Maxim MAX8858 Highly efficient, all-internal mosfet, 6-channel pmic for 2aa digital camera system Datasheet

ABRIDGED
19-4102; Rev 0; 5/08
Highly Efficient, All-Internal MOSFET, 6-Channel
PMIC for 2AA Digital Camera Systems
Features
The MAX8858 PMIC provides a complete power-supply
solution for digital still cameras (DSCs) and digital video
cameras (DVCs). The MAX8858 improves performance,
component count, and board space utilization compared
to currently available solutions for two AA cell and dualbattery designs. On-chip power MOSFETs provide up to
95% efficiency for critical power supplies. The CCD
inverter can operate directly from two AA/NiMH batteries
without the use of any additional external components.
• Step-up synchronous-rectified DC-DC converter
(SU). The MAX8858 is bootstrapped from VVSU.
♦ 95% Efficient Synchronous-Rectified DC-DC
Converters
•
MAIN synchronous-rectified step-up DC-DC converter
(M) with active discharge for DSP I/O supply voltage.
♦ Internal Compensation on All Channels
•
SDZ synchronous-rectified step-down DC-DC converter (SDZ) with active discharge for DSP DDR
supply voltage.
•
Low-voltage (down to 1V) synchronous-rectified
step-down DC-DC converter (SD) with active discharge for DSP core supply voltage.
♦ Soft-Start for Controlled Inrush Current
•
High-voltage step-up DC-DC converter (CCDBST)
for CCD imagers or positive LCD bias supplies.
♦ 2MHz ±5% Switching Frequency
•
Transformerless inverting DC-DC converter (CCDINV)
with active discharge for CCD imagers or negative
LCD bias supplies. This converter can connect
directly to two AA batteries.
♦ All Internal Power MOSFETs
♦ Preset Power-Up Sequencing for MAIN, SDZ, and
SD Converters
♦ Inverter Operates Directly from Two AA Batteries
♦ True Shutdown™ on All Step-Up Converters
♦ Overload Protection
♦ Startup into Short Protection
♦ 100% Duty Cycle on Step-Down Converters
♦ 0.1µA Shutdown Supply Current
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX8858ETJ+
-40°C to +85°C
32 Thin QFN-EP*
+Denotes a lead-free package.
*EP = Exposed pad.
MAIN STEP-UP
VSU 5V
VMAIN 3.3V
VSDZ 2.5V
ONZ/EN2
MAX8858
VSU
REF
FBBST
ONBST
17
16
LXBST
SWBST
PVSU 27
14
PVBST
PVSD 28
13
PVINV
12
OUTINV
MAX8858
LXSD 29
PVM 30
EP = EXPOSED PAD
LXM 32
+
1
2
FBM
ONSD/EN1 SDZ STEP-DOWN
VSD 1.8V
18
15
ONSD/EN1
SD STEP-DOWN
19
LXSU 26
LXM 31
ONM/SEQ
20
3
4
5
6
7
8
ONINV
ONSU
SU STEP-UP
21
FBINV
PVBST
22
ONZ/EN2
INPUT
0.9V TO 5.5V
23
FBZ
Typical Operating Circuit
24
LXSU 25
GND
PDAs and Portable Media Players
GND
TOP VIEW
DSCs and DVCs
FBSU
Pin Configuration
ONSU
Applications
♦ Transformerless Inverting Converter with Active
Discharge for CCD
FBSD
The MAX8858 is available in a 5mm x 5mm x 0.8mm,
32-pin thin QFN package and operates over the -40°C
to +85°C extended temperature range.
♦ Up to 85% Efficient, High-Voltage DC-DC
Converters
ONM/SEQ
Individual ON_ inputs provide independent on/off control
for the SU, CCDBST, and CCDINV converters, while dualfunction inputs allow independent on/off control or powerup sequencing of the MAIN, SDZ, and SD converters.
♦ Up to 90% Efficient Boost-Buck Operation
11
LXINV
10
PVZ
9
LXZ
THIN QFN-EP
5mm x 5mm
ONBST
CCDBST
VCCDBST +15V
ONINV
CCDINV
VCCDINV -7.5V
True Shutdown is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products
1
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.
MAX8858
General Description
ABRIDGED
MAX8858
Highly Efficient, All-Internal MOSFET, 6-Channel
PMIC for 2AA Digital Camera Systems
VBATT
R13
100Ω
C16
1μF
C18 VREF
0.22μF
13
PVINV
19
L1
2μH
VBATT
(1.8V TO 5.5V)
C1
22μF
25, 26
C2
22μF
REF
12
OUTINV
11
LXINV
L6
4.7μH
C3
22μF
R12
100kΩ
VREF
VCCDBST
(15V, 30mA)
D1
16
C15
2.2μF
R2
100kΩ
FBSU
PVBST
31, 32
VMAIN
(3.3V, 300mA)
30 PVM
C7
22μF
LXZ
1
R4
10kΩ
L3
4.7μH
VSD
(1.8V, 250mA)
29
PVSD
LXSD
C10
10μF
R6
100kΩ
FBSD
C14
1μF
VSU
C11
1μF
R10
100kΩ
10
9
L4
4.7μH
VSDZ
(2.5V, 200mA)
C12
10μF
C13
10μF
R7
150kΩ
4, 20
FBZ 5
ONSU
ONM/SEQ
3
VBATT
14
EP
GND
28
C9
10μF
FBM
VBATT
C8
10μF
PVZ
R9
1.4MΩ
18
LXM
L2
1μH
C6
22μF
FBBST
VBATT
C5
1μF
R5
80kΩ
15
L5
2.2μH
LXBST
23
R11
604kΩ
7
MAX8858
R1
402kΩ
R3
23.2kΩ
SWBST
27
PVSU
21
VSU
C4
22μF
C17
4.7μF
LXSU
FBINV
VSU
(5V, 500mA)
VCCDINV
(-7.5V, 100mA)
D2
ONSD/EN1
ONZ/EN2
ONBST
ONINV
22
R8
100kΩ
24
2
6
17
8
Figure 1. MAX8858 Typical Application Circuit
16
______________________________________________________________________________________
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