CXA1829N

CXA1829N 8ch. Read/Write Amplifier for Thin Film Heads of Hard Disk Drive For the availability of this product, please contact the sales office. Description The CXA1829N is a Read/Write amplifier for hard disk drive thin-film heads and is designed to handle up to 8-channel heads. Features • Operates on a single 5V power supply. • Low power consumption. Read: 115 mW Write (IW = 15 mA): 160 mW + IW × 5 Power Save: 7 mW • Write current can be varied through an external resistor. Built-in stabilizer circuit provides stable current, preventing voltage and temperature drift. • Drives up to 8 heads. • Supports thin film heads or 2-pin MIG heads. • Emitter follower-type Read amplifier features 290 times gain (typ.). • Write-unsafe detection circuit. • Damping resistance is switched at Write (315 Ω). • Simultaneous Write function. • Supply voltage monitor circuit prohibits error writing during power surge or abnormal voltage. • IC protection circuit for head-to-ground short circuit protection. • Differential input capacitance at Read: 14 pF (typ.). • Write data input minimum pulse width: 10 ns • Read data output in Write mode becomes a high impedance due to the improved Read data offset when Write is switched to Read. • Non-selected head DC voltage falls to GND level. Structure Bipolar silicon monolithic IC 30 pin SSOP (Plastic) Absolute Maximum Ratings (Ta=25°C) • Supply voltage VCC 7.0 V • Write current IW 20 mAo-p • Operating temperature Topr –20 to +75 °C • Operating temperature at Simultaneous Write Topr –20 to +30 °C • Storage temperature Tstg –55 to +150 °C • Allowable power dissipation PD 480 mW Recommended Operating Conditions • Supply voltage VCC 5V±10% V 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. —1— E94433A49-TE CXA1829N Block Diagram and Pin Configuration GND 1 30 GND H0X 2 DRIVER 29 MODE PS H0Y 3 AMP CONTROL 28 R/W H1X 4 DRIVER WRITE CURRENT SOURCE 27 WC H1Y 5 AMP AMP 26 RDY H2X 6 DRIVER 25 RDX H2Y 7 AMP 24 HEAD HS0 H3X 8 DRIVER 23 SELECT HS1 H3Y 9 AMP 22 HS2 H4X 10 DRIVER POWER ON/OFF DETECTOR 21 VCC H4Y 11 AMP T - FF 20 WDI H5X 12 DRIVER WRITE UNSAFE DETECTOR 19 WUS H5Y 13 AMP IC PROTECTOR WRITE SERVO 18 WSER H6X 14 DRIVER DRIVER 17 H7X H6Y 15 AMP AMP 16 H7Y —2— CXA1829N Pin Description No. 1, 30 2, 3 4, 5 6, 7 8, 9 10, 11 12, 13 14, 15 16, 17 Symbol GND H0X, H0Y H1X, H1Y H2X, H2Y H3X, H3Y H4X, H4Y H5X, H5Y H6X, H6Y H7X, H7Y Equivalent circuit Description GND connection. Head input. 8 channels provided. VCC 10 12 14 16 11 13 15 17 2 4 6 8 3 5 7 9 GND 200k 330 2k 2k 330 19 WUS VCC 19 Write-unsafe detection output. Open collector output. When it is high in Write mode, an error is detected. GND 20 WDI VCC Write data input. When high changes to low, input is triggered. 20 2.1V 1.4V GND 21 22 23 24 VCC HS2 HS1 HS0 22 23 24 100k 2.1V GND VCC VCC 5 V power supply. Head select signal input. Eight heads are selected as shown in Table 2. 28 R/W Read/Write signal input. Read at high; Write at low. 28 29 PS 29 2.1V GND Power save signal input. Power save at high. —3— CXA1829N No. 18 Symbol WSER Equivalent circuit VCC 100k 18 Description Simultaneous Write signal input. Set to low for simultaneous Write mode. 2.1V GND 25 26 RDX RDY VCC Read amplifier output. Becomes a high impedance at Write. 25 26 GND 27 WC VCC A setting resistor for the Write current value is connected between this pin and GND. 27 1.25V GND —4— CXA1829N Electrical Characteristics (unless otherwise specified, VCC = 5 V, Ta = 25°C, Write current IW = 15 mA) Refer to Measurement Circuit 1. Item Current consumption for Read Current consumption for Write Current consumption for Servo Current consumption for Power save Digital low input voltage Digital high input voltage Digital low input current Digital high input current Write-unsafe output saturation voltage Write-unsafe output leak current Power ON/OFF detector threshold voltage Write current setting range Write current accuracy Read amplifier differential voltage gain Bandwidth (-3 dB) Input conversion noise voltage Common mode rejection ratio Symbol Measurement conditions Measurement point E E E E B D VIH IL IH VWUS IWUS VTH IW Current flowing between head pins. When Write current is IW [mA], then: K ___(Rw:Ω), IW= Rw Refer to Fig. 12 (Characteristics) for K. Input voltage SG1:1mVp-p,300kHz Load resistance (RDX, RDY): 1kΩ Frequency at which Av drops by 3dB Head impedance: 0 Ω In-phase input voltage SG2:100mVp-p, 10 MHz F G H High applied voltage: 5 V Low applied voltage: 0 V I J C C VCC A A 3.6 5 3.9 70 0.5 10 4.3 15 V µA V mAo-p -70 µA 2.0 Min. Typ. Max. Unit IR IW ISE IP VIL R/W="H" R/W="L" WSER="L" PS="H" 17 24 +IW 71 +4×IW 0.8 23 32 +IW 91 +4×IW 1.4 33 45 +IW 111 +4×IW 2.0 0.8 V mA Output current: 1 mA ∆Iw A -8 8 % AV BW EN CMRR K K K K 245 60 290 335 V/V MHz 0.55 50 77 0.7 nV √Hz dB —5— CXA1829N Refer to Measurement Circuit 1. Item Symbol Measurement conditions Ripple voltage SG3: 5 V ± 100 mVp-p, Supply voltage rejection ratio 10 MHz PSRR When Read amplifier output is Vp (mVp-p), then: PSRR = 20 log (100/Vp) + 20 log Av Selected head input voltage: 0 mVp-p Non-selected head input voltage SG1: Channel separation CS 100 mVp-p, 10 MHz When Read amplifier output is Vcs (mVp-p), then: CS = 20 log (100/Vcs) + 20 log Av Non-selected head voltage Non VHUS selected head 0.2 V K 45 55 dB K 45 55 Measurement point Min. Typ. Max. Unit —6— CXA1829N Unless otherwise specified, VCC = 5 V, Ta = 25 °C, fWD (Write data frequency) = 5 MHz, IW = 15 mA, LH (head inductance) = 1 µH, RH (head DC resistance) = 30 Ω Refer to Measurement Circuit 2 and Timing Chart. Item Head differential voltage amplitude Write-unsafe detection maximum frequency Mode switching time Read to Write Mode switching time Read to Simultaneous Write Mode switching time Write to Read Mode switching time Safe to Unsafe Mode switching time Unsafe to Safe Mode switching time Power save to Read Symbol VSW Measurement conditions Potential difference between HX and HY pins when Write current is switched. FWUS is the Write data frequency when WUS pin is high in Write mode. Time required for Write current to reach 90% after Read mode is switched to Write mode. Time required for Write current to reach 90% after Read mode is switched to Simultaneous Write mode. Time required for Write current to reach 10% after Write mode is switched to Read mode. Time required for WUS pin to become high after the Write data is stopped in Write mode. Time required for WUS pin to become low after the Write data is input in Write mode. Time required for RD output to reach 90% after Power Save mode is switched to Read mode. Time required for RD output to reach 90% when the selected head is changed in Read mode. LH = 0, RH = 0 Time required for Write current to reach 90% after the Write data falling edge. LH = 0, RH = 0 T R is the time required for Write current to reach 90% from 10%; TF is the time required for it to reach 10% from 90%. Min. 4.4 Typ. 5.2 Max. Unit Vp-p FWUS 280 1000 kHz TRW 0.6 TRS 0.6 TWR 0.6 µs 3 7 11 TSA1 TSA2 1.0 TPR 1.0 Head switching time TH 0.6 Write current propagation delay time TPD 16 30 ns 5 10 Write current rise/fall time TR/TF —7— CXA1829N Measurement Circuit 1 VCC 5V ×1 1k AMP 1k 5V SG3 K A E 1µ 1µ J 30 29 II 10k 28 27 26 25 H 24 G 23 F 22 21 D 20 C 19 B 18 17 16 GND WUS RDX HS1 WSER RDY R/W HS0 HS2 WDI H7X H6X 14 PG VCC WC PS GND H1Y H3X H1X H3Y H1Y H4X H2X H4Y H0X H2Y H5X H5Y 1 2 3 4 5 6 7 8 9 10 11 12 13 15 A A SG2 SG1 Measurement Circuit 2 ×1 1k AMP 1k VCC 5V K 1µ PG PG 1µ PG PG 3.9k 1µH 17 16 10k 27 26 25 30 29 28 24 23 22 21 20 19 18 H6Y H7X 14 H7Y H6X 15 1µH GND WUS RDX HS1 GND WSER RDY R/W HS0 HS2 WDI H1Y H3X H1X H3Y H1Y H4X H2X H4Y H0X H2Y 1 2 3 4 5 6 7 1µH 8 9 1µH 10 11 12 H5X 13 1µH 1µH 1µH 1µH —8— H5Y H6Y H7Y VCC WC PS CXA1829N Timing Chart 1 WDI R/W (WSER) 50% 50% PS TRW (TRS) 90% IWX IWY 10% 90% 10% TWR 50% TWR TPR RDX RDY 90% 90% Fig. 3 Timing Chart 2 WDI 50% 50% TPD 90% IWX IWY 10% 90% 90% 10% TR TF TSA1 WUS TSA2 50% 50% Fig. 4 —9— CXA1829N Description of Functions Read amplifier This is a low-noise amplifier for amplifying the faint signals from the heads, and is an emitter follower output. It outputs the signals differentially to the RDX and RDY pins, and the X side of the head and RDX pin and the Y side of the head and RDY pin have the same polarity. RDX and RDY outputs in Write mode become high impedance. (The outputs should be capacitor-coupled.) Write circuit The Write data input to the WDI pin passes through a T flip-flop where its frequency is halved. It then drives the Write switch circuit and supplies the Write current to the heads. The Write data is triggered at the transition from high to low and the Write current is switched. The Write current flows from the X side when the mode changes from Read to Write. Mode control The modes are set as shown in Table 1 by the R/W, PS and WSER pins. Table 1. Mode selection R/W L H X X X PS L L H L L WSER H H X L L HSO X X X L H Mode Write Read Power save 0, 2, 4, 6-head simultaneous Write 1, 3, 5, 7-head simultaneous Write The WSER pin has a built-in pull-up resistor (100 kΩ). Head selection The heads are selected as shown in Table 2 by the HS0, HS1 and HS2 pins. Table 2. Head selection HS0 L H L H L H L H HS1 L L H H L L H H HS2 L L L L H H H H Head 0 1 2 3 4 5 6 7 —10— CXA1829N Write-unsafe detection circuit (refer to the “Notes on Operation.”) This circuit detects write errors. In normal Write mode, the WUS output is low; in the conditions listed below, it is high. • Head input is open. • Head input is shorted to GND or VCC. • Write data frequency is abnormally low. • There is no Write current. • In Read mode • In Power save mode • Supply voltage is abnormal (refer to the “Power supply ON/OFF detection.”) Power supply ON/OFF detection This circuit monitors VCC to detect erroneous Writes. The error status is established when VCC falls below the threshold voltage (VTH) of the power supply ON/OFF detector, in which case the recording and playback functions are prohibited. When VCC rises above VTH, the prohibition of these functions is released. Application Circuit +5V PULSE DETECTOR 1µ RW 10k 3.9k 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 GND WUS RDX HS1 GND WSER RDY R/W HS0 HS2 WDI H7X 14 H1Y H3X H5Y H1X H3Y H1Y H4X H2X H4Y H0X H2Y 1 2 3 4 5 6 7 8 9 10 11 12 H5X 13 H6X 15 Fig. 5 Application circuits shown are typical examples illustrating the operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits or for any infringement of third party patent and other right due to same. —11— H6Y H7Y VCC WC PS CXA1829N Notes on Operation • This IC handles high frequency and high gain signals. Please note the following; ◊ Connect VCC decoupling capacitor of approximately 1000 pF near the IC. ◊ Make the grounding area as large as possible. • Short-circuit the X and Y sides of unused head pins or leave them open. • Write data pulse width Set the pulse width to 10 ns or more at 1.5 V to prevent misoperation. • The WC pin is a constant voltage pin. When noise affects this pin, it creates noise in Write current. Therefore, locate Rw as close to the IC as possible. • Write-unsafe detection circuit The WUS detection circuit operates by voltage waveform of head pin. 1.5V Write data waveform T1 Voltage waveform of head pin VFB VTH=2V VTH GND Fig. 6 ◊ Use the IC at T1 > 10 ns for normal operation of the WUS detecting circuit. ◊ Use the IC with VFB of 2V or more. If the VFB is less than 2V, the write-unsafe detection maximum frequency may become 1 MHz or more. ◊ Please apply to the reference mentioned on this back cover since the operation range of the writeunsafe detection circuit is greatly affected by the head inductance, head DC resistance and Write current. • Use the IC with Ta at 30°C or less in Simultaneous Write mode. —12— CXA1829N Application Notes Use the following characteristics for reference. Item Differential output capacitance Differential output resistance Differential input capacitance Differential input resistance Output resistance Non-selected head differential current in Write mode Write current symmetry Symbol Measurement conditions C0 R0 C1 R1 RRD IUS TAS Between head input pins Min. Typ. VCC=5V, Ta=25°C Max. 15 235 315 14 0.7 1.4 40 60 0.2 -1 1 395 20 Unit pF Ω pF kΩ Ω mAp-p ns Write mode Read mode Between head input pins RDX or RDY LH=1µH, RH=30Ω IW=15mA LH=0µH, RH=0Ω IW=15mA —13— CXA1829N Example of Representative Characteristics Fig. 7 Normalized Write current vs. Supply voltage Ta=25°C RW=10k Ω Fig. 8 Normalized Write current vs. Ambient temperature VCC=5V RW=10k Ω Normalized Write current Normalized Write current 1.01 1.02 1.00 1.00 0.99 0.98 4.0 5.0 VCC-Supply voltage (V) 6.0 -25 0 25 50 75 Ta-Ambient temperature (°C) Fig. 9 Normalized Read amplifier differential voltage gain vs. Supply voltage Fig. 10 Normalized Read amplifier differential voltage gain vs. Ambient temperature Normalized Read amplifier differential voltage gain 1.06 1.04 1.02 1.00 0.98 0.96 0.94 Ta=25°C Vin=1mVp-p f=300kHz Normalized Read amplifier differential voltage gain 1.06 1.04 1.02 1.00 0.98 0.96 0.94 VCC=5V Vin=1mVp-p f=300kHz 4.0 5.0 VCC-Supply voltage (V) 6.0 -25 0 25 50 75 Ta-Ambient temperature (°C) Fig. 11 Power supply ON/OFF detector threshold voltage vs. Ambient temperature Fig. 12 Write current setting constant K vs. Write current K=IW•RW IW: mA, RW: k Ω Power supply ON/OFF detector threshold voltage (V) VCC=5V 4.0 K-Write current setting constant 75 VTH ON 150 148 146 144 142 140 3.9 VTH OFF 3.8 -25 0 25 50 5 Ta-Ambient temperature (°C) 10 15 IW-Write current (mA) —14— CXA1829N Package Outline Unit : mm 30PIN SSOP (PLASTIC) + 0.2 1.25 – 0.1 ∗9.7 ± 0.1 0.10 16 30 ∗5.6 ± 0.1 A 1 + 0.1 0.22 – 0.05 15 0.65 ± 0.12 + 0.05 0.15 – 0.02 0.1 ± 0.1 0° to 10° NOTE: “∗” Dimension do not include mold protrusion. DETAIL A PACKAGE STRUCTURE PACKAGE MATERIAL SONY CODE EIAJ CODE JEDEC CODE SSOP-30P-L01 SSOP030-P-0056 LEAD TREATMENT LEAD MATERIAL PACKAGE WEIGHT EPOXY RESIN SOLDER/PALLADIUM PLATING COPPER/42 ALLOY 0.1g —15— 0.5 ± 0.2 7.6 ± 0.2