Isolated Transformer Driver
for PCMCIA Applications
MAX845
____________________________Typical Operating Characteristics (continued)
(Typical
Operating Circuit,
V
IN
= 5V, C1 = 0.1µF, C2 = C3 = 0.33µF, T1 = Halo TGM-010P3, CR1 = CR2 = MBR0520, FS = V
CC
,
T
A
= +25°C, unless otherwise noted.)
SWITCHING WAVEFORMS
(TWO CYCLES)
SWITCHING WAVEFORM
(BREAK-BEFORE-MAKE)
D1OFF
D2OFF
D1
5V/div
500mV/div
D2
CIRCUIT
OF FIG. 1
D2ON
400ns/div
D1ON
200ns/div
TIME FROM SHUTDOWN TO POWER-UP
SD
2V/div
OUTPUT
5µs/div
_____________________Pin Description
V
IN
PIN
1
2
3
4
5
6
7
8
4
NAME
D1
GND1
FS
SD
N.C.
V
CC
GND2
D2
FUNCTION
Open Drain of N-Channel Transformer Drive 1
Ground. Connect both GND1 and GND2 to
ground.
Frequency Select (internal pull-up). If FS =
V
CC
or open, switch frequency = 725kHz; if
FS = 0V, switch frequency = 535kHz.
Shutdown. Ground for normal operation,
connect to V
CC
for shutdown.
No Connect. Not internally connected.
+5V Supply Voltage
Ground. Connect both GND1 and GND2 to
ground.
Open Drain of N-Channel Transformer Drive 2
5V
C1
0.1µF
4
ON / OFF
6
V
CC
SD
D1
R1
50Ω
1
R2
50Ω
D2
8
MAX845
3
FREQUENCY
SELECT
FS
GND1
2
GND2
7
Figure 1. Test Circuit
_______________________________________________________________________________________
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
