L6256 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'L6256' PDF : 28 Pages View PDF
Figure 14. Back EMF Phase Detection Timing Relantionships
L6256
TRANSITIONS
Transitioning from blind table drive to a back EMF mode drive is handled in the following manner. Re-
member, data written to the CPR takes effect only when SP_CLK receives a positive transition. The fol-
lowing steps must be taken:
● The programmer must ensure that the last state before state 0 has been output to the CPR and
clocked in using SP_CLK.
● An all 1’s value is written to the CPR to enable the state counter.
● The next SP_CLK will then produce a state 0 from the sequencer.
Voice Coil Driver (Vcm) Section
VCM SECTION SPECIFICATIONS
Parameter
Large Signal Voltage gain
Gain Bandwidth Product, A-Amp
3dB BW, total loop
Phase Margin, A Amp
Slew Rate, A Amp
Gain, B Amp
3dB Bandwidth, B
Total A+B saturation Resistance
Offset reflected to Isense
Vpwr/2 Input Impedance
Loopback Output Threshold (2)
Vsst Saturated seek comparator threshold
Test Conditions
Output Swing from 1 to
10V
I = 600mA
D/A reg @ 0
25°C
25°C
Output saturated either
polarity
(1) Total current offset of VCM loop must not exceed 3% of full scale current.
(2) Optional.
Min.
4.5
25
45
-1.17
2.3
38
30
Typ.
70
1.4
2
50
50
50
Max.
2
3
30
65
70
Units
dB
MHz
kHz
°
V/µs
*A gain
MHz
Ω
mV (1)
kΩ
mA/Ω
mV
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