Datasheet LC72720, LC72720M Datasheet (SANYO)

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Page 1

CMOS LSI

Ordering number : EN *5602

N2897HA (OT) No. 5602-1/14

Preliminary

LC72720, 72720M

SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters

TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN

Overview

The LC72720 and LC72720M are single-chip system LSIs that implement the signal processing required by the European Broadcasting Union RDS (Radio Data System) standard and by the US NRSC (National Radio System Committee) RDBS (Radio Broadcast Data System) standard. These LSIs include band-pass filter, demodulator, synchronization, and error correction circuits as well as data buffer RAM on chip and perform effective error correction using a soft-decision error correction technique.

Functions

• Band-pass filter: Switched capacitor filter (SCF)

• Demodulator: RDS data clock regeneration and demodulated data reliability information

• Synchronization: Block synchronization detection (with variable backward and forward protection conditions)

• Error correction: Soft-decision/hard-decision error correction

• Buffer RAM: Adequate for 24 blocks of data (about 500 ms) and flag memory

• Data I/O: CCB interface (power on reset)

Features

• Error correction capability improved by soft-decision error correction

• The load on the control microprocessor can be reduced by storing decoded data in the on-chip data buffer RAM.

• Two synchronization detection circuits provide continuous and stable detection of the synchronization timing.

• Data can be read out starting with the backwardprotection block data after a synchronization reset.

• Fully adjustment free

• Operating power-supply voltage: 4.5 to 5.5 V

• Operating temperature: –40 to +85°C

• Package: DIP24S, MFP24

Package Dimensions

unit: mm

3067-DIP24S

unit: mm

3045B-MFP24

SANYO: DIP24S

[LC72720]

SANYO: MFP24

[LC72720M]

• CCB is a trademark of SANYO ELECTRIC CO., LTD.

• CCB is SANYO’s original bus format and all the bus addresses are controlled by SANYO.

Single-Chip RDS

Signal-Processing System LSI

Page 2

Pin Assignment

Block Diagram

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LC72720, 72720M

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Pin Functions

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Pin No. Pin name Function I/O Pin circuit

1 VREF Reference voltage output (Vdda/2) Output

2 MPXIN Baseband (multiplexed) signal input Input

5 FLOUT Subcarrier output (filter output) Output

6 CIN Subcarrier input (comparator input) Input

3 Vdda Analog system power supply (+5 V) — — 4 Vssa Analog system ground — —

12 XOUT Crystal oscillator output (4.332/8.664 MHz) Output

13 XIN Crystal oscillator input (external reference signal input)

7 T1 Test input (This pin must always be connected to ground.) Input

8 T2

Test input (standby control) 0: Normal operation, 1: Standby state (crystal oscillator stopped)

9 T3 (RDCL) Test I/O (RDS clock output) 10 T4 (RDDA) Test I/O (RDS data output) 11 T5 (RSFT) Test I/O (soft-decision control data output)

16 T6 (ERROR/57K/BE1)

Test I/O (error status output, regenerated carrier output, error block count

I/O*

output)

17 T7 (CORREC/ARI-ID/BE0)

Test I/O (Error correction status output, SK detection output, error block count output)

18 SYNC Block synchronization detection output 19 RDS-ID RDS detection output

Output

20 DO Data output 21 CL Clock input 22 DI Data input

Input

23 CE Chip enable 24 SYR Synchronization and RAM address reset (active high) 14 Vddd Digital system power supply (+5 V) — — 15 Vssd Digital system ground — —

Note: * Normally function as an output pin. Used as an I/O pin in test mode, which is not available to user applications.

Serial data interface (CCB)

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No. 5602-4/14

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Parameter Symbol Conditions Ratings Unit

Maximum supply voltage V

max Vddd, Vdda –0.3 to +7.0 V

1 max CL, DI, CE, SYR, T1, T2, T3, T4, T5, T6, T7, SYNC –0.3 to +7.0 V

Maximum input voltage V

2 max XIN –0.3 to Vddd +0.3 V

3 max MPXIN, CIN –0.3 to Vdda +0.3 V

1 max DO, SYNC, RDS-ID, T3, T4, T5, T6, T7 –0.3 to +7.0 V

Maximum output voltage V

2 max XOUT –0.3 to Vddd +0.3 V

3 max FLOUT –0.3 to Vdda +0.3 V

1 max DO, T3, T4, T5, T6, T7 6.0 mA

Maximum output current I

2 max XOUT, FLOUT 3.0 mA

3 max SYNC, RDS-ID 20.0 mA

Allowable power dissipation Pd max Ta ≤ 85°C

DIP24S: 350 mW

MFP24: 300 mW Operating temperature Topr –40 to +85 °C Storage temperature Tstg –55 to +125 °C

Specifications

Absolute Maximum Ratings at Ta = 25°C, Vssd = Vssa = 0 V

Parameter Symbol Conditions

Ratings

Unit

min typ max

Supply voltage

1 Vddd, Vdda 4.5 5.0 5.5 V

2 Vddd: Serial data hold voltage 2.0 V

Input high-level voltage V

CL, DI, CE, SYR, T1, T2 0.7 Vddd 6.5 V

Input low-level voltage V

CL, DI, CE, SYR, T1, T2 0 0.3 Vddd V

Output voltage V

DO, SYNC, RDS-ID, T3, T4, T5, T6, T7 6.5 V

1 MPXIN : f = 57 ±2 kHz 50 mVrms

Input amplitude V

2 MPXIN : 100% modulation composite 100 mVrms

XIN

XIN 400 1500 mVrms

Guaranteed crystal oscillator frequencies Xtal

XIN, XOUT : CI ≤ 120 Ω (XS = 0) 4.332 MHz XIN, XOUT : CI ≤ 70 Ω (XS = 1) 8.664 MHz

Crystal oscillator frequency deviation TXtal XIN, XOUT : f

= 4.322 MHz, 8.664 MHz ±100 ppm

Data setup time t

DI, CL 0.75 µs

Data hold time t

DI, CL 0.75 µs

Clock low-level time t

CL 0.75 µs

Clock high-level time t

CL 0.75 µs

CE wait time t

CE, CL 0.75 µs

CE setup time t

CE, CL 0.75 µs

CE hold time t

CE, CL 0.75 µs

CE high-level time t

CE 20 ms

Data latch change time t

1.15 µs

DO, CL: Differs depending on the value of the

0.46 µs

Data output time

pull-up resistor used.

DO, CE: Differs depending on the value of the

0.46 µs

pull-up resistor used.

Allowable Operating Ranges at Ta = –40 to +85°C, Vssd = Vssa = 0 V

Parameter Symbol Conditions

Ratings

Unit

min typ max Input resistance Rmpxin MPXIN–Vssa : f = 57 kHz 23 kΩ Internal feedback resistance Rf XIN 1.0 MΩ Center frequency fc FLOUT 56.5 57.0 57.5 kHz –3 dB bandwidth BW – 3 dB FLOUT 2.5 3.0 3.5 kHz Gain Gain MPXIN–FLOOUT : f = 57 kHz 28 31 34 dB

Att1 FLOUT : ∆f = ±7 kHz 30 dB

Stop band attenuation Att2 FLOUT : f < 45 kHz, f > 70 kHz 40 dB

Att3 FLOUT : f < 20 kHz 50 dB

Electrical Characteristics at Ta = –40 to +85°C, Vssd = Vssa = 0 V

Continued on next page.

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No. 5602-5/14

LC72720, 72720M

Parameter Symbol Conditions

Ratings

Unit

min typ max Reference voltage output Vref VREF : Vdda = 5 V 2.5 V Hysteresis V

HIS

CL, DI, CE, SYR, T1, T2 0.1 Vddd V

Output low-level voltage

1 DO, T3, T4, T5, T6, T7 : I = 2 mA 0.4 V

2 SYNC, RDS-ID : I = 8 mA 0.4 V

Input high-level current

1 CL, DI, CE, SYR, T1, T2 : VI= 6.5 V 5.0 µA

2 XIN : VI= Vddd 2.0 11 µA

Input low-level current

1 CL, DI, CE, SYR, T1, T2 : VI= 0 V 5.0 µA

2 XIN : VI= 0 V 2.0 11 µA

Output off leakage current I

OFF

DO, SYNC, RDS-ID, T3, T4, T5, T6, T7 :

5.0 µA

= 6.5 V

Current drain Idd Vddd + Vdda 12 mA

Continued from preceding page.

CCB Output Data Format

• Each block of output data consists of 32 bits (4 bytes), of which 2 bytes are RDS data and 2 bytes are flag data.

• Any number of 32-bit output data blocks can be output consecutively.

• When there is no data that can be read out in the internal memory, the system outputs blocks of all-zero data consecutively.

• If data readout is interrupted, the next read operation starts with the 32-bit data block whose readout was interrupted. However, if only the last bit remains to be read, it will not be possible to reread that whole block.

• The check bits (10 bits) are not output.

1. Offset word detection flag (1 bit): OWD

2. Offset word information flag (3 bits): B0 to B2

OWD Offset word detection

1 Detected 0 Not detected (protection function operating)

B B B

Offset word

2 1 0 0 0 0 A 0 0 1 B 0 1 0 C 0 1 1 C’ 1 0 0 D 1 0 1 E 1 1 0 Unused 1 1 1 Unused

CCB address 6C

Output data/first bit

Last bit

(8) RDS data (7) Error information flags (6) Synchronization established flag (5) ARI (SK) detection flag (4) RAM data remaining flag (3) Consecutive RAM read out possible flag (2) Offset word information flag (1) Offset word detection flag Fixed pattern (1010)

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3. Consecutive RAM readout possible flag (1 bit): RE

RE RAM data information

1 The next data to be read out is in RAM. 0 This data item is the last item in RAM, and the next data is not present.

ARI SK signal

1 Detected 0 Not detected

4. RAM data remaining flag (2 bits): RF0, RF1

Caution: This value is only meaningful when RE is 1. When RE is 0, there is no data in RAM, even if RF is 00.

If a synchronization reset was applied using SYR, then the backward protection block data that was written to memory is also counted in this value.

Caution: This flag indicates the synchronization state of the circuit at the point where the data block being output was received.

On the other hand, the SYNC pin (pin 18) output indicates the current synchronization state of the circuit.

Caution: If the number of errors exceeds the value of the EC0 to EC2 setting (see the section on the CCB input format), the error information flags will be set

to the “Correction not possible” value.

RF1 RF0 Remaining data in RAM (number of blocks)

0 0 1 to 7 0 1 8 to 15 1 0 16 to 23 1 1 24

5. ARI (SK) detection flag (1 bit): ARI

SYC Synchronization detection

1 Synchronized 0 Not synchronized

6. Synchronization established flag (1 bit): SYC

7. Error information flags (3 bits): E0 to E2

8. RDS data (16 bits): D0 to D15

This data is output with the MSB first and the LSB last. Caution: When error correction was not possible, the input data is output without change.

E E E Number of 2 1 0 bits corrected

0 0 0 0 (no errors) 0 0 1 1 0 1 0 2 0 1 1 3 1 0 0 4 1 0 1 5 1 1 0 Correction not possible 1 1 1 Unused

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CCB Input Data Format

Caution: The bits labeled with an asterisk must be set to 0.

1. Synchronization protection (forward protection) method setting (4 bits): FS0 to FS3

FS3 = 0: If offset words in the correct order could not be detected continuously during the number of blocks specified

by FS0 to FS2, take that to be a lost synchronization state.

FS3 = 1: If blocks with uncorrectable errors were received consecutively during the number of blocks specified by

FS0 to FS2, take that to be a lost synchronization state.

No. 5602-7/14

LC72720, 72720M

Initial value: FS0 = 0, FS1 = 1, FS2 = 0, FS3 = 0

Initial value: BS = 0

F F F S S S Condition for detecting lost synchronization 0 1 2

0 0 0 If 3 consecutive blocks matching the FS3 condition are received. 1 0 0 If 4 consecutive blocks matching the FS3 condition are received. 0 1 0 If 5 consecutive blocks matching the FS3 condition are received. 1 1 0 If 6 consecutive blocks matching the FS3 condition are received. 0 0 1 If 8 consecutive blocks matching the FS3 condition are received. 1 0 1 If 10 consecutive blocks matching the FS3 condition are received. 0 1 1 If 12 consecutive blocks matching the FS3 condition are received. 1 1 1 If 16 consecutive blocks matching the FS3 condition are received.

2. Synchronization detection method setting (1 bit): BS

BS Synchronization detection conditions

0 If, during 3 blocks, 2 blocks of offset words were detected in the correct order. 1 If the offset words were detected in the correct order in 2 consecutive blocks.

[1] CCB address 6A

[2] CCB address 6B

IN1 data, first bit

IN2 data, first bit

(11) Circuit control

(5) Error correction method setting (4) RAM write control (3) Synchronization and RAM address reset (2) Synchronization detection method setting (1) Synchronization protection method setting

(10) Test mode settings

(9) Output pin settings (8) RDS/RBDS selection (7) Demodulation circuit phase control (6) Crystal oscillator frequency selection

(11) Circuit control

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3. Synchronization and RAM address reset (1 bit): SYR

Initial value: SYR =0

Caution: 1. To apply a synchronization reset, set SYR to 1 temporarily using the CCB, and then set it back to 0 again using the CCB.

The circuit will start synchronization capture operation at the point SYR is set to 0.

2. The SYR pin (pin 24) also provides an identical reset control operation. Applications can use either method. However, the control method that is not used must be set to 0 at all times. Any pulse with a width of over 250 ns will suffice.

3. A reset must be applied immediately after the reception channel is changed. If a reset is not applied, reception data from the previous channel may remain in memory.

4. Data read out after a synchronization reset is read out starting with the backward protection block data preceding the establishment of synchronization.

SYR Synchronization detection circuit RAM

0 Normal operation (reset cleared) Normal write (See the description of the OWE bit.) 1 Forced to the unsynchronized state (synchronization reset)

After the reset is cleared, start writing from the data prior to the establishment of synchronization, i.e. the data in backward protection.

Initial value: OWE = 0

Initial values: EC0 = 0, EC1 = 1, EC2 = 0, EC3 = 0, EC4 = 1 Caution: 1. If soft-decision A or soft-decision B is specified, soft-decision control will be performed even if the number of bits corrected is set to 0 (error

detection only). With these settings, data will be output for blocks with no errors.

2.As opposed to soft-decision B, the soft-decision A setting suppresses soft decision error correction.

4. RAM write control (1 bit): OWE

5. Error correction method setting (5 bits): EC0 to EC4

OWE RAM write conditions

0 Only data for which synchronization had been established is written. 1 Data for which synchronization not has been established (unsynchronized data) is also written. (However, this applies when SYR = 0.)

E E E

Number of

C C C

bits corrected

0 1 2 0 0 0 0 (error detection only) 1 0 0 1 or fewer bits 0 1 0 2 or fewer bits 1 1 0 3 or fewer bits 0 0 1 4 or fewer bits 1 0 1 5 or fewer bits 0 1 1 Illegal value 1 1 1 Illegal value

E E C C Soft-decision setting 3 4

0 0 Mode 0: Hard decision 1 0 Mode 1: Soft decision A 0 1 Mode 2: Soft decision B 1 1 Illegal value

6. Crystal oscillator frequency selection (1 bit): XS XS = 0: 4.332 MHz XS = 1: 8.664 MHz Initial value: XS = 0

7. Demodulation circuit phase control (2 bits): PL0, PL1

Initial values: PL0 = 0, PL1 = 1 Caution: 1. When PL0 is 0 (normal operation), the LSI detects the presence or absence of the ARI signal and reproduces the RDS data by automatically

controlling the demodulation phase with respect to the reproduced carrier. However, the initial phase following a synchronization reset is set by PL1.

2.If PL0 is set to 1, the demodulation circuit phase is locked according to the PL1 setting at either 90° (PL1 = 0) or 0° (PL1 = 1), allowing RDS data to be reproduced. When ARI is not present, PL1 should be set to 0, since the RDS data is reproduced by detecting at a phase of 90° with respect to the reproduced carrier. When ARI is present, PL1 should be set to 1, since detection is at 0°. In cases where the ARI presence is known in advance, more stable reproduction can be achieved by fixing the demodulation phase in this manner.

PL0 PL1 Demodulation circuit phase control

0 0/1 <Normal operation> when ARI presence or absence is unclear.

0 If the circuit determines that the ARI signal is absent: 90° phase 1 If the circuit determines that the ARI signal is present: 0° phase

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No. 5602-9/14

LC72720, 72720M

8. RDS/RBDS (MMBS) selection (1 bit): RM

Initial value: RM = 0

—: Open, ●●, ●: Output enabled (● = reverse polarity)

Initial values: PT0 = 1, PT1 = 1, PT2 = 0 (mode 3) Caution: 1. When PT2 is set to 1, the polarity of the T3 (RDCL), T6 (ERROR/57K), T7 (CORREC/ARI-ID) SYNC, and RDS-ID pins changes to active

high.

2.The output pins (T3 to T7, SYNC, and RDS-ID) are all open-drain pins, and require external pull-up resistors to output data.

These pins indicate the number of blocks in a set of 48 blocks that had errors before correction. The output polarity of these pins is fixed at the values listed in the table.

RM RBDS support Decoding method

0 None Only RDS data is decoded correctly (Offset word E is not detected.) 1 Provided RDS and MMBS data is decoded correctly (Offset word E is also detected.)

9. Output pin settings (3 bits): PT0 to PT2 These bits control the T3, T4, T5, T6, T7, SYNC, and RDS-ID pins.

P P P

T3 T4 T5 T6 T7

Mode T T T

0 1 2 RDCL RDDA RSFT ERROR 57K BE1 CORREC ARI-ID BE0 0 0 0 0 — — — — — — — — — 1 1 0 0 ●● ●● ●● — — — — — —

2 0 1 0 ●● ●● ●● — ●● — — ●● — 3 1 1 0 ●● ●● ●● ●● — — ●● — — 4 0 0 1 — — — — — ●● — — ●● 5 1 0 1 ● ●● ●● — — — — — — 6 0 1 1 ● ●● ●● — ● — — ● — 7 1 1 1 ● ●● ●● ● — — ● — —

Pin T3 (RDCL) PT2 = 0 Data (RDDA and RSFT) changes on this pin’s rising edge. PT2 = 1 Data (RDDA and RSFT) changes on this pin’s falling edge.

Mode 2 (PT2 = 0) Pin T7 (ARI-ID)

No SK High (1)

SK present Low (0)

Mode 3 (PT2 = 0) Pin T6 (ERROR) Pin T7 (CORREC)

Correction not possible Low (0) Low (0)

Errors corrected High (1) Low (0)

No errors High (1) High (1)

Mode 4

Pin T6 (BE1) Pin T7 (BE0)

Number of error blocks (B)

B = 0 Low (0) Low (0)

1 ≤ B ≤ 20 Low (0) High (1) 20 < B ≤ 40 High (1) Low (0) 40 < B ≤ 48 High (1) High (1)

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No. 5602-10/14

LC72720, 72720M

Caution: The output indicates the synchronization state for the previous block.

Mode (PT2 = 0) The SYNC pin

0 to 2 When synchronized: Low (0). When unsynchronized: High (1)

When synchronized: Goes high for a fixed period (421 µs) at

3 the start of a block and then goes low.

When unsynchronized: High (1)

When PT2 = 0 The RDS-ID pin

No RDS High (1)

RDS present Low (0)

10. Test mode settings (4 bits): TS0 to TS3 Initial values: TS0 = 0, TS1 = 0, TS2 = 0, TS3 = 0 (Applications must set these bits to the above values.)

Notes: The T1 and T2 pins (pins 7 and 8) are related to test mode as follows:

The T1 pin must be tied to VSS(0 V).

Initial values: CT0 = 0, CT1 = 0

Pin T1 Pin T2 LSI operation Notes

0 0 Normal operating mode

These states are user settable

0 1 Standby mode (crystal oscillator stopped) 1 0/1 LSI test mode Users cannot use this state

11. Circuit control (2 bits): CT0 and CT1

RDCL/RDDA/RSFT and ERROR/CORREC/SYNC Output Timing

Timing 1 (modes 1 to 3, PT2 = 0)

Timing 2 (mode 3, PT2 = 0)

Item Control CT0 RSFT control When set to 1, soft-decision control data (RSFT) is easier to generate. CT1 RDS-ID detection condition When set to 1, the RDS-ID detection conditions are made more restrictive.

RDCL output

RDDA output

RSFT output

Input data

Error crrection

SYNC output

ERROR output

CORREC output

Sync NG

Sync NGSync NG

Sync OK

Sync OKSync OK

Sync OK Sync OK

Data

corrected

Data

corrected

errors

Uncorrectable

Note: When PT2 = 0, RDDA and RSFT must be

aquired on the falling edge of RDCL.

Page 11

Serial Data Input and Output Methods

Data is input and output using the CCB (computer control bus), which is the Sanyo audio LSI serial bus format. This LSI adopts an 8-bit address CCB format.

Serial data input (IN1, IN2) tSU, tHD, tEL, tES, tEH≥ 0.75 µs tLC< 1.15µs tCE< 20 ms CL: Normal high

CL: Normal low

Caution: The serial data I/O function can access data only after the crystal oscillator circuit is operating.

No. 5602-11/14

LC72720, 72720M

I/O mode

(LSB) Address (MSB)

Comment

B0 B1 B2 B3 A0 A1 A2 A3

1 IN1 (6A) 0 1 0 1 0 1 1 0

· Control data input mode, also referred to as “serial data input” mode.

· This is a 16-bit data input mode.

2 IN2 (6B) 1 1 0 1 0 1 1 0

· Control data input mode, also referred to as “serial data input” mode.

· This is a 16-bit data input mode.

3 OUT (6C) 0 0 1 1 0 1 1 0

· Data output mode, also referred to as “serial data output” mode.

· The data for multiple blocks can be output sequentially in this mode.

I/O mode determined

For the CL normal high state For the CL normal low state

Internal data

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No. 5602-12/14

LC72720, 72720M

Serial data output (OUT) tSU, tHD, tEL, tES, tEH≥ 0.75 µs tDC, tDH< 0.46 µs tCE< 20 ms

CL: Normal high

CL: Normal low

Serial data timing

CL: Normal high

CL: Normal low

Caution:1. Since the DO pin is an n-channel open-drain output, the transition times (tDC, tDH) will differ with the value

of the pull-up resistor used.

2. The CE, CL, DI, and DO pins can be connected to the corresponding pins on other LSIs that use the CCB interface. (However, we recommend connecting the DO and CE pins separately if the number of available microcontroller ports allows it.)

Intenal data latch

Old

New

Page 13

Parameter Symbol Conditions

Ratings

Unit

min typ max

Data setup time t

DI, CL 0.75 µs

Data hold time t

DI, CL 0.75 µs

Clock low-level time t

CL 0.75 µs

Clock high-level time t

CL 0.75 µs

CE wait time t

CE, CL 0.75 µs

CE setup time t

CE, CL 0.75 µs

CE hold time t

CE, CL 0.75 µs

CE high-level time t

CE 20 ms

Data latch transition time t

1.15 µs

Data output time

DO, CL 0.46 µs

DO, CE 0.46 µs

No. 5602-13/14

LC72720, 72720M

Differs with the value of the pull-up resistor used.

DO pin operation

This LSI incorporates a RAM data buffer that can hold up to 24 blocks of data. At the point where one block of data is written to this RAM, the LSI issues a read request by switching the DO pin from high to low. The DO pin always goes high for a fixed period (Tdo = 265 µs) after a readout and CE goes low. When all the data in the data buffer has been read out, the DO pin is held in the high state until a new block of data has been written to the RAM. If there is data that has not yet been read remaining in the data buffer, the DO pin goes low after the Tdo time has elapsed. After a synchronization reset, the DO pin is held high until synchronization is established. It goes low at the point where the LSI synchronizes.

1. When the DO pin is high following the 265 µs period (Tdo) after data is read out Here, the buffer is in the empty state, i.e. the state where new data has not been written. After this, when the DO pin goes low, applications are guaranteed to be able to read out that data without it being overwritten by new data if they start a readout operation within 480 ms of DO going low.

2. When DO goes low 265 µs after data is read out Here, there is data that has not been read out remaining in the data buffer. In this case, applications are guaranteed to be able to read out that data without it being overwritten by new data if they start a readout operation within 20 ms of DO going low. (Note that this is the worst case condition.)

Notes: 1. Although an application can determine whether or not there is data remaining in the buffer by checking the DO

level with the above timing, checking the RE and RF flags in the serial data is a preferable method.

2. Applications are not limited to reading out one block of data at a time, but rather can read out multiple blocks of data continuously as described above. When using this method, if an application references the RE and RF flags in the data while reading out data, it can determine the amount of data remaining. However, the length of the period for data readout (the period the CE pin remains high) must be kept under 20 ms.

3. If the DO pin is shared with other LSIs that use the CCB interface, the application must identify which LSI issued the readout request. One method is to read out data from the LC72720 and either check whether meaningful data has been read (if the LC72720 is not requesting a read, data consisting of all zeros will be read out) or check whether the DO level goes low within the 256 µs following the completion of the read (if the DO pin goes low, then the request was from another LSI).

CE pin

DO pin

CE pin

DO pin

(Last data) - 1

Last data

New data

(Last data) - 2 (Last data) - 1

Last data

DO check (Tdo < T)

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No. 5602-14/14

LC72720, 72720M

This catalog provides information as of May, 1997. Specifications and information herein are subject to change without notice.

■ No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss.

■ Anyone purchasing any products described or contained herein for an above-mentioned use shall:

➀

Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use:

➁

Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally.

■ Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties.

Sample Application Circuit

Notes: 1. Determine the value of the DO pin pull-up resistor based on the required serial data transfer speed.

2. A 100-kΩ bias resistor must be connected between the CIN pin and the VREF pin. Note that this resistor is planned to be included internally to the LSI in later versions of this product.

3. If the SYR pin is unused, it must be connected to ground.

Datasheet LC72720, LC72720M Datasheet (SANYO)

Specifications and Main Features

Frequently Asked Questions

User Manual