Specifications

TC35 / TC37 Hardware Interface Description
TC35_37_HD_02_V03.10 - Released Page 54 of 92 21.12.2001
Function Signal
Name
Pin
No.
I/O Signal Level Comment
RTC
backup
VDDLP 30 O
I
IDLE/TALK/Power Down mode if
VBATT+ connected:
V
out
= VBATT+ - 0.6V
I
out,max
= 100mA
PD mode if VBATT+ disconnected:
V
in
= 2.0V...5.5V
I
in,max
= 30µA
t
RTC,on
≈ 30s @ 100µF (typically)
If unused keep pin
open. See also chap-
ter 3.3.4.
Power
down
For
emergency
only!
/PD 31 I/O IDLE/ TALK mode:
Input:
R
i
= 1k";
V
in,low,max
= 0.45V @ I = 0.1mA
input signal
~~~
|______|
~~~
active
low ≥ 3.5s
Watchdog Output:
R
i
= 22k"
V
out,low
= 0.35V @ 0.01mA
V
out,high
= 2.30V @ -0.01mA
f
out
= 0.5...2.0Hz
If unused keep pin
open
Open drain/collector
driver to GND
required.
/PD switches off the
GSM engine. A low
pulse at pin IGT
resets the GSM
Engine and restarts
the system.
The /PD pin also indi-
cates the watchdog
function.
Synchroni-
zation
SYNC 32 O IDLE/ TALK mode:
R
o
= 1k"
V
out,low,max
= 0.2V @ 0.1mA
V
out,high,min
= 2.25V @ -0.1mA
V
out,high,max
= 2.76V
Power Down mode:
be aware of backward supply
If unused keep pin
open
Indication of in-
creased current con-
sumption during
uplink transmission
burst