hmc472/docs/module-specs.md

HMC472A Digital RF Attenuator - Module Specifications

Extracted from Analog Devices HMC472A datasheet for the Amazon module variant.

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Electrical Specifications

Test Conditions: T_A = +25°C, Vdd = +5V, Vctl = 0/+5V (unless otherwise noted)

Parameter	Frequency	Min	Typ	Max	Units
Insertion Loss	DC - 1.5 GHz	—	1.4	1.8	dB
	1.5 - 3.0 GHz	—	1.7	2.3	dB
	3.0 - 3.8 GHz	—	1.9	3.0	dB
Attenuation Range	DC - 3.8 GHz	—	31.5	—	dB
Return Loss (RF1 & RF2, All States)	DC - 3.8 GHz	—	20	—	dB

Attenuation Accuracy

Referenced to insertion loss:

Attenuation States	Frequency	Max Error
All States	DC - 1.0 GHz	±(0.20 + 3% of Setting) dB
0.5 - 3.5 dB States	1.0 - 2.2 GHz	±(0.15 + 4% of Setting) dB
4.0 - 31.5 dB States	2.2 - 3.0 GHz	±(0.30 + 3% of Setting) dB
All States	3.0 - 3.8 GHz	±(0.35 + 5% of Setting) dB

Power Handling & Linearity

Parameter	Frequency	Value	Units
Input Power for 0.1 dB Compression	0.1 - 3.8 GHz	30	dBm
IIP3 (Two-Tone, 0 dBm each)
— REF to 15.5 dB States	0.1 - 3.8 GHz	54	dBm
— 16.0 to 31.5 dB States	0.1 - 3.8 GHz	49	dBm

Switching Characteristics

Parameter	Frequency	Typical	Units
t_RISE, t_FALL (10/90% RF)	DC - 3.8 GHz	40	ns
t_ON, t_OFF (50% CTL to 10/90% RF)	DC - 3.8 GHz	60	ns

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Bias Voltage & Current

Supply: Vdd = +5V ± 10%

Vdd (V)	Idd Typical (mA)
+4.5	2.4
+5.0	2.5
+5.5	2.6

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Control Voltage States

State	Bias Condition
Low	0 to +0.8 Vdc @ -5 µA Typ.
High	+2.0 to +5.0 Vdc @ 40 µA Typ.

Note: Vdd = +5V

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Truth Table

Each control pin (V1-V6) contributes a specific attenuation value when set Low:

Pin	Attenuation Value
V1	16 dB
V2	8 dB
V3	4 dB
V4	2 dB
V5	1 dB
V6	0.5 dB

Example Attenuation States

V1 (16dB)	V2 (8dB)	V3 (4dB)	V4 (2dB)	V5 (1dB)	V6 (0.5dB)	Total Attenuation
High	High	High	High	High	High	Reference (I.L.)
High	High	High	High	High	Low	0.5 dB
High	High	High	High	Low	High	1 dB
High	High	High	Low	High	High	2 dB
High	High	Low	High	High	High	4 dB
High	Low	High	High	High	High	8 dB
Low	High	High	High	High	High	16 dB
Low	Low	Low	Low	Low	Low	31.5 dB

Note: Any combination of the above states will provide an attenuation approximately equal to the sum of the bits selected.

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Functional Diagram & Pinout

Pin Assignment (24-Pin QFN, Top View)

Pin	Function	Pin	Function
1	N/C	13	ACG7
2	VDD	14	N/C
3	N/C	15	RF2
4	RF1	16	N/C
5	N/C	17	N/C
6	ACG1	18	N/C
7	ACG2	19	V1 (16 dB)
8	ACG3	20	V2 (8 dB)
9	ACG4	21	V3 (4 dB)
10	ACG5	22	V4 (2 dB)
11	ACG6	23	V5 (1 dB)
12	N/C	24	V6 (0.5 dB)
Base	GND

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Application Circuit

Recommended Component Values

Reference	Value	Function
C1	1000 pF	VDD bypass capacitor
C2	1000 pF	RF1 DC blocking / coupling
C3	1000 pF	RF2 DC blocking / coupling
C4-C8	330 pF	ACG2-ACG6 bypass capacitors
C9	330 pF	ACG7 bypass capacitor

Circuit Notes

• VDD (pin 2) requires 1000 pF bypass to ground
• RF1 (pin 4) and RF2 (pin 15) use 1000 pF DC blocking capacitors for AC coupling
• ACG pins (ACG2-ACG6 on pins 7-11, ACG7 on pin 13) require 330 pF bypass capacitors to ground

Note: For operations from 700 MHz to 2700 MHz, pins 6 through 13 (ACG1-ACG7) may be left unconnected.

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Performance Graphs

Insertion Loss vs Frequency

Two graphs showing insertion loss across temperature (+25°C, +85°C, -40°C):

1. Low Frequency Range (DC - 350 MHz)

   • Insertion loss approximately 1.0 to 1.2 dB
   • Minimal temperature variation

2. Full Frequency Range (DC - 4 GHz)

   • Insertion loss increases from ~1.2 dB at low frequencies to ~2.0 dB at 4 GHz
   • Temperature variation more pronounced at higher frequencies
   • -40°C shows best performance, +85°C shows highest loss

Return Loss RF1 & RF2

Two graphs showing return loss for major attenuation states:

1. Low Frequency Range (DC - 350 MHz)

   • Return loss typically better than -15 dB across all states
   • Best performance around 100 MHz

2. Full Frequency Range (DC - 4 GHz)

   • Reference and low attenuation states (0.5-16 dB): -15 to -25 dB return loss
   • Maximum attenuation state (31.5 dB): return loss degrades above 2 GHz
   • All states maintain better than -10 dB return loss across band

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Quick Reference Summary

Specification	Value
Frequency Range	DC - 3.8 GHz
Attenuation Range	0 - 31.5 dB
Step Size	0.5 dB
Insertion Loss (typ)	1.4 - 1.9 dB
Return Loss (typ)	20 dB
IIP3	49 - 54 dBm
Supply Voltage	+5V ± 10%
Supply Current	2.5 mA typ
Switching Speed	40 - 60 ns
Package	24-pin QFN
Input/Output Impedance	50Ω