Rainbow Electronics MAX1800 - Manual

General Description
The MAX1800 provides a complete power-supply solu-
tion for digital still cameras and video cameras. The
device integrates a high-efficiency main step-up DC-DC
converter, three auxiliary step-up controllers, and an
uncommitted gain block that drives an external P-channel
MOSFET for a linear regulator. The MAX1800 is targeted
for applications that use either two or three primary cells
or a single lithium-ion (Li+) battery.
The main DC-DC converter accepts inputs from +0.7V to
+5.5V and regulates a resistor-adjustable output from
2.7V to 5.5V. It uses an internal synchronous rectifier to
regulate the output with 95% efficiency. An adjustable
operating frequency facilitates designs for optimum size,
cost, and efficiency.
The auxiliary step-up controllers can be used to power a
digital camera’s CCD, LCD, and backlight. The MAX1800
also features expandability by supplying power, oscillator
signal, and reference to the MAX1801, a low-cost slave
DC-DC controller that supports step-up, SEPIC, and fly-
back configurations.
The MAX1800 is available in a space-saving 32-pin TQFP
package (5mm x 5mm body), and the MAX1801 is avail-
able in an 8-pin SOT package. An evaluation kit
(MAX1800EVKIT) featuring both devices is available to
expedite designs.
________________________Applications
Digital Still Cameras PDAs
Digital Video Cameras DVD Players
Hand-Held Devices
Internet Access Tablets
Features
♦ +0.7V to +5.5V Input Voltage Range
♦ Main DC-DC Converter
95% Efficiency
+2.7V to +5.5V Adjustable Output Voltage
1.5A Load Current
♦ Uncommitted Gain Block for Linear Regulator
♦ Three Independent Auxiliary Step-Up Controllers
Adjustable Maximum Duty Cycle
♦ Oscillator and Reference Outputs to Drive External
Slave Controllers (MAX1801)
♦ Power-Ready Output
♦ Up to 1MHz Switching Frequency
♦ 1µA Supply Current in Shutdown Mode
♦ Internal Soft-Start Control
♦ Overload Protection for all DC-DC Converters
♦ Compact 32-Pin TQFP Package (5mm x 5mm body)
MAX1800
Digital Camera Step-Up
Power Supply
________________________________________________________________ Maxim Integrated Products 1
Typical Operating Circuit
19-1833; 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.
EVALUATION KIT
AVAILABLE
Ordering Information
MAX1800
MASTER
MAX1801
SLAVE
INPUT
0.7V TO 5.5V
OSC REF
MOTOR
TFT
CCD
CCFL
CORE
MAIN
MAX1800
TQFP
TOP VIEW
32 28 29 30 31 25 26 27
ON3 FB3 COMP3 DCON3 DL3 ONA AO AI
10 13 15 14 16 11 12 9
ON2
COMP2
FB2 OUT
DCON2
GND
REF OSC
17
18
19
20
21
22
23 RDYM
24 ONM
POUT
LX
LX
PGND
COMPM
FBM
2
3
4
5
6
7
8 DL2
POUT
DCON1
COMP1
FB1
ON1
DL1
1 PGND
Pin Configuration
PART TEMP. RANGE PIN-PACKAGE
MAX1800EHJ -40 °C to +85°C 32 TQFP