Document
MAX8667/MAX8668
19-0784; Rev 1; 7/07 EVAALVUAAILTAIOBNLEKIT
1.5MHz Dual Step-Down DC-DC Converters with Dual LDOs and Individual Enables
General Description
The MAX8667/MAX8668 dual step-down converters with dual low-dropout (LDO) linear regulators are intended to power low-voltage microprocessors or DSPs in portable devices. They feature high efficiency with small external component size. The step-down converters are adjustable from 0.6V to 3.3V (MAX8668) or factory preset (MAX8667) with guaranteed output current of 600mA for OUT1 and 1200mA for OUT2. The 1.5MHz hysteretic-PWM control scheme allows for tiny external components and reduces no-load operating current to 100µA with all outputs enabled. Dual low-quiescent-current, low-noise LDOs operate down to 1.7V supply voltage. The MAX8667/MAX8668 have individual enables for each output, maximizing flexibility. The MAX8667/MAX8668 are available in the spacesaving, 3mm x 3mm, 16-pin thin QFN package.
Applications
Cell Phones/Smartphones PDA and Palmtop Computers Portable MP3 and DVD Players Digital Cameras, Camcorders PCMCIA Cards Handheld Instruments
Typical Operating Circuit
Features
o Tiny, Thin QFN 3mm x 3mm Package
o Individual Enables
o Step-Down Converters 600mA Guaranteed Output Current on OUT1 1200mA Guaranteed Output Current on OUT2 Tiny Size 2.2µH Chip Inductor (0805) Output Voltage from 0.6V to 3.3V (MAX8668) Ultra-Fast Line and Load Transients Low 25µA Supply Current Each
o LDOs 300mA Guaranteed Low 1.7V Minimum Supply Voltage Low Output Noise
Ordering Information
PART
PKG CODE
TOP MARK
MAX8667ETEAA+
T1633-4
AEQ
MAX8667ETEAB+
T1633-4
AFI
MAX8667ETEAC+
T1633-4
AFM
MAX8667ETECQ+
T1633-4
AFN
Note: All MAX8667/MAX8668 parts are in a 16-pin, thin QFN, 3mm x 3mm package and operate in the -40°C to +85°C extended temperature range.
+Denotes a lead-free package.
Ordering Information continued at the end of data sheet. Selector Guide appears at the end of data sheet.
Pin Configuration
LX1 IN12 LX2 PGND2
2.6V TO 5.5V 10µF
0.01µF
600mA
2.2µH
2.2µF
IN12 EN1 EN2 REF
IN34 EN3
EN4 OUT3
OUT4 GND
4.7µF
4.7µF 300mA 300mA 4.7µF
MAX8667
2.2µH
1.2A
LX1
LX2
OUT1
OUT2
PGND1 PGND2
2.2µF
TOP VIEW
12 11 10 9
PGND1 13
8 OUT2 (FB2)
OUT1 (FB1) 14 EN1 15 EN2 16
MAX8667 MAX8668
7 REF 6 GND 5 EN4
1234
EN3 OUT3 IN34 OUT4
THIN QFN (3mm x 3mm)
( ) ARE FOR THE MAX8668
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1.5MHz Dual Step-Down DC-DC Converters with Dual LDOs and Individual Enables
MAX8667/MAX8668
ABSOLUTE MAXIMUM RATINGS
IN12, IN34, FB1, FB2, EN1, EN2, EN3, EN4, OUT1, OUT2, REF to GND............................................-0.3V to +6.0V
OUT3, OUT4 to GND.....-0.3V to the lesser of + 6V or (VIN34 + 0.3V)
PGND1, PGND2 to GND .......................................-0.3V to +0.3V LX1, LX2 Current ..........................................................1.5A RMS LX1, LX2 to GND (Note 1) .......................-0.3V to (VIN12 + 0.3V)
Continuous Power Dissipation (TA = +70°C) 16-Pin, 3mm x 3mm Thin QFN (derate 20.8mW/°C above +70°C) .............................1667mW
Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ..................................................... +150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C
Note 1: LX_ has internal clamp diodes to GND and IN12. Applications that forward bias these diodes should take care not to exceed the IC’s package-dissipation limits.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN34 = VIN12 = 3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER IN34 Supply Range IN12 Supply Range IN12 Suppy Range Shutdown Supply Current, IIN12 + IIN34 No Load Supply Current, IIN12 + IIN34 UNDERVOLTAGE LOCKOUT
IN12 UVLO
IN34 UVLO
THERMAL SHUTDOWN Threshold Hysteresis REFERENCE Reference Bypass Output Voltage REF Supply Rejection LOGIC AND CONTROL INPUTS
CONDITIONS
VIN12 ≥ VIN34
MAX8668, VIN12 ≥ VIN34 MAX8667, VIN12 ≥ VIN34
VIN12 = VIN34 = 4.2V VEN_ = 0V
TA = +25°C TA = +85°C
MAX8667ETEJS+, all regulators enabled
VIN12 rising VIN12 hysteresis VIN34 rising VIN34 hysteresis
TA rising
2.6V ≤ (VIN12 = VIN34) ≤ 5.5V
MIN TYP 1.7 2.6 2.8
0.05 100
2.4
2.5
0.1
1.5
1.6
0.1
+160 1.