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. 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 Structure Bipolar silicon monolithic IC 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 H0X 2 H0Y 3 H1X 4 H1Y 5 30 GND 29 PS 28 R/W 27 WC 26 RDY 25 RDX 24 HS0 23 HS1 22 HS2 POWER ON/OFF DETECTOR 21 VCC T - FF 20 WDI WRITE UNSAFE DETECTOR 19 WUS WRITE SERVO 18 WSER 17 H7X 16 H7Y DRIVER MODE AMP CONTROL WRITE CURRENT SOURCE DRIVER AMP AMP H2X 6 H2Y 7 DRIVER AMP HEAD H3X 8 DRIVER SELECT H3Y 9 H4X 10 H4Y 11 H5X 12 AMP DRIVER AMP DRIVER H5Y 13 H6X 14 H6Y 15 AMP IC PROTECTOR DRIVER DRIVER AMP AMP —2— CXA1829N Pin Description No. Symbol 1, 30 2, 3 4, 5 6, 7 8, 9 10, 11 12, 13 14, 15 16, 17 GND H0X, H0Y H1X, H1Y H2X, H2Y H3X, H3Y H4X, H4Y H5X, H5Y H6X, H6Y H7X, H7Y 19 Equivalent circuit Description VCC 10 2 12 4 14 6 16 8 11 3 13 5 15 7 17 9 GND connection. Head input. 8 channels provided. 330 2k 2k 330 200k GND WUS Write-unsafe detection output. Open collector output. When it is high in Write mode, an error is detected. VCC 19 GND 20 WDI VCC Write data input. When high changes to low, input is triggered. 20 2.1V 1.4V GND 21 VCC 22 23 24 HS2 HS1 HS0 VCC 5 V power supply. Head select signal input. Eight heads are selected as shown in Table 2. 22 23 100k 24 28 R/W 29 PS 2.1V GND VCC Read/Write signal input. Read at high; Write at low. 28 Power save signal input. Power save at high. 29 2.1V GND —3— CXA1829N No. Symbol 18 WSER Equivalent circuit Description VCC 100k Simultaneous Write signal input. Set to low for simultaneous Write mode. 18 2.1V GND 25 26 RDX RDY VCC Read amplifier output. Becomes a high impedance at Write. 25 26 GND 27 WC VCC 27 1.25V GND —4— A setting resistor for the Write current value is connected between this pin and GND. 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 Symbol Measurement conditions Measurement point Min. Typ. Max. 17 23 33 24 32 45 +IW +IW +IW 71 91 111 +4×IW +4×IW +4×IW 0.8 1.4 2.0 IR R/W="H" E IW R/W="L" E ISE WSER="L" E IP PS="H" E B VIL F VIH mA 0.8 D Digital high input voltage Unit V 2.0 G 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 IL IH VWUS H High applied voltage: 5 V Low applied voltage: 0 V Output current: 1 mA IWUS µA J 70 C 0.5 V C 10 µA 4.3 V VCC VTH -70 I A 3.6 3.9 IW Current flowing between head pins. A 5 15 mAo-p ∆Iw When Write current is IW [mA], then: K ___ (Rw:Ω), IW= Rw Refer to Fig. 12 (Characteristics) for K. A -8 8 % K 245 335 V/V 60 AV Input voltage SG1:1mVp-p,300kHz BW Frequency at which Av drops by 3dB K EN Head impedance: 0 Ω K CMRR 290 Load resistance (RDX, RDY): 1kΩ In-phase input voltage SG2:100mVp-p, 10 MHz —5— K MHz 0.55 50 77 0.7 nV √Hz dB CXA1829N Refer to Measurement Circuit 1. Item Symbol Measurement conditions Measurement point Min. Typ. K 45 55 Max. Unit 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 dB 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 K 45 55 (mVp-p), then: CS = 20 log (100/Vcs) + 20 log Av Non-selected head voltage Non selected VHUS head —6— 0.2 V 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 Symbol Measurement conditions Min. Typ. Head differential voltage amplitude VSW Potential difference between HX and HY pins when Write current is switched. 4.4 5.2 Write-unsafe detection maximum frequency FWUS FWUS is the Write data frequency when WUS pin is high in Write mode. Mode switching time Read to Write TRW Mode switching time Read to Simultaneous Write TRS Mode switching time Write to Read TWR Mode switching time Safe to Unsafe TSA1 Mode switching time Unsafe to Safe TSA2 Mode switching time Power save to Read TPR Head switching time TH Write current propagation delay time TPD Write current rise/fall time TR/TF 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%. —7— 280 Max. Unit Vp-p 1000 kHz 0.6 0.6 0.6 µs 3 7 11 1.0 1.0 0.6 16 30 ns 5 10 CXA1829N Measurement Circuit 1 1k ×1 1k AMP K VCC 5V 5V A SG3 E 1µ 1µ II J H G F D C B 20 19 18 H3Y H4X H4Y H5X H5Y H6X H6Y 3 4 5 6 7 8 9 10 11 12 13 14 15 H7Y WSER WDI H7X HS1 H3X 2 WUS HS0 H2Y 1 VCC RDX 16 H2X 17 RDY 21 H1Y 22 WC 23 H1X 24 R/W 25 H1Y 26 PS 27 H0X 28 GND 29 GND 30 HS2 10k A A SG2 SG1 Measurement Circuit 2 1k ×1 1k VCC 5V AMP 1µ 1µ H6Y 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1µH 1µH 1µH 1µH —8— 1µH 1µH H7X H6X WSER H5Y WUS H5X WDI H4Y VCC 16 H4X 17 H3Y 18 HS1 19 H3X 20 HS0 21 H2Y 22 RDX 23 H2X 24 RDY 25 H1Y 26 WC 27 H1X 28 R/W 29 H1Y 30 1µH PG PS PG H0X PG GND PG GND PG HS2 10k 3.9k H7Y K 1µH CXA1829N Timing Chart 1 WDI R/W (WSER) 50% 50% 50% PS TRW (TRS) TWR 90% 90% IWX IWY 10% 10% TWR TPR 90% RDX RDY 90% Fig. 3 Timing Chart 2 WDI 50% 50% TPD 90% IWX IWY 90% 10% 10% TR WUS 90% TF TSA1 50% 50% TSA2 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 —10— Head 0 1 2 3 4 5 6 7 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 10k 3.9k H5Y H6X H6Y 5 6 7 8 9 10 11 12 13 14 15 H7X H5X 4 WSER H4Y 3 WUS H4X 2 WDI H3Y 1 VCC HS1 H3X H7Y 16 HS0 17 H2Y 18 RDX 19 H2X 20 RDY 21 H1Y 22 WC 23 H1X 24 R/W 25 H1Y 26 PS 27 H0X 28 GND 29 GND 30 HS2 RW 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— 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 VFB of head pin 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 Write mode Read mode Differential output capacitance Differential output resistance Differential input capacitance Differential input resistance Output resistance VCC=5V, Ta=25°C Symbol Measurement conditions C0 R0 C1 R1 RRD Non-selected head differential current in Write mode IUS Write current symmetry TAS Between head input pins Between head input pins Min. 235 0.7 —13— Max. Unit 15 pF 315 395 Ω 14 20 pF 1.4 40 RDX or RDY LH=1µH, RH=30Ω IW=15mA LH=0µH, RH=0Ω IW=15mA Typ. -1 kΩ 60 Ω 0.2 mAp-p 1 ns CXA1829N Example of Representative Characteristics Fig. 8 Normalized Write current vs. Ambient temperature Fig. 7 Normalized Write current vs. Supply voltage VCC=5V RW=10k Ω 1.01 Normalized Write current Normalized Write current Ta=25°C RW=10k Ω 1.00 0.99 4.0 5.0 VCC-Supply voltage (V) 25 50 1.04 1.02 1.00 0.98 0.96 0.94 5.0 VCC-Supply voltage (V) 6.0 VCC=5V Vin=1mVp-p f=300kHz 1.06 1.04 1.02 1.00 0.98 0.96 0.94 -25 0 25 50 Fig. 12 Write current setting constant K vs. Write current VCC=5V K=IW•RW IW: mA, RW: k Ω K-Write current setting constant VTH ON 3.9 VTH OFF 3.8 150 148 146 144 142 140 0 25 50 75 Ta-Ambient temperature (°C) 4.0 -25 75 Fig. 10 Normalized Read amplifier differential voltage gain vs. Ambient temperature Fig. 11 Power supply ON/OFF detector threshold voltage vs. Ambient temperature Power supply ON/OFF detector threshold voltage (V) 0 Ta-Ambient temperature (°C) Normalized Read amplifier differential voltage gain Normalized Read amplifier differential voltage gain 0.98 -25 Ta=25°C Vin=1mVp-p f=300kHz 4.0 1.00 6.0 Fig. 9 Normalized Read amplifier differential voltage gain vs. Supply voltage 1.06 1.02 75 5 Ta-Ambient temperature (°C) —14— 10 15 IW-Write current (mA) CXA1829N Package Outline Unit : mm 30PIN SSOP (PLASTIC) + 0.2 1.25 – 0.1 ∗9.7 ± 0.1 1 7.6 ± 0.2 16 ∗5.6 ± 0.1 30 0.10 A 15 + 0.1 0.22 – 0.05 + 0.05 0.15 – 0.02 0.65 ± 0.12 0.5 ± 0.2 0.1 ± 0.1 0° to 10° DETAIL A NOTE: “∗” Dimension do not include mold protrusion. PACKAGE STRUCTURE PACKAGE MATERIAL EPOXY RESIN SONY CODE SSOP-30P-L01 LEAD TREATMENT SOLDER/PALLADIUM PLATING EIAJ CODE SSOP030-P-0056 LEAD MATERIAL COPPER/42 ALLOY PACKAGE WEIGHT 0.1g JEDEC CODE —15—