Rainbow Electronics MAX8668 - Manual (Page 8)

MAX8667/MAX8668
1.5MHz Dual Step-Down DC-DC Converters
with Dual LDOs and Individual Enables
8 _______________________________________________________________________________________
Pin Description
NAME
PIN
MAX8667 MAX8668
FUNCTION
1 EN3 EN3
Enable Input for Regulator 3. Drive EN3 high or connect to IN34 to turn on regulator 3. Drive low
to turn off regulator 3 and reduce input quiescent current.
2 OUT3 OUT3
Output of Regulator 3. Bypass OUT3 with a 4.7µF ceramic capacitor to GND. OUT3 is
discharged to GND through an internal 1k
Ω in shutdown.
3 IN34 IN34
Input Voltage for LDO Regulators 3 and 4. Supply voltage range is from 1.7V to 5.5V. This
supply voltage must not exceed V
IN12 . Connect a 4.7µF or larger ceramic capacitor from IN34
to ground.
4 OUT4 OUT4
Output of Regulator 4. Bypass OUT4 with a 4.7µF ceramic capacitor to GND. OUT4 is
discharged to GND through an internal 1k
Ω in shutdown.
5 EN4 EN4
Enable Input for Regulator 4. Drive EN4 high or connect to IN34 to turn on regulator 4. Drive low
to turn off regulator 4 and reduce input quiescent current.
6 GND GND Ground
7 REF REF Reference Output. Bypass REF with a 0.01µF ceramic capacitor to GND.
8 OUT2 — Feedback Input for Regulator 2. Connect OUT2 directly to the output of step-down regulator 2.
— FB2
Feedback Input for Regulator 2. Connect FB2 to the center of a resistor feedback divider
between the output of regulator 2 and ground to set the output voltage. See the Setting the
Output Voltages and Voltage Positioning section.
9 PGND2 PGND2 Power Ground for Step-Down Regulator 2
10 LX2 LX2 Inductor Connection for Regulator 2
11 IN12 IN12
Input Voltage for Step-Down Regulators 1 and 2. Supply voltage range is from 2.6V to 5.5V. This
supply voltage must not be less than V
IN34 . Connect a 10µF or larger ceramic capacitor from
IN12 to ground.
12 LX1 LX1 Inductor Connection for Regulator 1
13 PGND1 PGND1 Power Ground for Step-Down Regulator 1
14 OUT1 — Feed b ack Inp ut for Reg ul ator 1. C onnect OU T1 d i r ectl y to the outp ut of step - d ow n r eg ul ator 1.
— FB1
Feedback Input for Regulator 1. Connect FB1 to the center of a resistor feedback divider
between the output of regulator 1 and ground to set the output voltage. See the Setting the
Output Voltages and Voltage Positioning section.
15 EN1 EN1
E nab l e Inp ut for Reg ul ator 1. D r i ve E N 1 hi g h or connect to IN 12 to tur n on step - d ow n r eg ul ator 1.
D r i ve l ow to tur n off the r eg ul ator and r ed uce i np ut q ui escent cur r ent.
16 EN2 EN2
E nab l e Inp ut for Reg ul ator 2. D r i ve E N 2 hi g h or connect to IN 12 to tur n on step - d ow n r eg ul ator 2.
D r i ve l ow to tur n off the r eg ul ator and r ed uce i np ut q ui escent cur r ent.
— EP EP Exposed Paddle. Connect to GND, PGND1, PGND2, and circuit ground.