E1466DFO ATMEL Corporation, E1466DFO Datasheet - Page 3

• Manufacturer Part Number: E1466DFO
• Description: 32 KHZ Clock CMOS IC WITH Digital Trimming
• Manufacturer: ATMEL Corporation

Functional Descripion
Oscillator
Trimming
Capacitors
Motor Drive
Output
4731A–CLOCK–06/03
An oscillator inverter with feedback resistor is provided to generate the 32768 Hz clock fre-
quency. Values for the fixed capacitors at OSCIN and OSCOUT are mask-selectable (see
note 3 of “Operating Characteristics”). Four capacitor pads, C1 to C4, enable the users to add
integrated trimming capacitors to OSCIN, providing 15 tuning steps.
A frequency variation of typically 4 ppm for each tuning step is obtained by bonding the capac-
itor pads to OSCIN. As none of these pads are bonded, the IC is in an untrimmed state. Figure
3 shows the trimming curve characteristic.
Note:
Capacitor pads C1 to C4: 0 = open, 1 = connected to OSCIN
Combination C1 + C4 is redundant and therefore eliminated from the list
Table 1. Frequency Trimming Table
The e1466D contains two push-pull output buffers for driving bipolar stepping motors. During a
motor pulse, the N-channel device of one buffer and the P-channel device of the other buffer
will be activated. Both N-channel transistors are on and conducting between output pulses.
The outputs are protected against inductive voltage spikes with diodes to both supply pins.
The motor output period and pulse width are mask-programmable, as listed below:
Available motor periods (T
Available max. pulse widths (t
Available motor periods for motor test (T
Note:
For applications which utilize this integrated trimming feature, Atmel will determine optimum val-
ues for the integrated capacitors COSCIN and COSCOUT.
C4
The following constraints for combination of motor period and pulse widths have to be consid-
ered: T
0
0
0
0
1
0
0
0
1
1
0
1
1
1
1
M
> 4 ´ t
M
, T
MT
M
C3
0
0
0
1
0
0
1
1
0
1
1
0
1
1
1
): 125, 250, 500 ms and 2, 16 s
> 4 ´ t
M
Capacitor Pads
): 15, 6, 23.4, 31.25, 46.9 ms and 1 s
M
or alternatively T
MT
): 250, 500 ms and 1 s
C2
0
0
1
0
0
1
0
1
1
0
1
1
0
1
1
M
= 2 ´ t
M
, T
MT
C1
0
1
0
0
0
1
1
0
0
0
1
1
1
0
1
= 2 ´ t
M
Trimming Step
e1466D
10
11
12
13
14
0
1
2
3
4
5
6
7
8
9
3