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For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, Chelmsford, MA 01824

Phone: 978-250-3343

Fax: 978-250-3373

Order On-line at www.hittite.com

Application Support: Phone: 978-250-3343 or apps@hittite.com

12

Serial Control Interface

Parallel Mode

(Direct Parallel Mode & Latched Parallel Mode)

The HMC628LP4(E) contains a 3-wire SPI compatible digital interface (DATA, CLK, LE). It is activated when P/S

is kept high. The 5-bit serial word must be loaded MSB first. The positive-edge sensitive CLK and LE requires

clean transitions. Standard logic families work well. If mechanical switches were used, sufficient debouncing should

be provided. When LE is high, 5-bit data in the serial input register is transferred to the attenuator. When LE is high

CLK is masked to prevent data transition during output loading.

When P/S is low, 3-wire SPI interface inputs (DATA, CLK, LE) are disabled and serial input register is loaded

asynchronously with parallel digital inputs (B0-B4). When Le is high, 5-bit parallel data is transferred to the attenuator.

For all modes of operations, attenuation state will stay constant while LE is kept low.

Note: The parallel mode is enabled when P/S is set to low.

Direct Parallel Mode - The attenuation state is changed by the Control Voltage Inputs directly. The LE (Latch Enable)

must be at a logic high to control the attenuator in this manner.

Latched Parallel Mode - The attenuation state is selected using the Control Voltage Inputs and set while the LE is in

the Low state. The attenuator will not change state while LE is Low. Once all Control Voltage Inputs are at the desired

states the LE is pulsed. See timing diagram above for reference.

HMC628LP4 / 628LP4E

v07.0410

BiCMOS MMIC 5-Bit DIGITAL

VARIABLE GAIN AMPLIFIER, 50 - 800 MHz

Parameter

Typ.

Min. serial period, t

SCK

100 ns

Control set-up time, t

CS

20 ns

Control hold-time, t

CH

20 ns

LE Set up-time, t

LN

10 ns

Min. LE pulse width, t

LEW

10 ns

Min LE pulse spacing, t

LES

530 ns

Serial clock hold-time from LE, t

CKN

10 ns

Hold Time, t

PH

0 ns

Latch Enable Minimum Width, t

LEN

10 ns

Setup Time, t

PS

2 ns

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other

rights of third parties that may result from its use. Specifications subject to change without notice. No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarks and registered trademarks are the property of their respective owners.

For price, delivery, and to place orders: Analog Devices, Inc.,

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106

Phone: 781-329-4700 • Order online at www.analog.com

Application Support: Phone: 1-800-ANALOG-D