AD1985JST Analog Devices Inc, AD1985JST Datasheet - Page 16

• Manufacturer Part Number: AD1985JST
• Description: IC CODEC STEREO 6-DAC 20B 48LQFP
• Manufacturer: Analog Devices Inc
• Series: SoundMAX®r
• Type: Audio Codec '97r

Specifications of AD1985JST

• Rohs Status: RoHS non-compliant
• Data Interface: Serial
• Resolution (bits): 16, 20 b
• Number Of Adcs / Dacs: 2 / 6
• Sigma Delta: No
• Dynamic Range, Adcs / Dacs (db) Typ: 84 / 90
• Voltage - Supply, Analog: 4.5 V ~ 5.5 V
• Voltage - Supply, Digital: 2.97 V ~ 3.63 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP

Reg Num Name
0x04
RHV[4:0]
HPRM
LHV[4:0]
HPM
AD1985
Headphone Volume Register (Index 0x04)
1
channels.
This register controls the headphone volume for both stereo
channels and mute bits. Each volume subregister contains five
bits, generating 32 volume levels with increments of 1.5 dB each.
AC ’97 defines the 6-bit volume registers, therefore, to maintain
compatibility whenever the D5 or D13 bit is set to 1, its
respective lower five volume bits are automatically set to 1 by
the codec logic. On readback, all lower five bits will read 1s
whenever these bits are set to 1 (see the Volume Settings for
For AC ’97 compatibility, Bit D7 (HPRM) is available only by setting the MSPLT bit in Register 0x76. The MSPLT bit enables separate mute bits for the left and right
Headphones Volume HPM
Right Headphone Volume Control. The least significant bit represents 1.5 dB. This register controls the output
from 0 dB to a maximum attenuation of 46.5 dB.
Right Channel Mute. Once enabled by the MSPLT bit in Register 0x76, this bit mutes the right channel
separately from the HPM bit. Otherwise, this bit will always read 0 and will have no effect when set to 1.
Left Headphone Volume Control. The least significant bit represents 1.5 dB. This register controls the output
from 0 dB to a maximum attenuation of 46.5 dB.
Headphones Volume Mute. When this bit is set to 1, both the left and right channels are muted, unless the
MSPLT bit in Register 0x76 is set to 1, in which case, this mute bit will only affect the left channel.
D15 D14 D13 D12 D11 D10 D9
X
X
LHV4 LHV3 LHV2 LHV1 LHV0 HPRM
Rev. A | Page 16 of 48
Master and Headphone table on the previous page).
Note that depending on the state of the AC97NC bit in Register
0x76, this register has the following additional functionality:
• For AC97NC = 0, the register has no control over the
• For AC97NC = 1, the register controls the
D8
SURR_OUT/HP_OUT outputs (see Register 0x38).
SURR_OUT/HP_OUT output attenuators.
D7
1
D6 D5 D4
X
X RHV4 RHV3 RHV2 RHV1 RHV0 0x8000
D3
D2
D1
D0
Default