Maxim MAX8680ETL Schematics
General Description
The MAX8680 highly efficient complete power-supply
solution is designed for digital still cameras (DSCs) and
digital video cameras (DVCs). The device integrates
seven on-chip power MOSFET DC-DC converters with
up to 95% efficiency to power all critical power supplies
in DSC systems. Each converter also features True
Shutdown™, as well as internal compensation to minimize external component count. The seven DC-DC
converter outputs are:
• Step-up synchronous-rectified DC-DC converter
(SU). The MAX8680 is bootstrapped from VSU.
• MAIN synchronous-rectified step-down DC-DC converter (M) for DSP I/O supply voltage.
• DDRZ synchronous-rectified step-down DC-DC
converter (Z) for DSP DDR supply voltage.
• Low-voltage (down to 1V) synchronous-rectified
step-down DC-DC converter (SD) for DSP core supply voltage.
• High-voltage, step-up DC-DC converter with current
regulation and PWM dimming control (LEDBST) for
white LEDs (WLED).
• High-voltage step-up DC-DC converter (CCDBST)
for CCD imagers or positive LCD bias supplies.
• Transformerless inverting DC-DC converter (CCDINV)
for CCD imagers or negative LCD bias supplies.
The MAX8680 has an independent/simultaneous
power-on sequence of the CCDBST and CCDINV converters. For a preset power-on sequence of CCDBST
before CCDINV, contact the factory.
The MAX8680 operates with 1-cell lithium-ion (Li+) battery, two-AA cell, or dual-battery designs and is available in a 5mm x 5mm, 40-pin thin QFN package. The
MAX8680 operates over the -40°C to +85°C extended
temperature range.
Applications
DSCs and DVCs
PDAs and Portable Media Players
GPS Navigation Systems
Features
♦ 95% Efficient Synchronous-Rectified DC-DC
Converters
♦ 90% Efficient Boost-Buck Operation
♦ 85% Efficient DC-DC Converters for CCD, LCD,
WLED, and/or OLED
♦ Internal Compensation on All Channels
♦ True Shutdown on All Step-Up Converters
♦ Overload Protection
♦ Soft-Start for Controlled Startup Current
♦ Dropout Operation (100% Duty Cycle) on Step-
Down Converters
♦ Regulated Current Output for Up to 6 White LEDs
♦ PWM Dimming of WLED Current
♦ Adjustable LED Overvoltage Protection Up to 27V
♦ Transformerless Inverting Converter for CCD
♦ 2MHz Switching Frequency for Low-Voltage
Channels
♦ ±2.5% Switching Frequency Accuracy
♦ 1µA Shutdown Supply Current
♦ Power-On Voltage Tracking for Core and Main
Outputs
♦ All Internal Power MOSFETs
♦ SDOK Power-OK Indicator
MAX8680
Smallest, All-Internal MOSFET, 7-Channel
DSC PMIC in Tiny 5mm x 5mm Thin QFN
________________________________________________________________
Maxim Integrated Products
1
Typical Operating Circuit
19-0681; Rev 2; 11/07
Pin Configuration appears at the end of data sheet.
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.
EVALUATION KIT
AVAILABLE
Ordering Information
PART
TEMP
PIN-PACKAGE
PKG
CODE
MAX8680ETL+
-40°C to
40 Thin QFN-EP*
T4055-2
+
Denotes a lead-free package.
*
EP= Exposed paddle.
True Shutdown is a trademark of Maxim Integrated Products, Inc.
ABRIDGED
RANGE
INPUT
2.7V TO 5.5V
BATT
ONSU
ONM
ONSD
ONZ
SDOK
ONLED
ONBST
ONINV
SU STEP-UP
MAIN STEP-DOWN
SD STEP-DOWN
DDRZ STEP-DOWN
MAX8680
LEDBST
CCDBST
CCDINV
V
SU
V
MAIN
V
SD
V
DDRZ
V
LEDBST
V
CCDBST
V
CCDINV
5V
1.8V
3.3V
2.5V
UP TO 6 WLEDs
+15V
-7.5V
+85°C
5mm x 5mm x 0.8mm
MAX8680
Smallest, All-Internal MOSFET, 7-Channel
DSC PMIC in Tiny 5mm x 5mm Thin QFN
14 ______________________________________________________________________________________
Figure 1. MAX8680 Typical Application Circuit (for Li+ Cell Design, Connect PVZ and PVINV to BATT; for Two-AA or Dual-Battery
Design, Connect PVZ and PVINV to PVSU)
NOTE: ALL CONVERTERS’ POWER GROUND CONNECTIONS
ARE THROUGH THE EXPOSED PADDLE (EP).
ABRIDGED
V
OR V
BATT
SU
V
BATT
(2V TO 5.5V)
C1
22μFC222μF
V
SU
(5V, 500mA)
C3
22μFC422μF
R1
402kΩ
R2
100kΩ
V
MAIN
(3.3V, 300mA)
R3
232kΩ
R4
100kΩ
V
SD
(1.8V, 250mA)
R5
80kΩ
R6
100kΩ
C5
1μF
C6
10μFC710μF
C8
10μF
C10
10μFC910μF
C20
0.1μF
L1
2μH
R17
100Ω
C16
0.1μF
V
SU
L2
4.7μH
V
BATT
L3
4.7μH
33
BATT
32
LXSU
31
LXSU
29
PVSU
30
PVSU
26
SU
27
FBSU
PGSU
(EP)
PGSU
(EP)
38
PVM
39
LXM
1
FBM
PGM
(EP)
34
PVSD
35
LXSD
5
FBSD
PGSD
(EP)
28
ONSU
40
ONM
6
ONSD
10
ONLED
21
ONBST
7
ONINV
2
ONZ
24
REF PVINV
MAX8680
16
LXINV
FBINV
SWBST
LXBST
PGBST
(EP)
FBBST
PVBST
PVLED
SWLED
LXLED
OVLED
FBLED
PGLED
(EP)
GND
PVZ
LXZ
FBZ
PGZ
(EP)
SDOK
EP
15
23
17
19, 20
22
18
13
14
11, 12
9
8
25
36
37
3
4
L5
4.7μH
L4
4.7μH
C18
1μF
L7
4.7μH
L6
4.7μH
V
V
V
BATT
V
R16
100kΩ
BATT
BATT
SU
V
D3
C19
4.7μF
D2
C17
1μF
C16
1μF
C14
1μF
D1
C15
1μF
OR
C11
1μF
C12
10μF
C13
10μF
V
BATT
(-7.5V, 100mA)
R13
604kΩ
R14
100kΩ
V
REF
V
CCDBST
(15V, 30mA)
R11
1.4MΩ
R12
100kΩ
R9
1.6MΩ
R10
100kΩ
(2.5V, 200mA)
R7
150kΩ
R8
100kΩ
CCDINV
V
DDRZ
V
LEDBST
(16V, 30mA)
D4
D5
D6
D7
R15
10Ω
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