TDA8798 Datasheet, PDF (4/24 Pages) NXP Semiconductors – Dual 8-bit, 100 Msps A/D converter with DPGA

Philips Semiconductors
Dual 8-bit, 100 Msps A/D converter with
DPGA
Objective specification
TDA8798
handbook, full pagewidth
IOUT
−IOUT
Co(DPGA)
Ro(DPGA)
DPGA⁽¹⁾
10 µH
L
100 nF _BUF(2)
C
Ri(ADC)
R
1 kΩ
Co(DPGA)
Ro(DPGA)
DPGAN^{(3) L}
10 µH
TDA8798
Ri(ADC)
C _BUFN(4)
100 nF
TDA8798
Ci(ADC)
Ci(ADC)
FCE267
External filtering may be used between DPGA and ADC to limit the noise bandwidth.
The external filter has a low-pass cut-off frequency of f_l(–3dB) ≈ _2--1--π-- × -R-----^⁄---2-----⁺-----R-L---^o---⁽--^D---^P----^G---^A----⁾ .
and a high-pass cut-off frequency of f_h(–3dB) ≈ _2--1--π-- × _R-----i-₍--_A----_D--1-_C----₎---_×----C--- _.
Other types of filter may be used if DC biasing is correct.
(1) DPGA1/DPGA2
(2) BUF1/BUF2
(3) DPGA1N/DPGA2N
(4) BUF1N/BUF2N
Fig.2 External filter.
PINNING
SYMBOL
DPGA2N
DPGA2
DPGAC2
V_ref2
V_DDA2
VIN2N
VIN2
V_SSA2
V_SSA1
VIN1
VIN1N
V_DDA1
V_ref1
DPGAC1
DPGA1
DPGA1N
PIN
DESCRIPTION
1
DPGA2 inverting output
2
DPGA2 non-inverting output
3
DPGA2 bandwidth limitation control
4
ADC2 reference output
5
DPGA2 analog supply voltage
6
DPGA2 inverting input voltage
7
DPGA2 non-inverting input voltage
8
DPGA2 analog ground
9
DPGA1 analog ground
10 DPGA1 non-inverting input voltage
11 DPGA1 inverting input voltage
12 DPGA1 analog supply voltage
13 ADC1 reference output
14 DPGA1 bandwidth limitation control
15 DPGA1 non-inverting output
16 DPGA1 inverting output
1999 Sep 16
4