cxa1720q

Manufacturer Part Numbercxa1720q
DescriptionRead/write Amplifier With Built-in Filters For Fdds
ManufacturerSony Electronics
cxa1720q datasheet
 
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Read/Write Amplifier (with Built-in Filters) for FDDs
For the availability of this product, please contact the sales office.
Description
The CXA1720Q is an IC for use with floppy disk
drives, and contains a Read circuit (with built-in
filters), Write circuit, Erase circuit, and supply
voltage detection circuit, all into a single chip.
Features
• Single 5 V power supply.
• Filter system can be switched among four modes:
1M/2M, and inner track/outer track. This allows for
a significant reduction in the number of external
parts such as differentiator constants, low-pass
filters, and switches. (Compared with conventional
Sony products, the number of parts has been
reduced by one-half.)
• Filter characteristics can be customized.
• Low pre-amplifier input conversion noise voltage of
2.0 nV/
Hz (typ.) keeps Read data output jitter to
a minimum. The pre-amplifier voltage gain can be
selected as either 100 or 200 .
• The monostable multivibrator No. 1 pulse width
switching function for the time domain filter permits
switching between 1M and 2M mode.
• Write current switching function permits switching
of the Write current among four modes: 1M/2M
and inner track/outer track. (Filter inner track/outer
track switching is separate.)
Block Diagram and Pin Configuration
Sony reserves the right to change products and specifications without prior notice. This information does not convey any license by
any implication or otherwise under any patents or other right. Application circuits shown, if any, are typical examples illustrating the
operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits.
CXA1720Q
• Supply voltage detection circuit prohibits error
writing during power ON/OFF or abnormal voltage.
• Power consumption is kept down to 115 mW (typ.)
and this IC is suitable for use with battery-driven
FDDs.
• Built in Time constant capacitors for monostable
multivibrator Nos. 1 and 2. (The pulse width for
monostable multivibrator No. 2 is fixed.)
• Power saving function reduces power consumption
when the IC is not in use. When in power saving
mode (5 mW typ.), only the power supply ON/OFF
detector functions.
• The Write driver has a built-in reset circuit. When
the mode is switched from Read mode to Write
mode, the Write current flows from head 0A if head
side 0 is selected and from head 1A if head side 1
is selected.
24
23
22
21
20
19
18
17
W/C 1
PREAMP
25
SET
FILTER
W/C 1
26
DIFF+LPF
COMP
(BPF)
W/C 2
27
SET
WRITE
DRIVER
W/C 2
28
COMP
D.GND
29
ERASE
DRIVER
ERASE
30
OUT 0
ERASE
POWER
CONTROL
31
OUT 1
MONITOR
LOGIC
POWER
32
SAVE
1
2
3
4
5
6
7
8
—1—
32 pin QFP (Plastic)
FILTER
16
OUT B
COMP
15
IN B
COMP
14
IN A
A.GND
13
MMVA
12
FILTER
11
SET
Vcc
10
HIGH
9
DENSITY
E93717-TE

cxa1720q Summary of contents

  • Page 1

    ... Read/Write Amplifier (with Built-in Filters) for FDDs For the availability of this product, please contact the sales office. Description The CXA1720Q for use with floppy disk drives, and contains a Read circuit (with built-in filters), Write circuit, Erase circuit, and supply voltage detection circuit, all into a single chip. ...

  • Page 2

    ... Note) WRITE DATA, WRITE CURRENT, WRITE GATE, ERASE GATE SIDE1, FILTER CONTROL, HIGH DENSITY, HIGH GAIN, POWER SAVE – Topr –20 to +75 °C Tstg –65 to +150 °C P 500 4 —2— CXA1720Q ...

  • Page 3

    ... Filter, time domain filter and Write current 1M/2M mode control. 2M mode is selected when the logical voltage is low. Pre-amplifier voltage gain selection. Gain of 100x is selected when the logical voltage is high; gain of 200x is selected when the logical voltage is low. —3— CXA1720Q (Ta=25 ° Description is below the specified value. CC ...

  • Page 4

    ... A.GND. 147 12 1.2V A.GND Analog system GND connection. Comparator differential inputs. Vcc 16k 10k 10k 147 147 60µ A.GND Filter differential outputs. Vcc 140 140 16 17 500µ A.GND —4— CXA1720Q Description between this pin and V to set the cut ...

  • Page 5

    ... Connection for 2M Write current compensation 28 resistor. Connect the Write current compensation resistor R between this pin and Pin 27 (W/C2SET) to WC2 A.GND set the amount of increase in the Write current. —5— CXA1720Q Description . set the Write current set the Write current. CC ...

  • Page 6

    ... Vcc 30 Erase current output for the HEAD1 system. 31 D.GND Power saving signal input. When the logical voltage is low, the power Vcc 162k saving mode. In power saving mode, only the power supply ON/OFF detection function operates. 1k 2.1V A.GND —6— CXA1720Q Description ...

  • Page 7

    ... V V0 BW0 SW4= =– BW1 SW4=a, b SW1, 5=b Bandwidth=400 Hz EN0 to 1 MHz Vi=0, SW4=b Bandwidth=400 MHz EN1 SW4=b Vi=0, SW1, 5=b —7— CXA1720Q (Ta=25 ° ment Min. Typ. Max. Unit point — 13.0 23.0 33.0 — 8.0 14.0 20.0 mA — 0.9 1.8 (Ta=25 °C) ment Min. Typ. ...

  • Page 8

    ... = = Vi=0.25 mVp mVp f=62.5 kHz Refer to Fig. 1 —8— CXA1720Q (Ta=25 ° ment Min. Typ. Max. Unit point F, G –500 +500 mV G 1.8 Vp –100 +100 2.8 Vp –10 ...

  • Page 9

    ... Monostable multivibrator No. 1 pulse width precision When HD = high ETM1 = –1 100 (%) 2.45 µS When HD is low ETM1' = –1 100 (%) 1.25 µS • Monostable multivibrator No. 2 pulse width = T • Peak shift 1 T – 100 (%) —9— CXA1720Q 1.4V TB ...

  • Page 10

    ... HD=“L” FC=“L” Refer to Fig Refer to Fig Refer to Fig —10— CXA1720Q (Ta=25 ° ment Min. Typ. Max. Unit point D, E 153.0 170.0 187.0 kHz G 3.6 5.5 7 –7.6 –7.1 –6.6 ...

  • Page 11

    ... (N Fig. 2 Filter frequency response measurement conditions —11— f(Hz CXA1720Q ...

  • Page 12

    ... WRITE CURRENT = “L” W Measure- Measure- Conditions ment circuit VLD 2 VHD ILD IHD —12— CXA1720Q (Ta=25 ° ment Min. Typ. Max. point LKJI –7 +7 LKJI –1 +1 LKJI –10 +10 LKJI 10 L’K’J’I’ M’ ...

  • Page 13

    ... W COMP CXA1720Q D.GND 29 M' ERASE 30 OUT 0 N' ERASE 31 OUT 1 POWER 32 SAVE —13— CXA1720Q 3300p 15 C 3300p 27k 11 3. SW3 9 a 0.1µ FILTER OUT B COMP COMP ...

  • Page 14

    ... R : filter setting resistance ( —14— CXA1720Q is set by external resistor used as a reference O1 Filter output A 17 Amp. Filter output B 16 Gain; 8.0dB f ratio O 1.00 1 ...

  • Page 15

    ... The ground should be as large as possible. is determined by the resistor 84R + 180 (nS LOW 42R + 110 (nS) A HIGH A connected between Pin 25 and set by the resistor —15— CXA1720Q between Pin 12 and A and between Pin 27 and CC connected between Pin 25 and Pin WC ...

  • Page 16

    ... WRITE DRIVER ERASE DRIVER POWER CONTROL LOGIC SIDE 1 READ WRITE WRITE ERASE DATA DATA CURRENT GATE GATE —16— CXA1720Q C REF 0.1µ FILTER OUT A 17 FILTER OUT 3300P C A 3300P 15 COMP COMP IN A A.GND 13 R ...

  • Page 17

    ... Customization Filter frequency response In 2M/inner track mode, the filter frequency response can be changed as shown below Tertiary Butterworth No Q=0.577 (Differential characteristics) Tertiary Chebyshev (High-band noise cut-off) (Comprehensive characteristics) —17— CXA1720Q 1dBRp No. 3 ...

  • Page 18

    ... Butterworth 2M/outer track Butterworth Butterworth 2M/inner track Chebyshev (1 dB ripple) Note) The boxed item indicates the setting for the CXA1720Q. in 1M/outer track mode as 1.00 as shown in Table fixed at 1.2 times the LPF cut-off frequency fc. In addition, the 1.28fo ...

  • Page 19

    ... Phase –40 –50 –50 –100 –60 –150 –70 –200 10k 50k f 04 —19— CXA1720Q Vcc=5V, Ta=25˚C When HD=high, low 120 150 100M 1M/inner track V =5V, Ta=25˚ =3.2k F 200 150 100 Voltage gain 50 0 Phase – ...

  • Page 20

    ... Ta-Ambient temperature (˚C) —20— f=100KHz Vcc=5V Vin=10mVp-p (HG="H") Vin=5mVp-p (HG="L") NGV=GV/GV (Ta=25˚ 3.2k F Vcc 80 Ta=25˚C f=100KHz Vin=10mVp-p (HG="H") Vin=5mVp-p (HG="L") NGV=GV/GV (Vcc=5V Vcc Vcc=5V NTA=TA/TA (Ta=25˚C) When HD=high, low 12 R 27k A 80 CXA1720Q ...

  • Page 21

    ... Normalized read data pulse width vs. Ambient temperature 1.05 1.00 0.95 – Ta-Ambient temperature (˚C) —21— Ta=25˚C NTA=TA/TA (Ta=25˚C) When HD=high, low 12 R 27k A A Vcc=5V Ta=25˚ =84R 180 (ns) A LOW =42R 110 (ns) A HIGH 100 Vcc=5V NTB=TB/TB (Ta=25˚C) 80 CXA1720Q ...

  • Page 22

    ... Normalized write current vs. Supply voltage 1.05 1.00 0.95 4.0 5.0 6.0 Vcc-Supply voltage (V) —22— Ta=25˚C NTB=TB/TB (Vcc=5V) Vcc=5V NIW=IW/IW (Ta=25˚ WC1 WC2 12k 12k R 4. 4.3k Vcc Vcc 80 Ta=25˚C NIW=IW/IW (Vcc=5V WC2 WC1 12k 12k 4. Vcc Vcc CXA1720Q ...

  • Page 23

    ... Vcc-Supply voltage (V) —23— Vcc=5V Ta=25˚C IW=11.6/Rw (mA Vcc Vcc Vcc=5V NIWC=IWC/IWC (Ta=25˚ WC2 WC1 12k 12k R 4. 4.3k Vcc Vcc 80 Ta=25˚C NIWC=IWC/IWC (Vcc=5V WC2 WC1 12k 12k 4. Vcc Vcc CXA1720Q ...

  • Page 24

    ... OFF threshold voltage 3.8 3.7 – Ta-Ambient temperature (˚C) Normalized filter peak frequency vs. Ambient temperature 1.05 1.00 0.95 4.0 5.0 Ta-Ambient temperature (˚C) —24— Vcc=5V Ta=25˚C IWC=10.8/Rwc (mA) Rwc ( WC1 WC2 R 4. 4.3k Vcc Vcc (k ) 100.0 80 Vcc= (Ta=25˚ 3.2k F Vcc 6.0 CXA1720Q ...

  • Page 25

    ... Normalized filter peak frequency vs. Supply voltage characteristics 1.05 1.00 0.95 4.0 6.0 5.0 Vcc-Supply voltage (V) 1M/outer track peak frequency vs 250 200 150 2.0 3.0 4 —25— CXA1720Q Vcc= (Ta=25˚ 3.2k F Vcc Vcc=5V Ta=25˚ Vcc + F =527/R 5.8 (KHz ...

  • Page 26

    ... SONY CODE EIAJ CODE JEDEC CODE 32PIN QFP (PLASTIC 0.15 0.3 – 0.1 0.24 M PACKAGE MATERIAL LEAD TREATMENT QFP-32P-L01 QFP032-P-0707 LEAD MATERIAL PACKAGE MASS —26— CXA1720Q 0.1 + 0.35 1.5 – 0.15 + 0.2 0.1 – 0.1 + 0.1 0.127 – 0.05 0° to 10° EPOXY RESIN SOLDER PLATING 42 ALLOY 0.2g ...