SC3333
TIMIING CHARACTERISTICS1,2
(V
DD
=5V±5%, A
GND
=D
GND
=0V, On-chip Reference, C
LKIN
=3.58MHZ, T
MIN
to T
MAX
=-40°C~+85°C.)
Parameter
t1
3
t2
t3
t4
3
t5
t6
Test Condition
F1 and F2 Pulse-width
F1 and F2 Pulse Period.
Time Between F1 Falling Edge and F2 Falling Edge
CF Pulse-width
CF Pulse Period.
Minimum Time Between F1 and F2 Pulse
parameter.
2. See the following figure.
3. The pulse-widths of F1, F2 and CF are not fixed for higher output frequencies.
Test Data
275
TBD
1/2 t2
90
TBD
CLKIN/4
Units
ms
sec
sec
ms
sec
sec
NOTE: 1. Sample tested during initial release and after any redesign or process change that may after this
Timing Diagram for Frequency outputs
Timing Diagram for Frequency Outputs shows a timing diagram for the various frequency outputs of the
SC3333. The low frequency outputs, F1 and F2 can drive electromechanical counters and two phase stepper
motors directly. As the figure show, the F1 and F2 outputs provide two alternating low going pulses. The pulse
width (t1) is set at 275ms and the time between the falling edges of F1 and F2 (t3) is approximately half the
period of F1 (t2). If however the period of F1 and F2 falls below 550 ms (1.81Hz) the pulse width of F1 and F2 is
set to half of their period. The frequency of F1 and F2 corresponds to the input voltages, and F=
2
（13.6*V1*V2*G）/
VREF
，The
values of G can be set by consumers, and the selection of G please refer to the
table I , V1 and V2 are the rms value of the two inputs, VREF is the voltage of reference, whose value is 2.5+0.2v
when the internal bandgap reference of SC3333 is valid.
The high frequency output, CF is intended for calibration and supplies instantaneous real power. CF produces
a 90ms wide active high pulse (t4) at a frequency proportional to active power. As in the case of F1 and F2, if the
period of CF (t5) falls below 180ms, the CF pulse-width is set to half the period.
APPENDIX
Table I. gain selection for channel 1
SET
0
1
Gain
1
16
Maximum Differential Signal
±470mV
±30mV
REV:1.1
2008.04.29
Page 5 of 8
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http
:
www.silan.com.cn
SILAN [ SILAN MICROELECTRONICS JOINT-STOCK ]
