ADM8845 Analog Devices, ADM8845 Datasheet - Page 3

• Manufacturer Part Number: ADM8845
• Description: Charge Pump Driver for 6 White LED LCD Backlights
• Manufacturer: Analog Devices

Specifications of ADM8845

• Vin Range: 2.6 to 5.5V
• Vout (v): Vin to 5.5
• Synchronous: No
• Package: 16-Lead LFCSP
• Led Configuration: Parallel
• Topology: Capacitive
• I2c Support: No
• Max Iout (ma): 30mA
• Brightness Control: PWM
• Peak Efficiency (%): 88%
• Switching Frequency: 1.5MHz

SPECIFICATIONS
V
Table 1.
Parameter
INPUT VOLTAGE, V
SUPPLY CURRENT, I
SHUTDOWN CURRENT
CHARGE PUMP FREQUENCY
CHARGE PUMP MODE THRESHOLDS
I
MIN COMPLIANCE ON FBx PIN
PWM
DIGITAL INPUTS
CHARGE PUMP POWER EFFICIENCY
V
SET
OUT
CC
1.5× to 2×
2× to 1.5×
1× to 1.5×
1.5× to 1×
LED: LED Matching
LED: I
I
I
Charge Pump Output Resistance
LED Current
Input High
Input Low
Input Leakage Current
SET
LED
PIN
= 2.6 V to 5.5 V; T
RIPPLE
Accuracy
Accuracy
Hysteresis
Accuracy
Accuracy
Hysteresis
Pin Voltage
to I
SET
SET
Accuracy
Ratio
CC
CC
A
= −40°C to +85°C, unless otherwise noted; C1, C2 = 1.0 µF; C3 = 2.2 µF; C4 = 4.7 µF.
Min
2.6
−1
−1
0.1
0.5 V
CC
Typ
2.6
1.5
3.33
3.36
40
4.77
4.81
40
1.18
120
0.2
1.2
3.5
8.0
88
30
Max
5.5
5
5
4
4
4
4
+1
+1
0.3
1.8
5.1
14
30
200
0.3 V
1
CC
Rev. C | Page 3 of 20
Unit
V
mA
µA
MHz
V
%
V
%
mV
V
%
V
%
mV
%
%
V
V
Ω
Ω
Ω
mA
kHz
V
V
µA
%
m V
Test Conditions
All six LEDs disabled, V
CTRL1 = 1, CRTL2 = 1
I
I
I
1× mode
1.5× mode
2× mode
Guaranteed by design. Not 100% production tested. See Figure 21.
CTRL1 = 1, CRTL2 = 1, V
V
LED
LED
SET
CC
= 20 mA
= 20 mA, V
= 20 mA, R
= 3.6 V, I
LED
FB
SET
= 20 mA, all six LEDs enabled
=0.4 V
= 7.08 kΩ, V
CC
CC
= 3.3 V, R
= 3.4 V, V
FB
= 0.4 V, V
SET
FB
= 7.08 kΩ
= 0.2 V, I
CC
= 3.6 V, T
FB
= 20 mA
A
ADM8845
= 25°C