MAX1570 Maxim Integrated Products, MAX1570 Datasheet - Page 6

• Manufacturer Part Number: MAX1570
• Description: White LED Current Regulator
• Manufacturer: Maxim Integrated Products

White LED Current Regulator with 1x/1.5x
High-Efficiency Charge Pump
6
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PIN
10
11
12
13
14
15
16
—
1
2
3
4
5
6
7
8
9
NAME
PGND
LED5
LED4
LED3
LED2
LED1
GND
OUT
C1N
C2N
C1P
EN2
EN1
C2P
SET
EP
IN
Transfer Capacitor 1 Positive Connection
Enable, Dimming Control Input 2. EN2 and EN1 control shutdown, 1/3 current, 2/3 current, and full
current (see Table1).
Analog Ground. Connect directly to the exposed paddle underneath the IC.
LED5 Cathode Connection. Current flowing into LED5 is 230 times the current flowing out of SET.
When using fewer than five LEDs, this pin can be left unconnected. LED5 is high impedance during
shutdown.
LED4 Cathode Connection. Current flowing into LED4 is 230 times the current flowing out of SET.
When using fewer than five LEDs, this pin can be left unconnected. LED4 is high impedance during
shutdown.
LED3 Cathode Connection. Current flowing into LED3 is 230 times the current flowing out of SET.
When using fewer than five LEDs, this pin can be left unconnected. LED3 is high impedance during
shutdown.
LED2 Cathode Connection. Current flowing into LED2 is 230 times the current flowing out of SET.
When using fewer than five LEDs, this pin can be left unconnected. LED2 is high impedance during
shutdown.
LED1 Cathode Connection and Charge-Pump Feedback. Current flowing into LED1 is 230 times the
current flowing out of SET. The charge pump regulates the voltage on LED1 to various voltages
depending upon the status of EN1 and EN2 (see Table 1). Grounding LED1 forces OUT to operate at
5V while LED2–LED5 regulate the LED current to 230 x V
shutdown.
Bias Current Set Input. The current flowing out of SET programs the bias current into each LED by
I
GND to set the bias current as V
Enable, Dimming Control Input 1. EN1 and EN2 control shutdown, 1/3 current, 2/3 current, and full
current (see Table 1).
Power Ground. Charge-pump switching current flows through this pin. Connect to GND and system
ground as close to the MAX1570 and the input bypass capacitor as possible.
Transfer Capacitor 1 Negative Connection
Supply Voltage Input. Bypass IN to PGND with a 1µF ceramic capacitor. The input voltage range is
2.7V to 5.5V. IN is high impedance during shutdown.
Transfer Capacitor 2 Positive Connection
Charge-Pump Output. Bypass to PGND with a 4.7µF ceramic capacitor as close to the IC as possible.
Connect to the anodes of all the LEDs. OUT is high impedance during shutdown.
Transfer Capacitor 2 Negative Connection
Exposed paddle. Connect to GND.
LED_
= 230 x I
SET
. V
SET
is internally biased to various voltages (see Table 1). Connect a resistor to
SET
/R
SET
. SET is high impedance during shutdown.
FUNCTION
SET
/R
SET
. LED1 is high impedance during
Pin Description
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