. If the load on
the ±15 V does not draw any current, the voltage on the ±15 V
outputs can rise up to ±16.5 V (see Figure 18). In this
configuration, VOUT (Pin 2) is connected to +5VIN (Pin 5).
17.0
16.5
16.0
15.5
15.0
14.5
14.0
Figure 18. +15 V/−15 V Output Voltage vs. Load Current,
0
100
Current Boost Configuration
200
I
LOAD
–15V AT 25°C
+15V AT 25°C
(µA)
300
400
ADM8839
500