General Description
The MAX1802 provides a complete power-supply solu-
tion for digital still cameras and video cameras by inte-
grating two high-efficiency step-down DC-DC converters
and three auxiliary step-up controllers. This complete
solution is targeted for applications that use either three
to four alkaline cells or two lithium-ion (Li+) cells.
The main step-down DC-DC controller accepts inputs
from 2.5V to 11V and regulates a resistor-adjustable out-
put from 2.7V to 5.5V. It uses a synchronous rectifier to
regulate the output with up to 94% efficiency. An
adjustable operating frequency (up to 1MHz) facilitates
designs for optimum size, cost, and efficiency.
The core step-down DC-DC converter accepts inputs
from 2.7V to 5.5V and regulates a resistor-adjustable
output from 1.25V to 5.5V. It delivers 500mA with up to
94% efficiency.
The three auxiliary step-up controllers can be used to
power the digital camera's CCD, LCD, and backlight.
The MAX1802 also features expandability by supplying
power, an oscillator signal, and a reference to the
MAX1801, a low-cost slave DC-DC controller that sup-
ports step-up, single-ended primary inductance con-
verter (SEPIC), and fly-back configurations.
The MAX1802 is available in a space-saving 32-pin
TQFP package (5mm x 5mm body), and the MAX1801
is available in an 8-pin SOT-23 package. An evaluation
kit (MAX1802EVKIT) featuring both devices is available
to expedite designs.
________________________Applications
Digital Still Cameras
Digital Video Cameras
Hand-Held Devices
Internet Access Tablets
PDAs
DVD Players
Features
o 2.5V to 11V Input Voltage Range
o Main DC-DC Controller
94% Efficiency
+2.7V to +5.5V Adjustable Output Voltage
Up to 100% Duty Cycle
Independent Shutdown
o Core DC-DC Converter
94% Efficiency
Up to 500mA Load Efficiency
Output Voltage Adjustable Down to 1.25V
Independent Shutdown
o Three Auxiliary DC-DC Controllers
Adjustable Maximum Duty Cycle
Independent Shutdown
o Power, Oscillator, and Reference Outputs to Drive
External Slave Controllers (MAX1801)
o Up to 1MHz Switching Frequency
o 3µA Supply Current in Shutdown Mode
o Internal Soft-Start
o Overload Protection for All DC-DC Converters
o Compact 32-Pin TQFP Package
MAX1802
Digital Camera Step-Down
Power Supply
________________________________________________________________ Maxim Integrated Products
1
Typical Operating Circuit
19-1850; Rev 0; 10/00
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.
Ordering Information
Note: Refer to the separate data sheet for MAX1801EKA in an 8-
pin SOT.
Pin Configuration appears at end of data sheet.
32 TQFP
PIN-PACKAGE
TEMP. RANGE
-40°C to +85°C
MAX1802EHJ
PART
MAX1802
MASTER
MAX1801
SLAVE
INPUT
2.5V TO 11V
OSC
POWER
REF
MOTOR
CORE
MAIN
CCD
CCFL
TFT
MAX1802
Digital Camera Step-Down
Power Supply
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V
VDDM
= 6V, V
VDDC
= 3V, PGNDM = PGND = GND, DCON1 = REF, V
ONM
= 3V, V
ONC
= V
ON1
= V
DCON2
=
V
DCON3
= 0, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
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.
VDDM, VH, ONM to GND .......................................-0.3V to +12V
PGNDM, PGND to GND ........................................-0.3V to +0.3V
VH to VDDM .............................................................-6V to +0.3V
VL to VDDM ............................................................-12V to +0.3V
VL, ONC, ON1, FB_, DCON_ to GND ......................-0.3V to +6V
VDDC, REF, OSC, COMP_ to GND ..............-0.3V to (VL + 0.3V)
DHM, DLM to PGNDM............................-0.3V to (VDDM + 0.3V)
LXM to PGNDM ......................................-0.6V to (VDDM + 0.6V)
DL1, DL2, DL3, LXC to PGND ................-0.3V to (VDDC + 0.3V)
Continuous Power Dissipation (T
A
= +70
°C)
32-Pin TQFP (derate 11.1mW/
°C above +70°C)........889mW
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
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
GENERAL
Input Voltage Range
V
IN
2.5
11
V
SUPPLY CURRENT
Shutdown Supply Current
(from VDDM and VDDC)
V
ONM
= 0
3
20
µA
V
FBM
= 1.5V, V
VDDC
= 0
370
600
Main DC-DC Converter
Supply Current (from VDDM)
V
FBM
= 1.5V, V
VDDC
= 3V
35
55
µA
Main DC-DC Converter
Supply Current (from VDDC)
V
FBM
= 1.5V, V
VDDC
= 3V
270
450
µA
Main plus Core Supply Current
(from VDDC)
V
FBM
= V
FBC
= 1.5V, V
ONC
= 3V
410
700
µA
Main plus Auxiliary 1
Supply Current (from VDDC)
V
FBM
= V
FB1
= 1.5V, V
ON1
= 3V
470
750
µA
Main plus Auxiliary 2
Supply Current (from VDDC)
V
FBM
= V
FB2
= 1.5V, V
DCON2
= 3V
470
750
µA
Main plus Auxiliary 3
Supply Current (from VDDC)
V
FBM
= V
FB3
= 1.5V, V
DCON3
= 3V
470
750
µA
Total Supply Current
(from VDDC)
V
FBM
= V
FBC
= V
FB1
= V
FB2
= V
FB3
= 1.5V,
V
ONC
= V
ON1
= V
DCON2
= V
DCON3
= 3V
960
1700
µA
VL REGULATOR
VL Output Voltage
6V < V
VDDM
< 11V, 0.1mA < I
LOAD
< 10mA
2.83
3.00
3.12
V
VL Supply Rejection
3.5V < V
VDDM
< 11V, V
VDDC
= 0
3
%
VL Undervoltage Lockout
Threshold
VL rising, 40mV hysteresis
2.25
2.40
2.50
V
VL Switchover Voltage to
VDDC
VL rising, 100mV hysteresis
2.3
2.4
2.5
V
VL to VDDC Switch Resistance
7
MAX1802
Digital Camera Step-Down
Power Supply
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
VDDM
= 6V, V
VDDC
= 3V, PGNDM = PGND = GND, DCON1 = REF, V
ONM
= 3V, V
ONC
= V
ON1
= V
DCON2
=
V
DCON3
= 0, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
REFERENCE
Reference Output Voltage
V
REF
I
REF
= 20
µA
1.235
1.248
1.260
V
REF Load Regulation
10
µA < I
REF
< 200
µA
5
9
mV
REF Line Rejection
2.7V < V
OUT
< 5.5V
1
5
mV
REF Undervoltage Lockout
Threshold
REF rising, 20mV hysteresis
0.9
1
1.1
V
OSCILLATOR
OSC Discharge Trip Level
OSC rising
1.225
1.250
1.275
V
OSC Input Bias Current
V
OSC
= 1.1V
0.2
100
nA
OSC Discharge Resistance
V
OSC
= 1.5V
30
100
OSC Discharge Pulse Width
100
ns
LOGIC INPUTS (ONM, ONC, ON1)
Input Low Level
V
IL
0.4
V
ONM
1.8
Input High Level
V
IH
ONC, ON1
1.6
V
Input Leakage Current
ONM: V
IN
= 0 or 11V;
ONC, ON1: V
IN
= 0 or 5V
0.01
1
µA
MAIN DC-DC CONVERTER
Main Output Voltage Adjust
Range
V
OUT
2.7
5.5
V
Main Idle ModeTM Threshold
V
OSC
= 0.625V, measured between VDDM
and LXM
8
20
32
mV
Main Current-Sense Amplifier
Voltage Gain
A
VCSM
Measured between VDDM and LXM
8.4
9.3
10.2
V/V
Main N Channel Turn-Off
Threshold
Measured between LXM and PGNDM
-26
-17
-8
mV
Main Slope Compensation
Gain
A
VSWM
0.16
0.20
0.24
V/V
MAIN ERROR AMPLIFIER
FBM Regulation Voltage
Unity gain configuration, FBM = COMPM
1.233
1.248
1.263
V
FBM to COMPM
Transconductance
G
EA
Unity gain configuration, FBM = COMPM,
-5
µA < I
LOAD
< 5
µA
70
100
160
µS
FBM Input Leakage Current
V
FBM
= 1.35V
5
100
nA
COMPM Minimum Output
Voltage
V
FBM
= 1.35V, COMPM open
0.3
V
COMPM Maximum Output
Voltage
V
COMPM (MAX)
V
FBM
= 1.15V, COMPM open
2.00
2.14
2.27
V
Idle Mode is a trademark of Maxim Integrated Products.
MAX1802
Digital Camera Step-Down
Power Supply
4
_______________________________________________________________________________________
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAIN SOFT-START
Soft-Start Interval
OSC falling edge
1024
OSC
cycles
MAIN DRIVERS (DHM, DLM)
Output Low Voltage
I
SINK
= 10mA
0.11
V
Output High Voltage
I
SOURCE
= 10mA
V
VDDM
-
0.11
V
Driver Resistance
I
DHM
= 10mA, I
DLM
= 10mA
4
11
Drive Current
Sourcing or sinking,
V
DHM
or V
VL
= V
VDDM
/ 2
400
mA
CORE DC-DC CONVERTER (V
ONC
= 3V)
Core Output Voltage Adjust
Range
V
OUT
1.25
5.5
V
Core Idle Mode Threshold
V
OSC
= 0.625V
70
190
320
mA
Core Current-Sense Amplifier
Transresistance
R
CSC
0.7
1.0
1.3
V/A
Core Slope Compensation Gain
A
VSWC
0.16
0.20
0.24
V/V
CORE ERROR AMPLIFIER (V
ONC
= 3V)
FBC Regulation Voltage
Unity gain configuration, FBC = COMPC
1.233
1.248
1.263
V
FBC to COMPC
Transconductance
G
EA
Unity gain configuration, FBC = COMPC,
-5
µA < I
LOAD
< 5
µA
70
100
160
µS
FBC Input Leakage Current
V
FBC
= 1.35V
5
100
nA
COMPC Minimum Output
Voltage
V
FBC
= 1.35V, COMPC open
0.3
V
COMPC Maximum Output
Voltage
V
COMPM (MAX)
V
FBC
= 1.15V, COMPC open
2.00
2.14
2.27
V
CORE SOFT-START (V
ONC
= 3V)
Soft-Start Interval
1024
OSC
cycles
CORE POWER SWITCHES (V
ONC
= 3V)
LXC Leakage Current
V
LXC
= 0, 5.5V
0.01
20
µA
R
DSN
N-channel, I
LXC
= 0.75A
150
350
Switch On-Resistance
R
DSP
P-channel, I
LXC
= 0.75A
180
400
m
P-Channel Current Limit
V
OSC
= 0.625V
0.75
A
N-Channel Turn-Off Current
18
100
180
mA
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
VDDM
= 6V, V
VDDC
= 3V, PGNDM = PGND = GND, DCON1 = REF, V
ONM
= 3V, V
ONC
= V
ON1
= V
DCON2
=
V
DCON3
= 0, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
MAX1802
Digital Camera Step-Down
Power Supply
_______________________________________________________________________________________
5
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
AUXILIARY DC-DC CONTROLLERS 1, 2, 3 (V
ON1
= V
CON
_ = 3V)
INTERNAL CLOCK
OSC Clock Low Trip Level
OSC falling edge
0.2
0.25
0.3
V
V
DCON
_ = 0.625V
0.575
0.625
0.675
OSC Clock High Trip Level
V
DCON
_ = 1.25V to V
VL
1.00
1.05
1.10
V
Maximum Duty Cycle
Adjustment Range
40
90
%
Maximum Duty Cycle
V
DCON
_ = 0.625V
43
%
Default Maximum Duty Cycle
V
DCON
_ = 1.25V to V
VL
76
%
DCON_ Input Leakage Current
V
DCON
_ = 0V to 3V
0.01
1
µA
DCON_ Input Sleep-Mode
Threshold
V
DCON
_ rising, 50mV hysteresis
0.35
0.4
0.45
V
AUXILIARY ERROR AMPLIFIER
FB_ Regulation Voltage
Unity gain configuration, FB_ = COMP_
1.233
1.248
1.263
V
FB_ to COMP_
Transconductance
G
EA
Unity gain configuration, FB_ = COMP_,
-5µA < ILOAD < 5µA
70
100
160
µs
FB_ Input Leakage Current
V
FB
_ = 1.35V
5
100
nA
AUXILIARY DRIVERS (DL1, DL2, DL3)
DL_ Driver Resistance
Output high or low
4
11
DL_ Drive Current
Sourcing or sinking, V
DL
_ = V
VDDC
/ 2
400
mA
AUXILIARY SOFT-START
Soft-Start Interval
1024
OSC
cycles
AUXILIARY SHORT-CIRCUIT PROTECTION
Fault Interval
1024
OSC
cycles
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
VDDM
= 6V, V
VDDC
= 3V, PGNDM = PGND = GND, DCON1 = REF, V
ONM
= 3V, V
ONC
= V
ON1
= V
DCON2
=
V
DCON3
= 0, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
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