LM96570SQX - National Semiconductor

LM96570

PRODUCT BRIEF

PRELIMINARY

November 30, 2010

Ultrasound Configurable Transmit Beamformer

General Description

The LM96570 is an eight-channel monolithic beamformer for

pulse generators in multi-channel medical ultrasound appli-

cations. It is well-suited for use with National’s LM965XX

series chipset which offers a complete medical ultrasound

solution targeted towards low-power, portable systems.

The LM96570 offers eight P and N output channels with indi-

vidual delays of up to 102.4 µs operating at pulse rates of up

to 80 MHz. A pulse sequence is launched on all channels si-

multaneously through a single firing signal. Advanced fea-

tures include delay resolution down to 0.78 ns and pro-

grammable patterns of up to 64 pulses. Pulse patterns and

delay settings are pre-programmed through a serial interface,

thereby simplifying the timing requirements on the driving cir-

cuitry.

The LM96570 is packaged in a 32-pin LLP.

Notice: This document is not a full datasheet. For more

information regarding this product or to order samples

please contact your local National Semiconductor sales

office or visit http://www.national.com/support/dir.html

Applications

■Ultrasound Imaging

Features

■Full control over selecting beam directions and pulse

patterns by programming individual channel parameters

■Outputs interface seamlessly with positive and negative

inputs on octal high-voltage pulser ICs

■Beamformer timing provides:

—Delay resolution of 0.78 ns

—Delay range of up to 102.4 μs

■Pulse patterns are locally generated with:

—Sequences of up to 64 pulses

—Adjustable Pulse widths

■2.5V to 3.3V CMOS logic interface

Key Specifications

I/O voltage 2.5 to 3.3 V

Core supply voltage 1.8 V

Output pulse rate 80 MHz

Reference frequency 40 (±5%) MHz

1σ Output Jitter

(@ 5MHz) 25 ps

Output Phase Noise

(@ 5MHz, 1kHz offset) −116 dBc/Hz

Delay resolution 0.78 ns

Delay range 102.4 μs

Max. pattern length 64 pulses

Serial interface speed 80 Mbps

Total Power 0.063 Watts

Operating Temp. 0 to +70 °C

Typical Application

8-Channel Transmit/Receive Chipset

30129703

LM96570 PRODUCT BRIEF

Connection Diagram

30129701

FIGURE 1. Pin Diagram of LM96570

Ordering Information

Part Number Package NSC Drawing Quantity

LM96570SQ

32–Lead LLP SQA32A

1000

LM96570SQE 250

LM96570SQX 4500

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LM96570

Pin Descriptions

Pin No. Name Type Function and Connection

1 – 4, 21 – 32 P0-7, N0-7 Output Control signals for pulser. P outputs control positive pulses and N outputs

control negative pulses..

13 PLL_CLK+ Input

PLL Reference Clock PLUS Input, LVDS compatible or Single-Ended LV

CMOS input, programmable through 4-Wire Serial Interface (Register

1Bh[0])

14 PLL_CLK- Input PLL Reference Clock MINUS input, LVDS compatible. For Single-Ended

PLL Reference Clock operation, tie this pin to AGND or VDDA.

7 TX_EN Input 1 = Beamformer starts firing

0 = Beamformer ceases firing

16 PLL_Vin Input Voltage range 0.8-1.2V for tuning internal PLL noise performance. Under

normal conditions, 0.94V is recommended.

17 PLL_Iin Input 100 μA current input

8 RST Input

Asynchronous Chip Reset

1 = Reset

0 = No Reset

12 sCLK Input 4-Wire Serial Interface Clock

10 sLE Input 4-Wire Serial Interface Latch Enable

11 sWR Input 4-Wire Serial Interface Data Input for writing data registers

9 sRD Output 4-Wire Serial Interface Data Output for reading data registers

15 VDDA Power Analog supply voltage (1.8V)

6 VDDC Power Digital core supply voltage (1.8V)

19 VIO Power Digital I/O supply voltage (2.5 to 3.3V)

0, 18 AGND Ground PLL Analog ground

5 DGND Ground Digital core ground

20 DGNDIO Ground Digital I/O ground

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LM96570

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

ESD Tolerance (Note 4)

Human Body Model 2kV

Machine Model 200V

Charge Device Model 750V

Maximum Junction Temperature (TJMAX)+150°C

Storage Temperature Range −40°C to +125°C

Supply Voltage (VDDA) −0.3V to +2.0V

Supply Voltage (VDDC) −0.3V and +2.0V

Supply Voltage (VIO) −0.3V and +3.6V

Voltage at Analog Inputs −0.3V and VDDA+0.3V

Voltage at Logic Inputs −0.3V and VIO+0.3

Operating Ratings (Note 1)

Operating Temperature Range(TA)0°C to + 70°C

VDDA, Analog Supply +1.71V to +1.89V

VDDC, Digital Core Supply +1.71V to +1.89V

VIO, Digital IO Supply +2.37 to +3.47

Package Thermal Resistance (θJA) (Note 3)37°C/W

Analog Electrical Characteristics

Unless otherwise stated, the following conditions apply VIO = +3.3V, VDDA = VDDC = +1.8V, TA = 25°C.

Pin Parameter Conditions Min Typ Max Units

PLL Phase Noise 5MHz pulse rate, 1kHz offset –116 dBc/Hz

VDDA

Power Supply Current Register with No Pattern (08h - 19h)

18.5

mAVDDC 2.4

VIO 0.3

VDDA

Power Supply Current

(08h - 19h), TX_EN = 15 kHz,

Pulse rate = 5 MHz

16.0

mAVDDC 6.50

VIO 13.4

PLL_CLK+ PLL Reference Clock

Frequency 38 40 42 MHz

Beamformer Output Timing Characteristics

Unless otherwise stated, the following conditions apply VIO = +3.3V, VDDA = VDDC = +1.8V, TA = 25°C.

Symbol Parameter Conditions Min Typ Max Units

Output Pulse Rate 0.625 80 MHz

Output Delay Range 102.4 µs

Output Delay Resolution 0.78 ns

Output Pattern Length 64 Pulses

tOD Output Propagation Delay Delay Profile (00−07h) = 0

Asynchronous TX_EN 32 47.5 ns

tR/F Output Rise/Fall ILOAD = 2mA 0.5 1.9 ns

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LM96570

Digital Electrical Characteristics

Unless otherwise stated, the following conditions apply VIO = +3.3V, VDDA = VDDC = +1.8V, TA = 25°C.

Symbol Parameter Conditions Min Typ Max Unit

PLL DIFFERENTIAL REFERENCE CLOCK DC SPECIFICATIONS

VID

PLL Reference Clock

Differential Input Amplitude

AC Coupled to pins 13 & 14. 1B[0] = 0

(see (Note 2)) 200 400 mV

VICM

PLL Reference Clock Input

Common Mode Voltage

Pins 13 & 14 bias voltage, VICM ≈ 0.5

X VDDA

0.9 V

RIN

Single-ended Input

Resistance

11 kΩ

PLL 1.8V LVCMOS SINGLE-ENDED REFERENCE CLOCK DC SPECIFICATIONS

VIH LVCMOS Input “HI” Voltage Pin 13. Register 1B[0] = 1 1.5

VIL LVCMOS Input “LO”

Voltage

Pin 13. Register 1B[0] = 1 0.3

RIN LVCMOS Input Resistance Pin 13 = 0V or VIO 11 kΩ

3.3V I/O DC SPECIFICATIONS

VIH Logic Input “HI” Voltage 2.2 V

VIL Logic Input “LO” Voltage 0.5

IIN-H/L Input Current −1 1 µA

VOH Logical Output “HI” Voltage IOH = 2 mA 2.9 V

VOL Logical Output “LO” Voltage IOL = 2 mA 0.34

IO-H/L Logic Output Current ±10 mA

Serial Interface Timing Characteristics

Unless otherwise stated, the following conditions apply VIO = +3.3V, VDDA = VDDC = +1.8V, TA = 25°C.

Symbol Parameter Conditions Min Typ Max Units

tLES sLE Setup Time 1.4

tLEH sLE Hold Time 1.9

tLEHI sLE HI Time 2.4

tWS sWR Setup Time 1.4

tWH sWR Hold Time 2.4

tRS sRD Data Valid Setup Time 6.3

tRH sRD Data Valid Hold Time 6.2

tSCLKR sCLK Rise Time 1.7 ns

tSCLKF sCLK Fall Time 1.7

tSCLKH sCLK High Time 2.4 ns

tSCLKL sCLK Low Time 3.4

fSCLK sCLK Frequency 80 MHz

Note 1: Absolute Maximum Ratings are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the device

can or should be operated at these limits.

Operating Ratings indicate conditions for which the device is guaranteed to be functional, but do not guarantee specific performance limits. Guaranteed speci-

fications and test conditions are specified in the Electrical Characteristics section. Operation of the device beyond the Operating Ratings is not recommended as

it may degrade the lifetime of the device.

Note 2: The combination of common mode and voltage swing on the clock input must ensure that the positive voltage peaks are not above VDDA and the negative

voltage peaks are not below AGND.

Note 3: The maximum power dissipation is a function of TJMAX, θJA and TA. The maximum allowable power dissipation at any ambient temperature is

PD = (TJMAX - TA)/ θJA. All numbers apply for package soldered directly into a 2 layer PC board with zero air flow.

Note 4: Human Body Model, applicable std. JESD22–A114–C. Machine Model, applicable std. JESD22–A115–A. Field induced Charge Device Model, applicable

std. JESD22–C101–C.

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LM96570

Timing Diagrams

30129704

FIGURE 2. 4-Wire Serial Interface WRITE Timing

30129705

FIGURE 3. 4-Wire Serial Interface READ Timing

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LM96570

Typical Performance Characteristics

1δ Output Jitter

30129718

Output Phase Noise

30129717

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LM96570

Overview

The LM96570 beamformer provides an 8-channel transmit

side solution for medical ultrasound applications suitable for

integration into multi-channel (128 / 256 channel) systems. Its

flexible, integrated pulse pattern generation and delay archi-

tecture enables low-power designs suitable for ultra-portable

applications. A complete system can be designed using

National’s companion LM9655x chipset.

30129702

FIGURE 4. Block Diagram of Beamformer with Pattern and Delay Generator

A functional block diagram of the IC is shown in Figure 4. Each

of the 8 output channels are designed to drive the positive and

negative pulse control inputs, Pn and Nn, respectively, of a

high-voltage ultrasound pulser, such as the LM96550. Upon

assertion of the common firing signal, each channel launches

an individually programmable pulse pattern with a maximum

delay of 102.4µs in adjustable in increments of 0.78 ns. The

length of a fired pulse pattern can extend up to 64 pulses.

Accurate timing of the pulse generation is enabled by an on-

chip PLL generating 8-phase 160 MHz internal clocks derived

from an external differential or single-ended 40MHz refer-

ence.

The pulse patterns and delay settings can be programmed

into and read out from the individual channel controls via a

four-wire serial interface. When the Latch Enable signal (sLE)

is low, the targeted on-chip registers can be written though

the serial data Write pin (sWR) at the positive clock edge

(sCLK). In the same way, they can also be read out through

the serial data Read pin (sRD). The writing and reading op-

erations have the same timing requirements, which are

shown in Figure 2 and Figure 3. The serial data stream starts

with a 6-bit address, in which the first 5-bits identify the mode

of updating which is interpreted by the Finite State Machine

(FSM), and the sixth bit of the address indicates the 4-wire

serial operation, either “WRITE” (0) or “READ” (1). The ad-

dress is followed by the data word, whose length can vary

from 8 bits to 64 bits. The data stream starts with the LSB and

ends with the MSB. The first 5-bit address indicates which of

the 27 registers is being accessed. In each 4-wire serial op-

eration, only one register can be written to or read from at a

time. TX_EN must be inactive during 4-wire serial interface

operation.

Upon a rising edge of the transmit signal “TX_EN”, the internal

“Fire” signal is pulled high after an internal propagation delay

relative to TX_EN elapses. Then the delay counter of each

channel begins counting according to the programmable de-

lay profile. When the counter reaches the 17-bit programmed

delay value, the programmed pulse pattern is sent out con-

tinuously at the programmed frequency until it reaches the

length of the pulse pattern.

The interface is compatible with CMOS logic powered at 2.5V

or 3.3V. The internal core supply is derived from 1.8V refer-

enced to 0V.

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LM96570

Physical Dimensions inches (millimeters) unless otherwise noted

32-Lead LLP Package

NS Package Number SQA32A

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LM96570

Notes

LM96570 PRODUCT BRIEF

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