SM9403BM Datasheet, PDF (15/18 Pages) Nippon Precision Circuits Inc – DVDRAM Servo-amplifier LSI

SM9403BM
Header Position Detector (CAPAP/N → CAPAREA, CAPIN, CAPOUT)
This stage converts a high-speed push-pull signal
(CAPAP/CAPAN) to single-ended signals, passes
the outputs through low-pass filters to form quan-
tized logic levels which are used as reference signals.
These reference signals are level shifted to form plus
and minus signals for use by comparators. The
amount of level shift can be controlled by serial
interface control bits.
After quantization logic conversion, retriggerable
mono-multivibrators convert the pulse strings to con-
tinuous signals. This creates inner shifted header
CAPIN and an outer shifted header CAPOUT output
signals.
In addition, the single-ended signal is also passed
through a high-pass filter, which similarly converts
to quantized logic signals. Retriggerable mono-mul-
tivibrators then convert the pulse strings to continu-
ous signals to create a header area CAPAREA signal.
The mono-multivibrator time constants are con-
trolled by serial interface control bits.
Table 9. Slice level shift voltages
LS3
LS2
LOW
LOW
LOW
LOW
LOW
HIGH
LOW
HIGH
HIGH
LOW
HIGH
LOW
HIGH
HIGH
HIGH
HIGH
1. Default is ±25 mV
LS1
LOW
HIGH
LOW
HIGH
LOW
HIGH
LOW
HIGH
Level shift
(mV)¹
±25
±50
±75
±100
±125
±150
±200
±250
Table 10. Mono-multivibrator time constants
MM2
MM1
CAPOUT/CAPIN
output (µs)¹
CAPAREA (µs)¹
LOW
LOW
4
8+α
LOW
HIGH
8
16 + α
HIGH LOW
12
24 + α
HIGH HIGH
16
32 + α
1. Default is 4 µs and (8 + α), where α ≈ 6 × ln(2V_LS/V_H ), V _H = input sig-
nal amplitude, V _LS = slice level absolute value shown in table 9.
Table 11. CAPOUT/CAPIN/CAPAREA logic
C A PA R E
A
LOW
LOW
HIGH
HAE¹
LOW
HIGH
LOW
HIGH
HIGH
1. Default is LOW
CAPOUT
Header signal
output
LOW
Header signal
output
Header signal
output
CAPIN
Header signal
output
LOW
Header signal
output
Header signal
output
NIPPON PRECISION CIRCUITS—15