MAX8645X/MAX8645Y
1x/1.5x/2x White LED Charge Pumps with
Two LDOs in 4mm x 4mm TQFN
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 3.6V, V
GND
= V
PGND
= 0V, ENM1 = ENM2 = ENF = IN, R
SETM
= R
SETF
= 6.8kΩ, P1 = P2 = unconnected, C
REF
= 0.01µF,
T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Soft-Start Done Time 100 µs
Dropout Voltage I
LDO_
= 200mA (Note 4) 120 320 mV
Load Regulation V
IN
= 3.7V, 100µA < I
LDO_
< 200mA 1.3 %
Power-Supply Rejection
ΔV
OUT
/ΔV
IN
10Hz to 10kHz, C
LDO_
= 1µF, I
LDO_
= 10µA -60 dB
Output Noise Voltage (RMS) 10Hz to 100kHz, C
LDO_
= 1µF, I
LDO_
= 10mA 40 µV
RMS
Note 1: All devices are 100% production tested at T
A
= +25°C. Limits over the operating temperature range are guaranteed by
design.
Note 2: LED dropout voltage is defined as the M_ or F_ to GND voltage at which current into M_ or F_ drops 10% from the value at
M_ or F_ = 0.2V.
Note 3: (Greater of 2.7V or (V
LDO_
+ 0.5V)) ≤ V
IN
≤ 5.5V.
Note 4: LDO dropout voltage is defined as V
IN
- V
OUT
when V
OUT
is 100mV below the value of V
OUT
measured when V
IN
=
V
OUT(NOM)
+ 1V. Since the minimum input voltage is 2.7V, this specification is only meaningful when V
OUT(NOM)
> 2.5V.
Typical Operating Characteristics
(V
IN
= V
EN_
= 3.6V, circuit of Figure 2, T
A
= +25°C, unless otherwise noted.)
EFFICIENCY vs. Li+ BATTERY
VOLTAGE DRIVING SIX MAIN LEDs
MAX8645Y toc01
Li+ BATTERY VOLTAGE (V)
EFFICIENCY P
LED
/P
BATT
(%)
3.93.63.33.0
50
60
70
80
90
100
40
2.7 4.2
15mA/LED
4.5mA/LED
1.5mA/LED
EFFICIENCY vs. Li+ BATTERY
VOLTAGE DRIVING FLASH LED MODULE
MAX8645Y toc02
Li+ BATTERY VOLTAGE (V)
EFFICIENCY P
LED
/P
BATT
(%)
3.93.63.33.0
50
60
70
80
90
100
40
2.7 4.2
80mA TOTAL
160mA TOTAL
400mA TOTAL
BATTERY CURRENT vs. SUPPLY VOLTAGE
DRIVING SIX MAIN LEDs
MAX8645Y toc03
SUPPLY VOLTAGE (V)
BATTERY CURRENT (mA)
3.93.63.33.0
30
60
90
120
150
180
0
2.7 4.2
I
LED
= 15mA
I
LED
= 4.5mA
I
LED
= 1.5mA
V
IN
FALLING
V
IN
RISING
