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_______________General Description
The MAX845 provides an isolated power supply small
enough to fit in thin PCMCIA cards and space-sensitive
applications. It drives a low-profile center-tapped trans-
former primary from a 5V or 3.3V DC power supply. The
secondary can be wound to provide any isolated posi-
tive or negative voltage at powers up to 750mW.
The MAX845 consists of an oscillator followed by a tog-
gle flip-flop. The flip-flop generates two 50% duty-cycle
square waves, which are complementary at half the
oscillator frequency (450kHz, min). These two signals
drive the ground-referenced N-channel power switch-
es. Internal circuitry ensures break-before-make action
between the two switches.
A low-power shutdown disables both the switches and
the oscillator, reducing power consumption. An evalua-
tion kit (MAX845EVKIT-MM) is available to evaluate low-
profile 5V 40mA and 5V 100mA applications.
________________________Applications
PCMCIA Modem Cards
Isolated Data Acquisition
Isolated Interface Power Supply
Noise-Immunity Communications Interface
Bridging Ground Differences
Medical Equipment
Process Control
Low-Power LAN Networks
____________________________Features
♦ Transformer Driver for Ultra-Thin 5V-µs Transformers
♦ Isolated DC-to-DC Power Supply for PCMCIA
Applications
♦ 450kHz Minimum Switching Frequency
♦ Ultra-Low Input Supply Current Ripple
♦ Single +5V or +3.3V Supply
♦ 5µW Low-Power Shutdown Mode
♦ 8-Pin SO and µMAX Packages
♦ Low Output Ripple Permits Miniature Output
Capacitors
MAX845
Isolated Transformer Driver
for PCMCIA Applications
________________________________________________________________
Maxim Integrated Products
1
1
2
3
4
8
7
6
5
D2
GND2
V
CC
N.C.
SD
FS
GND1
D1
SO/µMAX
TOP VIEW
MAX845
___________________Pin Configuration
MAX845
D1
D2FS
GND1 GND2
V
CC
1
8
46
27
3
V
IN
SD
FREQUENCY
SELECT
C2
C1
C3
5V @ 150mA
OUTPUT
5V
ON / OFF
T1
CR2
CR1
__________Typical Operating Circuit
19-0372; Rev 4; 10/97
PART
MAX845C/D
MAX845EUA -40°C to +85°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
Dice*
8 µMAX
EVALUATION KIT
AVAILABLE
*Contact factory for dice specifications.
_______________Ordering Information
MAX845ESA -40°C to +85°C 8 SO
Verzeichnis
- ・ Konfiguration des Pinbelegungsdiagramms on Seite 1 Seite 4
- ・ Abmessungen des Paketumrisses on Seite 16
- ・ Teilenummerierungssystem on Seite 1
- ・ Blockdiagramm on Seite 5
- ・ Beschreibung der Funktionen on Seite 1
- ・ Technische Daten on Seite 6
- ・ Anwendungsbereich on Seite 1 Seite 3 Seite 4 Seite 5 Seite 6
